Neutral Hardening

img-38Hardening by Austenitizing and then cooling at a rate that converts a substantial amount of austenite to martensite.

Austenitization means to heat the iron, iron-based metal, or steel to a temperature at which it changes crystal structure from ferrite to austenite.An incomplete initial austenitization can leave undissolved carbides in the matrix. For some irons, iron-based metals, and steels, the presence of carbides may occur during the austenitization step. The term commonly used for this is two-phase austenitization.