D1.6 WPQ Fillet - Code Incorrect?

[MaterialWorld]

I am attempting to qualify some welders to AWS D1.6 on a prequalified procedure of stainless steel to mild steel. It appears that the requirements for this test are not laid out anywhere, and the figure that the text points to is for fillet PQRs and not fillet WPQs. Does anyone know or see something I am missing that would describe exactly what tests and how many are required for a fillet welder qual in AWS D1.6?

-> Table 4.3 Performance Qual - Thickness Limits and Test Specimens - Groove Welds are covered, but no mention of fillet weld test specimen requirements

-> Section 4.10 Performance Qual - Types, Purposes, and Acceptance Criteria of Tests and Examinations for Welders and Welding Operators
- 4.10.4 Macroetch - specifies that fillet welds shall be macroetched for performance qualification, but does not specify how many need to be done, or from where to take them.
- 4.10.5 Fillet Weld Break Test - specifies that a 6in long section (per Fig 4.5) shall be tested as a fillet break

-> Fig 4.5 (as referenced in 4.10.5) is a figure for a PQR Fillet Weld Specimens (not WPQ). It does not show a 6in long fillet break with a start/stop. Instead it shows 3 macros, and the material fillet welded on both sides of the vertical member. It is impossible to do a fillet break test when both sides are welded.

WPQs are a regular part of my business (e.g. D1.1, ASME IX, etc), so I know how this type of testing should work, but D1.6 appears to have a serious lack of information. And unfortunately, my client went ahead and welded up specimens per Figure 4.5 (welded both sides) before they contacted us about testing. I need to know if the fillet break is actually required (as the text appears to indicate) or if only macros are actually required, per the figure.

Anyone have any guidance or experience?

 

[gtaw]

I never consider a weld between dissimilar metals to be prequalified per AWS D1.1 or D1.6.

AWS D1.6-2007, read clause 3.0 Scope. Prequalification extends only to base metals considered to be nominally austenitic stainless steels. Also read clause 1.2.3(1).

While joints between dissimilar ferrous metals is permitted, they do not necessarily meet the conditions of prequalification.

Best regards - Al

 

[MaterialWorld]

Great point, and one I had not considered, thank you.

I will bring this to the clients attention, and honestly, it may solve the issue, because we can treat the plates like a PQR, do the 3 required macroetches per Figure 4.5, and the welder who welded the PQR plate will automatically be qualified, per 4.7.4.

Any input or thoughts on fillet welder quals to D1.6 for procedures that are prequalified?

This is not the first time this issue has come up for us. We usually simply follow D1.1, but it would be great to have a better solution in the future.

 

[gtaw]

As the engineer, I would hesitate to accept a fillet weld procedure for dissimilar metals, in this case carbon steel to austenitic stainless steel, based on a couple of macros removed from a T-joint.

AWS D1.1 is applicable to carbon and low alloy steels. D1.6 is intended for welding high alloy steels, i.e., stainless steels. In either case, the combination of dissimilar base metal families are not addressed.

There are too many unknowns when welding combinations between two very different alloy groups. The mechanical properties are not verified by performing macros on the cross section of the fillet weld. There are a number of things that can happen in the HAZ and the weld that will not be detected by the macroetched samples. Examples of the potential problems that are not detected by the macroetch include the pressence of too much or too little ferrite, the presence of Sigma phase, or brittle martensite as a result of the carbon admixing with the chrome, etc.

There is no better means of qualifying the procedure than going with the full blown plate test that includes guided bend tests as well as the reduced section tensile tests to determine if the procedure will actually produce acceptable mechanical properties.

Best regards - Al

 

[Duwe6]

Real world: P-1 to P-8 is simple, safe, and easy if you remember "309".

AWS world: This will require a procedure; PQR and WPS, qualified to B2.1. The D1 specs do not cover dissimilar metal groups, as per gtaw.

 

[MaterialWorld]

Thank you for your input gtaw, these are items I had not considered, and I believe you are completely correct.

Thank you for the suggestion Duwe6, B2.1 is a great suggestion for dissimilar weld qualification guidance.

So without getting further distracted by this particular instance with dissimilar base metals, is there anyone who has experience or input on the question of testing for fillet welder quals under AWS D1.6? For instance, in the future, when we receive this type of qualification test that is stainless to stainless and therefore does fall under the code, does anyone have any guidance or suggestions on how to interpret what type and how many tests are required under the code?

Thank you all for your time and consideration.