EFFECT OF HEAT TREATMENT ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF 30MnB5 BORON STEEL

摘要

Boron-alloyed quenched and tempered steels are widely used in hot stamping in the automotive industry. Because of their lower carbon content, they are perfectly suited for the manufacturing of steels with good wear resistance and strength. In this study, the effect of heat-treatment parameters on the microstructure and mechanical behavior of the 30MnB5 boron steel are evaluated. The specimens were quenched after three different dwell times of (5, 15 and 30) min to define the optimum dwell time and then heat treated within the temperature range from 800 degrees C to 900 degrees C at the optimum dwell time. Tensile and hardness tests were performed at room temperature. Light and scanning electron microscopies were used to follow the microstructural changes, identify the fracture surfaces of the specimens exposed to the tensile test and their relation to the mechanical properties. The results showed that the heat-treatment parameters can substantially improve the mechanical properties of 30MnB5. The dwell time of 15 min at 850 degrees C and quenching were determined as the optimum process parameters for the 30MnB5 steel.