Dear Experts
Codes - AWS D1.1 & ASME SECTION IX
Is it allowed grinding after hot pass/fill/ capping passes?
Reason for grinding - spatter, incomplete side wall fusion, inter-run undercut
If yes or no , pls guide to the relvant section of the codes
Thanks
The only welding code I know of that prohibits grinding or the use of hand tools to improve the weld profile is AWS D1.5 Bridge Welding Code.
I feel it is good practice to develop the performance testing protocol in writing so there are no surprises once the welder begins the test. I review the test rules with the welder so he is aware of the restrictions or limitations before testing has begun. It is fair to the welder and to the contractor and it minimizes the opportunity for the test witness (me) to interject his personal views once the test is underway.
As for the third party inspector or the client's representative getting in on the act, it isn't his prerogative to interject their personal opinions on the subject unless it is relative to a requirement listed in the applicable welding standard or project specifications. Acting as the TPI, I once witnessed a fellow evaluating bend test samples that had some small cracks on the convex surface. After some effort spent with a grinder the cracks disappeared and the "inspector" pronounced the welder "certified to AWS D1.1." As polite as I could be after witnessing the "test," I informed the "inspector" the bend tests failed when the cracks were noted. "But they weren't that deep!" was his response.
When I give a welder qualification test, I limit the grinding permitted on a structural plate test to cleaning the groove and adjacent base metal before fit-up. I do not allow any grinding on the test piece once the test has started. On a pipe test however, grinding is permitted. Grinding of the tack welds is encouraged, if there is incomplete joint penetration in the root bead, I allow a portion (30%) of the root to be removed and rewelded to correct the joint penetration. That isn't a blank check to grind every weld bead. At some point the inspector has to make a judgment call that the welder is not skilled enough to pass the test. The last thing the contractor needs on the production floor or job-site is a welder that spends 75% of his time grinding out bad welds. After all, the performance test is intended to determine if the welder has the skills needed to deposit a sound weld, not to determine if he knows how to handle a grinder.
If the welder performance testing is per AWS D1.1 or ASME Section IX, the extent of grinding allowed or the use of a power brush to remove slag is left to the discretion of the contractor. Both D1.1 and ASME Section IX are silent on the subject. It is usually in the contractor's best interest to ensure the welder has reasonable skills and doesn't have to grind every weld bead before depositing the next weld bead. Grinding is expensive and often times counterproductive. I cannot recount how many times I've seen welders ruin a perfectly good weld by "touching it up" with a grinder.
Best regards - Al