Is There Any Such Thing as a Chromium Depletion Test? 1

[tc7]

I just found this fabulous SS Forum and have browsed around but could not find an answer to my issue mentioned below. If this is more correctly placed in one of the Code Forums, please advise:

We have a couple of weld procedures on 304L and 316L that we apply to AWS, Mil & on rare occasion to ASME projects. I have made the suggestion that if we ever hope to provide welding (GTAW & SMAW) on other 300 and 400 series alloys, we should develop new WPS's because our limited experience with 304L and 316L, which seems to be almost immune to carbide precipitation concerns, may require other post weld heat treatments. While my argument held some attention with the management for about a minute, I was told to answer what qualification tests required by Code or specification would provide proof that we can weld satisfactorily and deliver weldments that will not be vulnerable to intergranular corrosion.

Having gone through AWS D1.6, Mil-Std-278, ASME Sect IX and B31.3, I can't find mention of any test (any required test) that will show that a new procedure is capable of producing sound welds, free of chrome-carbides. I suppose some WPS's are application dependent and customers may dictate some kind of corrosion test.

But to my specific question: What Code required tests will address the potential carbide precipitation concern? Will this be revealed during a tension test, bend test or an impact test?

Thankyou.

 

[EdStainless]

ASTM A262 are the tests applied to detect sensitization in austenitic stainless grades.
Normally you start with a micro, and if the structure looks clean you are fine. If there is question then you proceed to one of the corrosion tests. Which test depends on the alloy. These are listed in the specification.

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[tc7]

Thanks for that reference Ed. It is interesting that this ASTM A262, paragraph 30, Bend Test refers back to ASME Sect IX but I cannot find a linkage from the parent specification (ASME Sect IX) to the need for this sensitization test. When would I be compelled to conduct these tests by Code?

What about 400 series stainless? are these not susceptible?

Thankyou.

 

[EdStainless]

ASTM A262 is part of a materials specification, it would need to be specified when material is purchased. There is no reason not to use this as part of a weld qualification, but this isn't what it was written for.

There is an electrochemical method also for 304/304L called G108. It gives you quantified results, but it requires special equipment.

The ferritic grades use the analogous A763.

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Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[tc7]

Got the A763! thanks for that also.