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Stabilize annealing 347H Stainless steel

Stabilize annealing 347H Stainless steel

Stabilize annealing 347H Stainless steel

After welding 347H pipe, we performed stabilizing annealing at 900°C for 4 hours followed by rapid cool with forced air.
Our client wants us to perform a hardness test but I do not think it is necessary because the stabilizing annealing is performed to improved the corrosion resistance and not for reducing the hardness. Design code is B31.3.
Please advise if a hardness testing is necessary? Many thanks.

RE: Stabilize annealing 347H Stainless steel


I saw that in ASME B31.3-2014 edition they took out the table with the requirements for the hardness test, so you don't have any reference. (maybe in the client specifications you can find something).

Do you have any supplementary requirements, such as NACE?

RE: Stabilize annealing 347H Stainless steel

Hardness testing is unnecessary and would yield no meaningful results regarding stabilization heat treatment.

RE: Stabilize annealing 347H Stainless steel

Thanks for the responses.
No, there is no NACE requirement. The requirement for hardness test comes from client's specification which vaguely says that hardness testing shall be conducted following the completion of all PWHT.

RE: Stabilize annealing 347H Stainless steel

If the client has not specified a minimum or maximum hardness, perform the test to provide the client information as that is all that it provides. While the test is metallurgically irrelavent, there is no harm in doing it to satisfy the contract.

RE: Stabilize annealing 347H Stainless steel

Client specifies 248 HV max.

RE: Stabilize annealing 347H Stainless steel

In this case you have to do it. (it's the client request). Make sure if the hardness is HV5 or HV10. Once i had a dispute about it, so maybe it will be helpful for you.

I suppose you can try also with a TQ, if you don't wanna do it.

RE: Stabilize annealing 347H Stainless steel

Thanks everybody for all the help.

RE: Stabilize annealing 347H Stainless steel

It sounds like the client has conflated carbon steels and stainless steels. HAZ hardness is an issue for carbon steel, but rarely for SS.
Perhaps another case of "a little knowledge is a dangerous thing".

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

RE: Stabilize annealing 347H Stainless steel

Hi JXWu,
Stabilizing Anneal is generally recommended to mitigate the effects of Polythinic Acid SCC(PTASCC) in refining environments. Susceptibility to PASCC can be determined by laboratory IGC corrosion testing according to ASTM A262 Practice C or Practice E. Many Oil and Gas refiners (Example Aramco) ask for this requirements(Ptractice C) in their operating specifications (SABP-A-001.)

NACE SP170-2012, elaborates on chemistry control , and operating practices, not on testing methods to detect the susceptibility of cracking (as above).

FYI ASTM A312, calls for IGC Practice E under supplementary clauses.
In your case the could be a supplementary requirement( which could be clarified by client only). However the emphasis should been on the IGC testing methods as above.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
All provided answer are personal opinions or personal judgements only. It's not connected with any employers by any means.

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