mr 0175 inquiries and responses

7/24/2019 Mr 0175 Inquiries and Responses

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NACE Standard MR0175, Metals for Sulfide Stress Cracking and StressCorrosion Cracking Resistance in Sour Oilfield Environments, was revised andreorganized over a seven-year period, resulting in the publication of the 2003edition in February 2003.

Because the changes were extensive, the Maintenance Panel formed to maintainthis widely used standard, which will soon be combined with ISO 15156 (based onMR0175), has received many questions regarding the requirements and revisions.

Following are the inquiries and responses provided thus far by the MaintenancePanel. Users of MR0175 who have questions are encouraged to review these todetermine whether your question may have been answered. Numbers aremissing from the sequence because not all inquiries have been answered; thisinformation will be updated periodically as more replies are formulated by theMaintenance Panel.

These responses represent a consensus of the members of the MaintenancePanel and should not be construed to reflect the opinions of NACE International,its officers, directors, or members.


2/25

MP INQUIRY #2003-02

QUESTION #1:Do Paragraphs 9.2 and 9.5 both apply to choke valves? Additionally, choke valves arealso used in applications where they are not directly mounted on the Christmas tree

(i.e., manifolds, heaters, separators, etc.); can we still consider the choke valve to fallunder Paragraph 9.2 for these applications?

ANSWER #1:Please see attached ISO 15156 Table A.1, which will provide the interpretation of NACEMR0175 Paragraphs 9.2, 9.3, and 9.5. NACE will be adopting ISO 15156 in 2003 as atechnically equivalent document.

QUESTION #2:If both Paragraphs 9.2 and 9.5 are applicable, as we believe they are, can we selectwhich paragraph we follow when they cover the same component or materials? Does

Paragraph 9.4 apply to choke valves?

ANSWER #2:Choke non-pressure-containing parts made of alloy UNS S17400 have noenvironmental restrictions in accordance with Paragraph 9.5.2, while there is a limit of0.5 psi H2S for pressure-containing parts in Paragraph 9.2.4.1.


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MP INQUIRY #2003-04

QUESTION #1:Paragraph 4.2Austenitic Steels (say 316SS). One of the acceptance limits for thesematerials is a maximum H2S partial pressure of 15 psia at a maximum of 140F when

no chlorides are present. Can I assume that I can still use a material from this categoryat a higher temperature than 140F if the partial pressure of H2S is lower than 15 psia?

ANSWER #1:Please see attached ISO 15156 Table A.2, which is the correct interpretation of NACEMR0175 Paragraph 4.2.2. With the exception of Alloy UNS S20910, the temperaturelimit of the austenitic stainless steels is 140F maximum for any H2S level within thescope of the document.

QUESTION #2:Paragraph 9.2Wellheads and Christmas trees. Does this paragraph include the valve

bodies that are on the Christmas trees as well as other valve bodies exposed to H2S?In other words, which paragraph in Section 9 refers to the valve body?

ANSWER #2:See attached ISO 15156 Table A.1, which will provide the interpretation of NACEMR0175 Paragraph 9.3. NACE will be adopting ISO 15156 in 2003 as a technicallyequivalent document. Please see ISO 15156 Part 1 for guidance as to how to use fieldexperience or laboratory data to qualify a material for H2S service.


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MP INQUIRY #2003-07

QUESTION:WIKA believes that Alloy 400, UNS N04400, should be included in both the latest

version of MR0175 and the imminent ISO 15156 standard. As outlined in the forewordof MR0175-2003, Many of the guidelines and specific requirements in this standard arebased on field experience with the materials listed. . .

We propose that Alloy 400, UNS N04400, be added to Section 8, Special Components,Paragraph 8.4.2, Diaphragms, Pressure-Measuring Devices, and Pressure Seals.

ANSWER:

NACE will adopt in 2003 the ISO 15156 document as being technicallyequivalent to MR0175. At this time there will be only a joint document, NACEMR0175/ISO 15156. The NACE MR0175 2003 edition will cease to exist.

NACE is soliciting ballot items for inclusion into a 2004 addendum to the jointdocument. Attached is the ballot format, which you may use to submit inclusionof the gauge alloys. The ballot proposal should include laboratory data and/ordocumented field experience. Please see ISO 15156 Part 1 for guidance. Youmay choose to use such field experience to support a paragraph similar toParagraph 10.7.2 or 10.7.3 in NACE Standard MR0175-2003.

Please let us know how we may be of assistance.


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MP INQUIRY #2003-08

QUESTION:In the past we have used 300 series SS pipes and valves in sour service. We are notsure of the implications and use of SS in sour service according to NACE StandardMR0175-2003. Could you please advise whether 300 series SS (304/316, etc.) can beused at lower H2S partial pressures for temperatures above 60C (140F)?

ANSWER:No, the maximum temperature for use of the austenitic stainless steels, as defined inNACE Standard MR0175 Paragraph 4.2, is 60C (140F).

Please see ISO 15156 Part 1 for guidance as to how to use field experience orlaboratory data to qualify a material for H2S service.


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MP INQUIRY #2003-09

QUESTION #1:In what paragraph are the requirements for wrought bar in nickel-copper alloy (i.e., UNS

N04400 and N04405)? In the 2002 version, these materials were covered in Paragraph4.1.1.

ANSWER #1:These alloys, UNS N04400 and N04405, are no longer in the standard except inParagraphs 10.6.2.2 and 10.7.3.

QUESTION #2:In the 2002 version of MR0175, the maximum hardness requirement for duplex UNSS32550 was covered in Paragraph 3.9.1. This same material is now covered inParagraph 4.9 of the 2003 version of this standard, but the hardness requirement

seems to be missing. Has the hardness requirement been dropped for this material, oris the hardness assumed to be acceptable as long as the material has been solutionannealed and liquid quenched?

ANSWER #2:This is correct. There is no hardness requirement for the duplex stainless steelscovered in Paragraph 4.9.1.

The Maintenance Panel will discuss at our upcoming meeting before Eurocorr 2003 theinclusion of a possible ballot for inclusion of N04400 and N04405 into ISO 15156 Part 3using the same words as in Paragraph 4.1.1 of NACE Standard MR0175, 2002 edition.You may wish to propose your own ballot item for these alloys.


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MP INQUIRY #2003-10

QUESTION #1:We manufacture a fluid-handling product machined from UNS N04400 and N04405 inthe cold-worked condition with a hardness less than 35 HRC. We have certified thatthis product meets MR0175 based on Paragraph 4.1.1.1 of MR0175-2002.a) May we continue to certify that this product meets MR0175-2003, since this materialis mentioned in Paragraph 10.6.2.2?b) Is it acceptable to continue to certify meeting MR0175-2002?

ANSWER #1:The MP cannot provide interpretations involving the certification of equipment. We canonly interpret the current edition of MR0175. Paragraph 10.6.2.2 states that UNSN04400 and N04405 may be used for gas lift equipment.

QUESTION #2:We manufacture a fluid-handling product machined from UNS N06600 in the cold-worked condition with a hardness less than 35 HRC. We have certified that this productmeets MR0175 based on Paragraph 4.1.4.1 of MR0175-2002.a) It appears this material is not included in MR0275-2003. Is it acceptable to certifythat this material meets MR0175-2003 based on the listing in previous versions?b) If not, is it acceptable to continue to certify meeting MR0175-2002?

ANSWER #2:The MP cannot provide interpretations involving the certification of equipment. We canonly interpret the current edition of MR0175.


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MP INQUIRY #2003-11

QUESTION:According to NACE Standard MR0175-2003, 625 material, as a solid-solution nickel-based alloy, is acceptable only in the solution-annealed condition. This constitutes amajor change with respect to previous editions, in which 625 material was accepted upto 35 HRC regardless of the delivery condition.

The annealed condition is considered the most suitable condition by most of ourcustomers and we are not aware of problems or failures with material 625 used in thiscondition for NACE applications. Unless a real problem exists in using annealed 625,we would like to understand whether:

The definition of solution annealing given in NACE Standard MR0175-2003 has tobe interpreted to exclude 625 material in the annealed condition; or

For 625 material, annealing performed in a given temperature range (to be suitablydefined, even more narrow than the range from 1,600 to 1,900F) can be considered asolution-annealing heat treatment as defined in Section 2.

ANSWER:Tables A.12, A.13, and A.14 in ISO 15156 provide answers to your requests forinterpretations.

NACE will be adopting ISO 15156 in 2003 as a technically equivalent document.

The nickel-based alloys may be used in the annealed or solution-annealed conditionwithin the requirements of these ISO tables.

Please also refer to the definition of solution-annealed in Section 2 of NACE StandardMR0175. This definition does not prescribe the temperature for the solution-annealingheat treatment.


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MP INQUIRY #2003-12

QUESTION #1:

Paragraph 1.10.2 states, The user may replace materials in kind for existing wellsor for new wells within a given field if the design basis for the equipment has notchanged.

Does this statement include valves or valve components that are used within wells?

ANSWER #1:Yes, this paragraph does apply to valves and valve components used within the wells.

QUESTION #2:Definition of pressure-containing parts on page 7. Those parts whose failure tofunction as intended would result in a release of retained fluid to the atmosphere.Examples are valve bodies, bonnets, and stems.

Are stems always defined as pressure-containing parts, regardless of features that bydesign keep the stem intact?Example #1: Internal entry stems for ball valves that have a shoulder that rests againstthe body around the stem bore.Example #2: Shafts for butterfly valves that have a retaining ring holding the shaftinside the valve.

ANSWER #2:NACE Standard MR0175 cannot interpret design issues. The Maintenance Panel mayonly refer you to the definition of pressure-containing parts in Section 2 and the use ofthis definition with restrictions in Section 9.

QUESTION #3:Paragraph 4.3.1 for UNS S20910 allows this material to be used in sulfur-freeenvironments when the maximum H2S partial pressure is 15 psia to 150F in theannealed or hot-rolled (hot/cold-worked) condition at 35 HRC maximum hardness.

Paragraph 9.4.1 for UNS S20910 allows this material to be used for valve shafts, stems,and pins at a maximum hardness level of 35 HRC in the cold-worked condition,provided this cold working is preceded by a solution-anneal heat treatment.

Does this mean that I can use UNS S20910 for valve stems in the cold-workedcondition (preceded by a solution-anneal heat treatment) at 35 HRC max with noenvironmental restrictions?

ANSWER #3:There are no environmental restrictions for UNS S20910 permitted at the higherhardness of 35 HRC in Paragraph 9.4.1 for the applications defined in Paragraph 9.4.


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Please see the attached Table A.3 from ISO 15156, which provides the correctinterpretation of this paragraph. NACE will be adopting ISO 15156 in 2003 as atechnically equivalent document.

QUESTION #4:

Paragraphs 9.2.4.1 and 9.5.2. Why is it that UNS S17400 can be used for pressure-containing wellhead and Christmas tree components (Paragraph 9.2.4.1) but not forpressure-containing valve components (Paragraph 9.5.2)?

ANSWER #4:Paragraph 9.5.2 allows UNS S17400 to be used with no environmental restrictions.Therefore, the alloy is not allowed for pressure-containing components in valves. Incomparison, Paragraph 9.2.4 has environmental restrictions and will therefore allow theuse of S17400 for parts other than bodies and bonnets.


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MP INQUIRY #2003-16

QUESTION:Paragraph 1.5.1 of NACE Standard MR0175-2003 states that SCC may be controlledby any or all of three measures: (1) using the materials and processes described in this

standard; (2) controlling the environment; or (3) isolating the components from the sourenvironment.

My client has an application in which Inconel 625 weld metal is overlay welded onto amartensitic steel component. The martensitic steel component base material and heat-affected zones are isolated from the fluids by the Inconel 625; all wetted surfaces areInconel 625.

My clients customer believes the base material must be stress relieved in accordancewith Paragraph 5.2.1, which states: Overlays applied to carbon and low-alloy steel orto martensitic stainless steels by thermal processes such as welding, silver brazing, or

spray metallizing systems are acceptable for use in sour environments, provided thesubstrate does not exceed the lower critical temperature during application. In thosecases in which the lower critical temperature is exceeded, the component must be heattreated or thermally stress relieved in accordance with procedures that have beenshown to return the base metal to the base metal hardness as specified in thisstandard.

We believe that Paragraph 5.2.1 does not apply since the base metal is isolated fromthe sour environment with Inconel 625, which is acceptable to 35 HRC.

ANSWER:The base material must be stress relieved in accordance with the requirements ofParagraphs 5.2 and 5.3 of NACE Standard MR0175.


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MP INQUIRY #2003-17

QUESTION:We need clarification of Paragraph 4.8.2Low-Carbon Martensitic Stainless Steels. In

the 2002 edition this was Paragraph 3.7.2.1. The 2002 edition allowed wrought materialmeeting the chemistry requirements of ASTM A 487 CA6NM. The 2003 edition appearsnot to allow these F6NM wrought materials (UNS S41500), just S42400, which is notthe same thing. Please advise whether this material is acceptable.

ANSWER:Wrought F6NM (UNS S41500) is included in Paragraph 4.8.2. UNS S41500 mustconform to all of the restrictions in Paragraphs 4.8 and 4.8.2.1.

The MP will discuss an editorial revision to ISO 15156 Part 3 to clarify this.


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MP INQUIRY #2003-18

QUESTION:Paragraphs 4.2 and 4.2.1 refer to all CRAs being used in contact with well fluids but donot necessarily include instrument or control tubing (Bourdon tubes) being used inpressure indicators as listed in Paragraph 8.4.4.1. Currently this means that 316stainless steel alloys (L, Ti, etc.) containing those elements are not ruled out from theirbeing used in gauges where the well fluid wetted parts are not exposed to fluids that donot exceed:4.2.2 The maximum acceptable H2S partial pressure shall be 100 kPa abs (15 psia) at amaximum temperature of 60C (140F), with no restrictions on chlorides, and noelemental sulfur.If the chloride content is less than 50 mg/L, the H2S partial pressure shall be less than150 kPa abs (50 psia).Each application is subject to the specific environmental conditions to the equipmentsupplier, particularly if the equipment will be used in sour service.

Under the above stated conditions, do gauges that are made with 316 SS alloy steelscomply with NACE Standard MR0175-2003?

ANSWER:You have correctly cited Paragraph 4.2 of MR0175 for the general use of austeniticstainless steels. It is the manufacturer's responsibility to determine whether the 316 SSmeets the metallurgical requirements of this paragraph, including the requirement thatthe alloy will be "free of cold work . . . "

--There is no exclusion for Type 316 stainless steel from the metallurgical or theenvironmental requirements of Paragraph 4.2 in Paragraph 8.4.2 of MR0175-2003.

--NACE will adopt in 2003 the ISO 15156 document as being technically equivalent toMR0175. At this time there will be only a joint standard, NACE MR0175/ISO 15156.The NACE MR0175 2003 edition will cease to exist.

--NACE is soliciting ballot items for inclusion into a 2004 addendum to the jointdocument. Attached is the ballot format that you may use to submit inclusion of yourchosen gauge alloys. The ballot proposal should include laboratory data and/ordocumented field experience. Please see ISO 15156 Part 1 for guidance. You maychoose to use such field experience to support a paragraph similar to Paragraph 10.7.2or 10.7.3 in MR0175-2003.


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MP INQUIRY #2003-19

QUESTION #1a:NACE Standard MR0175-2003 has two different highly alloyed austenitic SS families,one (Paragraph 4.4) with Ni% + 2 Mo% >30 (and Mo>=2%) and one (Paragraph 4.5)

with PREN >40. Both have two different ranges for temperature, partial H2S partialpressure, and maximum chloride content. Which environmental limits have to be usedfor materials applicable for both categories like UNS S31254?

ANSWER #1a:If UNS S31254 has a PREN >40, then the less restrictive environmental limits inParagraph 4.5 apply.

QUESTION #1b:In Paragraph 1.8.3.3.1 it is mentioned that interpolation between H2S levels andtemperature is acceptable. When applying this to Table 3 (as an example) what will bethe maximum partial H

2S pressure at 140C, where an interpolation is required between

2.8 MPa and unlimited? Does this mean that below 149C there is no limit to themaximum partial H2S pressure?

ANSWER #1b:ISO 15156, Clause 5, states: "Qualification, with respect to a particular mode of failure,for use in defined service conditions, also qualifies a material for use under otherservice conditions that are equal to or less severe in all respects than the conditions forwhich qualification was carried out." In this case, for the precipitation-hardenable nickel-based alloys addressed in Table 3, this automatically qualifies the material for use attemperatures below 149C and below 2.8 MPa H2S partial pressure. Qualification of amaterial for application under specific conditions that are more severe than those listedin ISO 15156/NACE MR0175 is allowed. Qualification on the basis of laboratory testingor field experience is required to comply with the (ISO) standard. The equipment user isresponsible for ensuring a material is properly qualified.

QUESTION #2:What is the foundation for limiting forged and cast UNS S31803 (Paragraph 4.9.3) to amaximum partial H2S pressure and temperature while the hot isostatic pressure-produced equivalent (Paragraph 4.9.4) is only limited to maximum hardness?

ANSWER #2:Paragraph 4.9.4 should have been 4.9.3.1, having the same environmental limits asParagraph 4.9.3, and this error has been corrected in an interpretation and in TableA2.4 of ISO 15156. Paragraph 4.9.4 was intended to provide metallurgicalrequirements only for the HIP alloy.


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MP INQUIRY #2003-20

QUESTION #1:Paragraph 4.4 in MR0175 identifies "Highly Alloyed Austenitic Stainless Steels with Ni%+ Mo>30 and 2% Mo minimum" as a category. Is it intended by the standard writers

that the two conditions be both present? In other words, is it Ni% + Mo>30 with 2% Mominimum? Or is the 2% Mo minimum another defined material group in the category? Ibelieve it to be the former as I am not aware of highly alloyed austenitic stainless steelsonly defined by the term "2% Mo minimum."

ANSWER #1:Paragraph 4.4 in NACE Standard MR0175 is a single alloy category defined by theadditive requirements of Ni% + Mo% >30 and 2% Mo. Both requirements for chemistrymust be met.

QUESTION #2:

Paragraph 11.4 of the standard, which is titled "Compressors and Pumps," appears tonot address many significant applications for pumps. None of the material classesaddressed in Paragraphs 11.4.2, 11.4.3, 11.4.4, 11.4.5, 11.4.6, or 11.4.7 speak toapplications in pumps in sour service. Is this intentional? It would appear that thelimitations applied to compressors would be also applicable to pumps.

ANSWER #2:It is intentional that the paragraphs you have cited apply only to compressors. TheParagraphs 11.4.2 and 11.4.3 come from the previous 2002 edition. The otherparagraphs were added as a result of the balloting process for the 2003 edition.


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MP INQUIRY #2003-21

QUESTION:Because UNS C72900 and C96900 are copper alloys, are they, by definition, coveredby Section 4 of NACE Standard MR0175, which basically states copper alloys are

suitable for use without restriction other than as noted in the footnote, which informs theuser that such materials may exhibit accelerated general weight-loss corrosion in somesour environments?

ANSWER:The UNS C72900 and UNS C96900 copper alloys are included in NACE StandardMR0175 Paragraph 4.20.


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MP INQUIRY #2003-22

QUESTION #1:Are the bolting materials and nuts specified in Paragraphs 6.2.1.2 and 6.2.1.3,respectively, the only acceptable materials in compliance with MR0175-2003 for

Exposed Bolting?

ANSWER #1:Bolting materials may be chosen in accordance with Sections 3 and 4 as described inMR0175-2003, Paragraph 6.2.1.1.

QUESTION #2:Does Paragraph 6.2.1.1 allow other nuts and bolting materials besides the ones listed inParagraphs 6.2.1.2 and 6.2.1.3?

ANSWER #2:

Yes, in accordance with NACE Standard MR0175-2003 Sections 3 and 4.

QUESTION #3:Are the following ASTM bolting materials and nuts acceptable for exposed bolting inaccordance with Paragraph 6.2 of MR0175-2003? (ASTM A 193, carbide solutiontreated, GR B8R, B8RA, B8, B8M; A 194, carbide solution treated, Gr 8R, 8RA; A 320,carbide solution treated, Gr B8, B8M)

ANSWER #3:The manufacturer is responsible for the effects of carbide solution treatment on thematerial properties.


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MP INQUIRY #2003-23

QUESTION #1:Paragraph 4.2.2 is new. Would you let us know which interpretation applies?

1. Paragraph 4.2.2 is intended to place a limit on acceptable H2S content under the

conditions stated, i.e., when temperature does not exceed 60C, when no elementalsulfur is present, but without restriction on chlorides.

2. Paragraph 4.2.2 places a maximum temperature limit of 60C on the use of austeniticstainless steel under any conditions in which MR0175 applies, for example, at 0.1 psiaH2S partial pressure with no chlorides present.

ANSWER #1:Please see the attached Table A.2 from the draft of ISO 15156 Part 3, which provides aclear interpretation of NACE Standard MR0175-2003 Paragraph 4.2.2 for the use ofaustenitic stainless steels in sour service.

QUESTION #2:In addition, please clarify the reason for the 60C limit in Paragraph 4.2.2:

We have noted that a limit of 60C is commonly cited with respect to chloride stresscorrosion for austenitic SST in other publications, and that chloride is mentioned inParagraph 4.2.2. Are we correct in assuming, therefore, that the 60C limit inParagraph 4.2.2 is based on chloride stress corrosion concerns above 60C whenchloride concentrations above 50 mg/L are present rather than H2S corrosion concerns?That is, the first sentence of Paragraph 4.2.2 does not have a limit on chlorides but doeshave a temperature limit, whereas the second sentence limits chlorides but does nothave a temperature limit.

ANSWER #2:Paragraph 4.2.2 limits austenitic stainless steels (as defined in Paragraph 4.2.1) to 60Cmaximum when used in hydrogen sulfide (H2S)-bearing hydrocarbon service. It allowsa maximum H2S partial pressure of 100 kPa abs (15 psia) with no restrictions onchlorides; or 350 kPa abs (50 psia) maximum H2S partial pressure if chlorides are lessthan 50 mg/L. In either case, there must be no elemental sulfur and the maximumtemperature is restricted to 60C (140F).

The phrase in the sentence in Paragraph 4.2.2 with no restrictions on chlorides means

that any chloride concentration from nil to several thousand ppm chlorides (for example)are acceptable up to 100 kPa H2S partial pressure up to a maximum temperature of140F.

See Paragraph 1.1 in NACE Standard MR0175-2003 for the scope of MR0175. Theenvironmental restrictions in Paragraph 4.2.2 were established to provide resistance tosulfide stress cracking (SSC) and/or stress corrosion cracking (SCC) in austeniticstainless steels.


19/25

MP INQUIRY #2003-24

QUESTION #1:In reference to Table D2, Acceptable Specifications for Tubular Goods, in the leftcolumn titled For All Temperatures, why is Pipea separate category from Tubing andCasing? In the API 5CT specification (see Paragraph 1.1), as well as the NACEMR0175-2003 standard, casing is identical to pipe (see Sections 10 and 2, TubularComponents).

ANSWER #1:Casing and tubing are generally but not always intended for the completion of oil andgas wells. These materials are referred to and specified in API Spec. 5CT.

Pipe may have many intended uses and is referred to and specified in API Spec. 5L andother industry standards.

QUESTION #2:

MR0175 is obviously written for guidance in meeting the H2S corrosion problem. Wheredoes NACE address chloride corrosion cracking, particularly in pipe and tube materials?We are seeing more and more customer specs calling for special materials. What is theNACE opinion on best pipe/tube materials for defeating chloride corrosion cracking?

ANSWER #2:Please refer to Section 1 of NACE Standard MR0175-2003 and also to ISO 15156 Part1 for the scope of the documents for which cracking mechanisms are considered in H2S

service.


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MP INQUIRY #2003-25

QUESTION:Paragraph 4.11 of NACE Standard MR0175-2003 does not stipulate a minimum cobaltcontent. Do solid-solution nickel-based alloy wrought materials complying with either of

the two chemical composition alternatives detailed in Paragraph 4.11.1, but with zeropercent cobalt, qualify for no environmental limits with respect to partial pressures ofH2S in accordance with Paragraph 4.11.2?

ANSWER:There are no environmental limits with respect to partial pressures of H2S or elementalsulfur as stated in NACE Standard MR0175-2003 Paragraph 4.11.2 for solid-solutionnickel-based alloys defined as a category in Paragraph 4.11. There is no individualrequirement for the minimum content of Co alone in Paragraph 4.11. Chemistryrequirements for Co are expressed only for the sum of nickel and cobalt.


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MP INQUIRY #2003-26

QUESTION #1:What are the reasons for the exclusion of nickel-copper alloys, e.g., UNS N04400, fromthe materials listed in Section 4?

ANSWER #1:The wrought nickel-copper alloys were removed from the general section of NACEStandard MR0175 because of concerns from field failures of UNS N05500. It wasexpected that as a result of ballots over the 6-plus years of drafts that the 2003 editionof MR0175 would include the reinsertion of UNS alloys N04400 and UNS N04405 intothe appropriate equipment sections. This has not been the case. There has not been asingle ballot for including these alloys. However, the ISO Maintenance Panel hasagreed to put forward for ballot to the ISO Oversight Committee and ISO WG 7 aproposal to include these two alloys into the Instrumentation and Control DevicesParagraph 8.4. If the ballot passes, the alloys will be included in a 2004 addendum to

ISO 15156/NACE MR0175-2004 in the table currently numbered A.16.

QUESTION #2:With reference to Paragraph 1.10.2: Equipment manufactured with UNS N04400 andoperating before the issuing of the last MR0175 edition may be replaced today withequipment manufactured with the same material, if the equipment design andenvironmental conditions have not been changed? If a conformity declaration toMR0175 is required for the new equipment, which edition must be declared (2003 orprevious)?

QUESTION #3:For new wells and/or petroleum plants designed according to MR0175 before its lastedition, but manufactured after the last edition was issued, may materials considered bythe design but not listed in the new standard edition be used?

If a conformity declaration to MR0175 is required for the equipment of the newwell/plant, which edition must be declared (2003 or previous)?

QUESTION #4:May materials not listed in the last edition of MR0175, that have successfully passedtest requirements of TM0177 and/or have demonstrated adequacy for serviceperformances, have your declaration of conformity and be certified by the manufacturer"in conformity with NACE MR0175-2003"?

ANSWERS #2, 3, 4:NACE and ISO support the latest editions of their documents. We cannot comment onconformity declarations. Please see ISO 15156 for requirements to document materialsperformance outside the current limits. This documentation may be through laboratorydata or from field experience.


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QUESTION #5:Is a NACE office available in Italy or in other European countries?

ANSWER #5:All inquiries should be transmitted to the ISO Maintenance Panel through Linda

Goldberg at NACE Headquarters in Houston, Texas. The Maintenance Panel hasinternational membership. A membership roster is attached.


23/25

MP INQUIRY #2003-27

QUESTION #1:Paragraph 9.2.4.1 Pressure Containing Components--What is the definition of bonnets?What about drain plugs?

ANSWER #1:Unfortunately, as you have noted, there are no NACE definitions for the terms you havelisted. Therefore, they are open to your interpretation.

QUESTION #2:Old (2002) Paragraph 4.1.5.1 UNS N06625 HRC >35New (2003) Paragraph 4.11 and A13: N06625 solution-annealed only: Technical

justification?

ANSWER #2:

The consensus during the balloting process for the 2003 edition was that no hardnesslimit was required for solution-annealed material. Alloy manufacturers did not object tothe change.

QUESTION #3:Zeron 100: Old (2002): Paragraph 3.9.6/3.9.7: pH2S


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The austenitic stainless steels were restricted because of industry and lab failures.Please see the attached documentation. Upon the final ballot, there was a singlenegative that was not withdrawn. This negative suggested making the restrictions on316 SS even more restrictive. However, upon review of the data, the ISO MaintenancePanel will propose a ballot for the 2004 addendum to ISO 15156/NACE MR0175 that

will not restrict the temperature limit for material in low-chloride service of 50 mg/L orless. If this ballot passes, it will be introduced as an amendment to the standard.


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MP INQUIRY #2003-29

QUESTION:NACE Standard MR0175-96, Section 4, includes Paragraph 4.1.1 titled Nickel-CopperAlloys specifically listing UNS N04400 (K-Monel), UNS N04405, and N05500. These

CRA metals have been omitted from MR0175-2003 except for brief mention underSection 10 for specific equipment not related to our business. We are a manufacturer ofprocess gauges, some of which are for use in sour gas environments. These metals(especially N04400) have always been used in our (and other manufacturers') gaugesfor pressure-containing parts having direct exposure to sour gas. Have these materialsbeen omitted for a reason or are they still acceptable?

ANSWER:The wrought nickel-copper alloys were removed from the general section of NACEMR0175 because of concerns from field failures of UNS N05500. It was expected thatballots over the 6-plus years of drafts would result in the 2003 edition of MR0175

including the reinsertion of UNS N04400 and UNS N04405 into the appropriateequipment sections. This has not been the case. There has not been a single ballot forincluding these alloys. However, the ISO Maintenance Panel has agreed to put forwardfor ballot to the ISO Oversight Committee and ISO/TC 67/WG 7 a proposal to includethese two alloys into Paragraph 8.4, Instrumentation and Control Devices. If the ballotpasses, the alloys will be included in a 2004 addendum to ISO 15156/NACE MR0175-2004 in the table currently numbered A.16.

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