Study On The Microstructure And Properties Of A Special Low-Alloy Steel With Wear-Heat Resistance

With the development of mine, metallurgy, chemical industry, electric power, architecture and engineering machine, especially the sharp increase of pie, the demands of materials with wear-heat resistance are greater and greater. People have gradually realized the importance of developing materials with wear-heat resistance, and scholars in many countries have started to investigate it widely. Therefore, it is great realistic meaning to accelerating our country's modern course and improving our comprehensive national power to strongly develop materials with wear-heat resistance.In this paper, the influence of alloy elements (Cr and V) on the microstructure and properties of a special low-alloy wear-heat resisting steel was studied by orthogonal experiment, and the other elements (C) effect was studied too. The special wear-heat resisting steel (SWHRS) was melted in a multifunctional plasma arc furnace and casted in water glass sand mould. It was showed that, in the circumstance of keeping 1.45% C content ,the special steel containing 2.45%Cr and 0.6%V (H4) has the best hardness, hot fatigue resistance and 500℃ wear resistance, 2.45%Cr and 0.4%V (H3) the best impact toughness and 700℃ wear resistance, 1.4%Cr and 0.6%V (H2) the best high temperature antioxidation. After reducing the content of Cr and V from 2.45% and 0.6%(H3) to 1.4% and 0.4%(H5), the impact toughness of the H5 increased a bit,the other properties declined.Reduced the carbon content of H3, H4, H5 from 1.45% to 0.35%, we got L3, L4, L5. The properties of low carbon SWHRS L3, L4, L5 was accordingly compared with high carbon SWHRS H3, H4, H5. The effect of moulding materials on the SWHRS and the cast technique of the special steel were discussed. The result was that hardness and wear resistance of the high carbon special steel after reducing its carbon content has a little decrease, while its impact toughness and antioxidation at high temperature has a great increase. The SWHRS is fit for water glass sand mould and has a good castability and machinability.At last, comparing the mechanics properties of 4 representative SWHRS(L4, L5, H3, H4) with several current irons and Cr-Mo steels showed that the cast hardness of the special steel is a bit higher than the current irons and Cr-Mo steels, and its quench-temper hardness is much higher; that the impact toughness of the high carbon special wear-heat resisting steel is very low (even lower than cast iron), but its wear resistance (especially at high temperature) is very good, and is very fit for the conditions of low impact and high temperature wear. In a word, wear resistance of the SWHRS at different temperatures is accordingly higher than the current steels and irons, at the same time the special steel has good hardness, impact toughness, high temperature antioxidation and hot fatigue resistance, is a super steel.The result of comprehensive analysis is that the high carbon special wear-heat resisting steel is fit for cool-work pie steel and the conditions of wear-heat resistance; while the low carbon special wear-heat resisting steel is fit for hot-work pie steel and the conditions of higher impact toughness and wear resistance.