Study On The Warm Deep Drawing Of ZK60 Magnesium Alloy Cups

The content of magnesium resource in nature is rich, it has a lot of advantages. Therefore, it is widely used in automotive, aerospace and 3C products. However, due to the close packed hexagonal crystal structure of magnesium alloy, its formability at room temperature is poor. From the perspective of warm forming, this article studied on process parameters of the forming quality of ZK60 magnesium cups. Specific contents are as follows:1) Research on the flow stress change law of ZK60 magnesium alloy under different temperature and strain rate, observed the microstructure of hot tensile specimen so that we can obtain organization transformation at different temperature and strain rate of ZK60 magnesium alloy hot tensile process;2) Based on Fields-Backofen mathematical model which added softening factor, we established constitutive equations which can accurately describe the rheological behavior of ZK60 magnesium alloy: σ= 2637.37ε374ε0.0262exp(-0.0099T-2.498ε)3) By using ABAQUS finite element simulation software, we studied on different process parameters, such as punch radius, temperature, blank holder force. From the research, conclusions are as follows:punch radius is 7mm; we studied different temperature 150℃,200℃,250℃,300℃,350℃ effect on the forming quality of ZK60 magnesium alloys cups, the results showed that at 250℃, the maximum depth of cylinder part is 34.9 mm. On this basis, we studied the constant blank-holder force and the variable blank-holder force on the influence of ZK60 magnesium cylinder parts, among them,6 different load models of VBHF was studied, the VBHF type which first increased and then decreased curve obtained deepest cup, and the maximum reduction rate is smaller than constant BHF;4) We designed the cylinder deep drawing mold of hot drawing, and had a finite element simulation experiments verify, specific experiment are as follows:the effect of cups at different temperature and sheet size, BHF, from the experimental results, the difference between simulation and experiment is small, which shows the effective of numerical simulations;5) In order to obtain the microstructure changing rule in different areas of the cylindrical parts, we observed the microstructure of bottom, punch round corners, straight wall, die round corners and flange, we found that at different regions of cylindrical part, there are different degree of dynamic recrystallization grain size, when the thickness strain is large, the degree of dynamic recrystallization increases.