7075铝合金端盖件液态模锻成形工艺研究

发布时间：2018-04-23 00:15

  本文选题：7075铝合金 + 液态模锻　； 参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：铝合金材料具有密度低、强度高的优良特点,在不同的热处理下可以得到优异的物理性能和机械性能,广泛应用于特种车辆零部件的加工制作。铝合金液态模锻成形方法具有产品质量高、成本低、易管理的优点,其中金属液的浇注过程是关键工艺环节,传统的浇注过程为手工浇注,存在着劳动强度高、尺寸精度差等一系列问题。本文以某特种车辆7075铝合金端盖成形为出发点,设计改进了金属液定量输料系统,可实现在全封闭环境下定量输送熔融金属液,提高金属液浇注精度,减少氧化缺陷,提高成形件质量。基于2000KN通用液压机,设计加工了端盖液态模锻成形模具,在该模具上配合金属液定量输料装置的浇注管道。选择液态模锻模拟软件Pro CAST对金属液充型过程进行了模拟分析,优化定量输料系统的各工艺参数,研究了不同充型速度下制件可能出现的缺陷状况,模拟分析了冲头水平运动速率等工艺参数对成形的影响规律,确定冲头活塞运动速率为0.08m/s。设计了成形试验方案,研究了金属液浇注温度、模具预热温度和补缩量等工艺参数对成形件的微观组织和力学性能的影响规律,确定最优金属液浇注温度为720℃~730℃之间,最优模具预热温度为200℃~250℃之间,确定最优补缩量为3mm~4mm之间。对成形件质量问题进行总结,分别是冷隔和浇不足、表面缺陷和内部缩松缩孔,通过提高保压时间、控制金属液温度和模具温度、改变模具润滑等方法加以解决。分析端盖不同位置组织结构和力学性能,法兰处组织比较致密,晶粒分布均匀,性能最好;端盖底部处容易出现缩松缩孔,力学性能相对较低;端盖侧壁易出现显微裂纹,影响成形件的使用寿命。对拉伸试样断口形貌进行观察分析,断口存在大量的韧窝和一定的微观孔洞,部分位置分布着沿晶断裂,总结断裂机理主要为韧性断裂,附带一定程度的解理断裂。
[Abstract]:Aluminum alloy has the advantages of low density and high strength. It can obtain excellent physical and mechanical properties under different heat treatment. It is widely used in the processing and manufacture of special vehicle parts. The liquid die forging method of aluminum alloy has the advantages of high product quality, low cost and easy management. The pouring process of molten metal is the key process, and the traditional casting process is manual casting, which has high labor intensity. A series of problems, such as poor dimensional accuracy, etc. Based on the forming of 7075 aluminum alloy end cover of a special vehicle, this paper designs and improves the quantitative feeding system of molten metal, which can realize the quantitative transportation of molten metal under the completely closed environment, improve the pouring precision of molten metal and reduce the oxidation defect. Improve the quality of forming parts. Based on 2000KN universal hydraulic press, the end cap liquid die forging forming die was designed and machined, and the pouring pipe of the liquid metal quantitative feeding device was used in the die. The liquid die forging simulation software Pro CAST was selected to simulate and analyze the filling process of liquid metal. The process parameters of the quantitative feeding system were optimized, and the possible defects of the parts at different filling speeds were studied. The influence of process parameters such as horizontal movement rate of punching head on the forming process is simulated and analyzed. The piston motion rate of punch head is determined to be 0.08 m / s. The forming test scheme was designed, and the influence of the process parameters such as pouring temperature of molten metal, preheating temperature of die and filling amount on the microstructure and mechanical properties of the forming parts was studied. The optimum pouring temperature of molten metal was found to be 720 鈩，

本文编号：1789578