What are the prevalent imperfections that are leading to rejection?  Could it be to do with the fact that every weld now has to be subjected to NDT, compared with say a small percentage in A106, and you are finding the 'true colours' of your welders?

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/

Welding of high yield pipe generally requires pre-heat which is not normally used for welding Grade B.

So are you pre-heating the welds?  Usually it is to 250 F.

the contract calls for 100%RT.THE WELDERS HAVE A 0% REJECT RATE ON A106B PIPE USING THE SMAW PROCESS.ONCE WE STARTED WELDING THE X60 PIPE OUR REJECT RATE STARTED TO GO UP.REJECTS HAVE BASED ON INTERNAL UNDERCUT,I.P. AND L.O.F.

YES WE HAVE TRIED PREHEATING WITH A ROSEBUD AND WITH COILS
AT 250 F.WITH NO SUCCESS

THE WELDERS INVOLVED HAVE HAD AN OUTSTANDING RT TRACK RECORD ON PREVIOUS JOBS,BUT NONE INVOLVED X60 MATERIAL

Which code are you welding to?

Also, did the welders qualify on a procedure using X60 pipe?  Base material is an essential variable in API 1104 and qualifying using Grade B doesn't necessarily qualify them on X60.

ODEM

we are welding to API 1104,19th edition.base metal may be an essential variable in API 1104 for welding procedure qualification,but base metal is not listed as an essential variable for welder qualification in paragraph 6.2.2.

the welders were qualified on A106GR B by radiography as allowed in paragraph 6.6

While they may be technically "qualified" but it appears that they are having some problems with the higher strength material.  There are subtle and not so subtle differences when welding high yeild pipe.  Most of the procedures I've reviewed the past couple of years use 5p+ (6010) bead and hot pass and 70+ (8010-G) fill and cap.  The 70+ works well on the high yeild pipe.

  

thanks for the info on using 5p+ on root and hot pass.
greatly appreciated
kukes1954

Evidence to support the use of actual pipeline materials for welder qualification as required by a lot of owners.  That way, the problems occur and are resolved before the job gets underway.  A bit more training time on X60 wouldn't go amiss for the lads either.

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdo/

thanks for everyones input.the problem has been resolved.
we performed analysis on the material which showed lamination.
we also had 3 independent level III review the film and all 3 accepted what the rt level II rejected.

thanks again