铝合金H形截面板筋件淬火过程热力耦合数值模拟

Coupled thermal-mechanical simulation on quenching of aluminum alloy H-shaped section plate reinforced part

基于有限元法处理复杂非线性问题的强大功能,建立铝合金H形截面板筋件淬火过程的热力耦合分析模型,研究在转移和淬火过程中其温度场和应力场的变化以及淬火结束后残余应力的分布规律。结果表明:铝合金H形板筋件转运过程温降幅度较小,所产生的热应力也很小;在淬火过程中,锻件前15 s温度梯度很大,随后趋于平缓;锻件心部金属应力状态由三向受压应力向三向受拉应力转变,表面金属由三向受拉应力向压应力转变,在淬火后45 s,表部和心部热应力逐渐趋于平稳;淬火终了阶段,锻件表部和心部温度趋于一致,残余应力成外部受拉应力、心部受压应力的格局,在锻件的筋部及筋部与腹板过度连接段受最大残余应力。模拟结果印证实际生产,并为后续残余应力消减提供理论依据。

Based on the powerful function of FEM in dealing with complex nonlinear problems, the coupled thermal-mechanical analysis model of quenched aluminum alloy H-shaped section plate reinforced part was built. The temperature field and stress field of part in the process of transfer and quenching as well as the distribution laws of residual stress after quenching were studied. The results demonstrate that the temperature dropping level is smaller and thermal stress is also small in the process of transfer. However, the temperature dropping gradient is larger in the first 15 s, and then tends to keep stable in the process of quenching. The three-dimensional stress condition is transformed from compressive stress into tensile stress in the center of component, while tensile stress is transformed into compressive stress in the outside of the component. After quenching for 45 s, the exterior and interior three-dimensional thermal stress tend to be stable. The surface and center temperature tend to be uniform, the part is subjected to tensile stress in the external part, and compressive stress in the internal part at the end of quenching, and the maximum residual stress is distributed in the ribs and webs over connection section. Simulation results can confirm the actual production and provide theoretical basis for subsequent residual stress reduction.