| 摘要 |
PROBLEM TO BE SOLVED: To attain the extension of service life and the lowering of manufacturing cost and to improve the quality of a product by adjusting the surface roghness on the surface of a die base material composed of a tool steel for hot or warm working, forming nitriding layer, washing this nitriding layer surface and forming a nitrogen-containing hardened film by a physical vapor deposition method. SOLUTION: The surface roughness adjustment by a diamond paste is applied to the surface of the die base material composed of the tool steel for hot or warm working and having >= about 50 Rockwell hardness, and the surface roughness is made to <= about 6.3 ten point average roughness R2 . On the surface of the die base material, the nitriding layer having >= about 20μm thickness, is formed and intensively stuck by using a plasma method, salt bath method, gas method, etc., and the nitriding layer surface is washed with an electrolytic method, etc., by using activating solution of hydro-chloric acid, etc., to activate the surface. On this nitriding layer surface, the hardened film containing the nitrogen is formed having good stickiness by the physical vapor deposition method using chromium nitride, titanium-aluminum nitride, etc.
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