WEAR RESISTANT SINTERED ALLOY FOR VALVE SEAT AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A wear resistant sintered alloy for valve seat is provided which improves wear resistance by containing iron as a principal constituent, carbon, chromium, molybdenum, vanadium, tungsten, cobalt, silicon and manganese and simultaneously performing copper infiltration and sintering treatment, and a manufacturing method thereof is provided. CONSTITUTION: The method comprises first process of press molding the blended alloy to a surface pressure of 5 to 8 tons/cm¬2 by blending a principal constituent of iron, 0.8 to 1.2 wt.% of carbon, 2.0 to 5.0 wt.% of chromium, 5.0 to 7.0 wt.% of molybdenum, 3.0 to 5.0 wt.% of vanadium, 8.0 to 12.0 wt.% of tungsten, 0.2 to 0.5 wt.% of manganese and 4.0 to 6.0 wt.% of cobalt; second process of air cooling the pure copper infiltrated and sintered alloy after infiltrating 20 to 30 wt.% of pure copper for the weight of the valve seat into the press molded alloy and sintering the pure copper infiltrated alloy at the same time at a temperature of 1,140 to 1,180 deg.C after finishing the first process; third process of rapidly cooling the heat treated alloy after heat treating the copper infiltrated and sintered alloy to a temperature of 1,130 to 1,180 deg.C after finishing the second process; fourth process of annealing the rapidly cooled alloy to a temperature of 600 to 700 deg.C after finishing the third process; and a process of proceeding some processing works on the annealed alloy at an ordinary temperature after finishing the fourth process.