First off let me say that I am VERY new to welding so please forgive my ignorance.
In general, do welders always need to qualify to a given procedure?
For instance, my company has two welders who are qualified to MIL-STD-278 to weld Groups S-1 (Carbon steels), S-8 (austenitic stainless steels), S-22 (aluminum), and S-1 to S-8) thickness .058"-.562". I know that 278 is a old canceled spec, but we still have it in contracts all the time.
We have recently gotten a contract that specifies AWS D17.1 Class C welds.
Reading through the AWS spec, I see that for class C welds, the written proceedure does NOT need to be qualified (4.4.2). We already have a written procedure (written for MIL-SSTD-278) in place that easily covers the perameters of the weld, but what about our welders? Since this is a Class C weld, does that mean that they do not need to to have qualification to AWS D 17.1? Or do the welders need qualification even though, the procedure does not?
A WPS is nothing more than a written instruction for the welder so he or she knows what has to be done. It makes sense that the welder should be given proper instructions regarding the welding process, filler metal, joint detail, etc., for the test he or she is about to take. It eliminates or minimizes the chance there will be miscommunication between the welder and the individual requesting and administering the test.
I am sure there are people out there giving tests with nothing more than a few soap stone marks on the work bench or the back of an envelope, but it is prudent to formalize the process so there is no questions after the test as to what, why, and how things were done.
Al
Hey Notso, welcome to the Forum!
I think you are in the right direction as far as procedure qualifications... As long as your engineering authority and customer/contract have no issue with you applying a similar procedure qualification.
D17.1
"4.4.5 Use of Existing Qualification. Alternatively, and in lieu of 4.4.2, an existing qualified
welding procedure may be accepted as equivalent to the requirement of this specification at the
sole discretion of the Engineering Authority."
As far as welder performance qualification goes. I don't see much wiggle room for crossing from a different code into D17 <with the possible exception of B2.1>
I don't see the weld "class" being a factor in welder performance qualifications. Surprisingly there isn't even any roll-over language for welder performance qualification to MIL-STD-1592 or MIL-STD-2219 which are the two prime aerospace specification that were superseeded by D17.
Unless I'm missing something in the text, your welders need to be qualified to D17 in order to do production work... And in order to do that you will need to qualify WPS/procedures. Even if you are only doing class "C" welds in production. 4.3.8.1 inferrs that *All* welding performance testing will be done to inspection criteria for Class "A" welds, and class "A" welds require a procedure that is qualified by testing.
"4.2.2 Qualification Requirements. To achieve qualified status, welders and welding
operators shall demonstrate their skill by producing acceptable test welds per the requirements of
Paragraph 4.3.8. Test welds should not be required for those welds that will not be required in
production welding. Qualifications, certifications, requalifications, and recertifications given
under this document do not transfer from one fabricator to another."
In my opinion you may be better off in the long run to go ahead and do the PQR's and qualify your personnel... In this way you will have the ability to contract later for all classes of D17. I think this Meta-narrative is more foreward looking. But also more costly.
Is it possible that the PQR's for your other MIL-Spec work in the past satisfy all the essencial variables for D17? That is a decision for your top engineering authority and well beyond the scope of what I could even guess about.
By notso
Date 02-25-2011 21:39
Thanks Lawrence, That's how I read it too. Although an interesting twist is that our company could also be interpreted as the "engineering authority" since we designed the whole system.
In general, do welders always need to qualify to a given procedure?
Per D17.1:2001 para 4.3.7
..."test welds shall be made in accordance with a written welding procedure"
So along those lines, are the limits of welder qualification pretty much always the same as the limits of a procedure qualification? Or are there situations where the welders qualification could be larger than the limits of the procedure that they used to qualify?
In the situation I mentioned above, would there be a way that our welder could have say qualified for GTAW in Stainless .083-.500, and therefor they are D17.1 qualified but then perform a class C weld in carbon using our "unqualified procedure"?
If not, what's the point of the note that says class C procedures do not need qualification? By default wouldn't the procedure be qualified when the welder qualified to it?
There is always a difference between procedure and welder performance qualifications.
To answer your question... If your welder is D17 qualified on stainless, they are not qualified on any other alloy... D17 has a list of base metal groupings.. Look for that to see how many alloys are contained in each group.
The weld classes are separated by inspection criteria, based on criticality for *fabrication* not for welder performance...
All welders must be class A qualified... to make a class A weld you need qualified procedures.
D17 fabricators must make a big investment in a quality program.. No way around it.
