Optimization Of Rolling Speed And Roll System Of AZ31 Magnesium Alloy Strip Warm Rolling Mill Based On Heat Transfer

Magnesium alloy is the minimum density metal structural material can be used in industrial production. Rolling out the quality of magnesium alloy plate and strip can be widely used in many industrial domains such as magnesium battery and 3C productions, it has a bright development prospect. Because the special crystal structure characteristics of magnesium alloy, it has the poor ability of plastic deformation at room temperature, the deformation plasticity increased significantly when the temperature is above 200°C, so the study on the temperature influence on the plastic deformation of magnesium alloys is important.According to the six roll mill through heat roll heating at the laboratory of USTL,preheating the rolled piece before rolling by tunnel furnace, rolling roll and the rolled piece temperature change is analyzed in the process of rolling AZ31 magnesium alloy. Using inverse analysis method combined with temperature measuring experiment and finite element simulation, calculates the synthetical heat transfer coefficient between roll and rolled piece, roll and the air of rolling mill in the process of rolling are 18000W/(m2·°C) and30W/(m2·°C). Through the thermocouple temperature measurement experiment getting the temperature curve on the different thickness of the magnesium alloy in the rolling process,comparing with the simulation temperature curve to authenticate the accuracy of the finite element simulation, as analysis the influence on the preheating rolled piece heated by tunnel furnace through temperature measured experiment. Using ANSYS FLOTRAN module to simulate, considering the factors to influence plate temperature from heat transfer prospect in the rolling process including the rolling temperature, rolling speed, preheating temperature and roll diameter. Getting limit parameters meet the condition that the sheet center temperature reaches 200°C by controlling variable method. Through the rolling experiments under the conditions of different rolling parameters and observing the microstructure,after200°C preheat before rolling, 3mm thick magnesium alloy can increase rolling rate is about10% under the same rolling force. When rolling without preheating,Surface deformation is serious, after the grain crushing the grain presents direct polygon, accompanied by a large number of twin. When rolling after preheating,the grain presents smooth and isometric,recrystallizational grain presents, deformation can penetrate, speed can be improved.This article optimize processing and roll system of AZ31 magnesium alloy six high warm rolling mill based on the angle of heat transfer, the rolled piece temperature as thethickness of rolled piece, rolling speed, roll diameter, regression formula of preheating temperature, provide guidance for the production.