Study On Centrifugal Casting Bimetallic Reduction Tank And Its Microstructure And Properties

At present,reduction tanks are the main expendable equipment used in most smelters.When the reduction tank works with high temperature oxidized flame of about 1200℃ outside,The chamber is in a vacuum.,and the periodic production(8-12 h per furnace)is likely to cause serious oxidation corrosion and the decrease of thermal strength,which leads to the invalidation of reduction tank.Some materials,such as the battery material "BCS",require particularly high purity in the reduction tank for the actual refining technology.The non-ferrous metal components such as nickel,silicon,chromium and manganese in the reduction tank can cause the harmful components of the product to greatly exceed the standard and affect the life of the battery.Therefore,this paper uses centrifugal casting of bimetallic ring parts using different metals in the inner and outer layers to meet the use of demand,the internal available high-purity,corrosion-resistant materials to meet the requirements of smelting metal purity,while the outer layer of metal using heat-resistant high-strength steel to save precious metals,and improve the life of the reduction tank.The causes of reduction tank failure are studied by examining the failure phenomena that occur in reduction tanks.In this paper,a bimetallic reduction tank using ZG35Cr26Ni8 NRE heat-resistant stainless steel for the outer layer and industrial pure iron for the inner layer is used as the experimental object,and the appropriate centrifugal casting process parameters are determined by calculation,and centrifugal casting experiments are conducted to obtain centrifugal casting reduction tanks with different intervals.The metallographic structure,microhardness,tensile strength and impact toughness of the reduction tank and the reduction tank in service for different days were studied.The experimental results showed that by observing the centrifugally cast bimetallic reduction cans,it was found that an interval of 150 S resulted in poor bonding of the inner and outer layers of the reduction cans,with the splitting of the inner and outer layers occurring at 65 days.interval of 60 S will lead to serious mixing of the two metal liquids when the inner and outer layers are poured,so that the thickness of the inner layer of industrial pure iron becomes less,and the reduction tank is not deformed before the industrial pure iron is completely diffused by the trace elements of the outer layer,thus failing.A suitable interval reduction tank can be used for about 140 days.The Arrhenius equation and the second theorem of diffusion were used to obtain a minimum thickness of 8.2 mm for industrial pure iron at 140 days of use in the reduction tank.The metallographic observation and mechanical properties of the middle region and the outer heat-resistant steel region of the bimetallic reduction cans with different service times were examined,and it was found that the microhardness of the bimetallic reduction cans varied in a gradient from the inside to the outside.With the increase of service time,the microhardness,tensile strength and yield strength are decreasing;the impact toughness rises first and then decreases.