Smelting method of low-phosphorus steel

A technology of molten steel smelting and molten steel, which is applied in the field of low-phosphorus steel production, can solve the problems of reducing the age of the converter, occupying a long time of the converter, damage to the lining of the converter, etc., and achieve the effects of shortening the smelting period of the converter, less erosion and less slag

A technology of molten steel smelting and molten steel, which is applied in the field of low-phosphorus steel production, can solve the problems of reducing the age of the converter, occupying a long time of the converter, damage to the lining of the converter, etc., and achieve the effects of shortening the smelting period of the converter, less erosion and less slag

CN101423879AInactive Publication Date: 2009-05-06ANGANG STEEL CO LTD
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Take the deep dephosphorization of 500kg induction furnace as an example.

[0020] Melt 500kg of molten steel in an intermediate frequency induction furnace, ω[P]=0.0070%, and the temperature of molten steel is 1678°C. Metallurgical lime, red iron oxide, and bauxite are used as slagging agents and deep dephosphorizing agents. The total amount of slag added is 2.5 kg, its composition is 35% CaO, 30% FeO, 13% Fe 2 o 3 , 18% Al 2 o 3 , 2% SiO2, 1% MnO, 1% MgO. Use induction current to stir, after 5 minutes of treatment, tilt the crucible, scrape out the steel slag from the crucible, after scraping out more than 95%, add 1kg of metallurgical lime to make new slag, cover molten steel, molten steel ω[P] from 0.0070% to 0.0015 %.

Embodiment 2

[0022] Take the 180-ton converter application as an example.

[0023] ω[P]=0.04% into the molten iron in the converter. In the converter smelting, metallurgical lime, iron balls and light-burned dolomite are used as the slagging agent. The slagging amount is 8.9 tons, the smelting time is 30 minutes, and the tapping amount is 190 tons. Converter molten steel ω[P]=0.008%, add 0.8 tons of deep dephosphorization agent to the ladle, and then add 1.6 tons of deep dephosphorization agent after tapping. The composition of the dephosphorization agent is: 33% CaO, 29% FeO, 13 %Fe 2 o 3 , 18% Al 2 o 3 , 3% SiO2, 2% MnO, 2% MgO. The temperature of the molten steel is 1675°C, argon bottom blowing and stirring is carried out, and the gas supply intensity is 20Nm 3 / min, stirring time 5min. Then carry out the slag removal treatment, remove more than 95% of the steel slag in the ladle, and re-slag, that is, complete the dephosphorization treatment, and the molten steel ω[P]=0.004%. Co...

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Abstract

The invention provides a smelting method for efficiently producing low-phosphorous liquid steel through one-time slagging in a converter. The method comprises converter smelting and ladle refining. The method is characterized in that the temperature of converter smelting liquid steel is higher than or equal to 1,680 DEG C; the phosphorous content of the liquid steel is less than 0.012 percent; activity oxygen in the liquid steel is controlled to account for 0.1 to 0.13 percent; before converter tapping, deep dephosphorization agents are put into a ladle; in a converter tapping process, slag stopping control is performed so as to ensure that the amount of outflow slag is less than or equal to 3 kilograms per ton of steel, and the liquid steel in the ladle is subjected to weak deoxidation treatment; after the tapping is over, the deep dephosphorization agents are put into the ladle again; then ladle bottom blowing and argon stirring are carried out; and finally, steel slag in the ladle is eliminated by use of a ladle slagging-off device. Compared with other methods, the low-phosphorous liquid steel smelting method reduces slag amount by more than 20 percent and shortens converter smelting period by more than 5 percent. As slagging is carried out only once in a converter, the method is little in the erosion of a converter lining, and rephosphorization phenomena can not occur in a secondary refining process of the liquid steel.

Description

technical field [0001] The invention belongs to the technical field of iron and steel smelting, and in particular relates to a production method of low-phosphorus steel. Background technique [0002] Phosphorus is a common harmful element in steel, which is easy to segregate at grain boundaries, causing low temperature brittleness and temper brittleness of steel. High-grade high-quality steel has increasingly stringent requirements for phosphorus content in steel, especially for low-temperature steel, marine steel, and hydrogen-induced cracking-resistant steel. Therefore, the problem of dephosphorization in steelmaking production has always been highly concerned by the metallurgical industry. In recent years, the smelting of pure steel has been highly valued by countries all over the world. As an important part of pure steel smelting, the production of low phosphorus steel (ω[P]<0.01%) and ultra-low phosphorus steel (ω[P]<0.003%) Production is a content that cannot be...

Claims

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Application Information

Patent Timeline
06 May 2009
Publication
CN101423879A
IPC
C21C5/28; C21C7/00
Inventors
李德刚; 廖相巍