solution re-annealing 17-4ph 4

[engamopar]

We have 17-4ph PARTS (originally made from soution annealed (AMS 5643) stock) that were supposed to recieve "HEAT TREAT TO H1075 (31-38 RC) FOR 4HRS-4:15MIN". In actuality, they accidentally received "HEAT TREAT TO H900 (40-47)" The result was "ACTUAL RC= 46.4". Can we just re-heat these parts as they should have been heat treated originally, or is it imperative that we first re-solution anneal and then [re-]heat treat them?
Thanks

 

[redpicker]

You should be able to just give them the H1075 treatment. This should produce the required 31-38 HRC hardness. If anything, you could expect slightly better properties since they will contain less retained austenite (although the effect would be minimal).

rp

 

[EdStainless]

I would not age them at 1075, but rather 1050. If you overshoot and go too soft you will have to anneal and start over.
And if they are still too hard you can go up slightly in temp and do it again.

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Plymouth Tube

 

[metalonis]

redpicker is 100% correct. Re-annealing is not necessary. In my opinion a competent heat-treater will process to the required temperature so go ahead with H1075.