Abstract: A tool steel material is capable of having its carbides sufficiently fined in microstructure and also capable of reducing segregation of any of its constituent elements to the smallest possible amount in the material. In producing the material, a plurality of cast steel pieces are prepared and stacked to form a lamination pack. This lamination pack is then subjected to a hot-working process under pressure. As a result, the cast steel pieces of the pack are press-bonded to each other and unified. During this press-bonding process, the pack is also subjected to a diffusion heat treatment for enhancing diffusion of the elements of the material by permitting the elements to pass through a contact surface of each of the cast steel pieces, through which contact surface adjacent ones of the cast steel pieces are brought into contact with each other in the lamination pack.

Abstract: A metal band saw is disclosed which is used to cut cutting-resistant materials such as SKD11, stainless steel, etc. and has characteristics of generating less chips on the cutting edge as well as improving wear resistance, resulting in very long service life. The blade material for the metallic band saw comprises high-speed steel containing 2 wt. % or less of vanadium (V), wherein 3 area % or more of carbide grains having a major diameter of 3 &mgr;m or more as observed in a metallographic structure.

Abstract: There is disclosed a bearing member which is enhanced in toughness without lowering the hardness of a core portion so as to prevent an instantaneous rupture of the bearing member, and is excellent in rolling fatigue service life characteristics. Martensitic Fe-based bearing steel of the invention contains, by weight, not more than 0.4% carbon, not more than 2% silicon, not more than 2% manganese, not more than 5% nickel, 3.5 to 7.0% chromium, at least one of tungsten and molybdenum an tungsten equivalent defined by (?W!+2?Mo!) of which at least one is 3 to 15%, and not less than 0.5% but less than 1.1% vanadium. A ratio of Cv/Ceq is not more than 0.3 where Cv represents a carbon equivalent of vanadium defined by 0.2?V!, and Ceq represents a carbon equivalent of carbide-forming elements defined by (0.063?Cr!+0.06?Mo!+0.033?W!+0.2?V!). With this construction, the precipitation of MC carbides is suppressed, and M.sub.