深冷处理对硬质合金的影响

综述了国内外硬质合金深冷处理的工艺过程及其深冷处理对硬质合金微观组织、相结构、残余应力状况、机械性能与切削性能的影响。深冷处理工艺包括降温和保温两个基本阶段,部分研究增加回火处理;深冷处理后硬质合金中η相含量增多且尺寸减小,Co对WC的粘结更紧密,但也有认为微观组织形貌变化不大的观点;Co相由面心立方向密排六方转变,而WC相变化不大;深冷处理可提高硬质合金耐磨性和延长使用寿命已得到共识,但对表面残余应力状况及硬度等影响尚存在不同观点。探索深冷处理对硬质合金的作用机理,并进行工艺参数的优化是目前研究工作的方向。

Effect of Deep Cryogenic Treatment on Cemented Carbide

Deep cryogenic treatment process and the effect of the treatment on microstructure, phase structure, residual stress, mechanical properties and cutting performance for cemented carbide are summarized. Some literature shows that the cryogenic treat- ment process consists of cooling and isothermal stages, a few researches follow by tempering; the content of η phase increases and the grain size decreases in the cemented carbide after the cryogenic treatmen4 and the tungsten carbide particles are more firmly held by cobal4 but some literature reports that little microstrueture is changed; the cobalt phase transforms form FCC to HCP phase, but the WC phase remains stable; It is agreed on that deep cryogenic treatment can improve the wear resistance and extend the service life of cemented carbide, but there are different opinions upon the effect on the residual stress and hardness changes. The mechanism research of deep cryogenic treatment on cemented carbide and process optimization are current research orientation.