Arc Welding 101: Qualified or not?
Q: I'm working with a company whose welders are certified on A36 plate with 0.045 solid wire. They have taken the test in a vertical-down progression using GMAW in globular transfer mode. They took it on 1-in. plate, single V-groove with backing. The company they want to do work for wants them qualified to do flat and horizontal fillet joints, but says they are not qualified because they welded their test plates in the vertical-down position.
A: Who’s right? My first reaction is that the customer is right, but we're inspectors, so we’ll dig a little deeper than that. For the sake of this question, I’m going to assume the qualification we’re discussing is AWS D1.1.
The welders should have been tested to a qualified weld procedure specification (WPS). They could not have taken the test using a prequalified procedure because it would have required them to weld in a vertical-up progression (see AWS D1.1-2010, Clause/Sub-section 3.7.1). The company you are working with must have on file a procedure qualification record (PQR) for welding groove welds in the vertical position with a downward progression.
I often audit small fabrication shops for compliance to AWS codes and standards. Welding to a prequalified WPS that does not fit within the guidelines of Clause 3 is something I come across all too frequently. The three factors that typically aren’t within those guidelines are:
1. Welding on materials not found in Table 3.1.
2. Welding vertically in a downward progression.
3. Failing to stay within the preheat/interpass requirements of Table 3.2.
Long story short, if the company has written weld procedures for the flat and horizontal positions and has qualified the vertical-down progression, then welders tested 3G down to a qualified procedure would be considered qualified (within the restrictions of Table 4.10).
It has been my experience that it's pretty tough to qualify a multipass procedure 3G down. That’s not to say it can't be done; I've just struggled with it.
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