Molten steel and method preparing the same

Abstract

Molten steel is produced in a converter from scrap steel and molten iron, with the amount of scrap steel being greater than or equal to 15 wt% of the total weight of the scrap steel and molten iron. The method for producing molten steel includes: adding scrap steel and molten iron to the converter; and blowing the scrap steel and molten iron to form molten steel. This molten steel can be produced using a higher amount of scrap steel to effectively reduce carbon emissions, and the nitrogen content in the molten steel can be precisely adjusted by regulating the gas flow rate at different stages of the blowing process.

Claims

1. A type of molten steel, which is produced from scrap steel and molten iron in a converter, wherein, Based on the total weight of the scrap steel and the molten iron, the amount of scrap steel used is greater than 15 wt%, and the molten steel contains less than or equal to 10 ppm of nitrogen.

2. The molten steel as described in claim 1, wherein, Based on the total weight of the scrap steel, the scrap steel comprises: greater than 0 wt% to less than or equal to 0.02 wt% of carbon; greater than 0 wt% to less than or equal to 0.01 wt% of silicon; greater than 0 wt% to less than or equal to 0.03 wt% of phosphorus; and greater than 0 wt% to less than or equal to 0.6 wt% of manganese.

3. The molten steel as described in claim 1, wherein, The molten iron comprises, by total weight: 4.0 to 4.5 wt% carbon; 0.15 to 0.25 wt% silicon; 0.1 to 0.2 wt% phosphorus; and 0.1 to 0.2 wt% manganese.

4. A method for manufacturing molten steel as described in claim 1, comprising: Add the scrap steel and the molten iron to the converter; The process involves blowing the scrap steel and the molten iron to form the molten steel, wherein blowing the scrap steel and the molten iron includes: blowing oxygen from the top of the converter; and blowing argon from the bottom of the converter; wherein, based on the total amount of oxygen blown in, when the amount of oxygen blown in is less than or equal to 20%, the blown oxygen has a first oxygen flow rate and the blown argon has a first argon flow rate; when the amount of oxygen blown in is greater than 20% and less than or equal to 65%, the blown oxygen has a second oxygen flow rate and the blown argon has a second argon flow rate; and when the amount of oxygen blown in is greater than 65%, the blown oxygen has a third oxygen flow rate and the blown argon has a third argon flow rate; wherein the second oxygen flow rate is less than the first oxygen flow rate and the third oxygen flow rate, and the second argon flow rate is less than the first argon flow rate and the third argon flow rate.

5. The method as described in claim 4, wherein, The first oxygen flow rate, the second oxygen flow rate, and the third oxygen flow rate are 2.4 to 3.5 Nm3 / t-min, and the first argon flow rate, the second argon flow rate, and the third argon flow rate are greater than 0 to 0.075 Nm3 / t-min.

6. The method as described in claim 4, wherein, The first argon flow rate is less than or equal to the third argon flow rate.