Carbon equivalent formula

The carbon equivalent is equal to the amount of carbon plus manganese and silicon divided by six, plus chrome, moly, and vanadium divided by five, plus nickel and copper divided by fifteen. I've also handed out, going around just now, something out of another book — a book on welding metallurgy — that gives you in one of their appendices a whole list of different carbon equivalents. Over the last eighty years there's a lot of people who wanted to develop their own carbon equivalent. It's basically an empirical relationship of depth of hardening as a function of alloy composition. I told you hardness is a function of carbon, hardenability is a function of all the alloying elements. This is just a formula — no one will tell you it's the hardenability, but in fact it's just a formula for the hardenability of the steel that you're using.