SK500 series, the materials are the special powder alloy steel for making screw which are imported from Japan and Germany.Trough 1080℃ vacuum quenching and three times of 580℃ tempering, four hours one time. The hardness will be HRC55-62, common function of toughness in high temperature,good function of softening resistance in high temperature, good function of anti-wear and normal function of anti corrosion. Alloy compsition: C:1.26, Cr:4.2,Mo:5,Si:0.9, W:6.4, V:1.9, Co:2.1

Good function of anti wear which will be fit for engineering plastic+50%GF+common fire retardant and high wear environment