I am a sheet metal mechanic, so it is my job to understand the properties of metal, so I understand what maleable means
Cryo treating is a process where the metal to be hardened is frozen using liquid nitrogen, then slowly heated up to about 350 degrees farenheit. The metal is cycled like this about 3 times over roughly 72 hours. Basically it is just an extension of heat treating, and usually provides about 100 % increase in fatigue strength, and wear, with some improvements in tensile strength as well. It works best on ferrous metals, like steel, that have already been heat treated. Good to use on highly stressed parts, with no negative side effects.
Shotpeening is a process where millions of tiny steel balls are shot at the part at high velocities. This causes the metal to be compressed, and refines the grain structure on the surface. Basically it is micro forging the metal into a harder layer, which makes it harder for a crack to start. It changes the structure of the metal about 0.005-0.010 of a inch deep. Typical improvements in the fatigue strength are in the 100-300% range. Very good at preventing breakage, typically used on airplanes.
The purpose is always to increase the strength of metals, and this occurs when heated metal is cooled rapidly. The result is a metal with small grains and increased resistance to penetration--hardness.
so with that, I am interested in induction hardening, because I have found through research, induction hardening is capable of improving wear resistance, strength, and fatigue, however I am not sure on what level. Look at shot peening, 300 % increase at a depth of 0.010 of an inch. Induction hardening can do the same thing to depths beyond 0.375 (3/8) of an inch. If not more, I am just curious if anyone here has more info??
