Study On Technics Of Twin-roll Casting Of Az61 Magnesium Alloy

Magnesium alloys are the lightest in the constructional metal materials.Due to their excellent properties such as high specific strength and stiffness, good damping and machinability, shock resistance, electromagnetic shielding, magnesium alloys are deemed as one of the most potential materials, and have received more and more attention. The consumptive quantity of magnesium alloy all over the world trends to rise constantly. Magnesium alloys are rapidly applied to vehicles,3C electronic product, and aerospace automobile, etc.Magnesium alloy strip is a product demanded urgently.However, the rolling formability of magnesium alloys is very poor owing to their crystallography. The conventional technology is complicated and low efficiency, which limits the development and application of magnesium alloys seriously. The twin-roll casting process of magnesium alloy strip is one of the main research tasks in magnesium alloys industry;it possesses the advantages such as short process, low energy consumption, less investment and so on.The key technical parameters in twin-roll casting process can affect the distribution of temperature field, flow field and stress field in the nozzle and cast-rolling zone significantly, and then decide whether the twin-roll casting process can be successfully established and high quality casting strips can be obtained. In this paper, the temperature field, flow field and stress field of the twin-roll strip casting were simulated with the ANSYS software, and the simulation conclusions were consulted to guide the experiment research, high quality magnesium alloy strip is manufactured by twin-roll casting. The main results are as followed:(1)The three-dimensional temperature field and flow field of the magnesium melt in the nozzle and cast-rolling zone under different casting speed and pouring temperature are established and simulated by the ANSYS software, and the rational ranges of casting speed and pouring temperature were got.(2)The three-dimensional stress field of the magnesium melt in the cast-rolling zone under different casting speed and pouring temperature is established and simulated by the ANSYS software, in order to predict where cracks may be formed by analyzing the influences different technical parameters have on them; it is recommended that increasing casting speed or pouring temperature properly can make the zone where stress value is maximum avoid being rolled srongly, and to prevent cracks from forming or expanding.(3)According to the results of simulation, the best technical parameters of twin-roll casting of AZ61 magnesium alloy are obtained by experimentalizing largely with AZ61 magnesium alloy, including the optimal ranges of pouring temperature(700～720℃)and casting speed(2.4±0.05m/min);at last, the qualitified AZ61 magnesium alloy thin strip was produced successfully, with the size of 5mm in thickness and 420mm in breadth.