W6Mo5Cr4V2高速钢刀具真空渗碳的组织与性能研究

Investigation on Structure and Properties of Cutter Made of High-Speed Steel, W6Mo5Gr4V2, in Vacuum Carburizing

本文对表面碳量为１．１７－１．５８％的渗层组织与性能进行了探讨。试验结果表 明：真空渗碳的 Ｍ２＊＊高速钢，获得最佳二次硬化效应所对应的碳量是个区间，渗层 中淬火碳化物的类型及成份变化与冶炼的高碳高速钢不尽相同，渗层淬火碳化物的分 布和形态得以明显的改善，渗层淬火基体的 Ｗ．Ｍｏ，Ｖ合金含量比心部增高，最高回 火硬度可达ＨＲＣ６８－６９，６００℃红硬性为ＨＲＣ６５－６６，冲击值与Ｍ２高速钢常 规处理的相当。真空渗碳指形铣刀实际铣削考核，使用寿命比常规处理的Ｍ２铣刀有 成倍提高。

The structure and properties of high speed steel in carburizing layer having 1. 17-1. 58% surface layer carbon content is discussed in this paper. Experimental results show that there is a carbon content range for the vacuum carburized M2 high speed steel to obtain the second optimum hardening effect. It has been found that the type and the composition change of quenching carbide in carburizing layer is not all the same as the commercial high carbon -high speed steel. The morphology and the distribution of quenching carbide in the carburizing layer has been remarkably improv ed and the W, Mo, V alloy- ing element content of the matrix in the carburizing layer is higher than that in the central portion. The maximum tempering hardness reached HRC 68-99 and the red hardness of steel at 600℃ is HRC 65-66. Impact toughness of the vacuum carburized high speed steel is as good as routinely heat treated M2 high speed steel. Milling cutting testings were conducted using finger type milling cutters heat treated with vacuum carburizing and routine techniques respectively and it has been proved that the service life of the milling cutter made of vacuum carburized steel is about twice as long as that made of rou- tinely heat treated M2 steel.