Effect Of TiC Particles And Retained Austenite On The Wear Performance In High Titanium Abrasion Resistant Steel

Low alloy wear-resistant steel has been widely used in equipment manufacturing of construction machinery,mining machinery,cement machinery and metallurgical machinery due to its low alloy content,good toughness and plasticity,bending and welding forming and excellent abrasion resistance.Generally,the wear resistance of low-alloy wear-resistant steel is closely related to the hardness,that is,the higher the hardness,the better the wear resistance,but the increase of hardness,will deteriorate the machining properties,molding and welding properties of the material.In this paper,there are amount of Ti and Mn elements are added to the composition of low-alloy wear-resistant steel alloy.The super-hard TiC particles and retained austenite were regulated into martensite matrix,the purpose of greatly improving wear resistance without increasing hardness is achieved.In this paper,regulation of the micron-size(Ti,Mo)xC particles and retained austenite,the effect of the micron-size(Ti,Mo)xC particle size,distribution and the volume fraction of retained austenite under different process conditions were analyzed,the relationship between(Ti,Mo)xC particle,retained austenite and the three-body wear property of the experimental steel was discussed,Finally,a high wear resistant steel with(Ti,Mo)xC particle and retained austenite is developed.The main research contents and conclusions are as follows:(1)By using the step slab thickness to control cooling rate during solidification after smelting,the micron-size(Ti,Mo)xC particles during solidification were controlled,and the average particle size was between 2.0 and 6.1 ?m2.The effect of morphology,size and distribution of(Ti,Mo)xC particles with slab thickness was studied.The results showed that the(Ti,Mo)xC particles formed in the solidification process of casting slab mainly presented rod-shaped and cubic shapes,and the rod-shaped particles were mainly distributed in grain boundary allotriomorphic in the matrix.The change of solidification cooling rate caused by the thickness of the slab led to the change of the size of the micron size(Ti,Mo)xC particle.When the thickness of the slab decreased from 90 mm to 30 mm,the average size of the micron-size(Ti,Mo)xC particle decreased from 6.09 to 3.24 ?m2.(2)The rules of micron particle distribution and mechanical properties of experimental steel due to the different of slab thickness and rolling compression ratio were studied under the same off-line heat treatment condition.The results show that,under the same rolling compression ratio and heat treatment conditions,the thickness of slab has a significant influence on the mechanical properties of the experimental steel.With the increase of slab thickness,the tensile strength,elongation and impact absorption energy of the samples all increased,and the mechanical properties of the 90 mm thick slab reached the best after rolling and heat treatment.The rolling process can crush and homogenize micron particles,with the compression ratio increases,the average size of micron particles generally decreases and the distribution of micron particles is homogenize.The larger the compression ratio is,the more homogenize the distribution of micron particles is,and the tensile strength,elongation and impact absorption energy of the experimental steel all increase.The mechanical properties of the experimental steel reach the best,When the slab thickness is 90 mm and rolled to 12 mm thickness by 7.5 compression ratio.(3)The wear resistance of low alloy martensite steel containing different micron particles under dry sand and wet sand rubber wheel abrasion wear mechanism was studied.The resulted show that the wear resistance and the average particle size under the dry sand rubber wheel abrasion wear mechanism is not linear,but rises at first and goes down latter with the increase of the average particle size,the optimum particle size was about 1.99 ?m2.The wear resistance of the steel decreased with the increase of the average particle size on the surface under wet sand rubber wheel abrasion wear mechanism,the optimum particle size was about 1.88 ?m2.(4)By controlling the temperature and time of austenite reverted transformation annealing,the retained austenite with different volume fraction is obtained in the experimental steel,and the toughness,plasticity and wear-resistance of the experimental steel are further improved.The results showed that the content of retained austenite volume fraction reached more than 30%after 8 h of austenite reverted transformation annealing,the tensile strength was 1000 MPa,the elongation rate was 17%,and the impact energy of the half-size model at-40? was 20 J.The existence of retained austenite decreases the strength of the experimental steel,but greatly improves the ductility and toughness of the experimental steel.Dry sand rubber wheel abrasive wear experiment results showed that,the relative wear resistance of the steel increase with the increase of the austenite volume fraction,when the retained austenite volume fraction between 0 to 32.1%.The hardness of the sample was 100 HV when the retained austenite volume fraction reaches 32.1%than that of the rolled sample,but wear resistance increased 0.23 times,the stress in the process of wear leads to induce martensitic phase transformation and the increase of toughness and plasticity of experimental steel,is the main reason for increasing the wear resistance.