I am struggling with the difinition of a concave weld and what is acceptable. Can you have a SAW weld with a reinforcement height not in excess of 1/8 inch and have the center of the weld dip down as long as it doesn't go below the base metal? I am using AWS D1.1 2004 and looking at Figure 5.4 which lists underfill but no mention of concavity in a butt weld. Under 5.26.1.2 Repairs it has Excessive concavity which leads me to believe that some concavity is acceptable.
Are you talking about a multi-pass weld? You could have the conditions you describe and still be acceptable. If it is a multi-pass weld, then you would need to evaluate the convexity of individual beads, as well as the overall weld. Also, review the criteria in 5.24.4 where a smooth transition is mentioned.
Chet, Single pass SAW that the operators are trying to comply with a European standard that limits the crown height to width ratio of 10%. In doing so the welds are 20mm wide and 2mm high and some of them are slightly concave, approximately .25-.5mm in the center of the weld. So there is a smooth transition and only slightly concave.
So then it sounds like if you were to grind the surface flush, there would be no concavity or "low spot". (You first post explaine that too) Unless I'm missing something, I don't see that you have a problem.
If I understood your post, I would say that as long as you met the min. throat dimn as required, concavity is not a problem.
Forum
