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NACE MR0175 Welding Requirement for P1

NACE MR0175 Welding Requirement for P1

NACE MR0175 Welding Requirement for P1

(OP)
Dear All,
I appologize if this topic has been covered, I could not find anything specific in the forum.
We have a project that requires ASME B31.3 piping and welding in accordance to NACE MR0175. The materials are all ASME XI P1 material group(SA106 Gr. B Pipe, SA105 Flanges, and SA234 WPB buttweld fittings)
In section 5.3.1.1 it states that "pressure vessel steels classsified as P-No. 1, Category 1 or 2, in the ASME Boiler and Pressure Vessel Code Section IX, meet the requirements of Paragraph 5.3.1 in the as-welded condition."
Sections 5.3.1.2 and 5.3.1.3 go on to explain that "control of welding variables" or a "PWHT" may be specified to achieve the required hardness.
Originally I had specified a PWHT on the piping in liu of "control of welding variables". The client, wanting to expidite the delivery, has commented that a PWHT should not be required since we are using all P1 materials. They even forwarded a copy of thier WPS and PQR, wich does have a hardness test but does not specify further restrictions such as carbon equivalent or heat input.
The question is,if I test the hardness of my PQR and control the base metal chemistry by restricting the material to P1 and other welding variables by controlling pre-heat and max interpass temperature does this alone meet the requirements of NACE MR0175? If true the client wins, shorter delivery and we win, less expense.
Another approach(mandatory to MR0103?) would be to calculate the C.E. of the PQR, hardness test, then ensure that the C.E. of every item welded is less than the C.E. on the approved PQR. Unfortunately, this would be nearly impossible since many of the items are already purchased. Any thought on the interpretation of this requirement?

Thanks in advance,
Patrick

RE: NACE MR0175 Welding Requirement for P1

The required CE is somehow very generously specified in the code;- however, if you exceed the CE on the material certificate, it is quite likely you won't make the required hardness in as welded condition. Also, you cannot mix and match the applicable MACE standard, one is for upstream applications and the other for refinery and the like applications. If not working strictly on an upstream project, you should only concentrate on complying with NACE MR0103, which is significantly less onerous than MR0175. I subscribe to that any P1 normally has a much lower CE than the maximum specified in the standard, hence the as welded condition could easily comply with the hardness requirement.
Cheers,
gr2vessels

RE: NACE MR0175 Welding Requirement for P1

What version and part of MR0175 are you looking at?

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

RE: NACE MR0175 Welding Requirement for P1

(OP)
I was working with MR0175-2003, I didn't realize there was a MR0175/ISO15156. Does one imply the other? I couldn't find a requirement for C.E. in either of them, just specific hardness, manufacturing, and chemical requirements. My understanding is that if my PQR is P1 with a hardness test, and all my materials either say NACE or meet the requirements then I do not have to PWHT. However, I could not rely upon the material marking alone and not PWHT.

RE: NACE MR0175 Welding Requirement for P1

You might wish to look at the 2009 version to confirm, but generally, a hardness tested PQR may be considered as compliant by a number of end users, but not by some others.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

RE: NACE MR0175 Welding Requirement for P1

I'm not sure how MR0175 is less onerous than MR0103. MR0103 mandates compliance with SP0472 which is much more onerous than MR0175.

RE: NACE MR0175 Welding Requirement for P1

Who said MR0175 is less onerous than MR0103?

RE: NACE MR0175 Welding Requirement for P1

Sorry,
Meant to ask how MR0103 is less onerous than MR0175. Sp0472 is much more strict on wps qualification and material selection for production use.

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