IGC Testing requirement in SS410S.

[Ronak_Patel]

We are using SS410S CLAD in Coke Drum at 450 degree temp.

Is IGC test required for SS410S material ?

How IGC is different in ferritic SS than in Austenitic SS ?

 

[EdStainless]

Do your requirements call for this testing?
Using what specification?
When looking for issues around IGC you are not looking for Cr carbides in the grain boundaries.
You are looking for Cr depletion adjacent to the carbides.
This is tough to do in 410 because the alloy has such low corrosion resistance to start with.

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P.E. Metallurgy, consulting work welcomed

 

[MagBen]

can still occur, IGC by sensitization in martensitic is much less likely than in austenitic stainless. There are standards testing, astm A262 for austenite, A763 for ferrite. i am not aware if any for martensite.

Martensitic SS tempered at intermediate temperature (500-600c) has the highest potential to get IGC. you can still use oxalic acid for a quick easy check but might hardly ask for a standard specification.

 

[EdStainless]

410S should be closer to ferritic than martensitic, the C is so low.
If this is weld overlay then the question is how much C is picked up from weld dilution?

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P.E. Metallurgy, consulting work welcomed

 

[btrueblood]

Would the alloy not pick up significant carbon from being a coke oven wall?

 

[weldstan]

I've never seeen it required for this service.

 

[Ronak_Patel]

Thank you all for your responses !!

@EdStainless , at present there is no requirement of IGC testing for SS410S in coke drum cladding in my organisation but why is what i'm trying to understand.

As per my understanding, IGC happens in ferritic SS as well if they are exposed to high temp(450 in my case) in operation , welding or PWHT. So why SS410S is not tested for IGC as per A763 ?

As you correctly mentioned , "You are looking for Cr depletion adjacent to the carbides." As SS410S has less corrosion resistance to starts with , will this not cause more problems in operation with services like coke which contains good amount of sulfur ?