Disclosure to Promote the Right To Information

Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public.

इंटरनेट मानक

“!ान $ एक न' भारत का +नम-ण”Satyanarayan Gangaram Pitroda

“Invent a New India Using Knowledge”

“प0रा1 को छोड न' 5 तरफ”Jawaharlal Nehru

“Step Out From the Old to the New”

“जान1 का अ+धकार, जी1 का अ+धकार”Mazdoor Kisan Shakti Sangathan

“The Right to Information, The Right to Live”

“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता है”Bhartṛhari—Nītiśatakam

“Knowledge is such a treasure which cannot be stolen”

“Invent a New India Using Knowledge”

है”ह”ह

IS 2629 (1985): Recommended Practice for Hot-DipGalvanizing of Iron and Steel [MTD 7: Light Metals andtheir Alloys]

IS : 2629 - 1985( Reaffirmed 1994 )

Indian StandardRECOMMENDED PRACTICE FOR

HOT-DIP GALVANIZING OF IRON AND STEEL

( First Revision)

Third Reprint AUGUST 1997

UDC 6()9.\ : 669.5~o.5

© Copyright 1986

B If I< E A () 0 FIN n I A N S TAN DAR [) SMANAK IHIAVAN, 9 BAIIADUR SHAll ZAFAR MARci

NI~W DFLIII 110002

Gr 7 November 1986

AMENDMENT NO.1 DECEMBER 1988TO

IS : 2629 - 1985 RECOMMENDED PRACTICE FORHOT-DIP GALVANIZING OF IRON AND STEEL

( Pages 15, 16 and 17, Appendix A, last column) - Substitute ' Maybe rejected' for 'Yf'S' and 'May be acc('pted' for' No' whereverappearing.

(SMDC 28)

Printed at Dee Kay Printer•• New Delhi. India

A1\JENDJ\tENT NO.2 MARCH 1995TO

IS 2629: 1985 nECOMMENDED PR~CTICE FORHOT·DIP GALVANIZING OF IRON AND STEEL

( PaR(' 3. (101/\(' 4I.J.2. 11/ \{ <c-uvnc (' ) -- Subvntutc the followlllg lor Ihel',,,lmg

. l'hc g!av,llIl/llIg proll'"'' L\II 11(' gfOUpl'lJ logether under three calr!:!one-" na mclv(it) we: pron''''', (h) drv prot cv-. .ind (c) a combmauon 01 dry and wei pro, e"" bvcouuuuou-, or h.itch !:!,l!v,lm/lll1!: •

(POIiC 9. (/011\1' 5.4) - Aut! the followlllg dllhl' cud of 1'I,llI"C.

'A lead bed 111.1\ be m.nnt.um-d ,J" II d..,.."..,l.., III d ro"''''1 II!:!.'

(Pa)!,c 11, 111/I1It' 5.9.1t1l1' 7) - - Add 'up 10' be/ore' J pcn cnt '

( MTD 20)

Pnntcd ~l Dee Kay PTlIl!Cf\ New Delhi !IOOI~ India

AM

EN

DM

EN

TN

O.

3JA

NU

AR

Y20

01T

OIS

2629

:19

85R

EC

OM

ME

ND

ED

PR

AC

fIC

EFO

RH

OT

-DIP

GA

LV

AN

IZIN

GO

FIR

ON

AN

DS

TE

EL

(Fir

stR

evis

ioll

)

(Pag

e8,

clau

seS

.I)

-S

ubst

itut

eth

efo

llow

ing

for

the

exis

tin

g:

'S.l

Qua

lity

of

Zin

c-

Zio

cus

edfo

rga

lvan

izin

gsh

all

conf

orm

toan

yo

fth

egr

ades

spec

ifie

din

IS20

9:

1992

Zin

cin

got(f

ourt

hre

visi

on)o

rIS

1322

9:19

91Z

inc

for

galv

aniz

ing.

'

(MT

D2

0)

Rep

rogr

apby

UB

iI,81

5,N

ewD

elhi

,Ind

ia

IS I 2629 • 1985

Indian Standard

RECOMMENDED PRACTICE FORHOT-DIP GALVANIZING OF IRON AND STEEL

( First Revision)

Hot-Dip, Sprayed and Diffusion Coatings Sectional Committee, SMDC 28

ChairT1UJn5IUU V. R. SUBIUX"'NI41'I

RepresIIIU"gIndUln Hot Dip Galvanizer's Association, New

Delhi

Karnam Engmcermg Corporal IOn Ltd, Bombay

Steel Authority of India Ltd ( Rourkela SteelPlant), Rourl..l'1a

The Trnplate Co of India Ltd, GolrnurrSteel Authority 01 India Ltd ( R&D Centre for

Iron & St ee l ), RanchiNational Test House, CalcuttaMrmstrv of Railways, Nr-w Delhi

MembersI'ltBl P. K. BA.NERJEES'lRI K.8. BANNINTHAY A

SRBI]. N.BHATTACHAI\YYA

CRUIl8T & ME'l'ALLUR018TA88ISTANTCUEIIl18T&

ME'U.LLUhGIST ( Alternate)SHRI G. GANF8HAN

SHIU B. G. SOBONI ( Allernale )SURI BllIJLAI. KUA8TIlIYA

S14IU J. N. IJIIAMIJIlY I Alternate)SHRI a. A]l[E~1I CUA"IDH.\ l\L\IlAJ 'N I hv Indian ~I{, 1 ..nd

JamdlPdpur\\ II e Products Ltd,

Spr cral Steels LId, Bombay

G'lut, K ..en. \VII .ia ms Lid, CalcuttaInd ian Lead I me Inforrnauon Centre,

New DeihlSHRI B. N, ~ All \ M rrnst ry of Defr-nci (DGI), New Del h.

SHllI A. IlJI,\T'r ALII AllY A ( Alternate )SHRI S. N. SJ'OIl Llc c t nra l Manut.u.turmg Co Lid, Calcutta

SlIlU M. M. MALlIOTJlA ( AllernaJ<JSURI N. K. SINGHAL Indian Iron and Stet I Co Ltd Bur npur

SII/II A. SENGIJPTA ( Alternate)SHRI]. L. SONFJI

SHRI M. R. DOl TOR ( Alternate)

Snur DAIISIIAN ~J"OIl ( Alternate )SUBI S. NEIJ:LAKANTA~ Zc rurh St e<1 PiP" Lid, Hom bay

Dlt A. R. KESKAll ( Alternate)SURI D. PAtH.SHBIL.PUGAZIIENTH)

( C.nllnued lin page 2 )

@ Cop)f1ghl 1986

BUREAU OF INDIAN STANDARDSThis pubhcanon IS protected under thl' Indian Copyrl~ht Acl \ XIV of 1957 ) andreproduction in whole or in part by any means except With wrrtrcn permission of thepublisher .hall be deemed to be aD IOfrmgcmcDt of cop}Tlght Ilnd!r the laid Act.

IS J 2629 .1985

(Ctmli_d!,,,m pa" I )

M,mIH,sSUBI S' G. TUDKKAB

SHRd. C. EaRY (,AI/",IIJ1,)SUBI K. RAOHAVKNDBAN,

Director ( Struc &: Met )

Rt/W'slJl/ingSteel Authority of India Ltd ( Bokaro Steel Ltd ),

Bobro Steel City

Director General, lSI ( Ex-offino MfmM)

S",6ta'JSURI S. K. GUPTA

Deputy Director ( Metal.), lSI

Hot-Dip Galvanizing Subcommittee, SMDC 28 : 1CotJllln"

SaBI V. R. SI1BllAMANUN Indian Hot Dip Galvanizer'. AaociatiOD,New Delhi

Electrical Manufacturing Co Pvt Ltd, Calcutta

Hydel Designs Directorate, ChandigarhHope's Metal Window. ( India) Ltd, Calcutta

Central Electricity Authority, New Delhi

MfmbmSIUn L. PUGAZBII:NTHY ( Altnul' to

Sbri V. R. Subramanian)SSBI V. P. Alf~NJ)

SBBI S. N. SUIOB ( A/I","11, )SBRI B. D. BALISBIUJ. S. B.Df

SlIBI A. K. SOBTI ( AlI"ruJ/, )SURI D. S. hRULLAR General Engineering Works, Bharatpur

StlRI M. S. MIIlUTA (A/I"MI, )DIRECTOR

Dv.PUTY DIRECTOB ( AI'''MI, )SSRI D. DUTTA The Indian Tube Co Ltd, Jam.hedpur

SIIRI N. R. NATARMAH (AI/"nal,)SURI A. K. GUBA The Fort William Co Ltd, Calcutta

SURI S. KUIIAR ( A/I"JllJI, )JOINT DmECTOR ( CHEX' ) Ministry of Railways

JOINT DmEcTOR ( TI )-1 (AII"na/, )SHRI R. C. MABAJAlf The Indian Steel & Wire Products

JamshedpurLtd.

Steel Authority of India Ltd ( Rourkela SteelPlant ), Rourkela

Directorate General of Technical Development,New Delhi

POlIti &. Telegraph Department, Calcutta

The Tata Iron &. Steel Co Ltd, JamshedpurZenith Steel Pipes Ltd, Bombay

Kamani Engineering Corporation Ltd, BombaySpecial Steels Ltd, Rombay

( AI ternat« )The Indian Iron & Steel Co Ltd, BurnpurDirectorate General of Supplies & Disposals,

New Delhi

SBRI AVTA. SUIOH ( .41"'TIIlI,)SHRI B. M.\IIAPATRA

\ SHRI S. S. SINHA ( AII"TIIlI, )S~ru S. MAJUMDAB

SHRI P. G. MUKRER;JKIDSHRI K. MITRA ( AI"'MI,)

DR T. MIJKflKnn:IlISHRI S.NEF.LAKANTAN

DR A. R. KESIUR ( AlI"TIIlI,)SHRI N. D. PAHlKBSURIR.A. SSANBIlAO

Sum S. S. MURANJ~NSHRI ..\. SnHluPTASnur K. M. T ANF.J A

SHill G. M. GUPTA ( .411,,"alt)5l1JU VIJ,\Y KAPoun Guest, Keen, Williams Ltd, Howrah

2

IS : 2629 • 1985

Indian Standard

RECOMMENDED PRACTICE FORHOT-DIP GALVANIZING OF IRON AND STEEL

( First Revision)

O. FOR E \V 0 R D

0.1 This Indian Standard ( FIrst Revision) was adopted by the IndianStandards Jnvututron on 20 June 198'), aflrr the dr ,If t Imahved b) theHot-Dip, Spi avec! and Diffusion (;o,ltln~,> "" I 'LOllal Couunutcc h.id brenapproved by the Strut tural and Metals ])1\ 1'>lllJ} Council

0.2 TIllS standard was first published In 196tJ The present revision hasbeen prepared In the hght of the experrcru c gamed smc e lb first publica­tion and further technical developments in th I~ field I'he continuous galva­niZIng proce~s has been included III this I C\ rsron. The tvprc.il photogI aphsfor the varrou-, dclects In galvaruzcd co,l.lln~~ on iron and steel have alsobeen included In Appendix A.

0.3 Hot-drp ~'llval1l71nb I~ an old .HId w. II known process of applyll1f{ zinccoating to IrOIl or ste-el surface for prou-ctron ,\galll~t (on o-ion The / Inccoatimr hrvtlv proterts the base JIlt tal by acting as an impervious shrcldbetween the metal and the atrnosplu re and secondly affords sacrrhr ra! pro­tection even when moderately siz ed area'> ( ~ mru dia, for example ) 01 thebase metal surface are exposed.

0.3.1 When a thoroughly cleaned article IS immersed In a ~alv,lf\lzlllg

bath, the metal surface reacts with molten 710L to for m a zmc-tro n alloy.As the article is withdrawn Irom the bath, It pick-, lip pure zinc whichsolidifies on cooling and forms tilt' outer layer. The intermediate alloylayer provides a stronu bond f>'etween the ferrous base rnater ial and thepure zinc and also resists corrosion and abrasron III the event of the purezmc layer being removed Under same conditions of prorcss or compo~l·

tion of the material the whole coating may consist of zrnc-iron alloy layers.

0.3.2 The galvaruzmg process can br- grouped under three broad catego­ries, namely (a) the wet process, (0) the dry process, and (c) the contmu­ous galvamzmq process ContllJUOUS galvamzmz process constvts of (leaningbase steel surface by first oxrchzmg' and subsequently reducing the sur­face oxides under controlled atmosphere or by any other m-Ime cleaning

3

IS: 2629 • 1985

method. The strip I~ heat- treated in lint" annealing/normalizing furnacefollowed by continuous ff'l'ding through molten zinc bath and passivatingtreatment by suitable agent hkc chromic acid. After g" lvanizing, when thesheet emerges from the zinc bath, the excess molten zinc on them is wipedoff by air or gas jets. There is no fluxing in this process.

0.3.3 Continuous galvanizing process has got advantages over both wetand dry processes with respect to high productivity, control of coatingthickness, uniformity of coating along the length, better coating adher­ence, less dross formation, better surface appearance, etc.

0.'1 A summary of defects, along with the typical photographs for illustra­tion, commonly met with in the hot-dip galvanizing practice, their causesand remedial measures are given in Appendix A. In this appendix, theinformation given in the last column aids inspectors in interpreting theappearance of the article and help them in arriving at a correct decisionfor accepting or rejecting the finished material.

0.5 Working conditions and safety measures which should be observed ingalvanizing plants are given in Appendix B.

J. SCOPE

1.1 This standard recommends important guidelines for general hot-dipgalvanizing of iron and steel.

2. TERMINOLOGY

2.0 For the purpose of this standard, the following definitions shall apply.

2.1 A.h - A mixture of zinc oxide and varying quantities of metalliczinc. The former is formed as a result of oxidation of clear zinc on thebath surface and when the oxide is skimmed off, a certain amount ofmetallic zinc gets entrapped and removed along with it.

2.2 Dro.. - An interrnetallic compound ( FeZnls ), which is a com piesmixture of zinc and iron, forms in the galvanizing bath as a result of thereaction of molten zinc with iron or iron salts and settles down at thebottom of the bath. Zinc content in dross will vary between 94 to 97 per­cent depending on the quantity of metallic zinc entrained in dross duringits removal from the pot.

2.3 Flax - A chemical compound applied in the form of an aqueoussolution and dried on to the work in the dry process or spread as a moltenblanket over the zinc bath in the wet process. The primary purpose of theflux is to help in keeping the surface of both work and molten zinc freefrom oxide at the time of reaction. In both the galvanizing processes flux­ing helps maintaining the surface of work free from oxides.

4

IS I 2629 • 1985

2.4 Over-Plcklbal - The undue attack of the underlying ferrous surfaceby the pickling solution after the removal of seal e.

2.5 r.hlbltor - A substance added to pickling solution to prevent undueattack on clea.n metal without affecting the scale removing property of thepickling solution.

2.6 White Ruat - A white corrosion product, mainly conta ining zincoxide and basic zinc carbonate, that accumulates on the galvanized surfaceexposed to water film or moist atmosphe, e.

2.7 Wettilll AleDt - A substance added to pickling and prefluxing101utions to facilitate wetting of the work surface.

3. BASE METAL FOR GALVANIZING

3.1 Steel - Mild steel is the most common material that is galvanizedand the variations in the range of compositions used have little influenceon the galvanizing process. The steel, however, should contain minimumamount of segregation, slag inclusions, rolled-in millscale, etc.

3.1.1 Carbon and silicon tend to increase the rate of reaction betweensteel and molten zinc. This effect, however, is not so apparent in the rangeof compositions encountered in mild steels as in high carbon and highsilicon steels.

3.2 Ca.t !rOD - Cast iron react with zinc differently depending on theexact composition, in particular, the silicon and phosphorus contents.

4. PREPARATIONGALVANIZING

OF THE METAL SURFACE FOR

4.1 Cleaalal - If an article is contaminated by oil, grease or paint,pretreatment in special solvents win be necessary for their removal. Seve­ral proprietary reagents are available. Generally a sodium hydroxide solu­tion obtained by dissolving 10 to.1..5 kg of sodium hydroxide in 100 litresof water is used.

4.1.1 The work should be so handled in the degreasing bath as to allowfree circulation of liquid over all parts, taking care to clean the scum thatmay collect. If necessary, the work should be raised and lowered in orderto allow the degreasing solution to enter inaccessible areas, threaded sec­tions, etc, for a thorcugh cleaning action. When using sodium hydroxideIOlution, the temperature of the solution may be usually kept between 85and 9000 and the immersion time varying from 1 to 20 minutes dependingon the nature and degree of contamination. When USIng other proprietarydegreasing agents; manufacturers' recommendation should be followed.

s

IS t 2629 • 1985

4.1.1.1 Immediately after degreasing, the work should be rinsed inhot water ( 6DoC ) followed, if possible, by a final rinse in cold runningwater. An Ideal arrangement for rinsing would be to provide an inlet andoutlet on two opposite sides of the rinsing tank; the inlet should be at thebottom of the tank and water should overflow from the top. This way therinse water is in a dynamic state thereby ensuring an efficient and athorough rinsing operation.

4.1.2 When lubricating materials have contaminated with the surfaceof the metal, it may be necessary to heat the part to bluing or scalingtemperature in order to burn off the offending material. Since this is anexpensive and difficult process, prior care should be taken to avoid suchcontamination.

4.2 Cleaning of Castings - Grey iron and malleable iron castings if notproperly cleaned before annealing, develop burnt-on and patches at thesurface which are not removed by normal pickling. Except in the case oflight castings which would be damaged, all castings should be shot or gritblasted prior to galvanizing. It is generally recommended to give a quickrinse in running water followed by cleaning with one of the pickling acids.I t is then processed according to normal fluxing practice

4.2.1 An alternative but less efficient method of cleaning castings withburnt-on sand is to employ a pickle solution containing hydrofluoric acid.For use, the commercial acid is diluted to various strengths, ranging fromone volume of acid and 59 volumes of water for a very weak pickle to onevolume of acid and 9 volumes of water for a very strong solution. With aweak solution pickling may take as long as 24 hours, while the stronli( solu­tion should pickle satisfactorily in 10 to 30 minutes.

4.2.1.1 A hydrofluoric acid pickle leaves a gelatinous layer on thesurface of the castings which shall be thoroughly removed by hosing withwater and scrapping and brushing. The casting shall then go through theordinary pickling process.

4.2.1.2 Solution containing 6 parts by volume of commercial hydrofluo­ric acid , 4 parts by volume of technical grade hydrochloric acid ( III IS :265-1976. ) and 40 parts by volume of water may also by used for pickling.When pickling of castings is done occasionally, a solution consisting of 4parts of dilute hydrochloric acid ( I : I ) and 1 part of hydrofluoric acidmay be used.

4.3 Pickling - Both hydrochloric acid (St8 4.3.1 ) and sulphuric acid(see 4.3.2) solutions may be used for pickling. Hydrochloric acid is used atroom temperature while with sulphuric acid best results are obtained whenit is hot ( 60 to BO"C )•

• Specrhcarion for hydrochloric acid ( SICIJrld rftlision ).

6

IS 12629· 1985

4.3.1 Hydrochloric Acid Solution ( 100-150 gIL) - Dilute technical gHdcacid conforming to IS : 265-1976* with an equal volume of water. Theactual concentration of hydrochloric acid solutions and the time of immcr­sion will depend on the nature of the work to be pickled,

4.3.1.1 A suitable inhibitor should be used with hydrochloric acid,

4.3.2 Sulphuric Acid Solution ( 100-150 gIL) - Dilute 6 to 8 ml of tcchni­cal grade acid conforming to IS : 266-1 <)77t to 100 ml. The actual concen­tration of sulphuric acid solutions, the temperature of till' hath .uul thrtime of immersion will depend on the nature of the work to be picl.lcd .

4.3.2.1 A suitable inhibitor should be used with sulphuric acid,

4.3.3 Agitation - Mild agitation of the work in the pir l.Iing tank redu­ces the time of pickling. Raise or lower the work once or twice to changethe acid layer in contact with the work. Air agitation is not recommended.

4.3.4 Control of the Acid Solution - To make the best use of the solution,reasonably close control of its acid content is necessary. The solutionshould be tested for acid and iron contents at regular intervals in accord.ance with the methods given in Appendix C. The strength of the solutionshould be maintained by periodic addition of fresh concentrated acid. Theiron salt. in the pickling bath gradually accumulate with continued work.in~ and when the iron content reaches to about 100 to 120 gil, thesolution should be discarded.

".3.5 Disposals of Waste Liquor - The acid and iron compounds may berecovered from the waste pickling solution. Where this is not done thepickling solution should be neutralized before dumping into sewers orstreams.

4.f Rinsing - After pickling, the article should be rinsed in runningwater. Two rinse tanks are preferable, the water cascading from one intothe other, that is cascading from the second tank into the first tank.

".5 Cleaning of Strip in the Continuous Galvanizing Process(ARMCO Sendizimir Process) - The cold-rolled strip is passedthrough an oxidizing furnace at temperature around 45()oC where rolhnglubricant is burnt and surface gets slightly oxidized. This is followed byreduction of surface oxides in the annealing/normalizing furnace undercontrolled atmosphere and subsequently allowing the strip to pass throughmolten zinc bath.

·Speclfication for hydroch loric acid ( second rlVlSlon ).tSpecification for sulphuric acid ( secondrtVlJlon ).

7

IS : 2629 - 1985

4.6 Fluxing

4.6.1 The 1 insed article, in the dry process, is dipped in a strong sohi­tion of zinc ammonium chloride ( ZnCI•.3NH. CI), although ammoniumchloride is also used to a certain extent. The actual concentration of theflux solution and its temperature depend on the work being undertakenand on individual circumstances. The working level is generally between200 to 400 g of zinc ammonium chloride per litre. Some wetting agent isusually added to the flux solution. The temperature may range from roomtemperature to 80°C.

4.6.1.1 When dry galvanizing is adopted. the article shall be thoro­ughly dried after fluxing over a hot-plate or in an air-oven. The tempera­ture should be about 120°C and should not exceed 150°C as the fluxdecomposes above this temperature.

4.6.1.2 In the wet process, a deep flux cover is used on the zincbath and the work is immersed through the flux layer with or withoutfluxing. In this case drying is not considered essential.

4.6.2 The article that has been prefluxed and dried should be galvaniz­ed without delay, as the flux coating picks up moisture from the air andalso tends to oxidize. The recommended time limit for galvanizing is with­in an hour of fluxing.

4.6.3 Control of Fluxing Solution - The specific gravity of the fluxsolution should be controlled by adding requi red quantities of flux crystalsand water to make up for the drag-out losses.

4.6.:to1 Free acid content of the solution should clso be checked,particularly if rinsing is not very thorough and pickle is CArried over. Themethod described in Appendix C may be used for determination of freeacid but the actual titration should be made on a 100 ml sample as theconcentration of acid in the solution will be very low. When more than2 g of free acid per litre of the solution is present, it should be neutrali­zed by adding ammonia solution or addition of zinc spelter.

5. GALVANIZING

5.1 Quality of Zinc - Zinc containing at least 98'5 percent Zn shouldbe used for the purpose of galvanizing.

5.1.1 Galvanizing Bath - The molten metal in the galvanizing bathshould contain not less than 98'5 percent by mass of zinc.

8

IS I 2629 • 1985

5.2 AlaDdDiulD AdditioDs - Aluminium may be added to the galvani­zing bath in the dry process to the extent 'of about 0'005 percent ( 0 OCJ'percent Max) ( 0'05-007 g/kg of zinc) to reduce the rate of oxidation ofthe molten metal and brighten the appearance of the article. In the conti­nuous strip galvanizing process, addition of aluminium is made in the bathin the form of Zn-AI alloy to maintain aluminium between 0'12 to 0'20percent to control alloy layer thickness and thereby imparting betteradherence. Lead is also added in the form of Zn-Pb alloy to providespangle on the surface.

5.3 Bath Temperatare - The control of bath temperature IS essentialif the quality of the product is to be consistent and zinc is to be usedeconomically. Articles should be galvanized at the lowest possible tempera­ture which will allow the free drainage of zinc from the work piece duringwithdrawal. A low temperature reduces the formation of ash and dross,besides safeguarding the pot and conserving fuel. The bath temperaturemay vary from 440°C to 460°C and a working temperature of 450"C iscommonly used. The temperature of the molten metal should not ordina­rily exceed 475°C to prevent excessive attack of molten zinc on the work.as well as on the pot. In case of high silicon steels, a higher galvanizingbath temperature of 550°C is adopted in order to obtain normal coatingmass - the behaviour of silicon steels at 550°C is similar to that ofordinary steels at the normal galvanizing temperature at 450°C. However,for high temperature galvanizing, top heated ceramic bath are generallyused.

5.4 Suspended Dross - Dross should be allowed to settle at the bottomof the zinc bath, and should not be disturbed more than necessary duringthe dipping operation ( see 5.5 ). As far as practicable the article shouldnot be sunk to the bottom of the bath during galvanizing. After dressingoperations, by dipping the articles once again, some time should be allow­ed for the dross stiU remaining in the kettle to settle down.

5.5 Rate of IlDlDersiou - The work should be immersed as rapidly aspossible but with due regard.jo operator's safety. This is especially impor­tant in wet galvanizing, where the amount of dross increases with the timeof contact with the flux blanket. The speed of immersion also influencesthe uniformity of coating, particularly with long work piece where thedifference in immersion time between the first and the last part to enterthe bath may be considerable.

5.5.1 In case of continuous strip galvanizing the rate of immersion/with­drawal is dependent on the thickness of the strip and line speed governedby furnace design.

9

IS I 2629 • 1985

Top choss is removed at n'~ular interval from the surface of the bath.Coating rolls and grooves are <-I' aru d regularly.

5.5.2 Time of Immersion - The timr- of immersion for a job depends onseveral factors like its chemistry, ~i/,e. thickness, type of job, etc. In mostcases the article shall be left in tl)(' bath until it reaches the temperature ofthe bath which is usually indicated by the stopping of the boiling action.It is thr-n withdrawn without milch delay.

5.6 Withdrawal - The rate of withdrawal, which determines the thick­ness of the unalloyed zinc layer left on the article, var i-s according to thetype of the process being operated and the form of article, With long arti­cle for which withdrawal occupies a large part of the total handling time,speeds are necessarily maintained at higher levels to ensure a reasonablerate of production. It is better to use special jigs and carriers for dippingand withdrawing the work in batches. The rate of withdrawal should becontrolled so that zinc drains freely from the surface.

5.6.1 Articles are withdrawn through a bath of clear zinc to avoid con­tamination by flux. However, withdrawal through a flux blanket has alsoits advantages in the removal of surplus zinc from the surface and in pro­ducing a uniform coatmg at relatively highrr speeds. III the latter case itis recommended to quench the material ( see 5.7 ) to remove fluxresidues,

5.7 Water Quenching - Where the article is withdrawn through a fluxblanket, the quench water needs to be changed flcquently to prevent theaccumulation of corrosive salts. For this purpose tanks having overflowweir may be used with advantage.

5.7.1 Light gauge articles should be spun quickly through the surface ofwater so that they retain sufficient heat after quenching to enable quickdrying. Heavy articles retain sufficient heat for drying.

5.8 Centrifuging - Small articles handled in baskets should be centrifu­ged to remove excess of zinc immediately after galvanizing while the coat­ing is still in the molten condition. The quality of the finish depends onthe rapidity with which the material is transferred from the galvanizingbath to the centrifuge. It is also important that the centrifuge should bepowered by a high starting torque electric motor to give rapid accelerationto peak speed within 2 to 3 seconds. After centrifuging, the articles shouldbe immediately tipped into water to allow the coating to set and preventthe articles from sticking to each other.

5.8.1 Thread Brushing - Threads on articles which are unsuited forcentrifuging shall be cleaned with a rotating wire brush immediately aftergalvanizing and before the coating sets. This process reduces the thicknessand the protective value of the coating. It should only be confined to thethreaded portions of the article.

10

IS I 2629 • )P8S

5.9 Post-Treatment - The zmc coating on freshly galvanized surface swhen r-xposed to humid, p iorly ventilated conditions during storage and/ortransport react with the moisture, c irbon dioxide, oxygen, etc, m theatmosphere formmg a mixture of salts which are white in colour. Tl1i, ISknown as , white rust' or ' wet storage stam ", Normally a post-treatmentlike chromatmg IS recommended ThIS IS a temporary treatment andretards white rust attack The chrornanng solution contains I percentsodium dichromate and hall percent sulphuric acid solution - the solutionI~ kept at room ternpe ra ture and ItS temperature' should never be allowedto rise above 6°)OC The g,lh -uuz ed articles are dipped mto the chromat­mg solution after the galvaruzmg and \\ ater quenchmg operations.

5.9.1 In case of contrnuous str ip ga lvamz.mg the strrp is sprayed withchromatmg solution, such as chromic acid and properly spread uniformlyby means of squee7er rolls Temperature of the chromic acid bath is main­tamed around 70-7')oC

5.10 Stacking -Artldr's should not be stacked Immediately after quench­mg (see 5.7) to avoid flakll1g of coatnig I he galvanl7ed articles should beallowed to dry before an; further handhnu operanon

6. TESTING AND INSPECTION

6.1 Freedom from Defects - The zmc cc aung shall be adherent,smooth, rr avonably bllgl-}t, r onunuous and free from such Imperfections asflux, ash and dl oss mclusrons, bare and bl.u k spots, pimples, lumpinessand runs. 11I~t ~t 111\5, bulk) white deposit s and blt\tl I S

6.2 Uniformity in Thickness - G ilvaruv ed articles shall be tested foruruforrmty 111 th rckncss of coatmg in 3( corrlance With preece test given inIS . 2h33-1 CJ86* For quick .ipproxrma«. measurements of thickness, mag­netic gauges may be used, hut such mstrurncnts shall be SUItably calibratedbefore use.

6.3 Mass ofCoating - The mass of zrnc coating may be determined In

accordance WIth IS 6745-1972t.

6.4 Adhesion Tests

6.4.1 PIVoted Hammer Test for Zmc Coated Fabricated Products ( Fabricatedfrom Plates, Bars, StYlP, etc) - The adherence of the ZlI1C coat109 on steelshall be deterrnmed by the pivoted hammer test. The hammer used shallconform to the drawmg shown in FII~ 1. The hammer shall be made ofnormalized 0 3-0 4 percent carbon steel The hammer blow shall be con­trolled by holdmg the pivoted base of the handle on a hor izontal surface

-Method of restmg umforrrury on zmc coated artrcles ( ulond revISIon)tM~lhods for dcterrmnatron of mass of zmc coating on zmr coated Iron and steel

artrcle.

11

IS I 2629 • 1985

of the galvanized member and allowing the hammer head to swing freelythrough an arc from vertical position to strike the horizontal surface. Thetest shall consist of two 01" more standards blows forming parallel impres­sions with 6 nun spacing and a common axis, as illustrated in Fig. I. Nopart of an impressron shall be closer than 12 mrn to the edge of themember. Removal or hfting of the coating in the area between the im­pressions shall constitute failure. An extruded ridge less than 2 mm wideimmediately adjacent to the impression shall be disregarded. The speci­men is tested in several places throughout its length.

6.4.2 Knife Test for Ziru; Coated Hardware and Assnnbl,d Steel Produ,ts ­When the coating is cut or pried into, such as with a stout knife appliedwith considerable pressure in a manner tending to remove a portion of thecoating, it shall only be possible to remove small particles of the coatingand it shall not be possible to peel any portion of the coating so as toexpose the underlying iron or steel.

6.4.3 Bifid and Wrapping Tests for Zrn, Coated Sheel and Wire - Thematerial such as sheet or wire shall be tested by bending or wrapping inaccordance with tests given in the relevant Indian Standards.

6.5 In case of continuous galvanized sheets, inspection and testing iscarried out in accordance with IS: 277·1977· or any other standardspecifications.

7. STORING, PACKING AND HANDLING

7.1 Sufficient care should be exercised while storing, packing and handlingof galvanized products. While storing and transporung them, adequateventilation should be provided as otherwise 'while rust' or 'wet storagestain' may result when galvanized coatings react with hwnidity and atmos­pheric gases. It is sometimes necessary to store galvanized articles withspacers in between them, they are also kept at an inclination to facilitatedrainge of water collected on the articles. In areas where there is a subs­tantial variation in day and night temperatures and hence condensation,the storage area kept warm by provision of heaters. In many cases, it willbe advisable to give a post-treatment like chromating to minimise thechances for formation of white rust.

·Spec::dicatioDfor galvanized deel .beet. ( plaiD and corrugated) ( tlr"d "l1li'011).

12

)00

6mm SPACING SYMMETRICAL

~~"

~

e::pTE S' IMPRESSIONS

PIVOTt:O .BASE

HAIolMEA

EFFECTivE WEIGHT OF HAMMER210 TO 215g

~--.---.-------

JEST POSITION

All dimemloDi in millimetrea.

FIG. I PIVOTED RIVETING HAMIOR

13

APPE~I>I:X::

A(

Glo

uses

02

an

d0

-4)

:D

EF

EC

TS

,.

T:I-

IEIR

..CA~SES

AN

'I>

R..E~E:I>I.A..I....l.

"IE

AS

UR

..E

S

DE

FE

CT

SG

..::

::-l;

I>

A...

...C

EF

<:>

:P;

AC

-C

EP

TA

.....

CE

:

R.E'.~.ECTJ:C>_

--, IYes.

ex

cep

th

ere

I~::.raeJl

~c:;;ss

'":.:e

Ig~e

1C>t:rr';:t~~~~~

Ik

ez.n

.e

c.ch

pa.

•n

'"s

sp

ca

....

.ng

etc

s...

.b

Je

el:

1:0

pc.o

rag

reem

en

.t;

b..

-'"

'...

...en

t;~e

gal

....a

>-X

U?er

an

d"'h

eb

u...

.er

Z.n

ecan

,sacT

.fic.aII

....p

ro

Itee.

bare

areas

rn

easu

r1

ng

ab

oL

l'"

I4-

rT

lO"l.

acro

ss

bu

tI

here

ag

a.n

.th

eI

allc>

_ab

le

Sl.7

eof"

"I

ba.re

sp

<o

ltsh

o...

..)d

,b

ea.g

,..-

eed

....p

on

\~:b::z:e~rn~~~~~le

J

slt

ee

)

~Iu

ad

d.

R.E

C0

2l.

![.J

W".E

I>

:E:I

>A

CT

:L

OS

Ch

eck

pre-A

LlX

:

c~n.

n.~I

T..o

:;sr

;,:.

.nrg

tlcu

,larl..

.h

ete

lT

lp

era

l:u

re

on

.ic

he

-.J<

:>b

be

­lI:J.g

dried

Reg

ula.te

t::t

O..

.-J.S

Ch

eck

...u

pp

l...

..F

<:eep

a.rt:1

cles

sep

ara.t:ed

Ch

eck

clean

.1.o

gp

ra

clI

:lc

es..

deg

rea.s

':E

:lg

reco

Trl._

~enclecl

Ch

eck

pIck

IIrig

P:>

""'-

CI:I

CeS

Ad

op

t:

rT

I....ch

an

.cal

clean

ln

gaV

Oid

Ico

al:erl

roo

ds

C...

.LS

ES

rP

aln

t:

grea.se,

Io

rcu

II I :

Scale

or

.-...

."'t

:I

res~d

.....e

sI

R",=

:,n

clu

a]

_elei

IIV

gslag

! IB

r..

,.a

kclo

......

.n.

or­

~H

ux

co

atIn

g

I II.,.

,.l...

.O-'l

rllL

lT

nC

OJ::

l.

rte

cH

:<

:>r

ba.tb

iR':;

;~n:

l~~r

ect;

sI

:aO

ba.S

19

,..te

e)

JA

rt.cle..

lr>

.C

Or>

.I

.a<

::1

:d

urIn

g:

Lg

a!va

r:lI

z1

Dg

Bare

sp

o.,

,.o

rIl

l::L

cl.

.S

PO

lS

r I

I-'I

lg

hg

a..

vax

.:l.

z.n

gte

rr.o

.pera._

:~~e;":o~ong

tlr:D

.eo

rb

oth

Gen

eral

ro

.g

h.n

.ess

rA

n:al)-

S.S

0"'-

a.r

"

~~~

r:..

~;lH

~':,

::.a

.~ef

""I

steel

I<

=>

verp

:lck

l.:n

g

-< : I I I L

Cb

eck

......

.pp

ly

R.ed

....c

ep

u::k

l.n

g1

:.ro

.eO

lt"

&.e

.dco

neen

tratllo

:n

•L

:lse

.n

hIb

__lo

r

-., I fN

"<.>

ex

:cep

tb

vp

rll

Oo

rag

reeIrllen

l>-

b""t

........een

gal

..a

Iru

zer

an

.d

p...

.II'

lch

.a.ser

I J

PllT

lp

les

AV

"c..

da

g:l

1:a

.1;.

OI:

1")

0'-

dro

ss

la.

....e

rI

No

"L

In

less

arC

''''",

ch

eck

carr...

:---

C-o

n.I

ta.>

:T>

.Ir-

a.1

:o

ver

0'-

p:l

.ck

Je

Ih

eav

vs.a

lts

J

""-pl~.ple

un

der

'-0

crO

Sco

pe

)

PtO

UB

.8D

ZP

BC

Ta

LU

Dlp

IDess

an

dru

ns

(U

DE

:ve

n

drain

ag

e;

(W

Ith

draw

al

Isp

eed

"to

oh

igh

IC

old

galv

an

i­J

zU

lgb

ath

-.<D

ela

yed

ru

D-

Io

ffsearns~

\JO

lotS

.b

olt

.I

ho

les.

etc

IA

ru

cle

sIn

co

n­

Ita

ct

du

r1o

.gl

'Wlt

hd

raW

'aI

ReD

:1o

ve

wo

rkslo

wly

In

cre..

ete

mp

e_

ratu

re

Rezo

ov

e~ork

Blo~ly

Keep

arb

.cle

ssep

ara'l

ed

G"O

ID.&

.1!I

'CB

'-O

RA

QC

KP

T..

....O

B!

1'l

lI:.

.;r:

SC

TIO

N

"I I I I I ~O

n}

...

by

prio

r1

ag

reen

len

t

I I I J

Ch

eck

S't

eel

pre­

paralJ

OD

Sk

un

.b

efo

rewl~drawal

Flu

xu

3clu

­S

IOU

..s

(S

tale

flu

xb

urn

t.I

on

du

rlD

gI

dip

pin

g~

Su

rface

resl­

ld

ues

VD

ste

el

IF

lux

pIck

ed

Iu

pfr

om

t.o

pL

oC

bath

Ref'

resh

or

reae'W

'1Flll~

sta

IDIi

IeE

efl

u%

.b

lan

ket

IO

Vte

ro

nt.

he

Jo

bJ

afte

rfl

ux

reD

lG­

}-v

al

..IS

no

tco

nsJ

.-

,~:~t~10nlU

~~d

th

en

ce

sh

ou

ldJ

Do

tb

ereje

ctecl

(A

rrrs

ceo

ste

wc

ew

ee

of'

flu

x"D

clu

slo

n)

CA

:O

_G~

....

..~

..~_

AC~A

..c:.

1~C"rl[o.N"

Ash

In

cll

U­

..io

ns

rA

sh

bl.

.l.r

D.c

on

.S

lo:u

:n.b

ath

bero

re

Id

uriD

.gd

ip

p-

dIp

pi.n

.g..0

(i:

og

IA

sh

pIck

ed

up

Sk

i:u

ll.

bat;b

be"'~re

I"'r

o.:

o.

~op

OK

__it:h

dr_

_a.1

Lb

a1

:b

, ~Y~

..iC

IIu

.:z:n

.ps

J

Du

ll

grey

co

at:in

g(all

a.l

lo

vrIO

Cree

Z1

T1

C)

IS

t:eel

CO

n:3

PO

S:L

_

I~io.D

(h

ig

hI

sjlico

:u

..ph~s-

Ip

ho

ru

so

rI

carb

on

)o

rI

SeV

ere

co

ld

I","

ark

:'8

10

_co

olu

':L

gI

aC

t:er

ga.l

va­

In

.i:z

ing

IR

.elea.s

eo

fa.b

­-.

::so

rb

ed

hydro~

Ig

en

du

rin

gI

,,"o

hd

:Lfic

a.t

:J.o

n]

oC

coa~J.Dg

I t I I I L

Ch

eck

st:eel

......

..p_

ply

f"o

rC

O:n

:llp

o­

"J.t

ioIl

l.jI

ll.

ord

er

'k>

ad

.j...

..st

Co

rg

....l

v...

m:z

;in

g

A'V

oid

bo

tst.

a.k

­in

g.

qu

e:r

::u

::h

Av

oid

pick

lin

g.

usc

i:n

hib

:L1

:<:>

r

.,

No

tif

'"d

ue

to

Isteel

cO

%Jl

op

oo

si_

I:~~:,~:1:L~~~

Ito

'Occa.s

i:::

on

.a.l

Iareas

CO

El.

tro

l.

Ib

yp

rJ.o

rag

ree­

IIl.

en

tG

rev

c.,

....

._ti:n

gIS

on

-Iy

d:L

s­

Ip

lea..

s:L

rltg

to

t:h

eI

ey

ean

dIS

.ri

ta.,

ra

cle

f"ect:

at

a..

))_

tIn

Ca

ct.

gre~

Ico

a..

"li

ng

.ca

::rn

_I

pared

1:0

ab

ro

gh

l:

1~::~Ing.r:s::~:~;

1-..

:l.d

is

ch

err:u

_I

ca.lly

~ore

):::

ro­

It:

ect:

i...

..-e

in

so

rn

.eI

e:n

.....

ire>

nrn

.en

tC

or

I.n..sl:aDC""'~

acu

::l.c

Je:n

....i:rot::>r:n~nt:.

(U

nd

er

a.~'l.cro

...c<:>pe~

r::b

ecrO

SS

sectIo

n)

R1

.1S

t:stain

s

C''''''''eepi:ng~

or

1acid~

et:

:c..

-<'-

ro:r

::n

.se

a.I

I1S

!S":=a~~lds

near

Lru

sty

rna~eri_l

Ch

eck

pro

.ch

..l.

ct:

-'

-:i;-~~c>~nd

Cab

-L

Ch

eck

st:o

rag

ei

co

n-d

itio

nJ

No

SIt

Oro

e.a

..n

dsh

:Lp

:o..

n'"l

J."o

,lo~

:th

....

....

..h

.1.<

o:

dry

"","

el1

-,-

eE

llc1

1...

.-I

de

po

sJ:'

l:s

ca

n.

te-d

co

n.a

J:1

:1C

>n

.s.

Ire

:o::

r.o

.ov

ed

b...

._

_p

a.r

a.:

l:e

a.r

to:l

.cle

sah~d

r~~bb.r:IIg.

"..

""h

..p

ac:er_

"""

\b

ru

sh

"n

.g

.e'l

c.

tern

.p<

:>ra.r

j.1

:r..

,,:a

1:-

'I.e

dep

oo

slts

are

:lJn

ell:

Jt1

:l.k

ec::

hro

-\

bo

ea..

..1

e..

-.

t:h

e...

.:r

:z1

a.t

arl

lg~5

rece-rn

.-

\sh

:oL

llb

ererrle>

..m

en

ded

1o

ed

an

.d

tb

e:Z

In

cD

ry

beC

e>

ore

pa.c

::k

.->-

coa.1.~n.g

be:n

ea.1

:h

:I.:

o.g••

ncl

.....d

ed

e-

Isb

.c...

..J.l

db

ee

es

ee-

crS

IC

Can

t!:

.At~rTl--

IC

or

tbu

::::

kn

.ess

~..-a.:ry

pro

tec_

Ib

ef"o

rea.ccep.~n.g

tI

.....e

'ltr

ea

t.rn

.ellr:

J."

t.I

<>

rre

Je

ctl-

og

th

e1:

1.10

0...

ch

re>

-=-:

>a.l

:arl

lgI

......

.h..t:

er.,

,.1

:a.t:~a.-

.Sreco

:rn

rn

.en

decl

Iek

e<

!g

a.l

...an~zO""d

Jp

reJo

ClL

.Oct'

"

GC:l~"""-:N"C~

FC

>R

AccE.F'"T.A._c~

RE

J:>

c.'

TIC

>=

:-"

R...E:CO~~:E:I>

AC-:;r1<>~S

C.A

.-crS

.E:S

1~n.fi.r:o.er:D.e~1:

.of"

Ic]c

:>se

pack

ed

\~~~es

cu;;

.~~~

II:

:.O

:12

SI

B'l.ilk:~

""",h

n::

...I

dep

aois

Jt:

I('"

••re

"t.

~to_-<

rag

est

;a.,

.lIr

:J..

.:P

'ack

.n.g

of"

__

h..re

r...

...st)

1_

rll.cles

_b

.le

Id

a.T

T'lp

I I I L

47

;

('\

t'\f

h•.,

e~sll:

Uln

.der

rr>

:l.c

:ro

-sc.:

op

e)

.Cg

en

eral

Ch

eck

steel

qu

a.­

l~ty

rE:>c:pan.s~on

of"

_..

....ra.p

ped

hy

-

~~~:~re

a.~

fl.a

.'-V

s

I I I II:

>r:

l.V

"ID

.g:

off

00

.U

se

sb

ot

bla

.sl.

:-<.

hy

dro

gen

.a.b

-IK

UO

tea.d

oC

p.c­

I$

<O

rb

ed

d...

..rI:

lD.g

kle

Ch

eck

steel

IJ::

nck

l:ll

l:lg

su

.p

ply

I IIlT

Ip

ro

Op

.,.r

rr>

.a.I

-C

heck

:r:n

.a.l

Jea.b

II_

Ile:ar..bl~z":Ig

CC

o,.

-z~ng

pra.c

"'u

:e

ID

nallea.b

le

:l>

ron

Lca.

t~lI:Igs

<>

n.l

y)

(A

bl"ster

......

....d

er

lI:I

I::I

.IC

roO

s.co

pe

)

T~DY

rE

ffect

I~~e.

~b.e~

'Ve

d.

on

.q

u.e

In

ch

ed

_o

rll:..

Ir:

u:>

ota

.bly

rTC

l.al-

Il

...a.b

le

c.a

.st­

::l

""'g

sI

l'vf.

ay

be

ca.u

s-

Ied

by

ga..

s-c

e'V

c>

IV"ed

.ro

lD1

l.I

th

e_

orll:.

1res

1..1

JI.

:.:E

:I.

gI

.ro

IT

l.a

bso

r

J:=

<o

r~;

:::k

'::

Id

o_

....

o.

IC:OrT>b~""'E"d

Ica

rb

on

JrI

I.e

ar

L...

....r

f'a

.ce

Use

sh

ot

bl.a..st"

I~te_d

o£p~ckle.

Ch

eck

rn

aJle

....b

l._

z.n

gtr

ea.l

.:rr.t

.en

tS

ho

uld

haV

"e

JrII.

O

;:::::I~~-:£~~:;~c

i !-~:s,.

.C;~~~"".-~~~

I.....,-~despr'""'_cl

I j

IS 12629.1985

APPENDIX B( Clause 0.5 )

WORKING CONDITIONS AND SAFETl' MEASURES

B-1. WORKING CONDITIONS

B-I.I The galvanizing shop should be' kept neat and tidy. Where possible,increased use should be made of hoods, extraction ducts and exhaust fansto give as good an atmosphere as possible.

B-2. SAFETY MEASURES

B-2.1 All safety measures should be properly exhibited.

8-2.2 The workers at the galvanizing bath should be provided with:

a) eye or face shield,

b) rubber boots,

c) steel-capped boots,

d) leather or leather on woollen base gloves,

e) rubber and leather aprons, and

f) long rubber or PVC or neoprene gloves.

B-2.3 While cleaning the articles with sodium hydroxide solution, theoperators should be warned that it produces severe flash burns. Specialprecautions should be taken to protect them from splashes of sodium hydro­xide solution.

B-2.4 Hydrofluoric acid sometimes used for pickling of castings (see 4.2 )is dangerous and causes very sever burns and sores when it comes in con­tact with the skin. It should, therefore, be carefully handled by wearingrubber boots, gloves and aprons.

8-2.5 Arrangement should be made to protect the galvanizer from thefumes over the zinc bath.

J9

IS I 2629 • 1985

APPENDIX C( Clauses 4.3.4 and 4.6.3.1 )

TEST METHODS

c.r, QUALITY OF REAGENTS

0.1.1 Unless otherwise specified, pure chemicals shall be employed in testsand distilled water (see IS : 1070.1977-) shall be used when the use ofwater as a reagent is intended.

NOTE - • Pure chemicals' shall mean chemicals that do not contain impuritietwhich affect the results of analysis.

C-2. DETERMINATION OF ACID CONTENT OF THE PICKLINGSOLUTION

0.2.1 Reagents

0.2.1.1 Standard Sodium Carbonate Solution - Approximately 0'5 N.

0.2.1.2 Methyl Orange Indicator Solution - Dissolve 0'05 g of methylorange in 100 ml of alcohol.

C-2.2 Procedure - Filter exactly 25 ml sample of the pickle liquor into250·ml measuring cylinder and make up to 250 ml by adding distilledwater mix thoroughly. Pipette out 25 ml of this solution in a 250 ml conicalflask. Add a few drops of methyl orange indicator and titrate it with thestandard sodium carbonate solution to yellow end point.

C·2.3 Calculation

Mass of hydrochloric acid in gil

Mass of sulphuric acid in gil ....

A X B X 36'52'5~ - -

A X B X 492'5

where

A = volume in ml of the standard sodium carbonate solutionrequired, and

B = normality of the standard sodium carbonate solution.

·Specification for water for general laboratory use ( Sleo"d rms;Dr/ ).

20

IS r 2629 • 1M5

C.:J. DETERMINATION OF IRON CONTENT OF THE PICKUNGSOLUTION

0-3.1 Measure density of the pickling solution with a hydrometer, then onthe corresponding nomograph ( SII Fig. 2 and 3 ) depending on the acidused for pickling, join with a transparent ruler the point representing thisreading shown on the left hand line with the point on the right hand linerepresenting the acid content ofthe pickle. Read off the iron content onthe middle line.

SUL PHUHI(IRON COliTENT ACID CONTHl1

gIl gIl1 a110

2S100

90 SO80

7')70

60 100

SO125

40

30 150

20

100

sp - gr

"30

"lW

~60:;-::r-1.=i'n~-----;-;'ll:n----_--":~

loS

S5

30 ·'·IS

35

40 1·20

OENSll v

50 1·25

25

20 144\40- G Bc

\S

\0 \·OS

5

o ,,00

FlO. 2 NOMOGRAPH RltLATINO THE IRON CONTENT OF SULPHURICActo PICkLE TO THE ACID CONTENT AND DENSITY

21

IS I 2629 • 1985

DE NSIT y

°T W sp - gr

3') -

30

2'i

IRON CONTENTgil

150

- 100

- 50

o

HYDROCHLORICACID CONTENT

9f.f.a

50

100

150

200

250

10 1·05300

o 1·00

FlO. 3 NO\fOORAPH RELATINO THE IRON CONTENT OF HYDROCHLORIO

ACID PICKLE TO THE ACID CONTENT AND DENSITY

22

BUREAU OF INDIAN STANDARDS

HeadquartersManak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002Telephones 3230131,3233375,3239402Fax 91 11 3234062,91 11 3239399, 91 11 3239382

3237617

3378662

603843

2352315

8329295

Telegrams Manaksanstha(Common to all Offices)

Telephone

8-77 00 32

Central Laboratory

Plot No 20/9, Site IV, Sahlbabad Industnal Area, Sahibabad 201010

Regional Offices:

Central Manak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002

·Eastern 1/14 CIT Scheme VII M, V I P Road, Mantktola, CALCUTTA 700054

Northern SCO 335-336, Sector 34-A, CHANDIGARH 160022

Southern CIT Campus, IV Cross Road, CHENNAI6001 13

tWestern Manakalaya, E9, Behind Marol Telephone Exchange, Andhen (East),MUMBAI 400093

Branch Offices::

Pushpak', Nurmohamed Shaikh Marg Khanpur, AHMEDABAD 380001

tPeenya Industnal Area, t et Stage Bangalore-Tumkur Road,BAN GALORE 560058

Gangotn Complex, 5th Floor, Bhadbhada Road, T T Nagar, BHOPAL 462003

Plot No 62-63, Unit VI, Ganga Nagar, BHUBANESHWAR 751001

Kalalkathlr BUIldings, 670 Avmash: Road, C01MBATORE 641037

Plot No 43, Sector 16 A, Mathura Road, FARIDABAD 121001

Savitn Complex, 116 G T Road, GHAZIABAD 201001

53/5 Ward No 29, R G Barua Road, 5th By-lane, GUWAHATI781003

5-8·56C, L N Gupta Marg, Nampally Slatlon Road, HYDERABAD 500001

E·52, Chuararqen Marg, C-Scheme, JAIPUR 302001

117/418 B, Sarvodaya Nagar, KANPUR 208005

Seth Bhawan, 2nd Floor, Behind Leela Cinema, Naval Klshore Road,LUCKNOW 226001

NIT BUilding, Second Floor, Gokulpat Market, NAGPUR 440010

Pathputra Industrial Estate, PATNA 800013

Institution of Engmeers (India) Building 1332 Shrvap Nagar, PUNE 411005

TC No ~4/1421, UnlversltyP 0 Palayam, THIRUVANANTHAPURAM 695034

5501348

8394955

554021

403627

21 01 41

8-288801

8-71 1996

5411 37

201083

372925

216876

238923

5251 71

262305

323635

621 17

·Sales Office is at 5 Chownnghee Approach, P 0 Pnncep Street,CALCU A 700072

tSales Offt IS at Novelty Chambers, Grant Road, MUMBAI 400007

tSales Offic IS at 'F' Block, Unity BUilding, NarashlmaraJa Square,BANGAL RE 560002

271085

3096528

2223971

.Printed at Dee Kay Pnnters. New Deihl, India