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Smelting process for producing low-carbon ultralow-phosphorus steel in converter

An ultra-low phosphorus steel and process technology, applied in the direction of manufacturing converters, etc., can solve the problems of increased equipment costs, increased process steps, and high product costs, and achieve the effects of short product flow, low cost, and energy saving

Inactive Publication Date: 2012-08-15
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] For some special-purpose low-carbon steel and alloy steel grades, such as 9Ni steel for LNG, customers usually require that the phosphorus content is less than 0.005% (ultra-low). From the current existing technology, it is necessary to make the P in molten steel ultra-low Level, it is difficult to use converter steelmaking, and it needs to adopt processes such as molten iron pretreatment and out-of-furnace refining, resulting in increased processes, increased equipment costs, and higher final product costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A smelting process for producing low-carbon ultra-low-phosphorus steel with a converter according to the present invention, in which the molten iron desulfurized once is produced through the smelting process of twice slagging in the converter to produce low-carbon ultra-low-phosphorus steel, and the specific steps are:

[0024] The molten iron after desulfurization once, with a P content of 0.13%, is dephosphorized by the slagging and blowing method twice in the early stage and the later stage, and the slag is adjusted by ferrosilicon. The degree of iron oxide in the slag is 1.9, and the iron oxide content in the slag is 15%; the temperature measured by the secondary gun at the blowing 75% in the later stage is 1540°C; the slag basicity is 4.8, the iron oxide content in the slag is 24%, and the target end point temperature is 1560°C . A low-carbon ultra-low phosphorus steel with a carbon content (mass percentage) of 0.038% and a phosphorus content (mass percentage) of 0...

Embodiment 2

[0026] A smelting process for producing low-carbon ultra-low-phosphorus steel with a converter according to the present invention, in which the molten iron desulfurized once is produced through the smelting process of twice slagging in the converter to produce low-carbon ultra-low-phosphorus steel, and the specific steps are:

[0027] The molten iron after desulfurization once, with P content of 0.12%, is dephosphorized by two slagging and blowing methods in the early stage and the later stage, and slag is adjusted by ferrosilicon. The degree of iron oxide in the slag is 1.5, and the iron oxide content in the slag is 12%; the temperature measured by the secondary gun at the blowing 79% in the later stage is 1550°C; , to obtain a carbon content (mass percentage) of 0.042%, a phosphorus content (mass percentage) of 0.0046% low-carbon ultra-low phosphorus steel.

Embodiment 3

[0029] A smelting process for producing low-carbon ultra-low-phosphorus steel by a converter according to the present invention, the process uses molten iron desulfurized once to produce low-carbon ultra-low-phosphorus steel through the smelting process of three times of slagging in the converter, and the specific steps are:

[0030] The molten iron after primary desulfurization, with a P content of 0.13%, is dephosphorized by three slagging and blowing methods in the early, middle and late stages, and ferrosilicon is used to adjust the slag. For slag dumping, the basicity of the slag is 1.1, and the iron oxide content in the slag is 11%; when the sub-lance is blowing 72%, the measured temperature is 1530°C, the slag dumping, the slag basicity is 4.1, and the iron oxide content in the slag is 20%; Then add lime and lightly burned dolomite in an appropriate amount to carry out the final carbon drawing and temperature rise. The target end point temperature is 1580°C, and the stee...

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Abstract

The invention discloses a smelting process for producing low-carbon ultralow-phosphorus steel in a converter. The smelting process comprises the following steps of: dephosphorizing molten iron desulfurized once by utilizing two times of slagging blowing process, namely, an early stage and a later, or three times of slagging blowing process, namely, an early stage, a middle stage and the later stage, or multiple times of slagging blowing process, wherein the content of phosphorus of the molten iron is 0.11-0.13%; utilizing silicon iron slag regulation, pouring the slag into a slag basin until the slag basin is full each time and controlling process temperature; pouring slag when oxygen blowing is carried out by 40-45%, wherein the target temperature of an early stage is 1,350-1,400 DEG C; and controlling the temperature between 1530 DEG C and 1550 DEG C when a sublance is used for blowing oxygen for 80%, and pouring the slag, so that the low-carbon ultralow-phosphorus steel with terminal phosphorus content being within 0.005% is obtained, wherein the terminal target temperature is 1560-1580 DEG C. The smelting process for producing the low-carbon ultralow-phosphorus steel in the converter, disclosed by the invention, can carry out multiple times of slagging on the molten iron desulfurized once in the converter and has the advantages of being small in molten iron physical heat loss, high in yield and efficiency, low in alloy consumption and cost, and energy-saving.

Description

technical field [0001] The invention relates to a smelting process for low-carbon and ultra-low-phosphorus steel, in particular to a smelting process for producing low-carbon and ultra-low-phosphorus steel by double-slag or multiple-slag methods in a converter. Background technique [0002] The smelting of ultra-low phosphorus steel is generally realized by the process of refining outside the furnace. For alloy steel, high carbon steel and special steel, the patents of publication numbers CN 101319261A, CN 101328529A and CN 101319262A adopt the process of refining outside the furnace for initial dephosphorization and deepening dephosphorization, and the phosphorus content can be controlled within 0.003%. But before refining, it is required that the phosphorus content of converter steel should be below 0.02%. Obviously, these methods need to add an extra-furnace refining process after converter steelmaking to reduce the phosphorus content, and add a specific dephosphorizatio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/36C21C7/064C21C7/068
Inventor 霍松波黄一新姚永宽蔡可森孟令东刘振宇谢章龙王春芳温永红樊振亚黄建华
Owner NANJING IRON & STEEL CO LTD
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