| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel product which allows the thickness of a hard layer formed on the surface to be freely set, has high hardness, has no fear of causing the hard layer to fall when blade tip is ground or polished, allows the reduction of producing cost and is suitable to material for blade, etc., and a produsing method thereof. SOLUTION: A second steel material 13 of carbon quantity >=15% (SUS440A) which is made in intermediate layer is inserted into a titanium or titanium alloy material 14, subsequently, a tantalum or niobium material 12 is inserted into the second steel material 13, lastly, a first steel material 11 of carbon quantity of <0.5% (SUS420J2) as a core material is inserted into the tantalum or niobium material 12, a rod type blank 10 is thus prepared, the rod type blank is subjected to hot rolling and, thereafter, is held for a prescribed time at a quenching temperature, carbon is diffused into titanium on the surface layer, water cooling is performed and, thereby, the rod type or sheet type clad steel material suitable to the material for blade, etc., provided with a hard layer containing titanium carbide(TiC) on the outermost layer is produced.
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