| In order to illustrate the influence of microalloy elements and their carbonitride to structure and property of the martensitic stainless steel hard-facing flux-cored wire deposited metal, three different kinds of the martensitic stainless steel hard-facing flux-cored wire with different components are made. Then the microscopic structure, hardness and the wear-resisting property are studied, the changes of the hardness and precipitation mechanics of second-phase particle are analysed with different postweld heat treatment temperature, precipitation hardening and dispersion precipitation mechanics and metallographic are discussed. Then the heat treating temperature interval for the optimal dispersion precipitation of the carbonitride is showed, the influence of microalloy elements and nitrogen on the structure and property of deposited metal is depicted through analyzing the forming of the second-phase.The result shows that the addition of the microalloy elements V,Ti,Nb can refine the grain of the deposited metal, refined and dispersed carbonitride plays a great part in precipitation strengthening, reducing the free nitrogen with the benefit for avoiding the nitrogen gas hole and improving the structure property of the deposited metal. Postweld heat treatment can lower abrasion mass loss and increase the wear-resisting property of the deposited metal. The deposited metal of SDY520 with 1%CrN has the apparent dispersed carbonitride, then the fine wear-resisting property is gotten, yet the deposited metal of OHY414 with a little content of nitrogen and no microalloy elements, has no dispersed carbonitride, then the not very good wear-resisting property is gotten. The deposited metal of alloy-steel SDY201 with only one kind of microalloy elements V and no nitrogen, has the maximal abrasion mass loss and the hardness changes little after the postweld heat treatment.Choosing the flux-cored wire OHY414 and SDY201 as the comparison material, implementing postweld heat treatment within 450℃-650℃, the result shows that the hardness peak and the minimal wear-resisting mass loss of the deposited metal of SDY520 with 0%CrN appears at around 600℃, the hardness peak of the deposited metal of SDY520 with 1%CrN appears at 650℃where the lowest wear-resisting mass loss and the deposited metal with the best strength and ductility are gotten, the deposited metal of SDY520 with 2%CrN has visible gas hole, the hardness peak and the minimal wear-resisting mass loss of the deposited metal of SDY201 appear at around 550℃, and to the deposited metal of OHY414, there is no hardness peak after heat treatment and the wear-resisting mass loss changes little with the various postweld heat treating.So after analyzing the microscopic structure, we got that to the martensitic stainless steel hard-facing flux-cored wire deposited metal with certain content of microalloy elements, carbon and nitrogen, the extent of refined grains and precipitation reinforcement is influenced by the temperature of postweld heat treatment, that means there is being a critical temperature Tc which works greatly on the performance of the deposited metal. So if the postweld heat treatment temperature below Tc, the second-phase particles can effectively prevent grain growth, improve hardness and wear-resisting property. Then the refined grain will be gotten in the deposited metal. This critical temperature Tc is called the grain growth coursing temperature.Above all, we can conclude that the good mate of microalloy elements, carbon, and nitrogen can fully exert the effect of microalloy elements, carbon, and nitrogen on deposited metal, and also can greatly improve the mechanical property of the hard-facing flux-cored wire deposited metal.
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