齿轮等温正火工艺的研究应用

Research and Application of Gear Isothermal Normalizing

在常规正火处理中,因各种因素使得齿轮毛坯的金相组织、应力和硬度的较大差别,导致切削加工性能恶化和渗氮淬火热处理变形量大,降低了齿轮成品精度等级。而等温正火较普通正火使零件能够获得均匀一致的显微组织和硬度。我们在研究应用等温正火工艺过程中,针对锻态齿轮毛坯零件种类繁多、材料品种多的现状,探索了相应的工艺方法,稳定地获得了均匀细小等轴状的珠光体+铁素体的金相组织,大幅度降低了齿轮渗氮淬火热处理的变形量;稳定地获得了HB160-190的齿轮毛坯硬度范围,使后续加工性能得到了显著改善。

In the conventional normalizing process, there will be large differences in metallographic structure, stress and hard-ness of the gear blank due to various factors, resulting in deterioration of maehinability and large deformation in nitriding quenching heat treatment, downgrading the precision of the finished gear. Rather than ordinary normalizing, isothermal normal- izing make parts to obtain uniform microstructure and hardness. During our research and applications of isothermal normalizing process, facing the situation of wide varieties of forging gear blanks and materials, we explore the corresponding process, stably obtain a metallographic structure with uniform fine and equiaxed pearlite ＆ ferrite, greatly reduce the deformation of gear nitrid- ing quenching heat treatment, steadily acquire hardness range of HB160-190 gear blank, making the subsequent processing performance improved significantly.