Study on the Evolution of Non-metallic Inclusions in the Production Process of Q355
Sampling analysis was conducted on the entire production process of Q355 steel to study the changes in the cleanliness of molten steel and the composition and size of non-metallic inclusions during the production process.The results showed that before calcium treatment,the inclusions in the steel were mainly Al2O3.Due to the addition of a small amount of calcium element in the alloy during the steelmaking process of the converter,there was also a small amount of CaO in the inclusions.Insufficient calcium addition during the calcium treatment process results in the transformation of inclusions into partially modified liquid calcium aluminate salts.As the cooling process progresses,CaS gradually precipitates and the inclusions become Al2O3-CaS composite inclusions.Meanwhile,using thermodynamic software FactSage,the reasonable calcium feeding amount under current production conditions was calculated.The thermodynamic calculation results are consistent with the actual production results.
calcium treatmentprecipitation of inclusionsthermodynamic calculation
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