Hi guys, I am reversing engineering a stamped part. I am a plastic injection mold designer and know practically nothing about stamping. So I am looking for some suggestions on what type of steel I am looking at. It is 1/8" thick (.121" to be exact) x 1 1/4 x 1 3/4. We have (5) samples of the part and the hardness checks from Rc36 to Rc39. We did a copper sulfate test and since it reacted relatively quickly, I am ruling out any type of stainless. It's a relatively loose tolerance part and they sell pretty cheap. The top and bottom surfaces show no signs of machining.

The question is, based on it not being some stainless, stamped from sheet stock and Rc36 to Rc39, what could this be made from?

I did a quick search of the posts and didn't come up with anything. If there is a better place to ask this question, please let me know.

Thanks