20Cr钢挺柱导套表面缺陷分析

Analysis on Surface Defects of 20Cr Steel Tappet Guide

经过渗碳、淬火和低温回火处理20Cr钢挺柱导套磨削后进行磁粉探伤时,发现表面有形似裂纹的纵向磁粉堆积。为查明该磁粉堆积显示的是裂纹还是其他缺陷,对挺柱导套进行了化学成分分析、金相检验和硬度检测等。结果表明:挺柱导套磁粉探伤显示的磁粉痕迹是暴露到表面的非金属夹杂物而非真实的裂纹。

When subjected to magnetic particle inspection after grinding,20Cr steel tappet guide which were carburized,hardened and low-temperature tempered exhibited crack-like longitudinal magnetic particle accumulation on its surface.To identify whether the magnetic particle accumulation represents crack or other defect,the tappet guide was subjected to chemical composition analysis,metallographic examination and hardness measurements.The results show that the magnetic particle accumulation represents non-metallic inclusions exposed to the tappet surface rather than real crack.