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A method for smelting ultra-low phosphorous die-cast steel

A smelting method and ultra-low phosphorus mold technology, applied in the direction of manufacturing converters, etc., can solve the problems of low output, increased production cost, low phosphorus content, etc.

Active Publication Date: 2017-12-26
HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the low-phosphorus steel produced by the existing technology has a small output. Relying on high-grade ore with a very low phosphorus content or dephosphorization by pretreatment of hot metal, the molten iron into the converter with a very low phosphorus content is obtained, which not only increases the production cost. , is not conducive to the further improvement of smelting technology
The phosphorus content of finished steel products obtained by conventional converter smelting methods is generally high, and the steel grades with better phosphorus content control have reached about 0.015%, while the phosphorus content required for stable production by double slag smelting is 0.005% to 0.010%. However, the steel grades that require a phosphorus content of no more than 0.004% cannot be stably produced. Therefore, it is necessary to study a new dephosphorization process that can stably control the phosphorus content in steel below 0.005% to meet the needs of ultra-low phosphorus steel grades. requirements

Method used

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  • A method for smelting ultra-low phosphorous die-cast steel

Examples

Experimental program
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Effect test

Embodiment 1

[0015] Example 1: A method for smelting ultra-low phosphorus die-cast steel

[0016] The molten iron is pretreated before entering the converter. After the treatment, the sulfur content of the molten iron is S=0.012%, and the temperature is 1296 °C. Before the molten iron enters the converter, the pretreatment slag of the molten iron must be removed. After the first furnace before BOF smelting, the remaining steel residue in the BOF should be poured out, and molten iron and scrap steel should be added into the BOF smelting, 135t of molten iron, 15t of scrap steel, P=0.148% and Si=0.47% in the hot metal.

[0017] (1) The converter smelting process control is operated according to the steel types required by conventional dephosphorization. The end point temperature of the converter is 1620 ℃, the end point oxygen content is 480 ppm, and the end point phosphorus content is 0.012%.

[0018] (2) Add 300kg of lime and 200kg of pre-melted slag to the ladle when the steel is tapped to...

Embodiment 2

[0022] Example 2: A method for smelting ultra-low phosphorous die-cast steel

[0023] The molten iron is pretreated before entering the converter. After the treatment, S=0.011% in the iron and the temperature is 1291 °C. Before the molten iron enters the converter, the molten iron pretreatment slag must be removed. After the first furnace before BOF smelting, the residual steel residue in the BOF should be poured out, and molten iron and scrap steel should be added into the BOF smelting, 134t of molten iron, 17t of scrap steel, P=0.142% and Si=0.41% in the molten iron.

[0024] (1) The converter smelting process control is operated according to the steel types required by conventional dephosphorization. The end point temperature of the converter is 1617 ℃, the end point oxygen content is O=467ppm, and the end point phosphorus content is P=0.014%.

[0025] (2) 300kg of lime and 300kg of pre-melted slag are poured into the ladle when the steel is tapped to 1 / 5. No deoxidation an...

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Abstract

The invention relates to an ultra-low phosphorus moulded steel smelting method. A revolving furnace is operated according to a conventional steel grade smelting process; oxygen and phosphorus are properly controlled at the end point of the revolving furnace; a proper number of proper slag materials are added into the steel tapping process of the revolving furnace; deoxidizing alloy is not added; the alloying is also not performed, so that the proper oxygen content of molten steel in a steel ladle is ensured; the slag discharging is not allowed during the steel tapping. After the steel tapping is completed, liquid steel is subjected to dephosphorization operation in the steel ladle; after the dephosphorization operation is finished, the steel ladle is subjected to raking phosphorus slag removal operation; at the moment, the phosphorus content in the steel can be smaller than or equal to 0.0025 percent; then, the steel ladle is hung to a refining station for refining operation; ultra-low phosphorus steel with the phosphorus content being smaller than or equal to 0.004 percent is obtained.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and in particular relates to a method for controlling the smelting of die-casting steels requiring ultra-low phosphorus content. Background technique [0002] At present, all walks of life are developing rapidly, and some industries need to use ultra-low phosphorus steel, requiring the phosphorus content in steel to be below 0.005%. In the ultra-low phosphorus steel grades in Japan and Europe, the phosphorus content has reached about 0.003% or even lower. Good dephosphorization is inseparable from good kinetic and thermodynamic conditions, especially the influence of slag alkalinity, slag content, dissolved oxygen content in steel, and molten steel temperature on dephosphorization. High-quality ultra-low phosphorus steel must optimize the process control method of the smelting process without greatly increasing the smelting cost. [0003] At present, the low-phosphorus steel produced by the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C5/28C21C7/064
CPCC21C5/28C21C7/064
Inventor 杨俊汤伟陈波涛脱臣德杜豪
Owner HUNAN VALIN XIANGTAN IRON & STEEL CO LTD