15-7 CH900 vs RH 950 for retainer rings

[kevlar49]

I would like to specify retainer rings per MS 16625-4250. The material we typically call out is 15-7 PH. I have spoken to one manufacturer and found that they produce it to RH 950. This has a "C" rating for SCC in MAPTIS (NASA database). I'd prefer to use CH900 which has an "A" rating for SCC in MAPTIS, but I don't know if it is commonly made. Does anyone have a feel for how readily available the CH900 is or if anyone actually makes it?

 

[EdStainless]

First, I am not sure that I would trust those ratings. Think about it, why would the higher strength material have a superior SCC resistance?
Secondly in order to CH material you need over 30% cold work after the final anneal. So the ring would need to be cold formed into the final size. No welding or annealing. That could be a tough order.

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Plymouth Tube

 

[kevlar49]

As opposed to getting the "C" condition from the stamping process. Could you buy it in the "C" condition? Would you say that forming it in the "C" condition would be possible or impractical? If you form in the "C" condition, then you can apply an H900 couldn't you?