Originally Posted by CTripps
I've heard that heating up the metal and quenching it in used motor oil will help strengthen it, but have never tired it. Something to do with the hot metal picking up the carbon from the used oil.
you must bring steel to cherry color.You are exactly right although we used to use a brine solution, (salt water)
with a layer of used oil about 2" thick in top of bucket, used oil has more carbon content but make sure you temper it back or it will be brittle,
we usually polished it a little and heat slowly till a straw color.
you must bring steel to cherry color and hold for about 10 minutes , quench, clean, temper. The higher the carbon the more the pitting after quench. This is called Heat Treating
hope this helps!
for surface hardening they have some stuff which is basically cyanide you heat the part cherry dip it in powder. high carbon content surface hardened about .050 deep