| 摘要 |
PURPOSE:To obtain high speed steel having high hardness, high toughness and superior wear and fatigue resistances, by heat treating under a suitable condition Mo high speed steel material manufactured by melting method and having a specified C content and a specified wire diameter or sheet thickness. CONSTITUTION:Mo high speed steel material manufactured by melting method, contg. 0.7-1.1wt% C and having 0.05-3.0mm wire diameter or sheet thickness is heated at 1,150-1,220 deg.C for 40-100sec, next cooled by >=100 deg.C/sec rate and quenched. Next, said material is subjected to at least one tempering process of heating at 550-650 deg.C for 50-150sec. By this way, high speed steel having high hardness and high toughness is obtd. After said heating and cooling processes, said material is quenched by cooling rapidly at <=-50 deg.C for 20sec, then subjected to said tempering, thereby toughness can be further improved. It is desirable to perform said heat treatment by passing said high sped steel through a pipe filled with gaseous nitrogen. |
