RU-2026109279-A - METHOD FOR DETERMINING THE OPTIMUM SILICON CONTENT IN LIQUID STEEL

Inventors

• АТУА, Эванжлин
• МЮЗИК, Селин
• ДЖАВАДИ ДУДРАН, Танназ
• РИВО, Бенжамин

Assignees

• АРСЕЛОРМИТТАЛ

Dates

Publication Date

20260508

Application Date

20240911

Priority Date

20230913

Claims (20)

1. 1. A method for determining the optimized silicon content %Si opt , which must be obtained in liquid steel (1) before casting, wherein said liquid steel (1) is obtained as a result of melting steel scrap containing copper, the method includes:
2. a. obtaining a reheating temperature T R determined for reheating the semi-finished products (5) obtained by casting the said liquid steel, wherein said reheating precedes hot rolling,
3. b. determination of the optimized silicon content %Si opt such that the following condition is met
4. ,
5. where σ(%Si opt ), ρ(%Si opt ) and β(%Si opt ) are predetermined coefficients that are independent of the reheat temperature T R , and where Δ is a constant threshold value that is independent of T R and %Si opt .
6. 2. The method according to paragraph 1, in which the value represents the ratio of the content of liquid fayalite eutectic FeO-Fe 2 SiO 4 formed during reheating to the total amount of oxides formed during reheating.
7. 3. The method according to claim 1 or 2, wherein the obtained liquid steel (1) contains at least 0.1 wt.% copper.
8. 4. The method according to any of paragraphs. 1 to 3, wherein the liquid steel (1) has a composition in which Sb ≤ 0.01%, As ≤ 0.1%, Sn ≤ 0.05%, 0.004% ≤ Si ≤ 6%, Ni ≤ 4.5%, P ≤ 0.46%, S ≤ 0.005%, Mo ≤ 2.2%, Cr ≤ 4.5%, Mn ≤ 2.5%, Al ≤ 0.6%, C ≤ 0.21%, Nb ≤ 0.21%, Ti ≤ 0.21%, V ≤ 0.21%, B ≤ 0.002% and Cu ≥ 0.1%, the remainder being iron and unavoidable impurities, all contents are expressed as mass percent.
9. 5. The method according to any one of paragraphs 1-4, in which the copper content in the liquid steel (1) is 0.1-0.3 wt.%.
10. 6. The method according to any one of claims 1-5, wherein the reheating temperature T R is 1100-1350°C.
11. 7. The method according to any one of paragraphs 1-6, further comprising a preliminary step of obtaining or calculating an estimated silicon content %Si est present in the liquid steel (1).
12. 8. The method according to claim 7, in which the set of coefficients σ(%Si opt ), ρ(%Si opt ) and β(%Si opt ) used to determine the optimized silicon content %Si opt , are selected from different sets of coefficients depending on the estimated silicon content %Si est in the liquid steel.
13. 9. The method according to claim 7 or 8, in which, when the estimated silicon content in the liquid steel %Si est is 0.004-0.38 mass percent, then σ(%Si opt ) = 9.96-6·%Si opt + 1.8233e-8, ρ(%Si opt ) = - (2.364e-2·%Si opt + 4.518e-5), β(%Si opt ) = 14.1511·%Si opt + 0.028104 and Δ=0.03.
14. 10. The method according to claim 7 or 8, in which, when the estimated silicon content in the liquid steel %Si est is 0.39 - 4.0 mass percent, then σ(%Si opt ) = -1.3157e-6·%Si opt ² + 1.3656e-5·%Si opt – 8.0137e-7, ρ(%Si opt ) = 3.1971e-3·%Si opt ² - 3.2969e-2·%Si opt + 2.0283e-3), β(%Si opt ) = -1.9492·%Si opt ² + 20.04·%Si opt - 1.2828 and Δ=0.03.
15. 11. The method according to claim 7 or 8, in which, when the estimated silicon content in the liquid steel %Si est is 4.1-6 wt.%, then σ(%Si opt ) = 5.8849E-6·%Si opt ² - 6.3844E-5·%Si opt + 1.9346E-4, ρ(%Si opt ) = -1.4669E-2·%Si opt ² + 0.15942·%Si opt -0.48037, β(%Si opt ) = 9.1268·%Si opt ² - 99.283·%Si opt + 297.99 and Δ=0.03.
16. 12. A method for hot rolling a steel semi-finished product (5), comprising the following stages:
17. A. obtaining liquid steel (1), wherein said obtaining stage includes melting steel scrap containing copper,
18. B. evaluation of the silicon content %Si est in the obtained liquid steel,
19. C. pouring liquid steel (1) to obtain a semi-finished product (5),
20. D. reheating the semi-finished product (5) to the reheating temperature T R ,