| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a tool steel intermediate material where crystal grain sizes can be fined without requiring normalizing treatment, and to provide a method for producing a tool steel using the tool steel intermediate material obtained thereby. SOLUTION: In the method for producing a tool steel intermediate material, a tool steel material comprising 0.10 to 2.0% C is heated at 1,050 to 1,250°C, is subjected to hot working, after the completion of the hot working, is cooled at a cooling velocity of that in air cooling or above till the surface temperature of the tool steel material reaches 500 to 700°C, is subsequently heated at 400 to 700°C in a heating furnace, is held, is then subjected to heating for increasing the temperature of the tool steel material, so as to increase the temperature of the tool steel material from a pearlite nose to a temperature range of -100°C, and, after the heating and holding, is cooled, thus a metallic structure where carbides are precipitated into a ferritic structure is obtained. In the method for heat treating a tool steel, after the above treatment, the material is heated at an Ac3 point or above, is quenched, and is subsequently subjected to tempering for one or more times, so as to be finer grains than No.6 by the average crystal grain size number. COPYRIGHT: (C)2007,JPO&INPIT
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