Welding API 5L X60 AGAINST A 694 F65

By eduardocwi Date 05-27-2009 14:42

Guys
I will weld those materials and the flange is suplied in a Quenched and tempered condition, do I need to qualify a welding procedure with a stress relief PWHT? The code I am using is DNV OS F 101 Ed 2000 amend 2005.
Thank you.

By Fredspoppy (**)

Date 05-27-2009 17:45

Eduardo,
This is a pretty common material combination in the Offshore Oil & Gas industry. Normally PWHT would only be required to meet maximum hardness requirements for sour service. If PWHT is required, another problem pops up and that is the resultant lowering of strength of the X60. PWHT temperatures required for the A694, F65 could likely turn the API 5L X60 into X50.

When using this material combination, a preheat of 350-400F, or somewhat higher, and a fairly high maximum interpass of 600-650F will provide acceptable as-welded hardness in the A694 HAZ.

DNV-OS-F101, App. C, Para G400 provides guidance for PWHT, when it is required.

By eduardocwi Date 05-28-2009 17:57

Fred
thank you for your quick response, that was helpful.