Intergranular corrosion test for C276 1

[Leon87]

Dear all,

We do intergranular corrosion test for C276 according to G 28A method, ASM handbook provide data of criteria for passing is 1mm/month. But I check 904l IGC criteria for passing is 0.05mm/month, and both materials are implemented in the same test method.
So, comparing C276 to 904l IGC test result, whether we can conclude that 904l have better IGC resistance than C276? If so, can you give me some theory interpretation?
If not, what's the purpose of IGC test, maybe just qualify supply conditon?
Thank you!

 

[EdStainless]

The IGA test is an artificial environment that is designed to cause accelerated corrosion of alloy depleted regions adjacent to grain boundaries containing detrimental secondary phases. Various alloys respond differently.
This is not a measure of corrosion resistance or of stability.
This test tells you weather an alloy was heat treated correctly or not, and nothing else.

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P.E. Metallurgy, Plymouth Tube

 

[Leon87]

Thanks for your reply.
Depending on yIour interpretation, IGA test is used to confirm heat treatment condition, and I agree with that.
But why IGA test result of 904l is so difference to C276?
Whether it means C276 contain more delepted region adjacent to grain boundary, if so, why?

 

[SJones]

It's different because they are different alloys that react differently to the same test solution. The corrosion rate figures are not for direct comparison.

Steve Jones
Corrosion Management Consultant

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

All answers are personal opinions only and are in no way connected with any employer.