AZ31B镁合金管材纵连轧损伤与温度场探索性研究

The Exploratory Research for Damage and Temperature Field with Continual Mandrel Rolling Process of AZ31B Magnesium Alloy Tube

摘要:

在轧制温度为350℃,轧辊角速度约为3.14rad/s,壁厚压下量分别为20％、30％、40％的条件下,对尺寸为50mmX7mmX1000mm的AZ31B镁合金管进行纵连轧热力耦合数值模拟,在相同温度不同压下量的轧制条件下,从轧制损伤的应力状态和温度场分布两方面对镁合金管材纵连轧的数值模拟结果进行了探索性研究。结果表明：在相同轧制温度条件下,随着压下量的增大,最大损伤值也随着增大,且最大损伤值均出现在轧辊的辊缝处。同时塑性变形产生的热量也增大,且因轧辊辊顶处和镁管间存在较大的热交换,所以辊缝处的温度要高于辊顶处,两者之间有一定的温度差,壁厚压下量越大则温度差越大。相同压下量条件下,纵连轧镁合金管的损伤程度要比镁合金板材轧制的小。

Abstract:

When the rolling temperature was 350℃, the angular velocity of the roller was about 3.14rad/s and the wall thickness reduction rate was 20%, 30% and 40% respectively, the coupled thermo-mechanical numerical simulation of the AZ31B magnesium alloy tube with the size of 50mmX7mmX1000mm in continual mandrel rolling process was carried. Then, the research on the damage stress and the distribution of temperature field of the simulation was conducted on the condition that the magnesium alloy tube was at the same rolling temperature but differ in reduction rate.The results show that: when the rolling temperature is same, the maximum damage value of the AZ31B magnesium alloy tube and the heat generated by the plastic deformation is increased with the increase of the wall thickness reduction ratio. With the location of the maximum damage value appears in the roller gap. And, because of the large heat exchange between the roller and the tube, the temperature of the roller gap is higher than the top of the roller, and the temperature difference is increased with the increase of the Wall thickness reduction ratio.So, when in the same rolling condition, the damage of magnesium alloy tube in Longitudinal rolling is smaller than the magnesium alloy sheet.