Re: [MW:29451] Re: query about sour service

Dear Dinesh.

 

The following answers have been found in '' A Compendium of Inquiries and interpretations for NACE MR0175/ISO 15156''.

as you can see, some  of raised questions not answered and not addressed in ISO15156.

1. if a material comply with requirements of annex A and clause 8 of MR0175, is there any need to be HIC tested?or based on clause 8, if any material that meet it, purchaser would request to do HIC test from manufacture?

ANSWER:The overall aim of ISO 15156-2, Clause 8, is to ensure that materials that give satisfactory HIC performance in sour service can be selected. It is not the intention of this Clause to provide detailed information that can lead to the qualification, without testing, of HIC-resistant steels.

If, in accordance with NACE MR0175/ISO 15156:2, Clause A.2.2.2, Paragraph 3, the HIC resistance of flat-rolled plate is uncertain then the equipment user can elect to carry out HIC testing, possibly for use in an application-specific environment. Testing in accordance with Annex B.5 is proposed as a means of qualifying the material to ISO 15156-2.

Testing is not necessary if the equipment user can document that he has evaluated the risk of HIC failure of his equipment and considers the risk acceptable.

Some guidance concerning acceptable sulfur levels is given in Section 8 of NACE MR0175/ISO 15156 Part 2. For seamless products, testing can also be performed according to Table B.3 if deemed necessary.

2.Based on table A.2 from ISO15156 part3, austenitic stainless steel can withstand any chloride concentration up to 60 c.how is it possible that any clscc not happen?or maybe say when service isn't sour, this condition is true to say that material has corrosion resistance under any chloride concentration up to 60c.

ANSWER:Q1: Regarding 15156-2 Table A.2 for UNS S31600, the remarks section defines acceptance for any chloride and in situ pH. Can UNS S31600 be acceptable with a chloride content of 5000 mg/L?

A1: Table A.2 permits any level of chloride for austenitic stainless steels defined in Clause A.2 with the following restrictions: temperature shall be no higher than 60°C, the partial pressure of H2S shall be no higher than 100 kPa and no elemental sulfur. Note that the material restrictions defined in note a in Table A.2 also apply.

Q2: How do I understand these figures in Table A.2?

A2: We cannot provide consulting services. You may need to employ a consultant to help your understanding of these material and application limits.

Based on Annex A of ISO15156 part3, hardness of the weld metal shall not exceed the maximum hardness limit of the respective alloy used

for the welding consumable.now the questions arised:

3a.If we have welded a joint by two different filler metals now how hardness limit can be specified?

3b.If we selected a consumable that has either higher corrosion resistance or lower than base metal which in first case H charged to base metal and in case 2 charged to weld metal, both cases rises susceptibility of GHSC. now for both cases especially case 2, requirement of ANNEX A can be applied for them?

3c.With regarding to chemical composition of weldment differs from consumable or parent metal due to dilution, if we use from a consumable not closed to parent, how the above mentioned requirement can be explained?

ANSWER:The hardness requirements for each material shall be met for both the base metal and HAZ. The standard does not specify requirements for the fusion line hardness between two dissimilar metals with different maximum hardness requirements. Qualification by successful laboratory testing in accordance with Annex B of ISO 15156-3 is required. Qualification based on satisfactory field experience is also acceptable. Such qualification shall comply with ISO 15156-1.

The question that you ask does not have a defined answer if the consumable used does not correspond to an existing UNS or does not fit one of defined alloy classes that is in the NACE MR0175/ISO 15156 standard.

Q1: Does the as-deposited filler metal have to comply with the UNS composition of the starting electrode?

ISO15156-3 does not state anything specific about the composition of the as-deposited filler metal. It does state that dilution can affect the corrosion resistance. The purpose of an overlay has historically been for corrosion resistance and not cracking resistance. If the enquirer wishes to consider the overlay as a barrier for cracking resistance, a ballot is required to define cracking limits for a specific as deposited composition for a define location within the weld.

Q2: If the answer to Q1 is yes, then what locations within a weld must meet the UNS composition allowing for some dilution?

This issue is not addressed by this standard. See answer to Q1.

Q3: Does a 625 overlay made to the prescribed API 6A requirements for FE10 meet NACE MR0175/ISO 15156?

The standard does not define the cracking limits for as-deposited filler material beyond the UNS compositions. See answer to Q1.

Regards.

On Friday, March 15, 2019 at 6:32:05 PM UTC+3:30, Dinesh Kumar wrote:

Dear Experts,

If you could answer the below questions, it will be of much useful to the group as we deal with sour environment.

Thanks 

Dunes 

On Sun, 3 Mar 2019 at 9:55 AM, <asghar...@gmail.com> wrote:

5.Does any body have any experiences about doing of SOHIC? if yes would you share it?and with regarding that this defect rarely happen, what time or conditions a client shall considered it?  

6.If a carbon steel calded with N0825 that welded to carbon steel (API X60),with filler metal of ER NiCrMo3 now GHSC test shall be done or not? 

7.Based on table A.2 from ISO15156 part3, austenitic stainless steel can withstand any chloride concentration up to 60 c.how is it possible that any clscc not happen?or maybe say when service isn't sour, this condition is true to say that material has corrosion resistance under any chloride concentration up to 60c.

Based on Annex A of ISO15156 part3, hardness of the weld metal shall not exceed the maximum hardness limit of the respective alloy used
for the welding consumable.now the questions arised:

8a.If we have welded a joint by two different filler metals now how hardness limit can be specified?

8b.If we selected a consumable that has either higher corrosion resistance or lower than base metal which in first case H charged to base metal and in case 2 charged to weld metal, both cases rises susceptibility of GHSC. now for both cases especially case 2, requirement of ANNEX A can be applied for them?

8c.With regarding to chemical composition of weldment differs from consumable or parent metal due to dilution, if we use from a consumable not closed to parent, how the above mentioned requirement can be explained?

9.What is the role of sulfur element in SCC&SSC?

10.If two different CRAs material joined, question 8 how can be answered?

Regards.

On Tuesday, February 26, 2019 at 5:48:48 AM UTC+3:30, asghar...@gmail.com wrote:

Dear All.

 I have some questions regarding sour service, would you help me about them.

1. if a material comply with requirements of annex A and clause 8 of MR0175, is there any need to be HIC tested?or based on clause 8, if any material that meet it, purchaser would request to do HIC test from manufacture?

2.if there is a conflict between requirements of A.2.1 and A.2.2, for example there is a P-No 1, Group 2 which has a higher hardness than criteria in A.2.1 either in weld or parent metal, what decision can be taken?

3.is there any document to explain about HIC testing of forging?

4.with considering that weld metal has a cast structure why in NACE TM 284 explain about sampling of weld?

Regards

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