weld groove dimensions ?

We are a manufacturer of materials handling equipment, welding both low carbon steels and aluminum to the AWS D1.1 and D1.2 welding codes. In our quality assurance manual we have the following provision:

When a welding procedure for a complete joint penetration groove weld has been qualified by fully testing, the welding parameters may be applied to pre-qualified complete joint penetration groove welds in AWS D1.1, recommended complete joint penetration groove welds in AWS D1.2, or any partial joint penetration groove weld, and only visual inspection and three macro etch cross section specimen are required for qualification. All welding essential variables shall be within the ranges permitted by the applicable welding code, except the groove type, groove angle, root opening, and root face may be changed as needed for partial joint penetration groove welds. The weld travel speed need only be limited so as to result in a weld bead size within those permitted by the welding code.

Our assumption is once we prove our basic welding parameters in a CJP groove weld, qualified by testing, we can then apply them to a variety of groove welds and just do three macro etches to verify the weld size. Our primary question is, do changes in the groove weld dimensions have any effect on the weld’s properties other than to possibly change the effective weld size?

 

[GRoberts]

Rajones,
I think your QA system is more than adequate, as it is going above and beyond the AWS D1.1 code, since qualification of a groove weld qualifies for all AWS prequalified joint details without further testing. I'm not sure off the top of my head what is required for D1.2 though, as I don't have one currently.

However, the groove dimensions have a lot more to do with welder technique than weld metal properties. On the mild steel you are welding, you would have to change your perameters significantly in order to affect the properties of the joint with perhaps the exception of impact toughness, if that is one of your requirements. Additionally, if you are using AWS prequalified groove weld dimensions, it has already been determined by AWS that any variation in the quality of the joint will be minimal enough that it would not be worth the effort of requalification. That is why they are prequlified joints. I think the macroetch test is not unreasonable amount of extra work, while also being a good choice, as it will show any incomplete fusion, or slag inclusions that could develop due to changes in welder technique from the different joint geometry. As far as the aluminum goes, again, if you are staying within the allowable perameters of the D1.2 code, you shouldn't have a problem, as the limiting strength in aluminum welds is in the heat affected zone. Since D1.2 limits the perameters that effect the HAZ, joint geometry should have little effect. Again, I think that the macro-etch is an even better test for the aluminum, as welder technique is more critical on aluminum than mild steel.