中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 26 No. 8 August 2016 |
（1. College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China;
2. Key Laboratory of Advanced Forging & Stamping Technology and Science,
Ministry of Education, Yanshan University, Qinhuangdao 066004, China;
3. College of Vehicles and Energy, Yanshan University, Qinhuangdao 066004, China）
Abstract:The cylindrical part of sheet metal based on hot-granule medium-pressure forming (HGMF) technology was investigated. The stress functions of the free deformation zone and the fracture instability theory were combined to establish the analytical expression of the critical pressure of punch. The results show that the active friction between the granule medium and the sheet metal, as well as the non-uniform internal pressure presented by the solid granule medium, can obviously improve the forming performance of the sheet metal. The critical pressure of punch increases with the increment of the friction coefficient between the granule medium and sheet metal, as well as the plastic strain ratio, whereas it decreases with the increase of the material-hardening exponent. Furthermore, the impact on the critical pressure from high to low order is the plastic strain ratio, the friction coefficient, and material-hardening exponent. The deep-drawing experiment with HGMF technology on AZ31B magnesium alloy sheet verified the instability theory.
Key words: hot-granule medium-pressure forming; deep-drawing; instability; cylindrical part
