Study Of Microstructure And Mechanical Properties Of New Low Alloy Wear-resistant Steel

Nowadays, the wear-resistant metal materials of austenite-Mn steel, wear-resistant white cast irons and high-Cr cast irons are widely used. While, among them, the high-Mn steel can not full play, because of its wear-resistance mechanism. The wear-resisting property only work well in good working condition, it will get a lot of wear and tear while in the worse working condition and in the initial stage. Therefore, doing research in and developing low-alloy wear-resistant steel to improve its comprehensive mechanical property especially in wear-resistant is significant for energy conservation, reduction of consumption and faster and better development of social economy.In this paper, different low-alloy wear-resisting steels are for the subjects investigated. Hot rolling texts of the subjects investigated are worked by the Φ450mm experiment units of RAL key laboratory under the different rolling technologies. Structure property of the rolling specimens are analysed by metallographic microscopic analysis, hardness profile, tensile mechanical performance, SEM fracture analysis and energy spectrum analysis.In this paper, the main conclusions are as follows:(1) The V-Ti system and Cr-Nb system specimens’true stress-true strain curve is belong to the strain-hardening type under the deformation temperature of800℃with the deformation conditions of strain rate of0.1s-l,strain capacity of0.7. The Cr-V-Ti system specimen’s true stress-true strain curve is belong to the dynamic recovery type under the deformation temperature of800℃,850℃and900℃. The V-Ti system specimen’s true stress-true strain curve is belong to the dynamic recovery type under the deformation temperature of850℃. The Cr-Nb system specimen’s true stress-true strain curve is also belong to the dynamic recovery type under the deformation temperature of850℃and900℃.The Cr-V-Ti system specimen’s true stress-true strain curve is belong to the dynamic recrystallization type under the deformation temperature of900℃and1000℃. The V-Ti system and Cr-Nb system specimens’true stress-true strain curve is belong to the dynamic recrystallization type under the deformation temperature of900℃～1000℃.(2) Impact experiments demonstrate that the main role of Ti elements is to strong deposition strengthening. And with the Cr and Ti element composite added, the material toughness reduced because of TiN separates out in grain boundary and deformation band at the last rolling. It is obvious that compound to add Nb elements to improve material of impact toughness effect, this cause that the impact toughness of Cr-V-Ti system and V-Ti system experimental steel only close to70J/cm2,the impact toughness values of Cr-Nb system experiment steel reached132.08J/cm2.(3) Results showed that temperature of last rolling impacts on performance of specimens obviously. The rolling at finishing temperature870℃is the austenitic unrecrystallization rolling, while the rolling at finishing temperature750℃is two phase area rolling. The grain organization of V-Ti system experimental steel in finishing temperature870℃is more bulky than750℃obviously(4) Combination property of Cr-Nb system specimen is the best under the750℃finishing temperature of technological conditions. The property is as follows, impact ductility of126.25J/cm2, yield strength of746MPa, tensile strength of959MPa,hardness of314HB and extensibility of15.43%.