Abstract：The technical principle of reaching ultra-hardness by secondary hardening at low temperature for organic matter cutting tool steel 9CrV has been studied in detail. Special heat treatment was used to precipitate numerous and fine alloy cementites directly in low temperature tempering, and then realize ultra-hardness via high-carbon matensitic hardening and precipitation strengthening of fine dispersed alloy cementites, the size of the cementites is refined to about 50nm and the hardness of the cutting tool steel reaches HRC 68 ~ 72.
2009, Vol. 44 
