| 摘要 |
PURPOSE:To inhibit an increase in the hardness of a sintered product of an Mn-Cr alloy steel contg. prescribed percentages of Mn and Cr and to improve the dimensional accuracy after sizing by treating the sintered product in gaseous hydrocarbon contg. gaseous ammonia. CONSTITUTION:Mn-Cr alloy steel powder contg. 0.4-2 wt.% Mn and/or 0.3-3 wt.% Cr is sintered. A gaseous mixture contg. 0.5-10 vol.% gaseous hydrocarbon and gaseous ammonia is prepd. The sintered product is heated in an atmosphere of the gaseous mixture to carry out carbonitriding and hardening.
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