GH4169高速铣削加工残余应力分布规律试验

Distribution Law Test of Residual Stress in High-speed Milling GH4169

目的通过研究GH4169高速铣削过程中切削工艺参数对加工残余应力的影响规律,改进工艺参数的选取,提高此类零件的疲劳寿命。方法设计了GH4169高速铣削工艺参数与加工残余应力之间的单因素试验。通过仅改变一个切削参数、其余切削参数不变的方式,得到了工件表面残余应力和切削深度方向残余应力与切削参数之间的变化规律。结果铣削进给方向(x方向)和垂直进给方向(y方向)的表面残余应力主要表现为拉应力,且随着铣削深度和每齿进给量的增加而增加,随着铣削速度的增加而减小;在切削深度方向上,不同切深值所在平面的x方向和y方向的残余应力主要表现为压应力,随着层深的增加先增大后减小。残余应力峰值随铣削深度和每齿进给量的增大而增大,随铣削速度的增大而减小,残余应力最大深度基本在80μm以内。结论 GH4169高速铣削加工中,如果要获得较小的表面残余拉应力,应该选用较小的铣削深度和每齿进给量,较大的铣削速度;在切深方向,如果要获得较大的残余压应力,应该选用较大的铣削深度和每齿进给量,较小的铣削速度。反之亦然。

GH4169 is a high temperature resistant nickel based alloy with excellent properties, which is widely used in the manufacture of hot components of aircraft and spacecraft. Therefore, it shall be provided with high anti-fatigue properties. The residual stress in machining has great influence on the fatigue strength of the parts. The work aims to improve the selection of cutting parameters and further improve the fatigue life of these parts by studying the effects of cutting parameters on the residual stress during GH4169 high speed milling. A single-factor experiment was designed between GH4169 high-speed milling parameters and machining-induced residual stress. The varying pattern among residual stress on the workpiece surface, residual stress in direction of cutting depth and cutting parameters was obtained by adjusting one cutting parameter only with others unchanged. The surface residual stress in feed direction of milling（x-direction） and the vertical feed direction（y-direction） was mainly present as tensile stress, which increased as milling depth and feed per tooth increased, and decreased as the milling speed increased. Along the direction of cutting depth, the residual stress in two directions of the plane in which different cutting depth values were present was mainly compressive stress, which firstly increased and then decreased with the increase of cutting depth. Peak value of the residual stress increased with the increase of milling depth and feed per tooth, decreased with the increase of milling speed, the maximum depth of residual stress was less than 80 μm. To obtain less surface residual tensile stress during GH4169 high-speed miling, less milling depth, feed per tooth and larger milling speed shall be selected. In addition, in order to obtain a large residual compressive stress in the direction of cutting depth, larger milling depth, feed per tooth and smaller milling speed shall be selected and vice vers.