In the US, typical structural steel welding is covered by either AWS D1.1 or AWS D1.5 (bridges). Both of these codes cover a wide range of carbon steels.

AWS has a separate code for welding stainless steels, AWS D1.6. There is some mention of welding to carbon steels, but this is mostly talking about choosing the filler metal and not the testing.

Neither D1.1 nor D1.5 cover stainless steel.

In this specific situation, I am looking at a fillet weld between a carbon steel plate and a stainless steel plate.

What is the procedure for qualifying (PQR and WPS) a weld between the two materials? Does one code control over the other? Would the weld have to be qualified per both specifications?


1 Answer 1


According to this slideshow it looks like a weld between stainless and carbon or low-alloy steels would be within the scope of D1.6 entirely. It would not be prequalified so it would have to be qualified by testing. Table 4.2 (reproduced in the slide show) covers the test types if you want to qualify with a CJP, but you would need a full copy of D1.6 to see the acceptance criteria and specific geometry for each test. If the fillet weld is all you need to cover, you could use table 4.4 and qualify with a fillet weld only (again, geometry is going to have to come from the full code.)

For what it's worth, this is a relatively young standard, and the third edition is expected out this year, so there's potential for some change.

  • $\begingroup$ I think ASME might have some procedures for welding stainless to carbon steel (the Boiler and Pressure Vessel code comes to mind, since I think this happens fairly frequently for pressure vessels). $\endgroup$
    – grfrazee
    Aug 5, 2015 at 15:26
  • $\begingroup$ ASME would not apply for structural work, correct? Only for pressure vessels? $\endgroup$
    – Ethan48
    Aug 5, 2015 at 21:25
  • 1
    $\begingroup$ Technically true. I've seen it used in US nuclear plants for structural components of reactor refuel canals, but that's a pretty specific case. $\endgroup$
    – grfrazee
    Aug 5, 2015 at 21:27

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