航空发动机零件疑似裂纹的分析鉴定

航空发动机零件存在的较深加工刀痕、磨痕、附着物、表面涂镀层凹凸不平等缺陷和特征,在质量检验过程中会产生疑似裂纹。采用金相分析等手段,初步总结常见疑似裂纹的特点。结果表明:较深的加工刀痕、磨痕导致的疑似裂纹呈一定规律性分布、在疑似裂纹的两端和深度方向底部较钝、可以隐约或清晰地观察疑似裂纹深处的形貌特征,且可以通过表面修磨去除;附着物导致的疑似裂纹一般较宽,疑似裂纹两侧有沿表面渗透的毛刺等特征;表面涂镀层开裂导致的疑似裂纹微观形貌一般呈现龟裂特征。通过显微镜、扫描电镜、修磨验证等手段获取疑似裂纹的特征信息,并结合零件工艺过程、使用履历综合分析判断,可确认疑似裂纹的性质。

Analysis and Verification of Suspected Cracks of Aero-engine Parts

For aircraft engine parts, deep machining marks, wear marks, attachments, and uneven coating surface may be considered as suspected cracks in the process of quality inspection. The characteristics of these common suspected cracks are summarized by means of metallographic analysis and other methods. Compared with real cracks, suspected cracks due to deep machining marks and wear marks are usually regularly distributed, blunt at both ends and the bottom of the depth direction of the suspected cracks. The bottom of the suspected cracks can be observed vaguely or even clearly, and they can be removed by surface grinding. The suspected cracks due to attachments are generally wide, sometimes with infiltration tips at both sides. The micro morphology of the suspected cracks due to surface coating cracks generally shows the characteristics of crazing. The characteristic information of the suspected cracks can be obtained by means of microscopy, scanning electron microscopy, grinding verification, etc., and the nature of the suspected cracks can be confirmed through comprehensive analysis and judgment based on the processing and application history.