PREPARATION OF HEAT RESISTANT CUTTER BIT FOR DENTAL DIE

摘要

PURPOSE:To provide excellent heat resistant strength and high temperature wear resistance, by solution heat treating a cutter bit blank cast with precipitation hardening type heat resistant steel and then by nitriding-treating and aging-treating the blank at the same time. CONSTITUTION:The molten metal of precipitation hardening type heat resistant steel is poured into a casting mold prepared by a lost wax process to prepare a cutter bit blank. Next, the cutter bit blank is heated at about 1,050 deg.C before it is water-quenched. Subsequently, the quenched blank is heated in an NH3 gas stream for about 20hrs at a temperature range of about 500-600 deg.C to nitride the blank, and a hard nitrided layer is formed on the surface of the cutter bit blank.