【摘要】 利用热压缩实验建立的本构模型结合挤压力极限方程和温升极限方程构建了2099合金的挤压极限图,给出了挤压极限曲线的临界方程,并对挤压极限图的正确性进行了验证。结果表明,随着初始锭温的升高,压力极限曲线所对应的挤压速度增加,而温升极限曲线所对应的挤压速度降低;2099合金最佳挤压温度为410~460℃,当挤压比λ分别为29和48时,挤压速度可分别在不超过10和6 mm/s内选取;在安全区进行挤压时,两种挤压比条件下均可得到表面无缺陷的型材;挤压温度升高到480℃,挤压速度在大于温升曲线临界值挤压时(λ=29),型材表面出现周期性裂纹;挤压实验结果验证了挤压极限图的正确性,并可用于指导实际生产。更多还原

【Abstract】 The extrusion limit diagram was constructed using hot compression experiments combining with extrusion force limit diagram and temperature rise limit diagram,the equations of critical extrusion limit curves were given,and the extrusion tests were conducted to confirm the reliability of extrusion limit diagram.The results show that with the increase of the initial ingot temperature the extrusion speed increases which is related to the pressure limit curve,whereas the extrusion speed decreases which is corresponding to the temperature rise limit curve.The optimum extrusion temperature range for 2099 alloy is 410~460 °C.When λ is 29 and 48 the corresponding extrusion speed can be selected within no more than 10 and 6 mm/s,respectively.The qualified profiles can be obtained in a safe zone.However,periodic cracks appear on the profile surface when extrusion speed exceeds the critical value of the temperature rise limit curve at 480 °C.Finally,the reliability of the extrusion limit diagram has been verified by extrusion tests.更多还原