铁基粉末冶金齿轮断裂失效分析及其工艺改进研究

针对某型粉末冶金齿轮在运行期间出现的断齿现象，通过扫描电镜、能谱仪分析断口形貌、成分，发现断口位置存在大量球状铁碳化合物，表明原工艺由于烧结温度、时间不足，造成了粉末之间结合力弱的缺陷。在此基础上，以Fe 1.8Ni-0.5Mo-1.2Cu-0.2C预合金粉为研究对象，改进烧结工艺，采用压制、烧结、淬火与低温回火的新工艺，制备出的齿轮珠光体数量级别为珠60，热处理后齿轮组织由回火马氏体和铁素体组成，冲击韧性由9.8 J/cm²提升至15.2 J/cm²。结果表明，改进工艺能够显著提升粉末间的扩散、熔焊和再结晶效果，提高组织致密性和冲击韧性并使组织具有一定塑性。

Fracture failure analysis and process improvement of iron-basedpowder metallurgy gears

The teeth of a powder metallurgy gear were fractured during operation. A large number of globular iron-carbon compounds were found at the fracture site using SEM and EDS analysis, which indicates a weak bonding between powders resulting from an insufficient sintering temperature and duration of the original process. An improved sintering process and a new process of pressing, sintering, quenching, and low-temperature tempering were applied to Fe-1.8Ni-0.5Mo-1.2Cu-0.2C prealloyed powder. The pearlite quantity in the prepared gear is 60, and the new prepared gear comprises tempered martensite and ferrite subsequent to heat treatment. The impact toughness improved from 9.8 J/cm² to 15.2 J/cm².