SUITABILITY OF AUSTEMPERED CAST IRON AS BRAKE DISK MATERIAL

Several cast irons which have different graphite shapes are strengthened and toughened by austempering. They are put to a high speed friction test with a small disk. The friction speeds are 7, 14, 21 m/s and the pressure is 0.5MPa. The heat-affected layers of the disks formed by friction are only 1 to 3mm deep, showing generally the effectiveness of the heat treatment. It appears that among the austempered cast irons tested the most suitable brake disk material is one with the pearlitic matrix and flake graphite cast iron austempered.