Effect of Boron Content on the Structure and Property of Fe-B-C Alloy

The microstructure and hardness of Fe-B-C alloys containing 0.5%~2.0%B were studied in as-cast and different quenching heat treated conditions.The experimental results showed that the as-cast Fe-B-C alloy containing 0.14%C and 0.50% B has simple structure and has no apparent eutectic boride with low hardness.When the boron content increased,the eutectic borides generated at the grain boundary,and the eutectic borides showed the distribution of network structure and with uniform grain.After quenching heat treatment,the eutectic borides network was broken.When the quenching temperature reached 950 ℃,the fracture of eutectic borides network was obvious.The microstructure of Fe-B-C alloy had no obvious growing up and the hardness reached 47 HRC,which was the optimal performance in present experimental conditions.As the quenching temperature increased further,the microstructure of Fe-B-C alloy began to grow up,and the hardness decreased slightly.While evaluating the microstructure and hardness of as-cast Fe-B-C alloy,the good overall performance of as-cast Fe-B-C alloy can be obtained as the boron content is 1.5% and quenching temperature is 950 ℃.