| 摘要 |
PURPOSE:To obtain an extruding pin for flame retardant plastics with improved corrosion resistance by subjecting a high Cr steel having a specified alloy composition to hardening, subzero treatment and tempering at specified temps. CONSTITUTION:A steel consisting of, by weight, 0.9-1.2% C, <=1.0% Si, <=1.0% Mn, 16.0-19.0% Cr, <=0.75% Mo and the balance Fe with impurities is quenched from 1,000-1,070 deg.C and subjected to subzero treatment at -70--196 deg.C to transform >=about 15% of the residual austenite into martensite by decomposition and to increase the hardness. The hardness of the steel is then regulated by tempering at 300-400 deg.C to obtain an extruding pin for plastics. The pin has high corrosion and wear resistance, so it can be used in the extrusion of flame retardant plastics without requiring Cr plating, etc. |
