Effect of carbon blending mode on sintering characteristics of ultra-low carbon continuous casting mold flux
Carbon increase is common in the production process of low-carbon stainless steel,which seriously affects the stability of production.In the process of producing 430 stainless steel in a factory,there were serious quality problems in the casting billet,and the use of imported powder-type ultra-low carbon mold flux effectively solved this problem,but there was a problem of developed slag ring.In order to solve this problem,the melting rate test was carried out by taking the imported powder-type ultra-low carbon mold flux as the basic flux system,combined with the automatic melting point melting rate meter equipment.The carbon blending mode of the imported powder-type ultra-low carbon mold flux was analyzed.The sintering characteristics were studied using the chamber resistance furnace equipment,and the carbon blending mode was optimized to obtain the mold flux with the same physical and chemical characteristics and lower sintering rate as the basic flux system.It is found that when the mass fraction ra-tio of medium and super carbon black to coarse-grained flake graphite is 1:3,the average melting rate of mold flux is 58.6 s,and the sintering rate at 700-1 000 ℃ is 53.47%-85.71%,which is similar to the melting rate of the basic flux system.When the mass fraction ratio of medium and super carbon black to 390 graphite is 4:1,the average melting rate of mold flux is 58.4 s,and the sintering rate at 700-1 000 ℃ is reduced by 19.96-39.64 percentage points.After optimizing the carbon blending mode,the carbon black content(mass fraction)is increased by 1.58 percentage points,the particle size of the graphite is decreased by 102.5 μm,and the specific surface area is also increased by 186.547 m2/kg,the solid-phase reaction temperature during the flux sintering process is increased by 100 ℃,and the sintering rate is significantly reduced.The research results provide basic data and theoretical support for the de-velopment of ultra-low carbon continuous casting mold flux.