| 摘要 |
PURPOSE:To produce hard ferrous parts having a uniform and adequate spring characteristic at a low cost by subjecting pure iron powder etc. to compression molding, sintering and gas carburization hardening then to high-temp. tempering. CONSTITUTION:The pure iron powder, alloy iron powder or low-carbon iron powder (about <=0.2% carbon content) is used as a raw material and is subjected to compaction molding to a prescribed shape in a compaction molding stage. The molding is then sintered for a prescribed period at about 1,100-1,150 deg.C in the sintering stage and is treated, if necessary, in a sizing stage and post working stage. The molding further heated to 800-850 deg.C in a gas carburization hardening or gas carburization nitrogen hardening stage and is thereafter tempered at about 400-500 deg.C in a high-temp. tempering stage. The ferrous parts having about 300-450Hmv hardness are thus obtd.
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