Effect of boron content and quenching temperature on the microstructure and wear resistance of high boron steel

Abstract This article investigates the change rule of the microstructure, hardness and wear resistance of high boron steel containing 0.1 wt.% to 0.5 wt.% boron in the cast state and after quenching at different temperatures. The results show that the microstructure of cast high boron steel with different contents of boron is composed of pearlite, ferrite and eutectic boride, which has lower hardness and wear resistance, and the higher the content of boron, the higher the hardness and the better the wear resistance. After quenching at 900–1,000 °C, pearlite and ferrite change into a large number of lamellar martensite and a small amount of lath martensite. After high-temperature quenching at 1,050 °C, retained austenite appears in the microstructure in addition to martensite, and borides are partially dissolved. The hardness and wear resistance are significantly improved compared to the as-cast high boron steel. As the quenching temperature increases, the dissolution of boride is obvious, the hardness and wear resistance are firstly increased and then decreased. When the content of boron is 0.5 wt.% and the quenching temperature is 1,000 °C, the hardness reaches a maximum value of 59.0 HRC, and the abrasion resistance is the best.