基于热力耦合分析的预应力切削残余应力研究

对预应力切削的已加工表面残余应力状态进行热力耦合分析,通过对机械应力和热应力在工件表面分布的叠加,发现加工表面存在3种不同的残余应力类型,文中定性讨论了其产生条件,并进一步分析了刀具切削刃钝圆和预应力对工件表面残余应力状态的影响.最后采用不同钝圆半径的刀具和预应力对表面淬火硬化的40Cr合金钢进行硬态切削实验,并将实验结果与理论分析结果进行了对比.结果表明:切削刃钝圆影响残余应力的大小和分布;钝圆半径越大,残余压应力越大,应力层也越厚;预应力可以有效提高加工表面的残余压应力,而对其分布基本没有影响;实验结果和理论分析相吻合,说明文中理论分析是正确的.

Investigation into Residual Stress of Pre-Stress Cutting Based on Thermo-Mechanical Coupling Analysis

In this paper,first,the residual stress state of the workpiece surface machined by pre-stress cutting was investigated via the thermo-mechanical coupling analysis.Next,three residual stress types of the machined surface were revealed by overlapping the mechanical stress and the thermal stress distributing on the workpiece surface,and the corresponding formation conditions are also qualitatively discussed.Then,the effects of the cutting edge roundness and the pre-stress on the residual stress state of the machined surface were further analyzed.Finally,some experiments of pre-stress hard cutting for 40Cr alloy steel with quench hardening were carried out at different cutting edge roundness and pre-stress,and the results were compared with the theoretical ones.It is found that both the value and the distribution of the residual stress depend on the cutting edge roundness,that both the residual compressive stress and the strained layer’ s thickness increase with the blunt round radius,that the pre-stress effectively increases the residual compressive stress of the machined surface,but it basically has no influence on the stress distribution,and that the proposed theory is reasonable because the experimental results accord well with the theoretical ones.