Abstract:

A new flow control forming(FCF) of sheet metal process for parts with step cross-section was performed using aluminum sheet materials. The equivalent stress and strain distribution were obtained through deforming simulation of parts during pressing and cold forging multiple processes using DEFORM through finite element analysis. The work-hardening characterization of parts was analyzed through measuring the hardness of part surfaces after forming. Experimental results indicate that the work-hardening effect of parts with step cross-section including triplex processes (blanking, extrusion and coining), is higher than that of parts with sole pressing or cold forging. The hardness in the low surface of parts is higher with the range of 5%~10% than that in the upper surface of parts. The hardening effects of parts in both low and upper surfaces will be weakening gradually within 0~1.4t (t represents thickness), with radial direction starting from inner hole or outer edge. One new work-hardening model was suggested. 

Key words: equivalent stress, equivalent strain;micro hardness, work-hardening model

摘要：

针对一种薄板台阶断面铝板材零件进行了FCF新工艺试验，采用DEFORM有限元软件对该零件冲压、冷锻组合加工变形过程进行了数值仿真，获得了其等效应力和应变分布，并通过显微硬度(HV)表征了试件表面的实际加工硬度特性。试验研究表明：成形过程中变形区及邻域材料的冷变形硬化效应比单一冲压和冷锻时更为显著，在该工艺中表现为冲裁与挤压、压印的迭加复合;零件下平面较上平面相应处的硬度值要高，差值范围在5%~10%之间;零件上下平面硬化效果从台阶内外缘处径向扩展逐步减弱，径向硬化效应区在0~1.4t（t为料厚）范围内。由此提出了一种新的加工硬化模型。
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关键词: 等效应力, 等效应变, 显微硬度, 加工硬化模型