球墨铸铁激光表面硬化处理的研究

Study on the Laser Surface Hardening for Spherical Graphite Iron

采用正交试验设计方法,系统地研究了不同的表面状态、激光功率、扫描速度、离焦量及气体流量,对球墨铸铁激光表面硬化处理后硬化层深度和宽度的影响。探讨了不同工艺条件下熔化层的金相组织及显微硬度。研究表明,球墨铸铁激光表面熔凝硬化处理,以胶体石墨作黑化剂,采用高功率、低扫描速度、较小的离焦量和较大的气体流量可以获得深层、硬度高、裂纹倾向小和表面光滑的硬化层。

In this paper,using orthogonal experimental design,we inves-tigated systematically the effect of surface condition,laser power,scanningspeed,defocused distance and the volume of gas flow on the width and depth oflaser hardening layer of spherical graphite iron.The feature of hardened layerswere been researched.It was found that colloidal graphite as blackening agent, and the use of higher beam power,lower scanning speed,smaller defocuseddistance and greater gas flow are suitable for laser surface melt hardening ofth(?)s cast iron.Thus,a deeper hardening layer with higher hardness,lesscrack tendency and more smooth surface can be produced.