yonderboy226
Mechanical
- Jul 9, 2012
- 4
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
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
