Simonraf

So would you recommend casing it again at a higher temperature or at 1600 f for much longer than seven hours?

I am in the process of making a surface grinding vice, all was going well until it came to hardening the main body. The body of the vice I m/c out of mild steel, as I wanted to have this hard and wear resistant I wanted it case hardened. I packed the part in bone charcoal in a heavy walled steel box, sealed the top with fireclay and put it in a over ramped up to 900oC/1600f I let it do it's magic for seven/eight hours. I turned the oven off and let it cool overnight the next day I put the vice body back in the oven and heated it up to 840 oC and let it sit at temperature for a hour, the part was then quenched in a large bucket of water. Unfortunately on closer inspection of the part it is still quite soft and easily scratches with a scribe, I was hoping someone could point me in the direction of what I have done wrong or a solution on how to cure this problem. Thanks