api 5l x70 heavy wall pipe 1

[vcmkumar]

thread330-171299:

Following the above thread, appreciate if anybody could advise if API 5L X70 heavy wall (above 19 mm) pipe welds would need post weld heat treatment or what are the points to consider while welding such pipes to say items like Monolithic Insulating Joints.

 

[stanweld]

The requirements for PWHT are specified by design/construction Codes. If Code is B31.8, PWHT is required for T > 1.25" or when the material has a carbon content in excess of 0.32% or a carbon equivalent > 0.65%. I have not seen any X70 pipe with chemistry remotely approaching that criteria. For offshore pipelines (Section A825) the PWHT may be deleted regardless of thickness if a welding procedure is properly qualified to the requirements listed therein.