| 摘要 |
PURPOSE:To develop a super hard tool for warm and hot forgings, by adding a binder for sintering prepared by mixing Ni and Co in a specific ratio to a WC powder, by subjecting the resulting powder mixture to compacting and sintering, and then by coating the surface of the sintered compact with a specific hard material. CONSTITUTION:At the time of manufacturing a super hard tool for precision forging and closed die forging by means of warm forging at 200-800 deg.C and hot forging at 800-1,100 deg.C and excellent in toughness, resistance to heat checks, and fracture loss resistance, a powder mixture of Ni and Co, as a binder for sintering, in which the value of Ni/Co is regulated to 0.02-0.25 is mixed by <=11%, by weight, with a WC powder as a hard phase in which grain size is regulated to 0.5-10mum and grains with >=2mum size comprise >=60%. Further, for improving hot hardness and toughness one or more elements among Cr, Mo, W, B, Al, Si, Mg, and Ca are added, if necessary, by 0.05-0.5% based on the quantity of the binder, and the resulting powder mixture is press- compacted and sintered. Then, the surface of the sintered tool is coated with one or more kinds among TiC, TiN, TiCN, Al2O3, SiC, BN, C, etc. In this way, the super hard tool having superior characteristics can be obtained.
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