I agree with that Bruce and it is in line with what we were saying toughness and strength are. I'd say you have it! There are so many details to consider and so many variables...that is what makes this tough. He mentions a correlation between hardness and strength...That is true most of the time but as I pointed out - diamonds, glass and ceramic are harder than steel yet not stronger so that breaks down the correlation between hardness and strength - but only when comparing non-steel materials to steel. The test used to test hardness is basically a tensile strength test for all intents and purposes. They push a diamond tipped instrument into the steel with a predetermined amount of force and measure the depth of the penetration. That is how they get the Rockwell hardness numbers. It makes sense that a steel with greater tensile strength would resist the penetration more than a weaker steel or material. I believe that is where the correlation exists and we did point that out last night. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> Makes sense?

I do believe you understand the concepts though and i believe we are on the same page. <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" /> This conversation is a doozie!