| Medium manganese martensitic wear-resistant steel is a new type of wear-resistant steel with low cost and high performance,which can be widely used in coal mining,mining equipment,construction machinery and other fields.In recent years,with the continuous development of related fields,it puts forward higher requirements on the properties of wear-resistant steel.In this paper,the austenite grain size and microstructure and mechanical properties of medium manganese martensitic NM500steel were systematically studied under different heat treatment processes,providing theoretical basis for the formulation of heat treatment process of the experimental steel.The main conclusions are as follows:(1)The austenite grains in the experimental steel by the way of charging to the temperature were smaller than those by the way of rising with furnace.In addition,in the range of 550～650℃,V(C,N)particles can be significantly precipitated by pre-quenching,and the austenite grains can be further refined.The grain size was 10.36μm finer than that of hot rolling after pre-quenching at 550℃,and then heating to850℃by the way of charging to the temperature.(2)The effect of heating temperature on the growth of austenite grain in the experimental steel was significantly greater than that of holding time,and the growth behavior of austenite grain in the experimental steel was affected by the precipitation behavior of V(C,N)particles in the matrix,which can be divided into two stages.Based on the Beck model,the isothermal austenite grain growth kinetic model of the experimental steel was established:(?).(3)With the increase of heating temperature,the size of martensitic packet gradually increased,and the mechanical properties gradually decreased.When the heating temperature and holding time were 850℃and 30 min respectively.The wear resistance test showed that with the increase of heating temperature,the wear resistance of the experimental steel decreased gradually. |
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