Research on the heat treatment process of Q235A steel

Abstract

Q235A steel was heat treated by using different heat treatment process parameters. The microstructure after heat treatment was observed microscopically and its hardness was measured. The results indicated that the complete austenitization temperature has not been reached at 850°C and even under water-cooled conditions, only a very small amount of martensite can be obtained. After water cooling at 900°C, 950°C, and 1000°C, lath martensite can be obtained, which made the hardness of water cooling significantly higher than that of oil cooling, air cooling, and furnace cooling. The quenching temperature of 1000°C was too high and the microstructure obtained after water cooling, oil cooling, air cooling, and furnace cooling was relatively coarse, which was not suitable as the heating temperature for heat treatment of Q235A steel.