| 摘要 |
PURPOSE:To make the grains of a tool steel fine by subjecting the steel to preworking, soln. heat treatment, reworking, and annealing. CONSTITUTION:A tool steel such as a material manufactured by melting or a sintered material of atomized powder is preworked by forging, extrusion, rolling or other method. The preworking temp. is made as low as possible so as to inhibit the coarsening of the grains. The preworked tool steel is subjected to soln. heat treatment at 1,000-1,300 deg.C, reworking as recrystallization treatment and annealing. |
