Analysis Of Inclusions In Longgang 20 Steel And Optimization Of Key Production Processes

The inclusion in steel has a direct impact on the properties of steel.The focus of20 steel production is on how to control the types,sizes,and contents of inclusions in steel within a reasonable range.This article analyzes the 20-steel smelting,refining,and continuous casting process of Longgang and tests the inclusions in the 20 steel production process.Based on this,the orthogonal experiment is applied to the key factors affecting the 20 steel inclusions.The method and integrated weighting method were used to optimize the 20 steel refining slag system.At the same time,the calcium treatment thermodynamic model of Longgang 20 Steel was established to further optimize the calcium treatment process.The following research results are obtained:?1?The refining slag in long steel 20 steel production process has high alkalinity,and the refining slag system is unreasonable need to be further optimized.There are a large number of Al₂O₃ inclusions in the large inclusions of 20 steel and the shape of inclusions with many edges and corners,indicating that the calcium treatment is not good,and the calcium treatment process needs to be optimized.?2?The melting point of 20 steel refining slag system is affected most by the size of alkalinity,and is the least influenced by the content of MgO;the viscosity of the 20steel refining slag system is the most influenced by the content of CaF₂,the least influenced by the content of MgO;the 20 steel refining slag is the most influenced by the alkalinity,the influence of the content of MgO is the least.The best combination calculation results of 20 steel refining slag system are as follows:alkalinity 5,CaF₂content 5%,Al₂O₃ content 25%,MgO content 9%.?3?With the increase of alkalinity,the melting point of 20 steel refining slag increases,and the viscosity first decreases and then increases;with the increase of MgO content,the melting point of 20 steel refining slag first decreases and then increases,and the viscosity first decreases and then increases.With the increase of Al₂O₃ content,the melting point of 20 steel refining slag first decreases and then increases,and the viscosity increases.With the increase of CaF₂ content,the melting point of 20 steel refining slag increases,and the viscosity first decreases and then increases.?4?A thermodynamic model of calcium treatment for 20 steel in long steel is given.According to the chemical composition and thermodynamic data of 20 steel,the thermodynamic equilibrium diagram of[Al]-[Ca]and[S]-[Ca]calcium treatment is calculated and drawn,which provides a theoretical basis for the calculation of calcium distribution in the 20 calcium treatment of dragon steel.Through the calcium treatment test of induction furnace,the reference of the calculation results of calcium treatment model to actual production is verified.In the calcium treatment experiment of induction furnace,the optimum Ca-Fe alloy ratio of20 steel is 19%Ca-81%Fe,and the optimum calcium adding amount is 0.75 g/kg steel.