Just to throw a bit more information into the arena , P20 in it's as bought state is about 300 Brinell which is about 33 Rockwell C scale. Hardox is designated by its Brinell hardness so Hardox 450 is about 450 Brinell which equates to about 47 Rockwell C scale. When you nitride P20 it will give a surface hardness of around 650 Hardness Vickers which equates to about 56 Rockwell C scale whilst retaining the original core hardness, this is what makes so P20 suitable for nitriding.

Heres are a couple of more links for P20

http://www.schmolz-bickenbach.com/fi...PLAST_2311.pdf

http://www.carrs-tool.co.uk/products/P20Spec.htm

and one for hardness conversion

http://en.wikipedia.org/wiki/Hardness_comparison

I'm still looking forward to seeing it in action.

PM sent.