Effect of hardenability on microstructure and property of low alloy abrasion-resistant steel

Low alloy abrasion resistant steel is widely applied in harsh working fields, such as mining, construction and cement production. Hardenability is one of principal factors which affect the service life of abrasion-resistant steel. The goal of this work was to investigate the effect of hardenability on microstructure and mechanical properties throughout thickness of low alloy abrasion resistant steel. Three kinds of 50 mm thickness wear resistant steels with different low alloy chemical composition and the same heat treatment process were produced and compared. Results show the hardness decreases along the thickness direction from surface to the middle and the hardness variations are 16.4%, 2.6% and 3.5% respectively. The strength in the 1/4 layer is larger than that in the 1/2 layer in both horizontal and vertical direction. The strength and impact toughness differences along thickness of the steels with more hardenability promoting elements are smaller, with tempered martensite dominates the whole thickness plate. While the hardened layer of the steel lack of hardenability elements is only about 10 mm and its 1/2 thickness layer is dominated by bainite with relatively poor wear property. Furthermore, the precipitates in 1/2 and 1/4 layers of three steels show remarkable differences.