粉末冶金法で製造された窒素添加高速度工具鋼の諸特性

概要

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Nitrogen free and nitrogen containing SKH51, 55V, 57 and 10 high speed steels were produced by HIP-ing gas atomized powders. Nitrogen was added to steels by heat-treating the powders in nitrogen gas before HIPing. The properties of abovementioned steels were compared with those of conventional steels, and the following results were obtained. 1) By adding nitrogen to high speed steels, the decrease of incipient melting temperature was not observed. 2) The amount of retained austenite was increased by the addition of nitrogen, especially, higher vanadium steels had more amounts of retained austenite because of more nitrogen contents. 3) The continuous cutting performance at low cutting speed and intermittent cutting performance were significantly improved by the addition of nitrogen. 4) In case of nitrogen free P/M steels, the bend strength was not reduced by the increase of vanadium content, because the change in carbide size was not observed among 4 kinds of P/M steels. 5) Higher vanadium P/M steels exhibited a better intermittent cutting performance than lower vanadium P/M steels. However, in case of conventional steels, higher vanadium steels exhibited the reverse property.
社団法人粉体粉末冶金協会の論文