weld groove dimensions?

By Rory Jones Date 08-28-2002 06:03

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?

By Michael Sherman (***)

Date 08-28-2002 11:22

Mr. Jones, a groove that is too large will require more weld metal, it can affect the HAZ area and size, it will cost more in labor and material. A groove weld that is too small will not allow access for proper welding techniques to be applied. I am certain there are other things but at the moment I cannot think of them.

Respectfully,
Mike Sherman
Shermans Welding

By GRoberts (***)

Date 08-28-2002 15:02

Mike,

Please correct me if I am wrong, but in using pre-qualified joint dimensions from AWS D1.1, is he not already going above and beyond the code by doing additional testing that is not stipulated for changes between prequalified joint geometries?

Thanks,
G Roberts

By Michael Sherman (***)

Date 08-28-2002 19:52

Mr. Roberts I have retracted my offensive statement and will keep that type of opinion to myself. I realize that what I consider lenient may well be above and beyond what is necessary for others, thank you for pointing this out to me and have a nice day.

Respectfully,
Mike Sherman
Shermans Welding

By GRoberts (***)

Date 08-29-2002 14:57

I did not find your post offinsive, I was just a little surprised when I read it. I applaud you for going above and beyond the code as an ordinary practice of yours, I am just surprised that there are customers willing to pay for it anymore. Faster, cheaper, or I'll get it from Taiwan seems to be what customers want. Hope you have a nice day also

G Roberts

By pipewelder_1999 (****)

Date 08-28-2002 11:40

A decrease in groove angle can also result in a joint configuration with a high depth to width ratio. Depending on the configuration, base metal, joint restraint, and process, these can be more prone to cracking/tearing in the weld metal at the centerline.

Have a nice day

Gerald Austin
Iuka, Miss.

By GRoberts (***)

Date 08-28-2002 15:05

Gerald,

I agree with your premise, but am curious if you have ever run into this problem with AWS prequlified joints? If a procedure is qualified, and thus already proven to avoid centerline cracking for the joint geometry used, do you think that switching to a different prequalified joint geometry could lead to centerline cracking. (It is a given that changing to the wrong non-prequalified joint geometry could easily produce this defect)

Thanks,

G Roberts

By pipewelder_1999 (****)

Date 08-28-2002 16:15

I have never seen this in prequalified joint designs.

I had understood the text of "or any partial joint penetration groove weld" to mean any joint and not only prequalified joints.

It still reads that way to me but I've been job hunting all AM so my brain could be going :)

Have a nice day

Gerald

By GRoberts (***)

Date 08-28-2002 14:59

Rory,
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.