| Wear resistant steel is widely used in mining machinery,coal mining and transportation,engineering machinery,agricultural machinery,railway transportation and other departments.Wear is one of the main failure forms of wear-resistant parts,which causes huge economic losses and material consumption.Therefore,in order to reduce the loss caused by wear,it is a work of great significance for the development of national economic construction to improve the quality of wear-resistant steel,to develop new high-performance wear-resistant steel,and to carry out in-depth study of steel wear mechanism.In this paper,two kinds of medium manganese wear-resistant experimental steels are studied,one is BTW steel,and the other is BTW steel with 0.1%titanium added on the basis of alloy composition.The two experimental steels are hot rolled,solid solution and aging heat treated.The evolution of microstructure,microhardness and wear resistance of two experimental steels under different treatment processes were studied.The effect of titanium on microstructure,microhardness and wear resistance of the experimental steels was analyzed.The wear failure mode and wear mechanism of medium manganese wear-resistant steel under different loads are revealed.The main conclusions of this paper are as follows:(1)The results show that the two experimental steels are all austenite in hot rolled state,After solution treatment at 1000℃ for 1h,the austenite grain growth and coarsening of Ti bearing BTW steel are effectively prevented due to the solid solution of TiC particles,and the average austenite grain size decreases from 32.2μm to 25.2μm.After aging treatment at 450650℃,a large amount of TiC or Ti(C,N)precipitates in the Ti bearing BTW steel matrix,and the Vickers Hardness increases from 297HV to 483HV.In contrast,the Vickers Hardness of BTW steel increased from 276HV in hot rolling state to 356HV.The rise is not as high as that of BTW steel with titanium.(2)The sliding wear experiments of titanium bearing BTW steel under different loads(50300N)were carried out,the results show that:under the action of low load(50-150N),the wear resistance of hot-rolled and 500℃ aged samples is the best.However,the wear loss of the samples aged at 450℃ and 550℃ increases with the increase of load;under the action of high load(200-300N),the wear loss of hot-rolled,solid solution and 550℃ aged samples increases rapidly.The wear of the samples aged at 450℃ and 500℃ increases slowly.It can be concluded that the wear resistance of the sample aged at 500℃ is the best under high and low loads.(3)The main wear morphologies of hot rolled BTW steel containing titanium are cracks,spalling pits and a small amount of plastic deformation.Under the normal load of 50N and 100N,there are a few cracks and oxidation.Under normal load of 100N,the crack is deeper,even spalling.When the normal load reaches 150N,there are a lot of delamination,pits and oxidation.When the normal load reaches 250N,the main wear morphologies are deep grooves,large pits and a large number of fine debris.When the normal load reaches 300N,the wear morphology becomes a little delamination and a lot of furrows.The wear morphology of the samples aged at 500℃ under different loads is similar to that of the hot rolled samples.However,the number of cracks and spalling pits under high load(200-300N)is obviously less than that of hot rolled samples.Therefore,the samples aged at 500℃ have better wear resistance.(4)The wear mark cross section of the aging treated samples with titanium at 500℃ is analyzed.Under the action of friction stress,the microstructure of the wear subsurface observer along the sliding direction ε phase transition.With the increase of load,the thickness of phase change layer increases gradually.Combined with the microstructure of SEM and TEM,the precipitation amount of TiC or Ti(C,N)in the samples aged at 500℃ is the largest,which greatly reduces the wear during the friction process.In addition,the stacking fault energy of austenite is reduced due to the precipitation of the second phase,the work hardening ability of the material is improved,and the wear resistance is greatly increased.Therefore,the wear resistance is the best. |
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