Method for producing high-speed tool steel material, method for producing high-speed tool steel product, and high-speed tool steel product

Abstract

Provided are: a method for producing a high-speed tool steel material capable of increasing carbides in the structure of a high-speed tool steel product; a method for producing a high-speed tool steel product; and a high-speed tool steel product. The method for producing a high-speed tool steel material is provided with: a casting step for casting molten steel to obtain a steel ingot; a blooming step for heating the steel ingot obtained in said casting step to a temperature higher than 1120° C. and thereafter hot-working same to obtain an intermediate material; and a finishing step for heating the intermediate material obtained in the blooming step to a temperature of 900-1120° C. and thereafter hot-working same to obtain the high-speed tool steel material. Further, said method for producing a high-speed tool steel material is provided with an annealing step for annealing the high-speed tool steel material obtained in said finishing step. The present invention is also: a method for producing a high-speed tool steel product, wherein quenching and annealing is performed on the high-speed tool steel material obtained in the production method above; and a high-speed tool steel product.

What is claimed is: 
     
         1 . A high speed tool steel product comprising, by mass %, C: 0.50% to 2.20%, Si: 0.10% to 1.00%, Mn: 0.10% to 1.00%, P: not more than 0.025%, S: not more than 0.0040%, Cr: 3.00% to 7.00%, Mo and W alone or in combination in an amount of (W+2Mo): 5.00% to 30.00%, V: 0.60 to 5.00%, and the balance of Fe and impurities,
 the product having a cross sectional structure wherein an area ratio of MC carbides having a maximum length being not shorter than 0.40 μm in the cross sectional structure is not less than 3.8%, and an area ratio of M 6 C carbides having a maximum length being not shorter than 0.40 μm in the cross sectional structure is not less than 6.8%.   
     
     
         2 . The high speed tool steel product according to  claim 1 , further comprising one or more of, by mass %, Co: not more than 10.00%, Al: not more than 0.30%, and Ca: not more than 0.0150%.