Preparation Techniques And Wear Mechanism Of Light-weight Wear Resistant Steel For Cone Crusher Lining Plate

With the metallurgy, mining and other industries continue to appear large-scale equipment, such as mining, crushing, mining and other equipment, its wear parts weighing a few tons to dozens of tons. Compared with the traditional high manganese steel, ultra-high manganese (Mn> 17%) steel has a stronger work hardening ability and higher low-temperature toughness. So it is widely used in strong load or extrusion conditions, such as crusher hammer, large ball mill liner. However, the traditional high-manganese steel (Hadfield steel) or ultra-high manganese steel due to the low yield strength and the initial hardness etc, the wear parts can not fully play its own characteristics due to deformation and retirement in the low load, which can not meet these large thick-walled wear requirements. Therefore, the paper from the aspects of composition design, smelting, casting, heat treatment and impact wear to investigate the wear mechanism and preparation techniques of high manganese-high aluminum light-weight wear resistant steel for cone crusher lining plate, which based on the design principle of high strength, high hardness, high toughness and low density.The effects of casting heat remained water toughening and conventional water toughening treatment on the microstructure and properties of novel light-weight wear resistant steel (Fe-24Mn-7.1Al-1.0C cast steel) were investigated. The results show that the novel light-weight wear resistant steel can be produced by the casting heat remained water toughening (residual heat temperature is higher than 850?), and its undissolved carbide grade W2, precipitation carbonization level X2. After the heat treatment, the impact toughness value (V notch) is 108 J/cm2, the surface hardness is 219 HB, the tensile strength is 784 MPa, the yield strength is 408 MPa, the elongation is 53.8%. The light-weight wear resistant steel has the best water-toughness temperature of 1050? for 1 h:the impact toughness is 231.3 J/cm2, the hardness is 205 HB, the tensile strength is 809 MPa, the yield strength is 410 MPa, the elongation is 59.6%.Aiming at the problem that the initial hardness and the yield strength of the light-weight wear-resisting steel were not enough, the aging method was proposed to improve the initial hardness and strength of the steel. The optimal heat treatment process of the light-weight wear resistant steel was optimized:heating to 1050?×1h water toughness, aging at 550? for 2 h, air cooling. The mechanical properties of the steel are improved obviously due to a large number of nano-sized (Fe, Mn)3AlC ?-carbide precipitates in austenite matrix, the tensile strength is 825 MPa, the yield strength is 574 MPa, the impact toughness is 156J/cm2, the hardness is 271 HB, the elongation is 32% respectively. The results show that the hardness, strength and impact toughness reach the best match value. The yield strength and the hardness are improved by 40.0% and 32.2% respectively.The wear resistance of light-weight wear resistant steel was studied by comparing with the modified Hadfield (Mn13Cr2) steel under the same wear conditions. The results show that the wear resistance of light-weight wear resistant steel is higher than that of Mn13Cr2 steel under 0.5 J-4 J impact energy after only conventional water toughening treatment. It is 1.09?1.17 times under medium and low load conditions (0.5 J-2 J), and 1.4 times under high impact energy (4 J). The wear resistance of steel is improved by the precipitation of K-carbides after aging 2 h at 550?, which is 2.09 times as high as that of Mn13Cr2 under the low impact load (0.5 J).Finally, by comparing the wear resistance, the wear surface morphology and sub-surface microstructure of light-weight wear resistant steel were compared (Fe-24Mn-7.1Al-1.0C cast steel) with ultra-high manganese steel (Fe-25Mn-1.1C cast steel), and the effects of aluminum (Al) on wear resistance, wear mechanism and hardening mechanism of ultra-high manganese steel were analyzed. The results show that:(1) The addition of Al reduces the activity and diffusion coefficient of austenite matrix carbon and increases the stability of carbon. The precipitation of coarse needle-shaped carbides is inhibited by aluminum, and a large amount of K-carbides of (Fe, Mn)3AlC is precipitated during the aging process, which improves the wear resistance of ultra-high manganese steel. (2) The addition of Al has little effect on the wear surface morphology of ultra-high manganese steel after only conventional water toughening treatment. The K-carbide precipitation increases the hardness of the matrix, which can reduce the depth of the worn surface and reduce the number of peeling pits of the wear-resistant steel. After aging for a longer time, the growth of K-carbide will be broken at the grain boundary to form microcracks due to impact deformation, and reduce the uniformity of wear-resistant matrix. (3) The addition of aluminum increases the stacking fault energy (from 36.5 mJ/m2 to 67.3 mJ/m2) of ultra-high manganese steel, reduces the work hardening rate, strongly inhibites the twin transformation and changes its work hardening mechanism. The wear hardening mechanism of light-weight wear resistant steel is dislocation entanglement and dislocation wall under low-impact after only conventional water toughening treatment, and high-density dislocation wall, high-density dislocation tangles after water toughening and aging at 550?.