40CrNiMoA钢轮缘堆焊后, 通过磁粉探伤发现堆焊层下存在大量裂纹。通过宏观检验、化学成分分析、金相检验、硬度测试、扫描电镜及能谱分析的方法, 对轮缘堆焊层下裂纹的产生原因进行了分析。结果表明: 由于堆焊过程中预热温度偏低, 在熔合线附近形成塑性、韧度极差的上贝氏体组织, 在焊接冷却过程中收缩应力的作用下产生裂纹。

A large number of cracks were found under the surfacing layer of a 40CrNiMoA steel rim through the magnetic particle inspection after surfacing welding. By methods of macrographic examination, chemical composition analysis, metallographic examination, hardness test, scanning electron microscope and energy spectrum analysis, the formation causes of cracks under the surfacing layer of the rim were analyzed. The results show that because of the low preheating temperature in the process of surfacing welding, the upper bainites were found in the vicinity of the fusion line, which caused cracks under the action of the shrinkage stress during the welding cooling process.