铣削参数对GH4169高温合金表面完整性的影响

Effects of Milling Parameters on Surface Integrity of GH4169 Superalloy

通过球头铣刀铣削工艺试验和表面状态测试,采用响应曲面法研究了铣削参数对GH4169高温合金表面完整性的影响,建立了表面粗糙度和表面残余应力预测模型,获得了铣削后GH4169高温合金表层微观力学和微观组织分布。结果表明:表面粗糙度与每齿进给量和铣削深度呈正相关,表面残余压应力与铣削深度呈正相关,与进给量呈负相关,随着铣削参数水平的增大,铣削表层趋向于残余拉应力状态;表层出现加工硬化现象,铣削参数水平的增大使得硬化层加深,最大硬化层深度约为65 m;近表层晶粒被切断破坏,发生了塑性流动,塑性变形层深度在10~25 m范围。

Through the ball end milling experiment and surface states test, the effects of milling parameters on surface integrity characteristics were investigated by utilizing the response surface methodology. The relationship model between surface roughness, surface residual stress and milling parameters was established by regression analysis. Moreover, the in-depth micromechanical and microstructure of milled GH4169 superalloy were investigated. The results show that the surface roughness is positively correlated with feed per tooth and milling depth. The surface compressive residual stress is positively correlated with milling depth and negatively with feed rate. With an increased milling parameter level, the milled subsurface tends to be the state of tensile residual stress. Work hardening occurs on the surface, and the increase in milling parameters level causes an increase in work-hardened layer(approximately 65μm). The grain locating near the surface is cut off and damaged, the plastic flow occurs, and the depth of plastic deformation layer is within the range of 10 ~ 25μm.