摘要:
在分析高速冷滚打成形原理的基础上, 建立了热力耦合数学模型, 通过常温和高温下不同应变速率的静态和动态压缩试验, 结合Johnson-Cook流动应力公式, 建立了40Cr调质钢的本构模型; 利用有限元软件对40Cr调质钢高速冷滚打成形进行数值模拟, 在考虑加工硬化与动态软化的综合效应下, 获得了工件应力、应变和温度的分布, 探讨了冷滚打成形过程中热力耦合形成的原因及成形速率对热效应的影响, 并用试验进行了验证。结果表明: 工件的温度分布和等效塑性应变分布是不均匀的, 剧烈应变区的等效塑性应变高, 温升高, 难变形区的等效塑性应变低, 温升低; 试验结果证明了模拟分析的正确性。
Abstract:
On the basis of analyzing the principle of high speed cold rolling forming, the mathematical model of thermo-mechanical coupling was established. Combining static and dynamic compression tests with different strain rates at room temperature or high temperature and the application of Johnson-Cook flow stress formula, the constitutive model of 40Cr quenched and tempered steel was established. Using finite element software, high speed cold rolling forming of 40Cr quenched and tempered steel was simulated. In considering the combined effect of work hardening and dynamic softening, the distribution of the stress, strain and temperature were obtained to discuss the forming reasons for thermo-mechanical coupling in cold roll process, and the influence of forming rate on thermal effect. Finally, verification test was carried out. The results show that the temperature distribution and equivalent plastic strain of the workpiece were not evenly distributed. In intense strain region, the equivalent plastic strain was relatively large and the temperature rising was high. In hard deformation zone, the equivalent plastic strain was small and temperature rising was low. The experimental results proved the correctness of the simulation.
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