Aluminum WPS challenge

Date 07-11-2009 21:52

I recently became involve in qualifying aluminum extrusions WPS for a new project.
Since this company already has been fabricating similar products for several years, I thought I’d review the existing qualified WPS’s to get a heads up, this where things start to get beyond me and have me feeling uncertain. I found qualification for 3/8” plate bevel groove, this is ok so far. The product is an extrusion where the material transitions from heavy (3/8”) to thin (0.085”) and the qualification range of the WPS only allows down to 1/8”. They are welding the whole extrusion bevel-groove on the heavy and square-groove on the thin with the hot parameters as used for the heavy. The method I found being used to prevent the 1-1/8” length of 0.085” from being blown away was to place a piece of brass or bronze as TM- removable backing at the thin section.
So I thought that since there is no-way that they would be able to sustain the parameter for the entire length o the AWS D1.2 figure 4.20 -20” test coupon, that maybe I could justify the existing procedure by macro-etching a cross section of the existing 1-1/8” length. The thought behind this is to not slow down production by having to requalify new parameters for the 0.085” portion of the extrusion weldment.

Any ideas?

The new extrusion is 1/8" to 0.85", and I qualify new WPS for this.

By Mwccwi

Date 07-14-2009 02:04

Any thoughts, Anybody???

By Kix

Date 07-14-2009 12:43

If it doesn't say that you can do that in the code, then you can't do it. To be totally legal, you have to qualify a procedure exactly to D1.2's criteria.

By Mwccwi

Date 08-30-2013 23:44

I know this is an old post. Up until now the work has been to internal standard, now we have to conform to D1.2.
I need to help our engineers get this right. First how do you develop a WPS for a length less than 2" with multiple qualified thickness ranges the thinnest is 0.0 52" and up to 2"? Next how would I control that we are following the WPS, within this 2" length 3/4" is @ 0.052" then 3/8" is @ 2" then 3/4" is @ 0.080" then 1/8" is @ 1/8".
Next how do you specify welding symbols for this when you transition from through thickness square groove to PJP bevel groove to through thickness bevel groove? Note even the through thickness are called out as PJP and GTAW.

By 803056

Date 08-31-2013 02:40

Length is not an essential variable, so you qualify on a full length plate.

Al

By Mwccwi

Date 09-03-2013 16:26

I underdtand that length is not an essential variable, what I can't understand is how can we apply WPS parameters in shuch short length. The material thickness range exceeds the qualifcation range at 3 different places within the 2" length. I'm talking hundereds of amp diferences.

By Mwccwi

Date 09-03-2013 16:35

Is is acceptable to write a WPS with huge paramerter ranges if I have PQRs for each set of ranges, the welder will not be able to see his parameters while welding but will use the foot pedal and the sense of experience (Feel) to know when to push the pedal harder for the heavier sections.

By Tyrone

Date 09-04-2013 10:42

Hey Mwccwi,
I cannot comment on the code requirement.
If I were the Customer, I would want to see PQRs for each joint change (proof that you are getting good welds). You could probably get away with a single WPS with at huge range of parameters but I think a WPS for each range would help now and for future jobs. You should also have seperate weld symbols.
Tyrone

By Mwccwi

Date 09-04-2013 22:17

We have qualified each thickness range individually and have WPS for each, the idea of 3 different welding symbols within a 2 inch long weld is more difficult than one would imagine, especially on the control side

Attachment: NewPicture.png (92k)

By Tyrone

Date 09-05-2013 10:42

You're right, drawings can get messy on complex geometries.
You could give each weld a designation (ex. A1, A2 & A3), lots of section views, then blow it up on a D-size dwg. That would help QA manage each weld individually.
Tyrone