采用20CrNi3制作活塞杆,最后进行表面镀铬。经镀铬处理后发现镀层表面产生了一些网纹,将镀铬层去掉后仍可看到网纹。对镀铬层及去掉镀铬层的网纹的形态和显微组织及成分等利用光学显微镜﹑扫描电镜附带的能谱分析等方法进行研究。结果表明,形成网格状裂纹的原因是,在镀铬前,样品表面局部区域就存在一些微裂纹及较高的残余应力。 Piston rod made of 20CrNi3, the last chrome plated. After chrome plating surface coating found some textured, the chrome layer removed can still see the texture. The chrome layer and remove the chrome layer pattern and the microstructure and composition of the use of optical microscopy, scanning electron microscopy incidental energy spectrum analysis and other methods were studied. The results show that the reason for the formation of grid-like cracks is that there are some micro-cracks and high residual stress in the local area of ​​the sample before chrome plating.