精锻齿轮模具失效分析

Failure Analysis on Precision Forging Die of Gears

通过成分分析、硬度测试和金相观察等手段对齿轮精锻模具进行失效分析,该模具失效形式为热疲劳失效,表现为齿顶龟裂、开裂和磨损。模具表面发生回火软化,金相观察发现该精锻模存在严重带状组织和热处理组织不均匀现象,机械性能下降。可采用高温扩散处理、多向锻造和超细化正火处理,减少因带状组织产生的各向异性;通过严格控制热处理工艺,保证模具得到良好组织,提高模具使用寿命。

Failure of precision forging die is analysed by composition analysis,hardness test and metallographic observation etc.The main failure mode is thermal fatigue that shows of chap,cracking and wear on the teeth tip.Temper softening happenes on the surface of die and the serious banded structure and non-uniform microstructure are found by metallographic observation,thus its mechanical properties decrease.Anisotropy caused by the banded structure can be reduced by the high temperature diffusion treatment,multidirectional forging and superfine normalization.Heat treatment process should strictly be controlled to gain good microstructure and increase service life.