G48 Test Temperature

[JMac2]

After many attempts we have finally been able to qualify our super duplex welding procedure with the G48 Method A at 40 degrees C. As part of our welder qualification process we are also requiring each welder to pass a G48 test. This has proved to be a bit problematic in that we have had several welder qualification fail the G48 even though they are welding inside the parameters of the weld procedure. This is a multiple pass manual weld (.375" wall). Our acceptance criteria is <4.0 g/m2 with no pitting on the test faces. We are considering changeing the test temperature to 35 degrees but we need to justify making this change to our specification. Any information that can help quantify the difference in testing temperatures (35 vs 40 degrees) would be appreciated.

 

[EdStainless]

My first thought is to move to Method C, it is a little more aggressive but also more repeatable.
Are you actually trying to test pitting resistance or are you looking for intermetallics? What is your sample prep?
If you are looking for intermetallics then the surfaces need to all be ground with no pickling or passivation.
For pitting the samples should be exactly like they are going into service.

At 40C you are already well below the raw material values (prob 65C or higher).
Maybe 35C with a slightly lower rejection level? We can identify pitting in samples with 2mg/cm2 weight loss.

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Plymouth Tube

 

[SJones]

Why are you imposing corrosion testing on your welders? It is the welding procedure specification that drives the corrosion performance. If you are getting failures from welds made within the procedure, does it not tend to suggest that the procedure is suspect?!!

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[metengr]

Agree with SJones.

 

[EdStainless]

If some welders have passed and others haven't then yes, you have a procedure issue for sure.

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Plymouth Tube

 

[HEC]

The process is the issue if some welders are passing and others are not. What specifically is the material, and where are the failures occuring? Is it pitting, in weld material, in parent or HAZ? Good quality background informatin gets best answers!


Mark Hutton