双相不锈钢换热板片回弹变形模拟与实验研究

Simulation and experimental study on springback deformation of duplex stainless steel heat exchanger sheet

针对双相不锈钢板片显著回弹变形使得其在可拆卸板式热交换器行业中的开发变得非常困难的问题,采用显/隐式相结合的方法对高强度双相不锈钢FDX27板片进行冲压成形回弹预测。首先,采用显式求解法对板料进行冲压成形分析;其次,移除上下模具后采用隐式求解法对板料的回弹变形进行预测,通过数值模拟对比分析不同模具圆角半径和摩擦系数对FDX27板片回弹变形高度的影响规律,同时选取3种不同材料板片进行对比分析;最后,设计不同的产品工艺试验对回弹数值模拟结果进行验证。结果表明,模具圆角半径对板片回弹变形高度效果影响不显著,而摩擦系数的影响效果显著;材料强度性能和硬化指数N值对板片回弹变形高度的影响效果均很显著;验证结果显示两者具有很好的一致性,证明了回弹数值分析方法是可靠的。研究结果对推动新材料在可拆卸板式热交换器行业中的开发应用具有实际意义。

The significant springback deformation of metal sheet makes the development of plate and frame heat exchanger extremely difficult for duplex stainless steel.In this paper,a coupled explicit to implicit finite element methods was adopted to predict springback deformation in forming processes of metal sheet for high strength duplex stainless steel FDX27 sheet.Firstly,the explicit method was utilized to analyze the contact-based forming operation of a production stamping process.Then,an implicit method was performed to simulate the springback deformation after the forming die was removed.By using numerical simulation method,the effects of different mold radius and friction coefficients on springback deformation of FDX27 sheet were analyzed.Meanwhile,the effect of material strength property on springback deformation was studied by choosing three different sheets.Finally,different product experiments were performed to verify the accuracy of springback simulation results.The results show that the die fillet radius is not sensitive to the springback deformation height,but affects the friction coefficients remarkably.The material strength properties and hardening index N have a significant effect on the springback demormation height.The experimental results are in good agreement with the simulation results,which shows that the springback numerical analysis method is reliable and the present work provide an instruction when new material was applied on heat exchanger R&D field.