A method for smelting coarse-grained steel

Abstract

The invention discloses a method for smelting coarse-grained steel. The method comprises an electric arc furnace (EAF) primary smelting process, a ladle furnace (LF) refining process and a vacuum degassing (VD) furnace vacuum treatment process. The method for smelting the coarse-grained steel is characterized in that high manganese or silicon manganese alloy and lime are added along with a steel stream in the tapping process of the EAF primary smelting process; in the LF refining process, molten steel is deoxidized and desulfurizes, and the chemical composition and the temperature of the molten steel are adjusted; in the VD furnace vacuum treatment process, the alloy composition is slightly adjusted, vacuum treatment is conducted, the temperature is adjusted, and the molten steel enters a continuous casting process or a mold casting process to be poured into a coarse-grained ingot blank. According to the method for smelting the coarse-grained steel, operation is easy and convenient, not only the effects of deoxidizing, desulfurizing, and removing impurities through the LF can be ensured, but also it can be ensured that Al in the steel accounts for 0.005% or less, what is more, the oxygen content and the sulfur content in the steel are low, the impurities are few, and a rolled steel plate meets the flaw detection requirements.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, in particular to a method for smelting coarse grain steel. Background technique [0002] Coarse-grained steel belongs to killed steel, and the internal quality of the steel is required to be high. Essential grain size refers to the tendency of steel to grow austenite grains under certain conditions. Measure austenite grains after holding at 930±10°C for 3-8 hours. If the grain size is 1-4, it is essentially coarse-grained steel; if the grain size is 5-8, it is essentially fine-grained steel. . In the smelting process of grain steel, Al and or Si are often used for deoxidation; among them, the steel deoxidized by Al contains AlN particles, and the grains are not easy to grow when heated at a certain temperature, so it is called fine grain steel; the steel deoxidized by Si , does not contain the second phase particles that can inhibit the growth of the grain, and the grain grows graduall...

AI Technical Summary

Problems solved by technology

If it is not properly controlled, the Al content in steel can easily exceed 0.005%, and it does not meet the grain size requirements of coarse-grained steel.

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