Optimization Of Multi-directional Precision Forging For High Strength Aluminum Alloy Casing

Lightweight weapons and equipments can effectively enhance the mobility of troops. Because of its small density and good mechanical properties, high-strength aluminum alloy is the optimum metal material for lightweight weapons. Therefore, the research of the forming process and processing technology of high-strength aluminum alloy parts has a high value.This paper outlines research status on high-strength aluminum alloy, aluminum alloy forging process and finite element simulation technology, and carry out research on forging process of 7A04 aluminum alloy casing of automatic rifles. Theoretical analysis of plastic forming, thermal-mechanical finite element numerical simulation and experimental study are involved in the research, and a multi-directional precision forging process for high strength aluminum alloy casing is developed successfully.According to the structure of the casing, detailed multi-directional precision forging process was proposed. Utilizing DEFORM-3D finite element analysis software, a series of simulation for multi-directional precision forging process were done. The results show that: based on the deformation work converted into heat principle, making full use of the advantages of high strain rate of multi-directional precision forging can reduce heat loss effectively in the forging process and improve the formability of aluminum alloy 7A04. Due to the finite element analysis and actual production conditions, the best forging process parameters were determined: initial forging temperature 430℃, the punch rate 30mm/s and the die temperature 250℃. Based on equal section principles and consider the heterogeneity of high strength aluminum alloy deformation characteristics, the size and shape of billet was optimized. A 3-stepped pre-forging part with hybrid rounding and angular chamfers was designed; target to the smallest material flow stroke, optimization function G(Δ) was established, and criterion for different section deformation was given, and the optimal solution was found.On the basis of the theory, the multi-directional precision forging experiments of typeⅠandⅢcasing were carried out. Qualified forging parts with precise dimension, smooth surface and bright color were obtained. The experiments show that: multi-directional precision forging process can significantly enhance material utilization rate and production efficiency; the process optimization methods developed are valuable to actual production.