Werkstoffe und Korrosion36, (1985) Abstr. 426-437 R33

Ferrous metals/Eisenmetalle

85-0426 The Effect of Thiourea on the Corrosion Kinetics of Mild Steel in H2Sos. The effect 01 thiourea (TU) on the corrosion kinetics of mild steel in I N H2S04 has been studied at various temperatures and concentrations. The effe- ciency of the inhibitor in reducing the rate of the hydrogen evolution reaction. P(,o) was compared to its efficiency in reducing the rate of the corrosion reaction, P(,,,,,). The ratio r = P~,,)/P~,,,,,) was shown to be a useful diagnostic criterion: 1.e. r 2 t indicates cathodic rate control while r C,,,,. the efficiency loss is rather sudden, thus pointing to the failure of TU to inhibit either the anodic or cathodic half reactions. Consideration of the protonation of TU and of the possi- ble zeta patentia\ eflects suggests thal the observed inhibition is due mainly to the blocking effect of the adsorbed molecular species and that the loss of efficiency at C > C,,,, is not primarily due to protonation. The activation energies of both the cathodic and overall reactions have been evaluated at constant concentration and at constant degree of coverage. 24 ref.-AA B.G. Ateya. B.E. El-Anadouli. and F.M. El-Nizamy. Corros. Sci., 1984, 24, (6). 497- 507, [in English]. ISSN 0010-938X.

85-0427 The Adsorption of Thiourea on Mild Steel. The adsorption be- haviour of thiourea on mild steel was investigated in 1N H2S0, over the tempera- ture range 20-50C in the region of high coverage. The process was treated as a substitutional adsorption process. Particular attention was paid to the effect of the lateral interaction and the size ratio (which is the number of water molecules dis- placed by each adsorbing thiourea molecule). The degree of surface coverage was found to increase with temperature and concentration. It was shown that. at 20C. the adsorption behaviour follows a Frumkin-type isotherm with strong lateral repulsion, where the molecules are vertically adsorbed on the surface. At 30-50C the adsorbed molecules change their orientation to be parallel to the surface, where the adsorption behaviour follows a Flory-Huggins isotherm with negligible lateral interaction. the size ratio calculated from experimental results agrees well with that calculated from molecular models. The free energy, enthalpy and entropy of adsorption were calculated. The effect of temperature on the degree of surface converage was attributed to an entropy, rather than an enthalpy. effect. 27 ref. -AA B.G Ateya. B.E El-Anadouli, and F.M. El-Nizamy Corros Sci., 1984, 24, (6), 509- 515, [in English]. ISSN 0010-938X.

85-0428 Highly Heat Resistant Austenitic Iron-Nickel-Chromium Alloys Which are Resistant to Neutron Induced Swelling and Corrosion by Liquid Sodium. A hiahlv heal resistant. austenitic iron-nickel-chromium alloy which is resistant to neutron induced swelling and to corrosion by liquid sodi- um, comprises by weight. 8.0 to 12.0% Cr, 19.5 to 25.05% Ni, 1.5 to 2.0% Mn. 1.3 to 1.7%Mo.2.5to3.0%Ti,0.5to 1.5%Al,0.3to 1.0%Si,0.05to0.l%C.lessthan 0.01% N. 0.003 to 0.01% B, manufacturing impurities comprising less than 0.005% in the form of P and less than 0.006% in the form of S, and the remainder, Fe. K. Ehrlich, W. Vaidya. L. Schafer. and Kernforschungszentrum Karlsruhe. 4 July 1984. Patent no. GB2132224A (UK). 28 May 1981.

85-0429 Stainless Duplex Ferritic-Austenitic Steel, Articles Made Therefrom and Method of Enhancing lntergranular Corrosion Resistance of a Weld of the Stainless Duplex Ferritic- Austenitic Steel. The steel consists of (in wt.%) C 0.03 max.. Mn 3.0 max., Si 1.0 max.. Cr 26.0-29.0, Ni 3.5- 5.2, Mo 3.5 max.. N 0.15 min., Cu 2.0 max., B 0.005 max and the balance essen- tially iron. The steel preferably contains N 0.17-0.35 wt.% for improved pitting re- sistance and for increased austenite content. Welds of the steel preferably contain at least about 17C austenite in the as-welded condition lor improved pit- ting and intergranular corrosion resistance. There is also disclosed a method of improving the intergranular corrosion resistance of an as-welded steel of similar composition but extending to Cr 11-30 wt.% and Ni 3.5-20 wt.%. T A. Debold, D.A. Englehart, J.W. Martin, and Carpenter Technology Corp. 18 July 1984. Patent no GB2133037A (UK). 5 Jan. 1984.

85-0430 Corrosion Resistant Stainless Steel Covered Electrode. A stainless steel welding electrode exhibiting corrosion resistant characteristics in chloride-containing environments comprises a core wire and a flux coating, the core wire including up to - 0.06% carbon, - 0.5% Si, from - 23.27% Ni, from - 19.22% Cr, from - 5 5.8% Mo, from - 0.2-2% Mn. up to - 0.2% Al. up to - 0.1% Ti, from - 0,005-0.1% of an element selected from the group Consisting of Ca and Mg. balance Fe; and the flux coating contains calcium carbonate, titania. manganese dioxide and manganese carbonate, Nb. cryolite, bentonite and mica. E.P. Sadowski, and International Nickel Co. Off. Gaz., 27 Mar. 1984, Patent no. US4439498 (USA). 21 Aug. 1978. ISSN 0360.5132.

85-0431 Assessment of the Susceptibility of Hydrogen Embrittlement. 11.-Effect of Specimen Geometry on Delayed Failure Time of 38 NiCrMo 4 Steel. Delayed failure tests. in which suitable samples were cathodically charged with hydrogen (current density 8 mA/cm2) in 0. tN sulphuric acid, while under sus.ained tensile loads. were carried out on a low alloyed Ni-Cr steel (UNI 38 NiCrMo 4). The effect of the geometry on the delayed failure time was as- sessed using specimens with different diameters (2, 3.4 mm) and different lengths (13, 23. 33 mm). The experimental results showed that the specimen geometry does not influence the material behaviour: only a minor effect on the threshold stress value was noted due to diameter variations. 21 ref.-AA E. Quadrini. and F. Veniali. Mater. Chem. Phys., May 1984. 10, (5). 457-463. [in En- glish]. ISSN 0254-0584.

85-0432 Cost Effective Use of Stainless Steel in Topside Module Cladding and Structural Applications. Topside modules on offshore platforms are conventionally clad with mild steel, protected from corrosion by galvanizing andlor painting. The North Sea marine environment is severe and causes coating failure in a few years, which necessitates inconvenient and very expensive mainte-

nance painting. The use of light-gage stainless steel cladding fabricated from 409, 430. 304 or 316 alloys eliminates maintenance and is cost effective over the life- time of most platforms. The cladding has full fire resistance up to. and including HI20 (120 min in a hydrocarbon lire) and the weight saving leads to more cost savings in the support structure. The modular, preinsulated system has now been proven and is being specified and used in an increasing number of North Sea platforms.-AA R.A.E Hooper Corrosion and Marine Growth on Offshore Structures [Proc. Conf.], Aberdeen, Scotland, Sept. 1982. John Wiley 8 Sons, Inc , 1 Wiley Dr.. Somerset, N.J. 08873, U.S.A., 1984. (Met A., 841 1-72-0705) 106-124. [in English].

85-0433 Chromium Depletion Near Grain Boundaries [and Environment-Sensitive Cracking] of Austenltic Stainless Steels. Auger spectroscopic analysis and thermodynamical calculations were conducted in order to determine the chromium concentration profiles near grain boundaries of austenitic stainless steels. Of several kinds of environmental-sensitive cracking of austenitic stainless steels. intergranular corrosion, intergranular stress corrosion cracking, and intergranular hydrogen embrittlement are discussed with particular respect to the chromium depletion occurring near grain boundaries. Results ob- tained are as follows. (1) The local chromium concentrations in the chromium de- pleted zone at grain boundaries could be qualitatively determined by Auger spectroscopic analysis (2) The local chromium concentrations in austenite at in- terfaces with Cr2& particles were calculated by using the chromium and carbon activities. The calculated results were in good agreement with the experimental results. (3) Intergranular corrosion attack and intergranular stress corrosion cracking susceptibilities were found to have a strong dependence on the minimum Cr concentration in the chromium depleted zone at grain boundaries. (4) Inter- granular hydrogen embrittlement, however. was affected mostly by chromium car- bide precipitation and not affected much by the minimum chromium concentration. 19 ref.-AA M. Kuribayashi. and H. Okabayashi. J. Jpn. fnsf. Met.. Dec. 1983. 47. (12). 1094- 1100, [in Japanese]. ISSN 0021-4876.

85-0434 Hydrogen Transport Through Highly Purified Iron. Precise mea- surements of hydrogen permeation through highly purified Fe have been per- formed utilizing the gaseous permeation technique with the hydrogen pressure ranging between 0.001 and 0.1 MPa in a wide temperature range from 420 to 1100K. The effect of surface oxide andlor lattice imperfections on hydrogen transport has also been investigated by changing the impurity level of hydrogen gas or by introducing lattice imperfections through deformation of the specimen without any change in other factors. Obtained values of permeability (a) and diffu- sivity (D) are 2.88 x top5 exp(-32.12 kJ mol - ' /RT) mollm s MPa"' and 6.04 x exp(-6.99 kJ mol- ' /RT) m21s. respectively. The hydrogen solubil- ity in iron is calculated from these quantities to be 4.77 x 10' exp(G25.14 kJ mol--'IRT) mo11m3 MPa"2. Values of are found to be reduced by sample defor- mation, probably due to hydrogen trapping by lattice imperfections produced by the deformation. Both d and D are also found to be reduced due to surface oxida- tion by impurity water vapor or oxygen included in hydrogen gas at temperatures below 500K, and the reduction of D is more pronounced than that of 0. 29 ref.-AA T. Tanabe. Y. Yamanishi, and S. Imoto. Trans. Jpn. Ins!. Met., Jan. 1984. 25. ( 1 ) . 1-10. [in English]. ISSN 0021-4434.

85-0435 Stress Corrosion Cracking of Hard 2'&rM0 Steel in Water at 200" and 300C. An account is given of experiments performed in 200 or 300' water to evaluate the susceptibility of the quench-hardened steel to stress corro- sion cracking. The work has covered self-stressed specmens (U-bends and C- rings). and constant load tests using tensile specimens and tubeltube plate welds of the type used for the UK Protoype Fast Reactor. At 200C. the effects have been examined of strength. Stress and oxygen level; at 300'C the effect of Quenching temperature (1400 or 1O5O0C) has been studied. Different mechanisms may be responsible at the two test temperatures. Hydrogen absorption in the re- gion of any localized corrosion is believed to be mechanistically significant in the case of 200*C cracking. but general embrittlement does not occur. At 300C the cracking has been linked with the increased probability of grain boundary segre- gation arising from the higher quenching temperature. The value of shot-peening as a means of inducing surface compressive stress. and hence reducing the risk of cracking. has been demonstrated and the factors that could counteract its use- fulness have been identified.-AA P. Hurst. H.C. Cowen, and C. Tyzack. Water Chemistry and Corrosion Problems in Nuclear Power Plants. [Roc. Confj. Vienna, Austria. 22-26 Nov. 1982, Interna- tional Atomic Energy Agency. Wagramerstrasse 5. P.O. Box 100, A-1400 Vienna, Austria. 1983, (Met.A., 841 1-72-0726) 401-420. [in English].

85-0436 Analysis of Fracture Morphology in Hydrogen Embrittlement for Cr-Mo Steel. An investigation has been made into the analysis of the frac- ture morphology of hydrogen embrittlement for a quenched and tempered Cr-Mo steel. The Cr-Mo steel showed tempered martensite embrittlement caused by 300C tempering treatment. The susceptibility to hydrogen embrittlement was highest lor the as-quenched specimen, and decreased with increasing tempering temperature, The ralio of intergranular lracture in the fractured Surface was high- est for the specimen tempered at 300C. The fracture morphology of tempered martensite embrittlement was intergranular with a flat surface. but the morphology of hydrogen embrittlement was intergranular fracture with tear ridges on the SUP face. The characteristic morphology of hydrogen embrittlement was quasi- cleavage fracture due to hydrogen (QCHE). which had the same small facet size as in martensite lath morphology, with secondary cracks along the martensite lath. This lracture morphology was the same as that of hydrogen embrittlement of HT8O steel previously indicated. 8 ref.-AA T. Enjo. T. Kuroda, and N. Mitsui. J. SOC. Mater. Sci., Jpn.. Apr. 1983, 32, (355). 413.418, [in Japanese]. ISSN 0514-5163.

85-0437 Experience With Ferritic and Austenitic Steel PWR Circuits. The first prototype PWR propulsion plant built for the Royal Navy used 1 Wt% chromium-0.5 wtoh molybdenum low alloy steel for the main circuit components. Subsequent plants have been constructed from austenitic stainless steel with aus- tenitic clad reactor pressure vessels. Experience with the two types of plant IS compared after periods of operation up to 15 years. In the building phase, strin- gent measures were required to protect the low alloy steel plant against general corrosion and pitting but during operation. chemistry control is virtually identical for the two materials. During shutdown periods when the circuit is opened up, addi- tional precautions are necessary to deal with oxygen ingress in the low alloy steel

R34 Abstr. 438-449 Werkstoffe und Korrosion 36, (1985)

plant. The main concern with stainless Steel plants is the avoidance of contami- nants which promote stress-corrosion cracking. Although low cobalt levels are more easily achieved in low alloy steel than in stainless steel, plant coolant cobalt levels are found to be dominated by the contribution from hard facing alloys. Low alloy steel steam generator tubes in the prototype plant initially operated succes- fully on sulphitelcongruent phosphate dosing, but following a change in operating conditions. serious pitting occurred on the secondary side of the tubes. This was controlled by changing to a low solids hydrazinelphosphate treatment. Stainless steel steam generators have performed well on sulphitel phosphate dosing. There have been no problems from stress corrosion, general corrosion, or denting at lube supports. It is concluded that, apart form steam generator tubing, for which low alloy steel is considered unsuitable, PWR plants in both ferritic and austenitic steels can be successfully built and operated. 13 ref.-AA J W. Barton. and F Arkless. Water Chemistry and Corrosion Problems in Nuclear Power Plants [Proc. Con/.], Vienna. Austria. 22-26 No". 1982. International Atomic Energy Agency. Wagramerstrasse 5, P.O. Box 100, A-1400 Vienna, Austria. 1983. (Met A,, 841 1-72-0726) 135-148. [in English].

85-0438 Influence of a Flowing Lithium Environment on the Fatigue and Tensile Properties of Type 316 Stainless Steel. Lowcycle fatigue and tensile data have been obtained on 316 stainless steel in a flowing Li environment of controlled purity. The results show that the fatigue life of the steel in flowing L i at 755K is greater than in air. Pre-exposure of the material to Li reduces fatigue life. The reduction in fatigue life may be altributed to the formation of a weak ferrite layer after Li exposure Tensile data for cold worked 316 stainless steel indicate that, at temp. between 476 and 755K. a flowing Li environment has little or no ef- fect on the tensile properties of the steel. 12 ref -AA 0 Chopra. and D Smith. Fusion Reactor Materials [Proc. Conf.1. Albuquerque, N. Mex., U S.A , 19-22 Sept. 1983. J. Nucl. Mater.. May (11) 1984, 123, (1-3), 1213. 1218, [in English]. ISSN 0022-3115.

85-0439 Main Cause of Tuberculation of Carbon Steels in Synthetic Cooling Water. The factors causing tuberculation of carbon steels in a variety of synthetic cooling waters have been investigated. A standard solution containing normal amounts of inorganic compounds was prepared as a synthetic cooling water, and it was concentrated several times to simulate the practical operation of heat exchangers in the process industries. Tubercles formed on the Steel tube covered with mill scale, and the chemical composition of the water was a small factor in lhis case. Acid-pickled carbon steel tube experienced general corrosion In the standard solution. but was attacked seriously by the concentrated solutions to lorm tubercles. An important factor was found to be the corrosion potential. and it is necessary for the potential to remain in the transition region between active diSSGlUtion and passivation of carbon steel when tuberculation takes place.-AA M Yasuda. K Suzuki. and F. Hine. J. SOC. Mafer. Sci., Jpn., Sept. 1983. 32. (3601, 1057-1061, [in Japanese]. ISSN 0514-5163.

85-0440 Steels and Cast Steel Used Currently in the Nitric Acid Industry. Corrosion problems occurring in the nitric acid industry are briefly pres- ented. Based on literature studies. actual world trends in production of steel and nickel-chromium cast steel for nitric acid industry requirements have been characterised The main condition of suitability of a given steel or cast steel grade lor this branch of the chemical industry. ensuring appropriately high corrosion re- sistance and Sufficiently high mechanical properties. is max. lowering of carbon and other contamination contents (P, S1 Moreover, especially high resistance in a range of high concentrations of nitric acid is shown by steels and nickel- Chromium cast steels and of relatively high silicon content (above 4%). 17 ref. -AA A Staronka. and M Holtrer. Ochr. P r i e d Koror.. Oct. 1983. 26, (101, 263-267. [in Polish] ISSN 0473-7733.

85-0441 High Cavitation Erosion Resistance Stainless Steel and Hydraulic Machines Being Made of the Same. A high cavitation erosion resis- tance stainless steel for use in hydraulic machine of which surfaces are damaged by cavitation erosion is comprised of at least either carbon of '$ - 0.2 wt.% or nitrogen in a n amount ranging from - 0.02-0.3 wt.% together with Si of b - 2.0h1. Cr in an amount ranging from - 11.0-15.0%, Ni > 3.O-10.O0/o and Mn - 2.0-20 0%. balance essentially Fe and in which the ferrite phase has not been formed so that the microstructure of the stainless steel is ferrite free but where at least either the ( phase or the austenite phase has been essentially formed. M. Yamamoto, T. Yebisuya, M Kawai, K. Honma. and Tokyo Shibaura Denki KK. Off. Gar.. 14 Feb 1984, Patent no. US4431446 (USA), 17 June 1980. ISSN 0360- 5132

85-0442 Anticorrosion Properties of Quaternary Ammonium Chlorides With Alkylthiomethyl Radical. The inhibition effect of chlorides: 3-bromo[(n- alkylthio)methyllpyridinium, 3-Chloro[(n-alkylthio)methyllpyridinium. 3 , 4 ~ dirnethyl[(n-alkylthio)mehtyl]pyridinum, 1 -methyl-2-methyl-3-[(n- alkylthio)methyllimidazolium. 1-but~l-3-~~n-alkylthio)methyllimidazolium and [(n- alk~lthio)methyllisoquinolinium on the corrosion of carbon steel in 2M hydrochloric acid, 2M sulphuric acid and drinking water was studied gravimetrically. The inhibi- tor efficiency is higher in acidic environments than in water. It appears that in stag- nant acid SOlUtiOnS at room temperature maxinum inhibiting efficiency IS obtained at the inhlbitor concenlration of 0 05 g l l and 8 h test duration. 11 ref.-AA J Pernak Werkst Korros.. Apr. 1984. 35. (4). 156.159, [in English]. ISSN 0043- 2822

85-0443 Steel Material Exhibiting Superior Hydrogen Cracking Resistance in a Wet Sour Gas Environment. The steel is obtained from large steel ingots or slabs more than 20 tons in weight through 3 hot rolling process. It contains less than 0.0810 C, with residual C ranging between 0.005 and 0.03%. 0 01 to O.5O0/c Si. 0.8 l o 2.541r Mn. less than 0 025% P, less than 0.004% S. and 0 005 to 0 1% Al. with one or more of Nb. Ti, and V in amounts less than 0.12% for Nb and less than 0 15% for Ti and V, the balance being Fe and unavoidable impuri- ties Optionally the steel contains one or more of Ca, Mg. and rare earth metals (REM) in amounts less than 0 007%, 0.007%, and 0 1% respectively. andior the steel con tam m e or more of Cu, Cr, Mo. Ni. Zr, and B, in amounts less than 1 0% for the first four elements, less than 0.2% for Zr, and less than 0.003% for 8. The steel exhibits a superior hydrogen cracking resistance in a hydrogen sulfide envi- ronment. T Taira e t a / , and Nippon Kokan KK. 27 June 1984. Patent no. GB2131832A (UK), 21 Oct 1983

85 -044 Treatment of Stainless Steel Apparatus Used in the Manufacture, Transport or Storage of Nitrogen Oxides. A method 01 clean- ing and passivating a Cr-containing stainless steel metal surface used in the manu- facture. transport or storage of highly pure nitrogen tetroxide comprises: cleaning the surface by contacting with an alkaline cleaner containing solution to remove fouling deposits and rinsing with water; pickling the surface by contacting with an aqueous nitric acid/ hydrofluoric acid solution to remove oxides, carbonates and mill scale and rinsing with water; passivating the surface by contacting with a nitric acid passivation solution and rinsing with water; pickling the surface by contacting with green nitrogen tetroxide and rinsing with water; cleaning the surface by con- tacting with a citric acid solution and rinsing with water; rinsing the surface with distilled or deionized water until it is chloride free; and purging the surface free of liouid with N. H.P. Heubusch. and Textron Inc. Off. Gaz.. (USA). 26 May 1982. ISSN 0360.5132.

21 Feb. 1984. Patent no US4432808

85-0445 Influences of Microalgae on Corrosion of Structural Steel. The microalgal community, producing copious mucilage. may have beneficial effects in consolidating the underlying scale or corrosion product on offshore oil and gas platforms and restricting the access of oxygen However, the local chemistry will be complex and vary with secretions, decay products and associated bacterial action. In particular, such action will result in the production of sulfide compounds and these could cause serious localized corrosion The mucilage produced by the algae and bacteria serve to concentrate these products and localize the affected areas, causing discontinuities giving rise to galvanic couples and localized corro- sion. 17 ref.-AA L.A. Terry, and R.G.J. Edyvean. Corrosion and Marine Growth on Offshore Struc- tures [Proc Conf]. Aberdeen. Scotland. Sept. 1982. John Wiley 8 Sons. Inc , 1 Wiley Dr., Somerset, N.J 08873. U.S A,. 1984. (Mef.A., 841 1-72-0705) 38-44. [in English].

85-0446 Fouling and Corrosion Off the Outer Hebrides. The problems associated with marine fouling and corrosion are common to many types 01 under- water structures. The National Wave Energy Program would involve the deploy- ment of devices in the northeast Atlantic west of the Outer Hebrides and studies have been concentrated into calculating the likely effects of the marine environ- ment on these structures. Among the effects of marine fouling, the modification of corrosion behavior of affected steel is considered l o be one of the most important and least understood. Some preliminary experiments have been conducted to study the effects of the Hebridean environment on corrosion of mild steel. the re- sults of which should provide additional technical guidance if hydrocarbon explo- ration should ever take place in that area.-AA M.J. Picken, and C. Grier. Corrosion and Marine Growth on Offshore Structures [Proc Conf] . Aberdeen. Scotland, Sept 1982. John Wiley 8 Sons, Inc., 1 Wiley Dr.. Somerset, N.J. 08873. U.S.A., 1984, (Mel.A.. 8411-72-0705) 45-52, [in En- glish].

85-0447 Oxide Films Produced by EDTA Treatment of Chromium- Containing Alloys and the Potential of this Process for Preconditioning Primary Circuits. The aim of this work is to develop oxide films on the internal surfaces of a PWR primary circuit that will reduce the release of corrosion prod- ucts such as cobalt which have undesirable activation characteristics It has been shown that a Na2HZEDTA-N2H, solution reacts with 304 stainless steel, lnconel 600 and stellites 3, 6 and 25, in the temperature range 170 l o 21O"C, l o form glassy oxide films which are shown by X-ray Photoelectron Spectroscopy (XPS) analysis to contain CrpOg and Fe,O, in the approximate ratio 5.1. At higher temp the Fe EDTA2* complex which has formed in solution breaks down and reacts with the Cr,O, glassy film to give an FeCr,O, spinel lattice. which has been identified by X-ray diffraction. Because Co EDTA'' and NI EDTA" are more Stable in so\u- tion, colbalt and nickel oxides cannot be detected in the oxide film by XPS It is suggested that the glassy film IS a Cr,O, cross-linked network which is kinetically inert because of high Cr-0 bond activation energy, but contains labile 0-H bonds which give it ion-exchange properties. The thermodynamic stability of chro- mites is discussed, and it is suggested that recrystallization of the Cr203-Fe304 matrix to FeCr,O, will give the optimum surface with regard to kinetic and thermo- dynamic stability 13 ref.--AA J.H. Carter, B.P. Gay, and J.C. Rivibre. Water Chemistry and Corrosion Problems in Nuclear Power Plants [Proc. Conf.1, Vienna, Austria, 22-26 Nov. 1982, Interna- tional Atomic Energy Agency, Wagramerstrasse 5. P.O. Box 100, A-1400 Vienna, Austria, 1983, W4el.A.. 841 1-72-0726) 451-464. [in English].

85-0448 Oxidation and Decontamination Mechanisms of Stainless Steels Studied by Electron Spectroscopy. The oxide layers of austenitic stainless steels (AISI 304 and 32 1) formed under simulated reactor (0,-enriched BWR and typical PWR) conditions have been studied by scanning electron micros- copy (SEMI. X-ray photo-electron spectroscopy (XPS) and Auger electron spec- troscopy (AES) It was found that the oxide on austenitic stainless steels has a layered structure. The outer layer consists of large, distinct oxide crystals and the inner uniform layer of small oxide crystals. Divalent and trivalent iron, trivalent chromium and divalent and metallic nickel exist in the oxide layers. The oxide lay- ers formed under PWR conditions consist of M 3 0 4 (M = Fe. Cr, Ni) spinels and under BWR conditions of M 3 0 , spinels and haematite (wFe203). Decontamination of autoclaved specimens was performed chemically with various methods, the main one being a two-step method conslsting of an alkaline potassium permanga- nate (AP) step and an oxalic acid, citric acid and EDTA (CiTROX E) step In addi- tion, electrochemical decontamination in phosphoric acid was employed. Alternating oxidation and decontamination tests (three cycles) have been per- formed. After various treatments the surfaces were analysed with SEM, XPS and AES. Composition changes in surfaces during decontamination affect the oxide growth in subsequent oxidations. 9 ref.-AA H.E. Hanninen. E. Jauhiainen, and T. Starkman. Water Chemistry and Corrosion Problems in Nuclear Power Plants [Proc. C0nf.j. Vienna. Austria, 22-26 Nov. 1962, International Atomic Energy Agency, Wagramerstrasse 5, P.O. Box 100, A-1400 Vienna, Austria, 1983, (MetA., 841 1-72-0726) 421-433, [in English].

85-0449 Hydrogen Induced Delayed Cracking In Stable Austenitic Stainless Steels. The behaviour of hydrogen induced delayed cracking (HIDC. i.e slow crack growth) in type 310 and type 16-20-20 (K55) stable austenitic stainless steels along w!th a type 321 unstable austenitic Stainless steel was in- vestigated with a single-edge notched tensile specimen. It was found that HIDC could occur in all three types of stainless steel and the threshold values were K,"/

Werkstoffe und Korrosion 36, (1985) Abstr. 450-462 R35

K, = 0.55, 0.70, and 0.80 for stainless steels 321, 310. and K55, respectively. i f the specimens were charged and loaded. HlDC could also occur if the precharged specimens were tested under a constant load in air. No HIOC. however, occurred in precharged and then outgassed specimens. It indicates that the delayed crack- ing in stable austenitic stainless steels is induced by atomic hydrogen. Because there is no hydrogen induced n martensite in type 310 and K55 stainleas steel. the existence 01 a is not necessary for the occurrence of HlDC in austenitic stainless steels, though it can lacilitate HIOC The mode of hydrogen induced delayed frac- ture in eifher stable or unstable austenitic stainless steels is correlated with the K, value; the fracture surface changed from ductile to brittle as K, decreased. 9 ref. - AA J Yao, W. Chu, and J. Xiao. Acta Metal). Sm. (Chma), Apr. 1984. 20, (2). A124~ A130. [in Chinese]. ISSN 0001-6179

85-0450 Duct i le Cast Iron. A ductile cast iron excellent in resistance to both oxidation at high temp. and thermal fatigue consists essentially of carbon 2.5- 3.80/0, Si 3 5-4 8% Mn 1.0% or less, phosphorus 0.1% or less, sulfur 0.1% or less, Mo 0.5~2.0%, Mg 0.03-0.18. at least one of Ce and La 0 02-0.5. balance Fe. K. Satou, M. Yoritaka. and Toyo Kogyo Co Ltd. Oft Gaz., 22 May 1984, Patent no US4450019 (USA). 1 Apr 1982 ISSN 0380-5132.

85-0451 Eastern Stainless T y p e 310s (Austeni t ic Chromium-Nickel Steel). Eastern Stainless Type 3105 has high resistance to corrosion and oxida- tion at high temp. It also has high strength at elevated temp. It is especially suit- able for service at high temp. It is very ductile and can be welded readily. Among the many appiicalions for Type 310s. a few typical uses include annealing boxes, chemical plant equipment. fire box sheets. furnace linings. heat exchangers. oil- refining equipment, kiln linings and tube hangers.-AA Alloy Dig, Aug 1984, (88-450). Pp 2. [in English]. ISSN 0002-614X

85-0452 I n v e s t i g a t i o n of an Fe-Mn-A l -Cr A u s t e n i t i c Heat - Resist ing Steel 37Mn31A13CrZMoVWNbB. An attempt was made to develop a new austenitic heat-resisting steel from the Fe-Mn-Al-Cr system. An experi- mental steels 37Mn31A13Cr2MoVWNb6, has been investigated Alloy phases such as V&,, NbC. and M3B, are round in the steel after treatment at 1150C for 1 h. water quenching. then treatment at 790C for 20 h followed by air cooling Among these. the V,C3 contributes markedly to the strength of the steel to such an extent that its high temperature strength approached that of A-266 Its resistance to oxidation is obviously improved because there is a smaller amount 01 Cr com- bined with Al. Cr can also promote the precipitation o f the X~phase if the steel is aged tor a long period up to 500 h at 650C. as well as the Laves-phase Some blades made of this steel were fitted on a turbosupercharger which has been suc- cessfully operated in a seagoing vessel for several thousand hours. This austen- itic heat-resisting steel seems to be quite promising for certain industrial applications. 9 ref.-AA Y Zhang, F Zhang. H. Gao. and G. Wang. Acta Mefall. Sin (China), Feb 1984, 20. ( l ) , Al-A8, [in Chinese] ISSN 0001-6179.

85-0453 Laboratory Study of Corrosion in a Crude Oil Fract ionator Overhead System. Using a laboratory sized glass tube in a shell condenser, a study was made of the corrosion of ASTM 179 carbon steel specimens placed at four locations along the condenser while it was being used to distill a 50:l mixture of gasoline and water containing various concentrations of HC (3 to 120 ppm) The max. corrosion rate occurred after the point of initial steam condensation. 20 ref. -AA Q.J M Slaiman. and H.J. Nassouri Mater. Perform.. Aug. 1984, 23, (8), 38-42. [in English]. ISSN 0094-1492.

85-0454 Potential-pH Diagram of Composi t ion/Structure of Passive Fi lms on Iron. The composition, layer structure, and thickness of the passive f i ! w formed on Fe in borate and phosphate solutions have been examined as func- tions of pH. potential, and lilm formation procedure (one-step and two-step oxida- tion) by using electrochemical and ellipsometric techniques. Ellipsometric measurements of 6P--6A curves during galvanostatlc-cathodic film reduction show that the layer structure of the passive film changes with pH from an outer barrier layer/an inner barrier layer in acid to a deposit layeran outer barrier layerian inner barrier layer in weak acid and to a deposit layerla barrier layer in neutral and alkaline solutions. The barrier layer consists of two layers in the pH re^ gion below pH 5.5. but is a single layer above this pH The barrier layer thickness mcreases nearly linearly with potential. but once the overpotential is fixed. it re- mains constant regardless of pH. anion species, and film formation procedure. The deposit layer thickness, which is almost independent of potential. tends to in- crease with increasing pH up to about pH 8 Chemical analyses of iron ions dis- solved from the lilm during cathodic reduction show no significant effect on the deposit layer composition (ZFe 3.00) of pH, anion species, potential, and film formation procedure except for a decrease in ZFe at low potentials. The mean 0x1- dation valency of the barrier layer, however. varies from Z F ~ 2 2.33 to ZF. = 3.00, depending on pH, anion species. potential. and film lormation procedure The re- sults are explained in terms of the ion selective property of the passive film, and the layer structure and composition are summarized in the potential-pH diagrams. 16 ref.-AA R. Nishimura. and N Sato J Jpn lnst. Met.. Dec 1983. 47, (12). 1086-1093. [in Japanese] ISSN 0021-4876.

85-0455 Effect, in Water, of Large Parameters on the K ine t ics of Damage to Steel b y Mult icycle Fatigue. Results are given lor an experimental study on the multicycle corrosion-fatigue strength of tubular specimens of steel 20 and 08Kht8N10T steel in distilled water at 300C and 14 MPa. The large parame- ters in the water were oblained in a special chamber placed in a slider-crank exci- tation unit where fatigue tests were perlormed under a symmetrical tension- compression cycle. Surface corrosion-fatigue damage was observed by means of a 98x microscope. The results point to the possibility of replacing stainless steel by the cheaper low-carbon steel 20. 7 ref.-AA P.A. Pavlov, B A. Kadyrbekov. and A I . Ainabekov Probl. Prochn.. Dec 1983, (12), 11-14, fin Russian]. ISSN 0556-171X.

85-0456 Inf luence of the Carbon Content in Steels on the Current Eff ic iency Dur ing Their Anodic Dissolution. An attempt is made to establish the inler relation between the current efficiency and the electrophysical properties (electrical resistance and type of conductivity) of the surface film formed in the an-

odic dissolution o f steel. This was undertaken because the film characteristics have a substantial influence on dissolution kinetics and parameters under such conditions. The materials investigated were Armco iron and three grades of spe- cial steels of increasing carbon content (St 10. 20 and 45). For Armco iron and St 10 steel the films formed were mainly of iron-deficient oxide (p-type) with pre- dominance ot cationic vacancies. For the higher-carbon steels the proportion of oxygen-deficient (n-type) oxide was higher The increased side reaction of gas evolution with growing electronic conductivity leads to a decrease in the current efficiency of the dissolution reaction 8 ref.-S K. E.M. Rumyantsev, and E K. Oshe Nekfrothimiya. Apr. 1984. 20, (4). 545-547. [in Russian] ISSN 0424-8570

85-0457 Corrosion Fatigue of S t e e l U n d e r C a v i t a t i o n E r o s i o n Generated intermit tent ly in 3% Salt Water (Results of Two-Stage Tests With and Without Cavi tat ion Erosion]. Two-stage fatigue tests with and wilh- out cavitation erosion were performed in 3% salt water When corrosion fatigue with cavitation erosion (erosion fatigue) is changed to corrosion fatigue during a test, the fatigue life decreases remarkably and the total number of stress cycles to failure becomes smaller than that for tests involving erosion fatigue only. In the reverse case, when corrosion fatigue conditions are changed to erosion fatigue conditions, the fatigue lile increases slightly compared with the life expected lrom the linear damage law (Miners law). The variation in fatigue strength can be ex- plained by the characteristics of crack propagation in each environment. From these results. it is presumed that the corrosion fatigue strength of the material ex- posed (a medium-carbon steel) intermittently to cavitation erosion decreases remarkably.-AA T. Okada, Y. Iwai, and S. Hattori Wear. 1 June 1984. 96, (1). 85-98, [in English].

85-0458 Stress Corrosion Crack Propagat ion Behavior in SUS 304 Duplex Weld Metal. Stress corrosion crack (SCC) propagation behavior was studied in 42% MgCI, aqueous sblution (143C) on SUS 304 stainless steel weld metals which exhibited 6-ferrite-austenite duplex phases and an austenite single-phase structure. Content of &ferrite was varied by heat treatment and ad. ding pure Ni powder into groove. Stress corrosion cracks in weld metal tends to propagate parallel or vertical to columnar crystal growth direction. It was made clear that SCC propagation rate in such inclined crack could be determined by apt calculation lor K value. In both weld metals with an austenite single phase and h- ferrite-austenite duplex phases (8% 6 ferrite content), a remarkable preferential crystal orientation was recognized and columnar crystal growth direction was al- most (100) by facet pit method. Microscopic SCC fracture plane was constituted mainly by < 100) Accordingly, it is considered that the selectivity of SCC growth directions in weld metals is caused by coherent preferential crystal orientations. 7 ref -AA Y. Mukai, and M Murata Trans Jpn Weld Soc., Apr. 1984. 15,

R36 Abstr. 463-476 Werkstoffe und Korrosion 36, (1985)

of columnar grains along the longitudinal direction is increased and the along the transverse direction decreased, while the growth rate of equiaxed grains of the outer layer oxide is also decreased. Consequently. their columnar feature become more pronounced For the alloy with no RE, more crystalline whiskers and fine crystals are found on the surface of the oxide layer It may be considered that the diffusion of Al ions through the n-Al,O, layer outwards is prevented by RE addition. and the oxide layer adherence is then improved. 8 ref.--AA B. Li, and Y Yan. Acta Melall. Sin. (China), Apr 1984, 20, (2). B71 877. [in Chi- nese] ISSN 0001-6179.

85-0463 A Contr ibut ion to the Sca l ing o f S tee l in Techn ica l F lue Gases. Armco iron was oxidized at temperatures between 1000 and 1300'C in Op-Co2-H,0-N2 gas mixtures The volume concentrations of the various com- ponents were 0 to 3% 02, 10% CO,, 10 and 20% H,O, rest N,. At the beginning of the oxidation process the layer of scale showed a linear gcowth, later a parabolic growth. Within the validility range of the linear law, diffusion through the adhering gas boundary layer was the rate determining step in the case of oxygen gas In bi- nary gas mixtures containing CO, or H20 together with N,, Ihe phase boundary re- action was the slowest step in the oxidation reaction at temperatures of up to 1100C. At higher temperatures, also with COP and H20 the diffusion in the gas phase had to be encountered as a resistance. This means that this resistance acts additionally to the resistance of the phase boundary reaction. The linear rate constant in multicomponent gas mixtures is the sum of the constants for the single oxidizing components. Within the validility range of the parabilic law, the parabolic scale constants partially depended on the gas composition. This could be ex- plained by the fact that i f the oxygen potential in the bulk gas phase is not high enough, the oxygen potential in the gas boundary layer may partially decrease below that of the wustite-magnetic equilibrium. 25 ref.-AA H:J. Selenz, and F Oeters Arch Eisenhuttenwes.. May 1984, 55. (5). 201.208, [in English] ISSN 0003-8962.

85-0464 High-Temperature Corrosion o f 12% Cr- A l Cas t Steels. The influence of Al. Ti and Nb on the high.temp. oxidation of Fe- 12Cr Steel was inves- tigated. The steels were tested at 850C before and after they were coated with NaCI, Fe,O, or Fe,O,-NaCI mixtures. Titanium and Al were found to be highly beneficial. Excellent corrosion resistance under all environments was shown by the steel containing 0.8'Yo Ti. Niobium was detrimental to the corrosion resistance. especially in Fe203-20%NaCI. The results were interpreted in the light of the pro^ tective nature of the films formed by Cr, Ti and AI. I t ref.-AA B. Zaghloul, N Nassif. and A.A Abdul Azim. Surf. Techno/., Aug. 1984, 22, (41, 387.396, [in English]. ISSN 0376 4583

85-0465 Mechanical and Corrosion Propert ies in Various Zones o f Grade 35K Steel Welds in Alkaline Solutions. Data are presented on low- cycle fatigue tests on Grade 15K steel welds produced by submerged arc welding Notched and unnotched specimens were tested in air and 40% NaOH Solution at 112OC Since the effects of the alkaline medium on fatigue endurance were most pronounced in the base metal, properties of welds can be predicted based on tests on wrought materials.-O.P. 0.1. Steklov, V K. Pigarev, an0 A.V Shishkin Svar. Proizvod., May 1984. (5), 24- 25, [in Russian] ISSN 0491-6441

85-0466 Microstructural Changes on the Surface o f Heat Resistant Steels. Backscattered electron images and quantitative electron microprobe analysis are used for failure analysts of furnace parts of stabilized austenitic stain. less steel X 10NiCrAITi32-20. The atmosphere in the oven changed often from car- burizing l o oxidizing or reducing. The oxidized. surface area was thinner than 50 pm Up to a depth of 1 mm the grains and grain and twin boundaries Cr-Fe carbides of the type M2&, are segregated. The Cr conlent in the solid solution depletes to '' t5k and Ihe material becomes brittle at fast quenching. 8 ref -AA D Meyer. and W Schular Metallography. Modern Methods for Microstructural Preparation for Studies of Materials Properties (Proc. Con/.], Gottingen. West Ger- many, 21-23 Sept 1983, Riederer-Verlag GrnbH. Gutbrodstrasse 9. 7000 Stuttgart 1. West Germany, 1984, (Met.A , 8411-72-0698) 381-390. [in German].

85-0487 Phenomenon o f Crack Branching. The development of crack branching has been recognized during unstable fracture of brittle solids arid the stabie cracking under environment. The present study, on a low-alloy Ni-Cr-Mo steel under H,S environment, reveals no branching, whereas the same steel when tested in NaCl solution produced micro- and macrobranching The presence of a plateau region and a limiting stress intensity factor appear l o constitute the criteria for branching. 14 ref.-AA A N. Kumar. and H.K Pandey. Jrans. lndian lnsl. Met., Dec. 1983. 36, (61, 436-441, [in English] ISSN 0019-493X.

85-0468 The Structure o f Ox ide Layers of Stainless Steels Formed in Simulated Light Water Reactor Conditions. The oxide layers of two types of stainless steels (AISI 304 and 321) formed under conditions typical of boiling water (BWR) and pressurized water (PWR) reactors have been studied. It was found that the oxlde layers of austeilitic stainless steel samples studied had a two layer Structure. the outer layer consisted of large (1 3 pm) distinct crystals and the inner uniform layer of small crystals (- 0.5 pm) Divalent and trivalent Fe, trivalent Cr and divaleiit and metallic Ni were found in the layers. The oxide layers lormed under PWR conditions consisted of Mo30, (M = Fe. Cr. Ni) spinels and those formed under BWR conditions of M30, spinels and hematite (wFez03) En ricnment of NI and depletion of Cr were found in the oxide layers of 304 steel under BWR conditions and enrchment of Fe in the oxide layers of 304 steel under PWR conditions. Sensitization and plastic delormation had no eflect on the structure of the oxide layers Electrolytically polished surfaces exhibited thinner oxide layers than mechanicallv finished ones. 20 rel.-AA E Jauhiainen, E Minni, and H Hanninen Scand J Metall, 1984. 13. (3) 166 172 [in English] ISSN 0371 0459

85-0469 V a r i a t i o n o f the D i s t r i b u t i o n o f Crack Length D u r i n g Corrosion Fatigue. The initiation and growth behavior of distributed cracks on the surlace of an annealed carbon steel plate JIS 5541. was investigated during corrosion fatigue testing in 3% NaCILwater at 298K Statistical calculations tak ing into account the variation of number of cracks during slress cycling and the scatter of crack growth rate explain the distribution of crack lengths for certain stress cycles -J H B

S Ishihara. K. Shiozawa. and K. Miyao Scr Mt?la l l . July 1984, 18. (7), 687-691 [in English]. ISSN 0036-9748

85-0470 Corrosion Behavior of Ultrafine-Grained Austenitic Stainless Steel. Ultrafine-grained AlSl 304 steel was produced by low-temp. recrystalliza- lion after subzero working and the corrosion behavior of these steels was investi- gated in various corrosive environments. The general corrosion rate increased with decreasing grain dia. On the other hand, the resistance l o intergranular corro- sion, pitting corrosion and stress corrosion cracking increased with decreasing grain dia. The pitting corrosion and stress corrosion cracking resistance of ultrafine-grained 304 steel was particularly improved by grain refining. This in- crease of local corrosion resistance seems to be related to an increase of grain boundary density I unit volume and the resultant film destabilization.-AA M. Hasegawa, and M. Osawa. Corrosion. July 1984. 40, (7). 371-374, [in English]. ISSN 0010-9312.

85-0471 T h e Ef fec t o f Sensitization Heat Treatment on the Stress Corrosion Crack ing of AlSl 304 Stainless Steel. Constant extension rate ex- periments at controlled potentials have been performed in aqueous solutions con- taining 100 ppm NaCl and 100 ppm NanSO, at 290C on 304 stainless Steel specimens that were heat treated at 820, 870 and 820OC for different time peri- ods. As long as chromium carbides did not nucleate along grain boundaries, the alloy was susceptible to transgranular stress corrosion cracking. Once nucleation occurred, the alloy became susceptible to intergranular cracking. The shift in the fracture mode from transgranular to intergranular cracking was accompanied by a several hundred millivolt decrease in the critical cracking potential. Anodic polar- ization experiments were performed in an acidified chloride solution at room temp. on specimens heat treated to simulate progressive stages of chromium carbide nucleation. The longer the exposure time and sensitization temp., the more active was the breakdown potential. The results suggest that the Cr concentration at the grain boundaries is the major factor determining the potential at which intergranu- lar stress corrosion cracking initiates and breakdown 01 the passive ti\m occurs. 16 ref.-AA A. Poznansky. and D.J. Duquette Corrosion, July 1984, 40, (7), 375-381, [in En- glish]. ISSN 0010-9312.

85-0472 Ef fec t of Veloci ty on Cor ros ion of Stainless Steel in Sulfuric Acid. The nature of attack on the metal surface by an electrolyte is different in a static condition from the condition where either the liquid or the metal is in motion. The greater accessibility of oxygen at higher velocity may increase or decrease the rate of attack depending on the nature of a metal. In the present communica- tion either the metal, stainless steel (304. 321) was stationary and the liquid (H2S04 solution) was moving or the metal was rotated in the liquid. When the metal was stationary and fhe liquid was moving the greater accessibility of 0 was benefi- cial but this positive effect was destroyed in the presence of a small amount of nat- ural soil When a metal specimen was rotated in different concentrations of H,SO, with different velocities, the velocity was able to protect the metal only in lower concentration of H2S04 whereas in higher concentrations there was only an insig- nificant reduction in weight loss value; even the very high values of the velocity were not proved to be beneficial Results showed inhibition when the specimens were subjected to turbulent conditions -AA S. Gupta, D Pandey, and G N. Pandey. Corros. Prev Control, June 1984, 31, (3).

85-0473 G r o w t h and Repass iva t ion of S i n g l e C o r r o s i o n P i t s in Stainless Steel. Single pits were produced in AlSl 304 stainless steel using a neutral 1M sodium chloride solution with 0.04M sodium thiosulfate The depen- dence of pit growth kinetics on potential was measured electrochemically. The protection potential showed a small scatter for the 80 pits examined and had no Systematic dependence on pit size The results are interpreted using a simple ohmic model of pit growth 19 ref.-AA R C. Newman, and E M. Franz. Corrosion. July 1984, 40, (7). 325-330, [in English]. ISSN 0010-9312

85-0474 Hydrogen-Induced Crack ing in Pipel ine Steels. Work conducted at the British Gas Engineering Research Station (ERS) using laboratory tests of the BP and NACE type to assess the hydrogen-induced cracking (HIC) IS de- scribed. Various grades of linepipe and fittings Steels have been studied and the metallurgical parameters controlling HIC resistance have been established In par- ticular. the effects of nonmetallic inclusions, sulfur content, alloy segregation and microstructure are described On the basis of the results, it is suggested that pipe. line steels tor sour gas/oil service should have a low S contenf (. 0 005%) and effective inclusion shape control by Ca or rare earth metal (REM) treatment. Re- duction of the Mn content to the lowest possible level and lhe use of quenched and tempered steels would also be beneficial. Small additions of Cu. Ni andlor Cr may offer some protection under certain operating conditions. 16 ref.-AA A Brown. and C.L. Jones. Corros!on, July 1964, 40, (7). 330-336, [in English]. ISSN 0010-93 12.

85-0475 A Study of Reagents for Grain Boundary Exposure in Steels. A method of etching is used to show austenite grain boundaries in carbon and alloy Steels with martensitic transformation, 22 reagents were tested to establish the croscopy has been used to investigate the radiation damage in Mo along the path of P ions having energies of 5-20 keV. It is shown that in all cases assemblies of interstitial atoms are formed, while at energies exceeding 10 keV defects of the vacancy type are found to occur in the subsurface layer of the Mo. The threshold energy of the vacancy clusters which are formed at displacement cascades and which are visible in the electron microscope was determined, as well as the mean length of the substitution chain in Mo. 9 ref.-AA V F. Reutov, and S.P. Vagin. Fiz. Tverd. Tela. Apr. 1984, 26, (4). 1040-1043, [in Russian]. ISSN 0367-3294.

85-0476 Fre t t ing Fat igue Pall iatives: Some Comparat ive Experiments. When relative movement can arise between mating parts and one is subjected to cyclic stresses. then the fatigue life can be very much reduced. Such phenomena are referred to as fretting fatigue. Experiments using 35Ni-Cr-Mo-V steel on various palliatives are reported and their relevant merits compared. The data de- rived are also reviewed in the light of a companion document considering stress distributions associated with contact conditions. It is demonstrated that, for the particular contact conditions employed, the most significant single palliative treat- ment was the reduction in the stress concentration associated with the geometry

19-20. [in English]. ISSN 0010-9371.

Werkstoffe und Korrosion 36, (1985) Abstr. 477-490 R 37

tested. The use of surface shot peening, which introduces residual compressive stresses. was beneficial, as was the use of graphite-impregnated epoxy resin. Thin soft metallic coatings did not endure the test conditions and ion-plated com- ponents were no more durable than those treated by conventional electroplating. 14 ref.-AA T.C. Chivers, and S.C. Gordelier. Wear. 22 June 1984, 96, (2), 153-175, [in En- glish]. ISSN 0043-1648.

85-0477 Hydrogen-Induced Inter ior Crack- l ip Morphologies in High- Strength Steel. WOL specimens of high-strength 4340 steel were used to obtain information on the interior, or near plane strain, crack-tip morphology resulting from hydrogen-assisted crack growth. including the position of secondary cracks in relation to the region of max. triaxial stress. crack-tip plastic zone size and grain size. The interior, or near plane strain, regions were revealed by removing thin sec- tions. by and grinding a polishing procedure, from the surfaces of specimens that underwent H-assisted crack growth. The results appear to indicate that advance of the crack occurs by growth of protrusions. or steps. from the main crack front, followed by linkup of these protrusions by sideways growth along grain bounda- ries. 28 ref.-AA P.W. Keefe, S V. Nair, and J.K. Tien. Metall. Trans. A. Oct. 1984. 15A, (10). 1865- 1871, [in English]. ISSN 0360-2133.

85-0478 A Frac tog raph ic Study o f Cor ros ion-Fat igue Crack Propagation in a Duplex Stainless Steel. A fractographic study of fatigue propagation in air and in white water indicates that the ferritic phase of KCR 171, a duplex stainless steel is susceptible to corrosion-fatigue which occurs by hydro- gen embrittlement. The crystallography of the cleavage-like facets is identified. The strong tendency for crack propagation in a crystallographic direction results in twinning in the vicinity of the crack tip when the local crack propagation direc- tion must change. 23 ref.-AA M. Ait Bassidi. J. Masounave. J -P. Bailon, and J.I. Dickson. Defects, Fracture and Fatigue [ R o c Con/.], Mont Gabriel. Quebec, Canada, 30 May-5 June 1982. Mar- tinus Nijhoff. Distributed by Kluwer Academic Publishers Group, P.O. Box 322, 3300 AH Dordrecht, The Netherlands, 1983, (Mef.A., 841 1-72-0712) 359-371, [in English].

85-0479 Corrosive Behavior o f CT-3 and 09G2 Steels in Condit ions of Continuous Wett ing Under the Inf luence o f Chloride Ion. The corrosive be- havior of CT-3 (olain carbon steel) and 09G2 (low-alloy steel) under the influence of chloride ion at 100% relative humidity was studied. Different concentrations of chloride were applied to different samples for SIX months. The corrosion was eval- uated by weight loss. Corrosion rate-chloride concentration and anodic polariza- tion curves with the corroded samples were traced for both steels. The results show that it is possible. in a comparative way, to know the degree of chloride pol- lution in the corrosion products.-AA A. Abreu, and F. Corvo. Rev. Cjenc. Ouim.. 1983. 14, ( I ) , 175-182. [in Spanish].

85-0480 Fat igue Proper t ies of SUS 304 Stainless Stee l in H igh Pressure Hydrogen a t Room Temperature. Fatigue properties of soluted and sensitized SUS 304 stainless steel have been investigated in high pressure hydro- gen up to 4 02 MPa and atmospheric argon at room temperature. The results are as follows. ( 1 ) The number of cycles to failure of both the soluted and the sensi- tized steel decreased with increasing hydrogen pressure. The decrease was greater for the sensitized steel than for the soluted steel. (2) The fatigue limits of the soluted and the sensitized steel decreased with increasing hydrogen pres- sure. Little difference was observed for the fatigue limits between the soluted and the sensitized steel (3) Typical fatigue fracture modes were observed on the frac- ture surface in the fatigue crack growth area (Area II) depending on the type of gas, that is argon of hydrogen. In this area, striations were observed on the sur- face fractured in argon and brittle transgranular fracture in hydrogen. 9 ref.-AA S. Fukuyama. K. Yokogawa, and K. Kudo. J. SOC. Mafer. Sci.. Jpn.. Apr. 1983, 32, (355). 430-434. [in Japanese]. ISSN 0514-5163.

85-0481 Fa t igue Crack G r o w t h Behav iour in H y d r o g e n Gas Environment. The fatigue crack growth behaviour in hydrogen gas was examined using compact tension specimens of five kinds of materials, i.e.. low alloy steels (Ni-Mo-V), Ni-Cr)Mo-V), austenitic alloy steels (18Mn-5Cr. SUH660) and a copper alloy (Be-Cu). The fatigue crack growth rates in laboratory air and hydro- gen gas were obtained and the relation between the fatigue crack growth rate and fracture morphology is discussed based on the fractographical observations. The main results are as follows. (1) The effect of hydrogen gas on the fatigue crack growth rate was classified into the following four types. (a) No effect of hydrogen gas was observed (18Mn-5Cr, SUH660) (b) A slight decrease in fatigue crack growth rate was observed (Be-Cu). (c) A considerable increase in fatigue crack growth rate was observed, but no effect of frequency was observed (Ni-Mo-V). (d) A considerable increase in fatigue crack growth rate was observed, and an ef- fect of frequency was also observed (Ni-Cr-Mo-V). (2) In the materials of types (c) and (d). cleavage fracture was observed and the area percentage of in- tergranular fracture on the fracture surface increased in hydrogen gas. The change of fracture morphology in hydrogen gas had a direct influence on the fa- tigue crack growth rate. (3) A good correspondence between the striation spacing and the fatigue crack growth rate was observed in both air and hydrogen gas ex- cept for Ni-Cr-Ma-V steel. 12 ref.-AA S . Yoshioka, M. Demizu, and M. Kumasawa. J. SOC. Mater. Sci.. Jpn., Apr. 1983, 32. (355), 435-440. [in Japanese], ISSN 0514-5163.

85-0482 Mic ros t ruc tu re and Cor ros ion Behav io r of A luminum Containing a Small Addi t ion of Tin. The corrosion behavior of A l containing small amounts of Sn (280 ppm) in a media of 20% HCI solution was investigated. SEM was used to determine microstructural teatures at various intervals of the corrosion process. It was concluded that grain boundary corrosion, as evidenced by pitting. resulted from the presence of Sn-rich inclusions near grain boundaries. Pits were observed at those sites where inclusions intersected the free surface. 8 ref.-G.P.K. U. Erb. and K.T. Aust J. Mater. Sc i Lett., July 1984, 3, (71, 585-587, [In English] ISSN 026143028,

85-0483 Compatibil i ty of Materials fo r Use in Liquid-Metal Blankets o f Fusion Reactors. A corrosion and environmental effects on the mechanical prop- erties of austenitic (316, 304) and ferritic (HT-9. 9Cr- 1Mo) steels for use with Iiq-

uid melals in fusion reactors are reviewed. The mechanisms and kinetics of the corrosion processes in liquid Li and Pb- 17Li systems are examined and their in- fluence on degradation of structural material is discussed. Requirements for addi- tional data are identified. 54 ref.-AA O.K. Chopra. and P F. Tortorelli. Fusion Reactor Materials, Albuquerque, New Mex.. U.S.A., 19-22 Sept. 1983. J Nucl. Mater.. May (11) 1984, 123, (1-3), 1201- 1212. [in English]. ISSN 0022-31 15.

85-0484 Corrosion o f Fe r rous A l loys in Eu tec t i c Lead-Li th ium Environment. Corrosion data have been obtained on austenitic prime candidate alloy (PCA) and 316 stainless steel and ferritic HT-9 and Fe-9Cr- 1Mo steels in a flowing Pb- 17 at Yo Li environment at 727 and 700K. The results indicate that the dissolution rates tor both austenitic and ferritic steels in Pb- 17Li are an order of magnitude greater than in flowing Li. The influence of time, temp. and alloy com- position on the corrosion behavior in Pb- 17Li is similar l o that in Li. The weight losses for the austenitic steels are an order of magnitude greater than for the fer- ritiC steels. The rate of weight loss for the ferritic steels is constant. whereas the dissolution rates for the austenitic steels decrease with time. After exposure to Pb- 17Li, the austenitic steels develop a very weak and porous ferrite layer which easily spalls from the specimen surface. 7 ref.-AA 0. Chopra. and D. Smith. Fusion Reactor Materials, Albuquerque, New Mex., U S.A , 19-22 Sept 1983, J. Nucl. Mater., May (11) 1984. 123. (1.31, 1219-1224. [in English]. ISSN 0022-31 15.

85-0485 Oxidat ion Behavior o f Stainless Stee l f o r Fas t Breeder Reactor Fue l Cladding. Oxidation behavior of 316 stainless steel for a fast breeder reactor fuel cladding was studied in the range 873- 1073K. The oxygen pressure in the fuel-cladding gap was simulated by the Mo/MoOa or the NbOg/ Nb705 oxygen buffer. The oxidation kinetics was found to obey the parabolic rate law. The temp. dependence of the parabolic rate constants is given by the follow- ing equations: under the 0 pressure controlled by the NbO~iNbZOS 0 buffer (pop = 1.6 x 10-z5 Pa)-k (T) = 6 50 x I O F exp (-99.0 x ~ o ~ ) R T , under 0 pressure controlled by th; MolMoO 0 buffer (pOz = 1.9 x lo- Pa), k (T) 7 4.75 x lo- exp (-99.6 x t03/RT), where k, and the activation en- eygy are expressed in terms of kg2/m4.s and Jlrnole. respectively. The oxidation mechanism is discussed on the basis of the metallographical information and the value of activation energy of the parabolic rate constant. 18 ref.-AA M Saito. Y Ishikawa, K Ikeda, and H Furuya. J Nucl 1984, 21. (5), 356 365, [in English] ISSN 0022-3131

sci. Techno!.

85-0486 Ef fec t of Atmospheric Corrosion Products o f Steel on Further Course of Corrosion. The results of two-year tests of carbon steel corrosion in natural environments of different corrosive power are presented. The protective properties of corrosion products became constant after several months expo- sure. At the initial stage, corrosion products can both inhibit and accelerate the rate of atmospheric corrosion. A new way of evaluating the effect of corrosion products on the further course of corrosion is proposed. 9 ref.-AA S. Frackiewicz. Uchr. PrzedKoror., July 1983. 26, (7). 165-168, [in Polish]. ISSN 0473-7733

85-0487 Analysis o f Gravimetric Curves o f Etching Carbon Steels. Gravimetric curves are presented of the etching of scaled and non-scaled Armco and high carbon steel samples in diluted sulphuric acid solution free of, or contain- ing, inhibitor. From the etching curves, a number of process parameters were de- termined such as optimum etching time. inhibitor efficiency coefficient, scale etching coefficient and surface overpickling degree. 35 ref.-AA H. Bala, and H. Przewhcka Ochr. Przed Koroz., Sept. 1983, 26, (9), 226-232. [in Polish]. ISSN 0473-7733.

85-0488 Examinat ion o f Cor ros ion Resistance of Const ruc t iona l Materials in Silage Environment. The factors affecting the course of corrosion of constructional steels in silages are determined Methodology and procedures are also described. It was found that the corrosive power of silage is mostly de- pendent on acetic and lactic acids contained therein and their pH values The stan- dard solution of electrochemical properties simiiar to those of a water extract from natural silage ha5 been developed and examined This makes it possible to per- form Comparative and comparable accelerated corrosion tests of constructional steels independently of the place and date of lest.-AA S. Stezala. A. Kitowski. and M. Machalska. Uchr Przed Koroz , Sept. 1983, 26, (9). 232-235. [in Polisfi]. ISSN 0473.7733.

85-0489 The Microstructure o f the Scale Formed During the High Temperature Oxidat ion of a Fecral loy Steel. The protective scales formed on Fecralloy steel exposed to an oxidizing environment at temperatures of 1000, 1100 or 1200C have been characterized with the aid of a range of microstructural techniques. The scales formed at the higher two temperatures are predominantly composed of alpha alumina The alpha form of alumina has the desirable property of a low native defect concentration in addition to a low volatility and the surfaces of these scales are generally smooth The scales formed at 1000C on cold worked specimens include a substantial component of a transition alumina (proba- bly theta alumina) which is strucurally related to gamma alumina and is highly de- fective This form of alumina grows as high aspect ratio whiskers at the outer suuface of the scale and their appearance suggests a quite different growth mech- anism from that of the alpha alumina in the scales Once formed. the whiskers of defective alumina can be transformed to the alpha crystal structure. with no change in external morphology, by heating to 1200C. The alpha alumina phase exhibits a much greater crystallite strain when it is accompanied in the scale by the transition alumina than when it is not. There is some yttrium present in the oxide layer, concentrated linearly near to where grain boundaries in the steel emerge at the oxidizing surface. The yttrium is present mainly as VAIO, and Y3AI,0,2. 17 ref.-AA P.T Moseley, K.R Hyde, B.A Bellamy. and G Tappin Corros. Sci, 1984. 24, (6), 547-565. [in English]. ISSN 0010-938X.

85-0490 Fine Grained and Boiler Constructional Steels: Testing for Susceptibil i ty to Cracking. Samples of steels 13MnNiMo 5 4, StE500, StE371. 17Mn4 and 15Mo3 were evaluated for hydrogen induced cracking under marine conditions to assess their suitability for off-shore structures. Standard Jones specimens were exposed for one year to total immersion, partial immersion snd salt spray conditions of the North Sea off Helgoland. Previous experience with

R38 Abstr. 491-505 Werkstoffe und Korrosion 36, (1985)

StE5OO in water storage tanks at a nuclear power plant had shown the material to be particularly susceptible. Similar findings were observed in the marine environ- ment. the heat affected zone of the weld region being particularly prone to crack- ing especially in the region of high hardness The softer steel grades did not suffer the problem.-C.E D.R. A. Baumel. StahlEisen, 14 May 1984. 104, (10). 513.516. [in German]. ISSN 0340- 4803.

85-0491 Creep Rupture Properties of Heat Resistant Alloys for Nuclear Steel Making and Their Degradation in Helium and Reducing Gas Atmospheres. Cf. ibid.. p 2045. Creep rupture properties of heat resistant alloys with carbide or carbide and 7' precipitates were investigated in the temperature range 900 to 1050C in He and reducing gas atmospheres The degradation of the rupture strength tool place in the alloy which have carbide as a strengthener, due to decarburization in the He atmosphere at temperatures higher than 1000C In the alloy which was strengthened mainly by y' , the solutioning of 7' led to degrada- tion of the rupture strengths, but to the restoration of rupture ductilities to a greater extent. A new method to predict the rupture life, steady state creep rate. etc from 0.2% proof stress is proposed. In most cases, the method was found to be satis- factory in the sense that it represents the degradation of the alloys from various causes 10 ref.-AA T. Tanabe et a/. Telsu-to-Hagane (J. /ron Steel Inst. Jpn.). Dec. 1983. 69, (16). 2052-2059. [in Japanese]. ISSN 0021- 1575

85-0492 Effect of Oxyanions on the IGSCC Inhibition of Sensitized 304 Stainless Steel in High Temperature Water. The effect of oxyanions such as MOO:-. WOf-. and CrOf- on the intergranular Stress corrosion cracking (IGSCC) of Type 304 stainless steel in high temperature water was studied. The results obtained are as follows. (1) Addition of oxyanions such as MOO$-. WOf ~ , and CrOf- supresses IGSCC of sensitized Type 304 stainless steel in high tem- perature non-deaerated water. The effectiveness of the inhibitive action by the oxyanion is ranked in the order MOO$- > WOf- z CrOf-.. (2) The mechanism of IGSCC inhibition by MOO:- ion for sensitized Type 304 stainless steel in high tem- perature water is considered to be that the presence MOO:- ions decreases the dissolution rate of the Cr depleted zone at grain boundaries to the level of the ma- trix by helping the formation of a Cr rich film containing MOO, or adsorbed MOO: ions on the surface of the steel. 15 ref.-AA J. Tsuge. J. Murayama. and H. Nagano Tetsu-to-Hagane (J. Iron Steel lnsf. Jpn ), Dec. 1983. 69. (16). 2068-2075. [in Japanese]. ISSN 0021-1575.

85-0493 Biguanide-a Potential Corrosion Inhibitor in Neutral SOlUtiOnS. Corrosion current measurements of Fe in normal K,S04. with and with- out biguanide sulfate and halides, show that these additives have a synergistic corrosion inhibition effect. Experimental procedure is outlined. results are dis- cussed and tabled and an explanation is postulated. 8 ref.-J.V.R. A. Maitra, G. Singh. and 6.8. Chakraborty. Trans. SAEST. Oct -0ec. 1983. 18. (4). 335-337. [in English] ISSN 0036-0678.

85-0494 Ring Test of 304 Stainless Steel Tube Oxidized in High- Temperature Steam. The residual mechanical strength and ductility of 304 stainless steel claddings were studied in tests of ring compression, ring tension and hardness. The tests were made after the Specimens had been heated in steam and in Ar gas to temp between 900 and 1350C The effects of crystal grain growth and oxygen absorption in the metal on the residual properties were also studied. The experiments showed that the claddings retained their ductility well at temp < 13OODC and when the oxide scale thickness was < 40% of the ini- tial wall thickness. The claddings maintained a constant level of residual strength when heated at temp. > 1000C or when the oxide thickness was > 5% These results were used to support proposals for limits on Stainless steel cladding dam- age in a LOCA. 17 ref.-AA T. Ishida. J. Nucl. Mater.. June 1984. 125, ( l ) , 33-51. [in English]. ISSN 0022-31 15.

85-0495 Corrosion Fatigue of Pressure Vessel Steels in PWR Environments-Influence of Steel Sulfur Content. Large effects of simu- lated light water reactor environments at 288C on fatigue crack growth in low- alloy A533-B and A508-1 11 pressure vessel steels are observed only when s p e ~ citic mechanical, metallurgical and electrochemical conditions are satisfied simul- taneously. The relative importance of three key variables-steel impurity content, water chemistry and flow rate-and their interaction with loading rate or strain rate are examined. In particular, the results of a systematic examination Of the in- fluence of a steel's sulfur content are described 20 ref.-AA P.M Scott. A.E. Truswell. and S.G. Druce. Corrosion.'July 1984, 40. (7). 350~357. [in English] ISSN 0010-9312

85-0496 Influence of Hydrogen Uptake in Prestressed Concrete Steel on Tensile Mechanical Properties. Recent cases of damage in prestressed concrete construction have been traced to hydrogen uptake during corrosion of the steel leading to the formation of cracks and fractures. Laboratory experiments described were correlated with experience from construction sites, reported else- where. Four steels were used, two as-hot-rolled (A-0.73 carbon, 0.74 Si. 1.37 Mn, 0.17 Cu, and 6-0.71 C. 0.81 Si, 1 41 Mn, 0 26 vanadium), one heat treated (D2-0.5 C, 1.8 Si, 0.62 Mn. 0.4 Cr), one cold drawn (E-0.83C) Testing occurred in two steps. In the first. the samples were exposed to electrolytes similar to those encountered in construction sites while prestressed to 80% of their tensile strength. Little significant change was noted in the first set of tests. In the second. yield and tensile strengths were generally unaffected, but ductility properties were significantly reduced, depending on the steel and the corroding medium. Highest resistance to embrittlement was exhibited by steels A and E, least by B and. espe- cially, 02. 10 ref .43.L. B. Isecke. Materials Testing 1983 (Werkstoffprutung 1983) [Proc. Conf.]. Bad Nauheim. W. Germany, 8-9 Dec 1983, Deutscher Verband fur Materialprufiing ev, Unter den Eichen 87, 1000 Berlin 45, W Germany, 1984. (Met A , , 841 1-72-0695) 215-230, [in German].

85-0497 Examination of Adsorptive and Inhibitive Properties of Some Aminomethyl Phosphoric Acids in Aqueous Environments. The general re- lationships between structure of phospho organic compounds and their adsorptive and inhibitive properties were determined. Adsorption conditions and thermal dy- namic adsorption characteristics for three aminoalkyl phosophric acids at a sta- tionary Fe electrode in neutral aqueous environment were determined by measuring the differential capacitance of the double layer. It was found that inhibi-

tion power is dependent on their adsorptive capabilities. The adsorption of the most effective compound i.e nitryl trimethyl phosphoric acid is intermediate be- tween physical adsorption and chemisorption. 10 ref.-AA J. Kubicki. P. Falewicz, B. Pyrwanow. and A. Waligora. Ochr. Przed Koror., July 1983. 26. (7). 169-171. [in Polish]. ISSN 0473-7733.

85-0498 Phase Stability and Corrosion of Cr-Mn Austenitic Steels Exposed to Pure Lithium. Samples of four commercial, nitrogen-alloyed Cr-Mn austenitic steels (Nitronic 32, AMCR. ICL004, 316) were heat treated at 873K up to 4000 h in the presence of pure Li. Phase and elemental composition changes occurring in the materials were investigated by electron microscopy and analytical techniques. The results are compared with those obtained with AlSl 316 for the same experimental conditions. 9 ref.-AA E. Ruedl. V. Coen. T. Sasaki. and H. Kolbe. Fusion Reactor Materials. Albuquer- que. New Mex, U S.A., 19-22 Sept. 1983. J. Nucl. Mater.. May(II) 1984, 123, (1-3), 1247-1251, [in English]. ISSN 0022-3115.

85-0499 Corrosion Resistance of Stainless Steels in CI2 and HCI. The corrosion resistance of 10Kh14AG15, 10Kh14G14N4T. 08Kh22N5T, and 08Kh21N6M2T steels in CI, and HCI in the temp range 100-500C over 5-70 h has been studied. The specimens were placed in a quartz retort, heated in an inert gas atmosphere up to the desired temp and then C12 or HCI was introduced of a rate of 0 033 mls . The corrosion resistance was estimated from the mass losses, and the corrosion mechanism and chemical composition of the corrosion products were determined by chemical and metallographical methods Corrosion occurs in a CI, atmosphere up to 200C and in HCI up to 300C according to the equation Am = K,lg T and at higher temp according to Amn = K2 T The temp. dependence of the corrosion rate satisfies the Arrhenius equation. Activation energies were calculated to be in CI,, 105-120 kJimole up to 200C and 21-33 kJ/mole above 200C; in HCI up to 300"C, 109-126 kJ/mole and above 300C. 25-37 kJ/mole. The corrosion products in a C12 atmosphere are FeCI3. NiCI,. CrCI, and MnCI,. The higher corrosion resistance against HCI attack is explained.-M.R: G.N Verizhnikova. L.L Mighai, and B K. Opara. Tsvetn. Metall. Nauchno-Tekh. Sb.. 1-15 Sept. 1983, (17), 39-41,'rin Russian].

85-0500 Corrosion Resistance of Stainless Steels in the Environment for Polycrystalline Silicon Production. The corrosion resistance of stainless steels was investigated over the temp interval 100-500C in an atmosphere of H2 90-93%, SiHCI, + SiCI, 5%. HCI 3.5% by determining the mass difference after re- moving the corrosion products With increase in exposure time of 12Kh18NlOT steel it is observed that corrosion is retarded and then the corrosion rate becomes constant Similar dependences were obtained for all the steels investigated. The higher corrosion resistance of 06KhN28MDT and 10Kh17N13M3T steels in com- parison with that of 12Kh18NlOT. 10Kh14G14N4T. 08Kh22N6T. 08Kh21N6M2T. 08Kh18G8NZT. and 10Kh14AGt5 steels is explained by the higher Cr and Ni con- tent of the first two steels -M.R L.L Mighai. G.N Verizhnikova, and V.1 Arons. Tsvetn Metall Nauchno-Tekh S b , 1-15 Oct 1983. (19). 36-38, [in Russian].

85-0501 Mass Transfer Behavior of a Modified Austenitic Stainless Steel in Lithium. An austenitic stainless steel that was developed to resist neu- tron damage was exposed to Li in the high-temp. part of a thermal convection loop for 6700 h. Specimens of this Prime Candidate Alloy (PCA) composed of 65 OFe- 15.9Ni- 14 OCr- 1 9Mo- 1 9Mn-0.4Si-0.3Ti-0.05C (wt %) were exposed at 600 and 570C in both solution annealed and cold worked forms. The dissolution process was found to be similar to other austenitic alloys in flowing Li: weight losses 01 PCA eventually became linearly proportional to exposure time with the specimen surfaces exhibiting porous layers depleted in Ni and Cr. Howev. er, the measured weight losses and dissolution rates of these PCA specimens were higher than those of 316 stainless steel exposed under similar conditions and can be attributed to the higher Ni concentration of the former alloy. The effect of cold work on dislocation rates was less definitive. particularly at 570C. At lon- ger exposure times, the annealed PCA specimen exposed at 600C suffered greater dissolution than the cold worked material: no effect of prior deformation was observed by analysis of the respective surfaces. 8 ref -AA P F. Tortorelli. and J H. DeVan. Fusion Reactor Materials, Albuquerque. New Mex.. U.S.A., 19-22 Sept. 1963, J. Nucl Mater.. May (11) 1984, 123, (1-3), 1258-1263. [in English] ISSN 0022-31 15

85-0502 Anodic Protection of Steel CT-3 in Sulfuric Acid. I.-Corrosive Electrochemical Behavior. The sulfuric acid concentration de- pendence of the corrosion rate of steel CT-3, in the concentration range 3-90%, for three different periods 01 attack-6, 12 and 24 h-was studied. Stationary poten- tial-time variations were also investigated 7 ref.-AA L Nufiez. and A Cepero. Rev. Cienc. Ouim.. 1983, 14. ( l ) , 117.123, [in Spanish].

85-0503 Anodic Protection of Steel CT-3 in Sulfuric Acid. 11.-Determination of the Fundamental Electrochemical Parameters. Ct. preceding abs!ract. A laboratory scale study made to determine the possible ap- plication of anodic protection to steel CT-3 in sulfuric acid includes: anodic polar- ization curves, current density variations at constant protection potential in the passive region, corrosion rate determinations under potentiostatic conditions and stationary potential--time variations after protection has been disconnected. 12 ref.-AA L Nufiez, and A Cepero Rev Cfenc Ouim., 1983, 14, (1). 125-134. [in Spanish].

85-0504 Influence of Different Factors on the Corrosion of Carbon Steels in Water. Bibliographic Review. The corrosive action of waters on Fe and its alloys was analyzed concerning the influence of different factors on the process. Although general qualitative dependences of the influence of some phys- icochemical parameters on the corrosion processes in water are known, it is not possible, on the basis of the existent data. to define its specific action. It is con- cluded that the effectiveness of the protective methods used will depend directly OF the acquired knowledge of the corrosive electrochemical behavior of steel in this system and lhat concerning the influence of factors, such as temp , flow veloc- ity and salt content. 104 ref -AA Rev Cienc Ouim., 1983, 14, (1). 135-168, [in Spanish].

85-0505 Status of Tritium Permeation Barrier Development on Austenitic Structural Alloys. A literature review and recent results on the devel-

Werkstoffe und Korrosion 36, (1985) Abstr. 506-521 R 39

opment of tritium permeation barriers is presented. A standard pretreatment and oxidation procedure for some austenitic Cr-containing alloys (Incoloy 800H, IN5 19. Hastelloy X, lN586, lnconel 617) was established and the progress achieved has been made visible. Hemmtaktors 2 1000 can be proved between 650 and 950C under realistic conditions of testing. Results on steady-state and nonstationary permeation measurements are discussed.-AA D. Stsver. H.P. Buchkremer, R. Hecker, and H.J. Leyers. Fusion Reactor Materials [Proc. ConLj, Albuquerque, N. Mex.. U.S.A.. 19-22Sept. 1983. J. Nucl. Maler.. May (11) 1984. 123. (1.31, 1541-1546, [in English]. ISSN 0022-31 15.

85-0506 T h e E f f e c t o f S u r f a c e C o m p o s i t i o n on P lasma-Dr iven Permeat ion of Deuter ium Through 304 Stainless Steel. The effect of inci- dent ion energy on plasma-driven permeation of deuterium through 304 stainless steel has been studied experimentally. The relationship of permeation rate to ion- induced surface composition changes was determined by in situ Auger electron spectroscopy. The presence of either carbon or oxygen on the upstream surface increased the permeation rate as compared to a sputter-cleaned surface Carbon in the form of near surface carbide, however, had little or no effect on the perme- ation rate. 11 ref.-AA R.A. Causey, R.A. Kerst. and B.E. Mills. Fusion Reactor Materials [Proc. Conf.], Al- buquerque. N. Mex.. U.S.A.. 19-22 Sept. 1983, J. Nucl. Mater, May (11) 1984. 123. (1-3), 1547.1552, [in English]. ISSN 0022-31 15.

85-0507 Ef fec ts o f Buf fe rs on Hydrogen Evolut ion at Iron Electrodes. In unbuflered aqueous solution. the hydrogen evolution at Fe electrodes is usually first order in H-ion dependence at pH < - 7 and pH independent at higher pH. This indicates that H ions and water molecules are the main electroactive reac- tants for this reaction in acid and alkaline solution. respectively. In buffered solu- tion. however, also the acid component of the buffer might be such a reactant. Information about this is often needed in corrosion research, but appears rather hidden in the literature. Some pertinent studies have therefore been made and are described.-AA T. Hurlen, S Gunvaldsen. and F. Blaker. Electrochim Acla. Aug. 1984. 29. (8). 1163-1164. [in English]. ISSN 0013-4686.

85-0508 Vibrat ions o f an Oscillator on a Meta l Surface. (Translation). See Met A,, 8406-34-0542. A.I. Volokitin. Sov. Phys. SolidSfate. Jan. 1984, 26, (1). 91-93. [in English]. ISSN 0038-5654.

85-0509 The Sys tem Iron- Water-Hydrogen Under High Pressure. To study hydrogen behavior in Fe, large quantities of H were dissolved in Fe under high pressure. Calculation of H concentration vs. temp. as s function of pressure shows that the critical point for solubility increase i s at 600K and 4.2 GPa The solubilities of H at 3 GPa, 973 and 573K estimated from the observed increase in lattice constants due to H dissolved in Fe agree well with the calculation. The ef- fect of dissolved H on phase stability and the decomposition reaction of Fe with water is discussed. Dissolved H lowers the y - N transition temp. by nearly 5OOK due to ?-phase stabilization by H. Spherical particles of Fe were observed in the reaction product obtained from a mixture of Fe. Si0,.xH20 and MgcOH), at 1500K. 5.4 GPa after 20 min reaction This indicates that dissolved H has lowered the melting point 01 Fe.-K.0 Y Fukai. Bull. Jpn. lnst Met , 1984, 23, (9, 369-372. [in Japanese]. ISSN 0021- 4426.

85-0510 Hydrogen Transport in Stainless Steels. The precise measure- ments of hydrogen permeability (4) and diffusivity (0) were performed for some stainless steels (301. 304, 316, YUS170) and high-temp. materials (Incoloy 800. lnconel 600. lnconel X) utilizing an extremely purified H under pressure of 0 001 0 1 MPa at temp between 500 and 1200K. Most of the determined values of @ and Dgive good Arrhenius relationship against inverse temp. The effect of alloying ele- ments, particularly of Cr, is discussed by comparing the obtained values of 6 and 0. 17 ref.-AA T. Tanabe. Y. Yamanishi. K. Sawada. and S. Imoto. Fusion Reactor Materials IProc. Conf.1, Albuquerque, N. Mex., U.S.A.. 19-22 Sept. 1983. J. Nuct. Mater, May (11) 1984. 123, (1-3), 1568-1572. [in English]. ISSN 0022-3115.

85-0511 Some Resuits Concerning the Electrochemical Behavior of Steels CT-3 and 09G2. Anodic polarization curves were plotted for a low-carbon steel (CT-3) and a low-alloy steel (09G2) (Mn - 1.6 and 0.3% each of Cr, Ni. and Cu) at 76 mVimin in a buffer solution of borax and boric acid (pH 7.6). The curves showed the strong influence of alloying elements on the electrochemical behavior of steel in a neutral medium The influence of chloride ions on the electrochemical corrosion of the steels was tested in the same buffer solution with additions of dif- ferent concentrations of NaCl (0.1, 1. 10 g i l l . Anodic polarization curves lor steel CT-3 showed an increase in the active current with the increase in the chloride ions and, at 10 g i l of NaCI. the passive range for this steel practically disap- peared. Steel 09G2 behaved similarly, but with a smaller passive range at the same chloride concentration. The second set of curves seems to explain the in- crease in the corrosion rate of both steels, with exposure time in a marine atmo- sphere, and indicates that the use of the more expensive 09G2 is not justified under such conditions unless suitable protection is applied.-S.M. A. Abreu. and F. Corvo. Rev. Cienc. Uuirn.. 1963, 14. (2). 363-367. [in Spanish1

85-0512 Radlochemical Study on OL 32 Carbon Steel Corrosion, The kinetics and thermodynamics of OL 32 carbon steel corrosion process are studied with a method based on isotropic dilution. As corrosive medium, 0 05M HCI so lu~ tion was used and the respective reactions were carried out in the absence and in the presence of certain inhibitory organic substances. On the basis of experimen- tal data, the following kinetic and thermodynamic parameters were calculated. corrosion reaction rate constant and apparent activation enthalpy and entropy and Gibbs tree activation energy. 19 ref.-AA A. Cecal. Metalurgia (8ucharest). Aug. 1983. 35, (8). 396-400, [in Romanian]. ISSN 0461-9579

85-0513 Fat igue Propert ies of S tee ls fo r Dr i l l P ipes Opera t ing in Corrosion Medium. An installation has been developed along with a method for testing flat samples by alternating bending in liquid corrosion medium suitable tor checking the materials sampled from drill pipes. Different chemical analysis of the Steel in equal strength values and in equal heat treatment type has been ascer- tained to account for possible differences in fatigue behavior. Those differences

in fatigue behavior may be induced by the differences in corrosion losses ascer- tained in current corrosion tests. Both the processes-corrosion and latigue- take place in surface layers of the specimens.-AA A. Kslivoda Hutn Listy. June 1984, 39, (61, 416-419. [in Czech]. ISSN 0018-8069

85-0514 Patterns of Macrofoul ing on Steel P la t fo rms in the Central and Northern Nor th Sea. The Offshore Marine Studies Unit, University of Aber- deen. Scotland has studied marine growth on steel installations placed in 12 oil- fields in the central and northern North Sea. Samples, color photographs and video recordings have been analyzed and studies made of the thickness of fouling layers at major elevations of platforms. Early predictive analyses of marine growth have been found lo be inaccurate. No distinctive differences in the fouling assem- blages on steel platforms in the central and northern North Sea are apparent Twenty-one sessile organisms are common and abundant on most platforms stud- ied. In addition. five other species are abundant on a minority of platlorms. The bi- ology of these organisms is discussed and the present lack of information on their possible role in bringing sboul corrosion is highlighted. 28 ref -AA G.N.R. Forteath. G.B. Picken. and R. Ralph. Corrosion and Marine Growth on Off- shore Structures IProc. Conf.1. Aberdeen. Scotland, Sept. 1982. John Wiley & Sons, Inc.. 1 Wiley D r , Somerset. N.J. 08873, U.S.A.. 1984, (Mel .A, 841 1-72- 0705) 10-22. [in English].

85-0515 Failure b y Carbur izat ion and Ox ida t ion o f Heat Resistant Steel Links. Links of a heat treatment furnace bell made of heat resistant steel type HK failed after two years of service. The causes 01 the failure were attributed to: materials carburization and oxidation due to their alternate exposure to carbu- rizing and oxidizing atmospheres and the formation of 2 P Kajimoto, and S. Wolynec. Mefal. ABM, June 1984, 40, (319), 321-324, [in Portuguese]. ISSN 0026-0983.

85-0516 Stress Corrosion Crack ing o f Austeni t ic Steels in Chloride- Containing Media. A review of the literature concerning stress corrosion crack- ing (SCC) of austenitic steels (304L. 316) in solutions containing chloride ions is presented. Effects of stress, chemical cornposition and environment (temp.. pH, oxygen concentration, etc.) are discussed Methods of testing and mechanism of SCC are described. It was noted that effects of SCC could be minimized by metal- lurgical removal of harmful impurities, especially phosphorus. The literature data seem to indicate that development and application of an economical method of de- phosphorization may bring significant improvement of resistance of austenitic steels to SCC in chloride solutions in presence of tensile stresses. 201 ref.-AA S. Czyzowicz. f r Inst. Mefat. Zelaza, 1982. 34. (2). 9 9 ~ 1 12. [in Polish]. ISSN 0137- 994 1.

85-0517. , Deuter ium Permeat ion Through Oxidized Fecralloy. Deuterium perineabilities were determined for a series of 19 samples of Fecralloy A (an Fe- Cr-AI alloy) oxidized in air at temp. from 900 to 1150C for 4 to 192 h. Perme- ability reductions of 10 to 500 times were observed with practically all of the sam- ples falling in the 10 to 1bo range. By depositing Pd over some of the oxidized samples it was determined that a significant part of the observed permeability re- duction was due to surface effects related to defects in the oxide