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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。
Developed a carbide size is very small, high hardness HRC67 high toughness high hardness steel, namely 25W3Mo4Cr2V7Co5 steel. Forging performance far superior to the traditional high-speed steel, heat treatment process is only slightly complicated in the traditional high-speed steel. The distribution of carbon concentration in infiltration layer was studied by chemical analysis, metallographic analysis, X-ray structure analysis, surface hardness and microhardness determination. The effects of carburizing temperature and time, quenching temperature, Microstructure, phase composition, depth, surface hardness and hardness gradient. The results show that the eutectic carbide size of 25W3Mo4Cr2V7Co5 steel is small (the average size is about 2 ~ 4μm, the maximum size is only about 8μm, only 1/3 ~ 1/2 of the superhard hard steel M42) After carbon standard treatment, the average carbide size is only 4 ~ 6μm (the maximum size is only 10μm), and the hardness can reach the hardness level of M42, that is HRC67 ~ 70.