大型船用曲轴曲拐的弯锻过程模拟与实验研究

SIMULATION AND EXPERIMENT STUDY OF BENDING PROCESS OF LARGE MARINE CRANKTHROW

通过测试大型船用曲轴曲拐S34MnV钢在高温不同应变速率下的应力-应变曲线,建立了该钢的本构关系模型．运 用ABAQUS软件对该曲拐的弯锻过程进行了热力耦合模拟,得到了曲拐锻造过程的应力、应变和温度随时间的变化情况,分析 了曲拐的金属流动机制,研究了曲拐典型位置的静水压力和表面拉／压应力的变化,模拟计算了锻造过程产生的“细腰”、裂纹、 “喇叭口”等缺陷的位置,并预测了曲拐的最终形状和尺寸．模拟结果与实验结果很好吻合．在此基础上提出了改进性意见,为锻 造工艺参数的优化提供了依据．

A constitutive equation was established based on stress-strain curves of S34MnV at different strain rates and high temperatures. The coupling of thermal-mechanical process in bending large marine crankthrow was simulated by using ABAQUS code. From the simulation results, the strain-stress field and temperature field in the forging process were obtained. In order to analyze the mechanism of metal flow of crankthrow, the evolutions of the hydrostatic pressure and the surface tensile/compressive stress of typical positions on the crankthrow were investigated. The simulated defect positions, such as the “slim waist”, crack and “horn mouth” etc, as well as the final shape and size of the crankthrow agree well with the experimental ones. Furthermore, an improved suggestion was given, which could be helpful to optimize the forging Darameters.