Effect Of Microstructure And Performance Of Dual-Phase Wear-resistant Steel During The Heat-treatment Process

Low-alloy dual-phase wear-resisting steel is a kind of new wear-resistant material, It can acquire different contents of martensite and bainite to meet the different wear conditions on the mechanical performance of materials by adjusting chemical composition, heat treatment, casting factors and other related factors.Dual-phase wear-resisting steel studied in this paper is mainly used as tank track materials with Si and Mn as the main alloying elements. In order to improve the reliability of tank tracks and extend its life, based on the mechanical properties of low alloy dual-phase wear-resisting, we try to further enhance the strength and toughness by means of heat treatment and vacuum refining. The paper’s contents are as followed:(1) Take protect Heat-treatment on dual-phase wear-resisting steel, examine the microstructure and test mechanical properties, check out its effect on surface decarburization of dual-phase wear-resisting steel.(2) Take abrasive wear test on dual-phase wear-resisting steel, measure wear and tear, check out the effect on wear resistance during the heat-treatment process.(3) Cast the dual-phase wear-resisting steel by vacuum refining, test the fatigue, impact and stretch mechanical properties, check out its effect on the mechanical properties.The main conclusions were as followed:(1) The depth of decarburized layer of test steel with argon protecting heat-treatment is about0.4to0.5millimeter, the depth of decarburized layer of test steel with coating protecting heat-treatment is about0.5to0.6millimeter and the depth of decarburized layer with of test steel normal heat-treatment is about06millimeter. The depth of decarburization layer of test steel with protecting heat-treatment is smaller than that with normal heat-treatment and the result shows that argon protecting heat-treatment is better.(2) After the abrasive wear for440hours, the total wear volume of test steel with argon protecting heat-treatment is0.0215gram, the total wear volume of test steel with coating protecting heat-treatment is0.0320gram, the total wear volume of test steel with normal heat-treatment is0.0369gram. When the surface of test steel is worn, the wear volume of core steel is almost the same. The wear volume of the surface of test steel with protecting heat-treatment is lower than the test steel with normal heat-treatment, also the abrasion performance of the surface is improving.(3) After refining, the mechanical property of dual-phase steel is improved. The fatigue strength is improved from300MPa to355MPa, the impact strength is improved from30.8J/cm2to50.6J/cm2, tensile strength is improving from1560MPa to1630MPa, extensibility is improved from6.3percent to8.6percent. Refining treatment is an effective method to improve the properties of high strength wear-resistant steel.