1 National Key Laboratory of Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China;
2 School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
Abstract：The limit drawing ratio is influenced by the bending and unbending effect during reverse deep drawing of plate. The 5A06 aluminum alloy plate widely applied in aerospace industry was used, and the reverse deep drawing of the 4.5mm thick plate was investigated experimentally and numerically. The stress and strain distributions of plate were analyzed, the deformation behaviour was discussed for three types of cross section of die during the reverse deep drawing process; moreover, the changing rule of strain paths with the die profile was also discussed. Results show that a maximum radial stress is induced by the bending effect at the transient region between the inside die radius and straight wall, where a radial stress and strain gradient along the thickness direction appears and the fracture is easy to occur. For the semi-circle profiled die structure, the limited punch stroke is 203mm which is increased by 40% than that for the die with a planar profile section. The semi-circle profiled die structure can reduce the bending effect, effectively reduce the stress gradient and the maximum stress value in the transient region, and is helpful to improve the limit drawing ratio of the 5A06 aluminum alloy plate.
 董鹏, 孙大千, 李洪梅, 等. 6005A-T6铝合金搅拌摩擦焊接头组织与力学性能特征[J]. 材料工程, 2012(4):27-31. DONG P, SUN D Q, LI H M, et al. Microstructural and mechanical characteristics of friction stir welded 6005A-T6 aluminium alloy[J]. Journal of Materials Engineering, 2012(4):27-31.
 刘杰, 杨景宏, 韩凤武, 等. 厚板铝合金搅拌摩擦焊匙孔补焊接头组织与性能[J]. 材料工程, 2012(7):29-33. LIU J, YANG J H, HAN F W, et al. Microstructures and properties of thickness aluminium alloy eleocellarium repairing welding joint by friction stir welding[J]. Journal of Materials Engineering, 2012(7):29-33.
 ESCHE S K, AHMETOGLU M A, KINZEL G L, et al. Numerical and experimental investigation of redrawing of sheet metals[J]. Journal of Materials Processing Technology, 2000, 98(1):17-24.
 ESCHE S K, KHAMITKAR S, KINZEL G L, et al. Process and die design for multi-step forming of round parts from sheet metal[J]. Journal of Materials Processing Technology, 1996, 59(1):24-33.
 PARSA M H, YAMAGUCHI K, TAKAKURA N, et al. Consideration of the re-drawing of sheet metals based on finite element simulation[J]. Journal of Materials Processing Technology, 1994, 47(1/2):87-101.
 江学强, 吉卫, 曹海桥, 等. 厚壁筒形件热拉深成形数值模拟及工艺研究[J]. 热加工工艺, 2014, 43(11):148-150. JIANG X Q, JI W, CAO H Q, et al. Numerical simulation and technical study of hot drawing forming thick-wall cylinder[J]. Hot Working Technology, 2014, 43(11):148-150.
 CHUNG S Y. Stress analysis of reverse redrawing of cylindrical shells[J]. Sheet Metal Industries, 1951(28):453-458.
 ZHARKOV V A. Theory of the drawing of cylindrical parts from sheet materials[J]. J Mater Process Technol, 1992,(31):379-392.
 CHANG D F, WANG J E. Wall thickness distribution analysis of a drawn-redrawn can[J]. Transactions of the North American Manufacturing Research Institution of SME, 1996, 24:125-130.
 MAJLESSI S A, LEE D. Development of multistage sheet metal forming analysis method[J]. Journal of Materials Shaping Technology, 1988, 6(1):41-54.
 PAUNOIU V, RAMOS M G, MANGAS V L. Experimental and numerical analysis of multistage deep drawing[J]. The Annals of "Dun?rea de Jos" University of Galati:Fascicle V, 2012, 1:79-84.
 THUILLIER S, MANACH P Y, MENEZES L F, et al. Experimental and numerical study of reverse re-drawing of anisotropic sheet metals[J]. Journal of Materials Processing Technology, 2002, 125:764-771.
 ZHAO S D, ZHANG Z Y, ZHANG Y, et al. The study on forming principle in the process of hydro-mechanical reverse deep drawing with axial pushing force for cylindrical cups[J]. Journal of Materials Processing Technology, 2007, 187:300-303.
 WANG H, GAO L, CHEN M. Hydrodynamic deep drawing process assisted by radial pressure with inward flowing liquid[J]. International Journal of Mechanical Sciences, 2011, 53(9):793-799.
 GRAF A, HOSFORD W. The influence of strain-path changes on forming limit diagrams of A16111 T4[J]. International Journal of Mechanical Sciences, 1994, 36(10):897-910.
 STOUGHTON T B, ZHU X. Review of theoretical models of the strain-based FLD and their relevance to the stress-based FLD[J]. International Journal of Plasticity, 2004, 20(8):1463-1486.
 KURODA M, TVERGAARD V. Effect of strain path change on limits to ductility of anisotropic metal sheets[J]. International Journal of Mechanical Sciences, 2000, 42(5):867-887.