工艺参数对铝合金微齿轮热挤压成形的影响

Effect of Process Parameters on Hot Extrusion Forming of Aluminum Alloy Micro-gear

针对7075铝合金微齿轮挤压过程中出现的微尺度效应问题,将退火后的7075铝合金进行等温微压缩试验,获得材料的真实应力应变曲线,导入DEFORM软件,并模拟微挤压成形过程。定义挤出端凸度来评定微挤压件的成形性能,挤出端凸度越小,则成形性越好。设计正交试验,研究入模角、坯料直径、挤压温度、挤压速度和摩擦因数等对微齿轮热挤压成形过程中最大成形载荷和成形性能的影响规律。分析结果表明:坯料直径对最大成形载荷和挤出端凸度的影响均最大;挤压速度对成形载荷的影响较大,挤压温度的影响次之;挤压温度对挤出端凸度的影响较大,挤压速度的影响次之;入模角和摩擦因数对成形载荷和挤出端凸度影响均较小。通过优化工艺参数模拟挤压得到质量良好的微齿轮。

Aiming at microscale effect in micro-extrusion process for 7075 aluminum alloy gear,the true stress-strain curve of 7075 aluminum alloy were obtained by isothermal and micro compression experiment.Numerical simulation for forming process of micro-gear extrusion was studied by using DEFORM software with the true stress-strain data.The standard of convexity of extruding parts is initialized to evaluate the formability of micro-extrusion parts.The effect of die angle,blank diameter,extrusion temperature,extrusion velocity and friction coefficient on the maximum forming load and convexity of extruding was investigated by using orthogonal array method.The results showed that the blank diameter had the greatest influence on both the maximum forming load and convexity of extruding parts.And die angle and friction coefficient had little influence on the experiment indicators.The extrusion velocity had greater influence on forming load while that of the extrusion temperature is inferior.The extrusion temperature had greater influence on convexity of extruding while that of extrusion velocity is inferior.The micro-gear with good dimensional accuracy and surface quality was obtained by optimizing the process parameters.