高韧高硬高速钢的研究

The Study of High Toughness High Hardness High Speed Steel

研制开发了一种碳化物尺寸甚小、硬度高于HRC67的高韧高硬高速钢,即25W3Mo4Cr2V7Co5钢。其锻造性能远优于传统高速钢,热处理工艺仅略复杂于传统高速钢。用化学分析法、金相分析法、X射线结构分析法以及表面硬度和显微硬度测定法研究了渗碳温度和时间、淬火加热温度以及回火温度和次数对其渗层的碳浓度分布、金相组织、相组成、层深、表面硬度和硬度梯度的影响规律。结果表明,25W3Mo4Cr2V7Co5钢的共晶碳化物尺寸细小(其平均尺寸约为2～4μm,最大尺寸仅约为8μm,仅及超硬高速钢M42的1/3～1/2);经最佳渗碳规范处理后,其碳化物平均尺寸仅为4～6μm(最大尺寸仅为10μm),其硬度可达M42的硬度水平,即HRC67～70。

A series of new high toughness high hardness, high speed steels 25W3Mo4Cr2V7Co5 containing carbides with fine particle size, possessing much better forgeability are developed. The effect of carburizing temperature and duration, quenching temperature, tempering temperature and times on the carbon content distribution, microstructure, phase composition, depth, surface hardness and microhardness distribution of carburized layers of the new high speed steel by chemical analysis, microscopic analysis X ray structure analysis surface hardness determination and microhardness test was studied in this paper. The results show that the size of eutecfic carbides of steel 25W3Mo4Cr2V7Co5 is very small. The average size of carbides is 2～4μm and the maximum size is'6～8μm, which is equal to 1/3～1/2 of carbide size of super hard high speed steel M42. The average size of carbides of carburized layer is 4～6μm and the maximum size is only 10μm. The hardness of carburizing can reach HRC 67～70, which is the hardness level of steel M42.