高速切削高温合金GH4169数值模拟与实验

为了准确模拟高温合金GH4169高速切削过程，深入研究了高速切削GH4169的有限元建模技术，包括有限元模型的建立、材料本构模型、切屑分离准则以及接触摩擦模型等关键技术。为了模拟高速切削GH4169的切屑分离过程，研究切屑形态及其形成机理，分别采用Johnson-Cook和各项同性硬化本构关系模型对GH4169的高速加工过程进行二维正交切削有限元模拟，2种模型都获得了相类似的锯齿状切屑。在此基础上，模拟了基于上述2种模型的应力场、温度场和切削力曲线。为了验证有限元模型的有效性和正确性，在CA6140机床进行了GH4169高速车削实验，实验获得的锯齿形切屑验证了2种有限元模型的正确性，实验结果表明:随着切削速度的增大，锯齿状切屑的锯齿化程度增大；绝热剪切是导致高速切削GH4169生成锯齿状切屑的主要原因。实验测量的切削力曲线和切削温度场，与有限元模型A输出结果更好地吻合，进一步表明模型A比模型B更能反映GH4169的实际高速加工特性。 

Numerical simulation and experiment in high-speed cutting superalloy GH4169

The finite element modeling technologies of the high-speed cutting superalloy GH4169 were investigated to simulate the cutting process correctly, which include establishing the finite element model, selecting the material constitutive model, and determining the chip separation criteria and contacting friction model, etc. To simulate the chip separation process and research the chip formation mechanism in high-speed cutting GH4169, the two-dimensional orthogonal cutting finite element models were constructed using Johnson-Cook model and isotropic hardening material constitutive model respectively. As a result, two models obtained the similar serrated chip. On this basis, equivalent plastic strain, cutting temperature and cutting force curve were simulated further. To verify the validity of the finite element model, an experiment was carried out by high-speed turning GH4169 on the machine of CA6140, and the serrated chip generated from the turning experiment verifies the validity of two finite element models. The results show that the serrated chip sawtooth degree increases with the increase of cutting speed and the adiabatic shear is the main reason to cause the serrated chip on high-speed cutting superalloy GH4169. The cutting force curve and cutting temperature generated from the experiment accord better with model A, which demonstrates that model A exceeds model B in reflecting the machining characteristics of high-speed cutting GH4169.