TC4钛合金盘铣开槽加工残余应力

整体叶盘盘铣开槽加工过程中铣削力大,铣削温度高,会在加工表面表成较深的残余应力层,对零件的疲劳寿命造成严重影响。为提高零件的疲劳寿命,本文以钛合金试块为研究对象,利用残余应力测试分析系统测量表面残余应力,利用拨层法测量次表面的残余应力,采用线性回归技术建立残余应力预测模型,并利用极差分析法分析工艺参数对残余应力的影响规律。试验结果表明:盘铣表面均为压应力,且轮毂面上的残余应力大于叶盆叶背面上的残余应力,均由挤光效应引起;回归预测模型的显著性水平为0. 01,其回归效果良好;各因素对σAx、σAy(σAx、σAy分别表示轮毂面x、y方向残余应力)的影响程度依次为主轴转速>进给速度>切削深度;对σBx(σBx表示叶盆叶背面x方向上的残余应力)的影响程度依次为主轴转速>切削深度>进给速度;残余应力纵向均为压应力,轮毂面上的分布深度为230~270μm,叶盆叶背面上的分布深度为170~175μm。

Residual Stress of Disc-Milling Slotting of TC4 Titanium Alloy

In the process of disc milling grooving in blisk,the milling force is large and the milling temperature is high,these factors will form a deep residual stress layer on the machined surface,which will seriously affect the fatigue life of the parts. In order to improve the fatigue life of parts,based on the titanium alloy block as the research object,the surface residual stress is measured by the residual stress test analysis system,and the subsurface residual stress is studied using the dial layer method. The linear regression technique is adopted to establish the prediction model of residual stress,and the range analysis method is used to analyze the influence law of process parameters on the residual stress. The test results show that the residual compressive stress are generated on the machined surface caused by extrusion effect,and the residual stress on hub surface is greater than that on the convex/concave surface.The significance level of the regression prediction model is 0. 01,and the regression effect is good. The influence degree of each factor on σAx、σAy(σAx、σAy represent residual stress in x and y directions of hub surface respectively)is spindle speed>feed speed>depth of cut(DOC)respectively. The influence degree of each factor on σBx(σBx refers to residual stress in the x direction on the convex/concave surface)is in turn spindle speed>DOC>feed speed respectively. The longitudinal residual stress is compressive stress,the distribution depth on the hub surface is 230 to270 μm,and the distribution depth on the convex/concave surface is 170 to 175 μm.