Dear All, Can any body tell me about the requirement of PWHT for a hydrogen line service weld joint with socket weld configeration. What code governs that. Thanks and Regards, Mumtaz

PWHT is mandatory for all weld joints in hydrogen service whether they are butt welds or socket welds. You may see API 582 for reference and guidelines on the same. It states that code exemption for PWHT of P.No. 4 & 5 materials is not permitted for applications in sour or hydrogen service or when the nominal chromium content of the material exceeds 1.25 %. PWHT specifications (heating rate. holding temperature range, holding time, cooling rate) and allowable maximum hardness vary as per material. Hope this would help. Regards, Ashfaq Anwer thepetrostreet.com >Dear All, > >Can any body tell me about the requirement of PWHT for a >hydrogen line service weld joint with socket weld >configeration. What code governs that. > >Thanks and Regards, > >Mumtaz

Mumtaz Considering hydrogen service, in this case, adopt PWHT immaterial of hardness at socket weld is lower than 200 BHN. Hardness accuracy may vary by + or - 10% in socket weld measurement due to configuration as pointed out by Raghuram. Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India April 21, 2010 E-mail: nishi@vsnl.com > >PWHT generally requested when hardness exceeds 200BHN. >however Some clent specs states PWHT for socket welds is >mandatory irrespective of hradness values, becuase accurate >hardness mesaurement is not possible on socketwelds due to >its configuration. > >Raghuram Bathula