Molten steel continuous pouring method for extremely-low phosphorus-sulfur high alloy steel through single LF furnace and multiple tanks

A high-alloy steel, phosphorus-sulfur technology, applied to the improvement of process efficiency, manufacturing converters, etc., can solve the problems of high production cost per ton of steel, long processing time of molten steel, and poor steel quality, so as to reduce smelting costs, Save process energy consumption and improve quality

Active Publication Date: 2017-05-24
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The problems in the above method: one is that the molten steel is seriously polluted due to the long processing time of the molten steel, and the quality of the steel is deteriorated
Second,

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] 1. Before the production of the converter, arrange to cast low-silicon aluminum-killed steel once, control the converter tapping P≤0.015%, and rinse the RH vacuum tube for 3 times.

[0025] 2. The ladle containing molten steel is rinsed with low-silicon aluminum-killed steel for 4 times to control the rephosphorization of the ladle.

[0026] 3. The molten iron Si is controlled at 0.4%, the temperature is 1350°C, the scrap steel is 25 tons of light and pure scrap steel, and the molten iron is 270 tons. The charging sequence is to add scrap steel first and then add molten iron to prevent the scrap steel from sticking to the large surface.

[0027] 4. After pre-desulfurization of molten iron, the sulfur is 0.0010%, and the slag is removed thoroughly, and there is no block of slag on the surface of the molten iron.

[0028] 5. The converter is smelted by a double-link method. In order to improve the dephosphorization effect in the early stage, the oxygen blowing flow rate o...

Embodiment 2

[0034] 1. Before the production of the converter, arrange to cast low-silicon aluminum-killed steel once, control the converter tapping P≤0.015%, and rinse the RH vacuum tube for 4 times.

[0035] 2. The ladle containing molten steel is rinsed with low-silicon aluminum-killed steel for 3 times to control the rephosphorization of the ladle.

[0036] 3. The molten iron Si is controlled at 0.5%, the temperature is 1320°C, the scrap steel is 23 tons of light and pure scrap steel, and the molten iron is 270 tons. The charging sequence is to add scrap steel first and then add molten iron to prevent the scrap steel from sticking to the large surface.

[0037] 4. After the molten iron is pre-desulfurized, the sulfur is 0.0008%, and the slag is removed thoroughly, and there is no block of slag on the surface of the molten iron.

[0038] 5. The converter is smelted by the double-link method, and the oxygen blowing flow rate of the dephosphorization furnace top gun is set to 48000m 3 / h...

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PUM

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Abstract

The invention provides a molten steel continuous pouring method for extremely-low phosphorus-sulfur high alloy steel through a single LF furnace and multiple tanks. Before production is conduced, to-be-used molten steel tanks and a to-be-used molten vacuum chamber which are used for low silicon-aluminum killed steel rinsing for a time are arranged, and after molten iron is desulfurized, sulfur is equal to or less than 0.0010%; after a converter starts blowing, active lime, light roasting dolomite and two-thirds ores are added, blowing is conducted for 4-5 min, deslagging is conducted in the molten iron, and then slagging is conducted again; blowing is conducted for 8.5-9.5min, when the temperature reaches 1400-1450 DEG C, steel tapping is conducted, steel tapping C is ensured to be 2.00-2.30%, and P is ensured to be less than 0.025%; before a decarburization furnace starts blowing, a carburant used for raising the temperature is added, when a terminal point C is 0.03-0.05%, steel tapping is conducted, and in the process of steel tapping, slag tapping is strictly prohibited; top slag Als of the LF furnace needs to be accurately controlled to be 0.015-0.020%; and the RH vacuum degree is equal to or less than 200 Pa, circulation is conducted for 30 min or more, and after vacuum is broken, argon bottom blowing is conducted for 15-20 min. Through the method, steel tapping P can be controlled to be 10-20 ppm, rephosphoration is within 15 ppm, and finished product P is within 35 ppm. The LF treatment period is shortened to 70 min, the number of continuous pouring tanks is increased to be four, and steel-iron materials are reduced 52 kg/t steel.

Description

technical field [0001] The invention belongs to the technical field of smelting technology, and in particular relates to a method for cleaning and continuous pouring of molten steel in multiple tanks in a single LF furnace for ultra-low phosphorus and sulfur high alloy steel. Background technique [0002] Very low-phosphorus, high-sulfur alloy steel, such as ultra-low temperature pressure vessel steel 9Ni, composition: nickel 9%, phosphorus less than 0.005%, sulfur less than 0.002%. About 20ppm. In order to control the phosphorus content of the finished product to meet the quality requirements, the tapping slag + molten steel slag removal process is adopted to control the phosphorus return of molten steel. After adopting this process, the LF treatment is forced to be divided into three steps: 1. Raise the temperature first when entering the station, but do not modify the steel slag to prevent phosphorus return after modification; 2. Remove slag from molten steel after heatin...

Claims

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Application Information

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IPC IPC(8): C21C5/28C21C7/06C21C7/10
CPCY02P10/20
Inventor 刘文飞马宁王鲁毅金百刚徐国义尹宏军李海峰张立夫赵雷
Owner ANGANG STEEL CO LTD
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