Is there any important information one must know when working with structural steel and moment connections? A fab shop that mainly deals with welding beams with mostly 1G welds and very few 2G. If moment welds are being completed with plate to beam flange applications with backing, is there any pertinent info a person must be familiar with. I ask this as it relates to welder qualification and WPS's and inspection.
I always believed in testing the welders in the positions required for production. A little time spent with the contractor beforehand to find out exactly what is needed to fulfill their production needs is worth the time and effort. If all the welding is done on the flat position, there is no need to qualify in the 2G position.
The first paragraph of Clause 4 Part C states that the welder qualification tests described in Clause 4 are specifically designed for the purpose of assessing the welder's skills and they are not intended to replicate production joints (paraphrased). The test assemblies to be used for welder qualification are defined in Clause 4. There is no reference in Clause 4 Part C (that I can recollect) allowing the welders to be tested with a groove detail depicted in Figures 3.3 or 3.4. The specific joint details to be used for performance qualification are depicted in the various figures included in clause 4.
I routinely reject welder qualification tests reports that reference a prequalified detail; fillet, groove, or otherwise. My reasoning is simple, consider the fillet test using the T-joint. The appropriate figure in Clause 4 shows the T-joint with no root opening. There are no tolerances for the root opening. It is intended to be tight to assess the welder's ability to achieve complete fusion to the root. Were the qualifier to allow the welder to apply the tolerances for a fillet weld to the test assembly, the test would not accurately assess the welder's skill, i.e., the ability to achieve fusion to the root. The same holds true when qualifying the welder for grooves. The figures in Clause 4 show the root opening of the groove as 1/4 inch. One of the goals of the performance test is to assess the welder's ability to thoroughly fuse the plates and the backing with the root bead. Allowing the welder to apply the tolerances of a prequalified groove to the root opening does not assess welders ability to properly achieve fusion in the root under the conditions expected. Allowing the welder to increase the root opening to the maximum permitted by a prequalified joint detail may well enable the welder to pass the qualification test, but it does little to assess the welder's skill and ability to manipulate the arc in more difficult root conditions.
It is my contention that if the code committee wanted the employer to use a prequalified joint, any prequalified joint, they would have simply referenced Clause 3 and a joint detail that was appropriate. That isn't the case. Instead, Clause 4 references specific figures found in Clause 4. The intent seems to be pretty clear to me . The code committee does not want the tolerances of a prequalified joint to be applied to performance testing.
The goal of the qualifier should not be to pass as many welders as possible, it should be to accurately assess the welders' skill to ensure they have the minimum skills needed to produce sound production welds. Welder qualification is a method used by the employer to cull those welders that do not have the required skills from the herd.
The qualifier's job is to ensure the welder that takes the test is the person listed by the welder performance test report, to ensure the welder works within the constraints of the WPS, to ensure the welder welds the test assembly in the proper test position and so on. Both Brent's and Lawrence's advice is spot on.
But, hey, that's just my opinion on the matter. My opinion and a couple of dollars will get you a small cup of coffee at most coffee shops.
Best regards - Al