Research On Cold Stamping Properties And Cold Stamping Process Of AZ31B Magnesium Alloy Sheet

Magnesium alloys have higher specific strength, specific stiffness, damping performance etc. Their products have potential applications in the automotive and electronics. However, the magnesium is a close-packed hexagonal structure, conventional rolling generally gives rise to a strong basal texture in magnesium alloy sheets, which leads to poor stamping formability at the room temperature. The non-basal slip systems are activated at high temperature, which increases stamping formability. However, when magnesium alloy sheets carry out hot stamping, heating and insulation equipment are needed, production process is complex, and magnesium alloy products have lower strength and poorer surface quality, so cold stamping, is just to overcome these deficiencies, and facilitate the realization of large-scale production.In previous researches, a method that we had termed'repeated unidirectional bending'(RUB) could effectively improve the (0002) basal texture of magnesium alloy sheets which can enhance its formability. Stamping formability and the cold stamping process of cell phone house for magnesium alloy sheet with different texture were investigated systematically. The following conclusions were obtained.â‘ The RUB process can induce the c-axes of grains to tended to incline from the TD towards the RD, which can improve mechanical properties of magnesium alloy sheet. Compared with the as received specimens, the RUB processed specimens show a much lower yield strength ratio and a larger fracture elongation. The fracture elongations of the RUB processed specimens are improved especially in the RD with the largest increase from 19.2% to 26.7%.â‘¡The RUB process has important implications for n value and r value of magnesium alloy sheet. Compared with the as received specimens, the RUB processed specimens show a much smaller r-value and a larger n-value especially in the RD, which decreases from 2.15 to 0.92 and increases from 0.20 to 0.29, respectively.â‘¢The RUB process can improve stamping formability of AZ31B magnesium alloy sheets effectively. Compared with as received specimens, the Limit drawing ratio(LDR) of the RUB processed specimens increase from the 1.2 to 1.5.â‘£The RUB process can effectively improve the cold drawing performability of rectangular parts for magnesium alloy sheets, the results of numerical simulation and experimental investigations have shown that cell phone houses can be stamped successfully in crank press using the RUB processed AZ31B magnesium alloy sheet.