Baking custom 455 after pickle 4

[FWMengineering]

Is it really necessary to bake custom 455 at 300/350F after a acid pickle in HF and nitric?
If it is needed what is the reasoning behind it?

 

[RPstress]

Suggest you red flag this one and re-post in the Metal and Metallurgy forum. (Unless someone sufficiently knowledgable posts.)

I think the bake is to remove hydrogen introduced during the pickling op, which can otherwise lead to hydrogen embrittlement. High strength stainless like Custom 455 is a bit vulnerable to that sort of contamination. However, those guys (metal and metallurgy) will know for sure.

 

[WKTaylor]

Refer to AMS2759/9D Hydrogen Embrittlement Relief (Baking) of Steel Part, Table 1 TABLE 1 - MINIMUM BAKE SOAK TIME (HOURS) AT 375 °F (191 °C), Chemical treatments column "CHEM (3)".

For Custom 455 in temper conditions H950 and H1000, there is a mandatory 3-hr bake @375 F beginning within 4-hrs after acid etch [pickling].

Regards, Wil Taylor

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