The size effect of martensite laths and precipitates on high strength wear-resistant steels

Abstract

Low alloy high strength wear resistant steels are with high toughness, low cost and good abrasion resistance. It can effectively resist the propagation of wear cracks and prolong the service life of machine components. This paper focuses on the internal relationship between macroscopic physical properties and microscopic martensite lath and precipitate size throughout thickness of wear resistant steel. Four kinds of 40mm thickness wear resistant steels with different alloy chemical composition were produced and investigated. Results show the strength and hardness performance of ARIV are obviously higher than other three steels. ARI have a relatively large strength difference through thickness. The impact toughness of ARIV is relatively uniform, which is greater than that of the ARIII at middle layer and lower than that of the ARIII at 1/4 layer. The width of martensite lath of ARIV is relatively small, mainly 100 ∼ 300 nm, while that of ARII and ARIII is mainly 200 ∼ 400 nm. ARIV steel has shorter martensite lath band and more precipitates below 50 nm. It indicates that the size of martensite laths and precipitates of wear-resistant steels are important factors to determine its performance throughout thickness.