Hot rolling of magnesium alloys and the process of making clad magnesium alloys sheets

Abstract

For a study to find out the proper condition in hot rolling process magnesium slabs kept under the temperature of 350°C were rolled with the rolls heated at different surface temperature in the range of 150°C to 300°C. The maximum rolling reduction rate increased from 60% to 90% or more with the increase in temperature of the rolls.The difference in rolling direction of mechanic properties of the sheets were decreased as the temperature in surface of the rolls was increased. When the surface temperature of rolls was kept at 300°C, the magnesium alloys could easily rolled into sheets without any intermediate annealing.Generrally, heat-treatable high strength magnesium alloys, for example AZ91, have poor corrosion resistance.It was attempted, therefore, to coat these alloys with high purity magnesium, which has high corrosion resistance, and to make clad sheet by hot rolling.The favourable conditions to make them in clad form were found out as follows:1. The temperature of surface of the rolls should be kept at 250°C∼300°C.2. The temperature of the slabs should be at about 400°C.3. The reduction rate for the first pass should be 50% or more.The clad sheets thus produced had high corrosion resistance and good mechanical properties.