Method for producing low-phosphorus steel or extremely low-phosphorus steel by using limestone slag-single slag method

Abstract

The invention provides a method for producing low phosphorus steel or extra-low phosphorus steel by using a limestone slagging-single slagging method, and belongs to the technical field of steelmaking. The method for producing low phosphorus steel or extra-low phosphorus steel by using the limestone slagging-single slagging comprises the steps that when slagging is conducted by using limestone, the oxygen consumption range of ton steel is controlled in 40-65 cubic meters, and the total adding amount of ton steel, the limestone and dolomite is 40-100 kg; the dolomite is about 1 / 4-1 / 5, accordingto converter capacity, the oxygen supplying intensity is controlled at 2-5 cubic meter / cent.ton steel, the alkalinity of final slag is controlled at 3. 0-6. 0, and the oxygen lance position is controlled within about 50% range of the decarbonization gun position; the furnace atmosphere is adjusted, the molten slag temperature is controlled between 1450-1630 DEG C, the adding batch of the limestone is controlled at 2-20 times, the eight of each batch of limestone is 30-0.5 kg / ton steel, and molten iron can be efficiently dephosphorized; and the single slagging method can produce low phosphorussteel or extra-low phosphorus steel. According to the method for producing low phosphorus steel or extra-low phosphorus steel by using the limestone slagging-single slagging, the goal of dephosphorization can be achieved by easy operating, resources and energy can also be reduced, and workers easily master the method for producing low phosphorus steel or extra-low phosphorus steel by using the limestone slagging-single slagging.

Description

Technical field [0001] The invention relates to the technical field of steelmaking, in particular to a method for producing low-phosphorus steel or extremely low-phosphorus steel by using limestone slagging-single slag method. Background technique [0002] It is difficult to produce low-phosphorus steel or very low-phosphorus steel by using lime slag for molten iron steelmaking. At present, the molten iron used for steelmaking converters has a phosphorus content of 0.08~0.20%, a carbon content of 3.9~5.0%, a silicon content of 0.15~0.85%, and a temperature range of 1250~1450℃. The dephosphorization adopts lime to make double slag or multiple slag. What's more, the double steelmaking method is used, that is, the pre-dephosphorization and slag removal (pre-dephosphorization of molten iron) in the converter or other molten iron containers, and then the molten iron is poured into the converter for secondary dephosphorization and decarburization. Lime has a slow melting speed and is ...

AI Technical Summary

Problems solved by technology

At present, the phosphorus content of molten iron used in steelmaking converters ranges from 0.08 to 0.20%, the carbon content is 3.9 to 5.0%, the silicon content is 0.15 to 0.85%, and the temperature range is 1250 to 1450 ° C. Lime is used for dephosphorization to make double slag or multiple slag. What's more, the dual steelmaking method is used, that is, pre-dephosphorization and slag removal in the converter or other molten iron containers (pre-dephosphorization of molten iron), and then the molten iron is mixed into the converter for secondary dephosphorization and decarburization, but due to The melting speed of lime is slow, it is difficult to form slag, and the temperature drop of slag is small, it is difficult to remove phosphorus from molten iron to low-phosphorus steel (0.01%≥[P]>0.005) or extremely low-phosphorus steel ([P]≤0.005%) level, but the consumption of energy and materials has paid too much, increasing environmental pollution