Microstructure Control And Wear Properties Of A New Type Of Ti Micro-alloy High Strength Wear-Resistant

Fracture、corrosion and wear are the three main failure modes of material failure.Wear failure accounts for more than 60%of them.The development of high-performance wearresistant steel materials is an effective way to reduce wear and tear.At the same time,highperformance wear-resistant steel materials research and development contribute a lot to device enlargement,large-scale,lightweight and longevity.Compared with the wear-resistant steel materials such as traditional wear-resistant cast iron,the low-alloy wear-resistant has the advantages of low alloy content,high toughness and plasticity,good welding performance and high moldability.It is widely used in engineering machinery,mining machinery,metallurgy Machinery and cement chemical machinery and other equipment manufacturing.At present,such materials are mainly martensitic matrix,improves wear resistance by the increase of carbon content to increase the hardness.However,as the carbon content increases,the toughness,weld ability and formability of the material are reduced.In this paper,a new type of Ti micro-alloy high-strength wear-resistant is studied,Through its cast structure,rolling process,off-line heat treatment and heat treatment with points(Q-P),a large number of TiC particles and metastable austenite are distributed on the matrix,and the wear properties are studied.The main contents and innovations of this paper are as follows:(1)The study on cast structure in the experimental steel shows that more TiC precipitates are observed in the cast structure.The particles show two typical morphologies,that is barshaped and square particles.The square particles are mainly(Ti,Mo)x(N,C),the bar-shaped(Ti,Mo)xC particles appeared in cast structure in the form of grain boundaries.(2)The microstructure and hardness of the experimental steel obtained under different cooling rates and phase transitions were analyzed.The CCT were drawn.The results show that the phase transition of the experimental steel is divided into pearlite、ferrite、bainite and martensite zone.When the cooling rate meet 10℃/s under the deformation conditions,the experimental steel get all martensite,meet the hardness requirements of the NM500.(3)The experimental steel rolling and off-line heat treatment test results show that after the experimental steel two-stage controlled rolling directly quenched to room temperature,with a long time tempering isothermal,and then off-line heat treatment can get higher strength.Experiment of steel under different quenching temperatures show that the experimental steel quenched at 880℃ can get the best comprehensive mechanical properties.(4)Quenching and Partitioning(Q-P) experiment was conducted on the experimental steel during off-line quenching.The residuals and wear resistance at different quenching temperature were studied.The results show that when quenched at 880℃ and then quenched to 280℃,then heated to 400℃(Partitioning temperature),the experimental steel can obtain the best mechanical properties and wear resistance.