| Low alloy high strength wear-resistant steel not only has good wear resistance and toughness,but also reduces the use of alloy elements,reduces production costs,and is widely used in various wear occasions.However,the low alloy high strength wear-resistant steel produced by domestic manufacturers has some shortcomings,such as high alloy content,low hardness and poor low impact toughness.Therefore,the further research and development of low alloy high strength wear resistant steel is particularly important.In this paper,the composition of low alloy high strength wear resistant steel was designed by microalloying method.The continuous cooling phase transformation behavior of the experimental steel was studied.A series of steel plates were produced by TMCP and heat treatment process.The effects of different composition and process on the structure,mechanical properties and wear resistance of the finished steel plates were analyzed.The main results are as follows:(1)The experimental steels have good hardenability.The experimental steels can obtain martensite structure at cooling rate of 2 C/s.With the increase of cooling rate,more and more martensite structure and hardness of steel increase obviously.When the cooling rate is above 10/s,the hardness of 1#steel with Nb is above 350HB,and the maximum hardness is 391HB.The hardness of 2#steel without Nb is above 450HB,and the maximum hardness is 511HB.(2)After the experimental steel is deformed,the structure is refined.The temperature of the phase transition of 1#steel with Nb increases,and the temperature range of bainite formation expands;the transformation of austenite in 2#steel without Nb is suppressed,the temperature at the beginning of phase transformation decreases,but the range of cold gas generated by bainite increases.(3)The tempered martensite steel was obtained by controlled rolling,controlled cooling and heat treatment of 1#steel with Nb.The tensile strength reached 1282 MPa,the hardness reached 331 HB,the elongation was 13.4%,and the impact energy at-20? reached 69.2 J.The material has high strength,high hardness and good low temperature impact toughness.(4)Through the controlled rolling and controlled cooling of 2#experimental steel without Nb,the bainite-martensitic steel was obtained,and its tensile strength reached 1057MPa,the elongation was 12.8%,the hardness was 308HB,and the impact energy at-20? reached 27.3 J.(5)Tempered martensitic steel was obtained by TMCP and heat treatment of 2#experimental steel without Nb.The tensile strength was 1728 MPa,the elongation was 10.6%,the hardness was 466HB,and the impact energy reached 16.5J at-20?.The product has high strength and hardness,slightly low elongation and low impact toughness at low temperature.(6)The bainite-martensitic steel and the tempered martensitic steel obtained in the experiment have good wear resistance.The analysis shows that the wear of the experimental steel is mainly caused by multiple plastic wear and micro-cutting wear.The higher the wear resistance,the greater the effect of micro-cutting wear. |
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