Smelting method of low-phosphorous steel

Abstract

The invention discloses a smelting method of low-phosphorous steel, which comprises the steps that after melted iron is added to scrap steel, the scrap steel is dephosphorized through converter blowing to obtain dephosphorized liquid steel and dephosphorized slag; bauxite is added to a converter, the adding quantity is 5-15kg every ton of steel, and the mass percentage of Al2O3 in the dephosphorized slag is controlled at 10-15%; 1-2 minutes after the bauxite is added, the dephosphorized slag is discharged from the converter; the dephosphorized liquid steel is dephosphorized through the converter blowing to obtain low-phosphorous liquid steel and decarbonized slag; the converter tapping is conducted; and the decarbonized slag is discharged from the converter. With the adoption of the smelting method of the low-phosphorous steel, the proportion of the discharged slag amount to the total dephosphorized slag amount is equal to or greater than 70% in the converter dephosphorization process; rephosphorization is prevented; in addition, the slag formation raw material is more environmental-friendly without pollution of the environment; and the mass percentage of phosphorus in the finally obtained low-phosphorous liquid steel can be less than 0.0060%.

Description

technical field

[0001] The invention belongs to the technical field of converter steelmaking, in particular to a method for smelting low phosphorus steel. Background technique

[0002] Traditional converter smelting adopts the process of "adding scrap steel and molten iron→converter blowing→converter tapping". This method is suitable for smelting steel grades with general quality requirements. With the improvement of the requirements for clean steel, the phosphorus content in steel is required to be below 0.0080%, which increases the difficulty of converter dephosphorization. In order to produce ultra-low phosphorus steel, there are currently two main processes: (1) The process of double slag smelting is adopted, and the slag dumping operation is carried out after the dephosphorization is completed, and a part of the dephosphorization slag is poured out, and then blowing is carried out. However, in order to ensure the dephosphorization effect in the operation, high-positio...