For a long time, the most widely used ultra-high strength wear-resistant steel plate in China is 30CrMnSiNi2A wear-resistant steel plate, until recent years, scientific researchers are still carrying out research on all aspects of the steel. On the basis of 30CrMnSiNi2A wear-resistant steel plate, reduce the C content, increase the Cr content, and add about 1% W and 0.5% Mo to form another important high-strength steel plate for aviation - 30Cr2MnSiNi2WMo wear-resistant steel plate. The steel is often used in complex shape parts and parts used at a certain temperature, has good tempering stability, has good comprehensive performance at higher temperatures, and the working temperature can reach more than 400℃. In this paper, the microstructure of 30Cr2MnSiNi2WMo wear-resistant steel plate after tempering at different temperatures is deeply studied, and the reason of its high tempering resistance is analyzed from the aspect of microstructure.
The 30Cr2MnSiNi2WMo wear-resistant steel plate used in the test was remelted by vacuum arc, heated at 910℃, air-quenched, and then tempered at 210℃ and 510℃. TEM samples were prepared by ion electrolysis thinning. The microstructure was observed by JEM-2010 transmission electron microscope.
The test results show that:
(1) When the tempering temperature is between 210 and 325℃, the tensile strength of 30Cr2MnSiNi2WMo wear-resistant steel plate is lower than that of 30CrMnSiNi2A wear-resistant steel plate, and when the tempering temperature is higher than 325℃, the tensile strength of 30Cr2MnSiNi2WMo wear-resistant steel plate is higher than that of 30CrMnSiNi2A wear-resistant steel plate. With the increase of tempering temperature, the tensile strength of 30CrMnSiNi2A wear-resisting steel plate decreases rapidly, while the tensile strength of 30Cr2MnSiNi2WMo wear-resisting steel plate shows a slow decline trend before 510℃. It can be seen that 30Cr2MnSiNi2WMo wear-resistant steel plate has stronger tempering resistance.
(2) After tempering at 210℃, the microstructure of 30Cr2MnSiNi2WMo wear-resistant steel plate is lat martensite with high density dislocation and M2C cograted with matrix; After tempering at 510℃, M2C dispersed in the matrix and α phase recovered obviously.
(3) Due to the increase of Cr content and the addition of W and Mo alloying elements, the tempering resistance of 30Cr2MnSiNi2WMo wear-resistant steel plate is improved. After tempering, M2C is formed in 30Cr2MnSiNi2WMo wear-resistant steel plate, and the uniform precipitation of M2C is the reason for the high strength and high toughness of double-hardened ultra-high strength wear-resistant steel plate.
