X65 welded to X52/X42 duel grade pipe

[dman25]

We want to weld a X-65 cap to a X42/X52 duel grade pipe. I know according to API 1104 that when welding materials of two seperate material groups that the WPS for for the higher strength material is to be used.

My issue/question: Is procedure for X-65 allowable for the X42/X52 duel grade pipe. I'm thrown off by the X-42 since that would mean three different material groups. I have only dealt with going a group up or down but not jumping from group a to c.

Any guidance???

 

[SJones]

Use the designated grade of material, either X52 or X42, that was employed in the pipeline design and that should resolve your number of groups quandary.

Steve Jones
Materials & Corrosion Engineer

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

 

[dman25]

The designated material is X-42. So are there any issues with going from X-42 to X-65? It seems like too big of a jump.

 

[metengr]

No.

 

[stanweld]

dman25
There can be a problem if pipeline is in sour service and X42 was selected and purchased with appropriate chemistry and mechanical property limitations.

 

[Welder4956]

The X42 is going to require a heavier wall thickness than the X65. So a transition piece will need to be made from X65 of the same wall thickness as the X42 that is counterbored at the other end to match the X65. Preheat temperature and welding electrode should be based on the X65. Other than that, there should be no welding issues.