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RH vacuum refining method of ultra-low carbon stainless steel

A vacuum refining and stainless steel technology, applied in the refining field of ultra-low carbon steel, can solve the problem that the decarburization advantage of RH vacuum device cannot be effectively expanded, and achieve the effect of rapid denitrification and decarburization

Inactive Publication Date: 2011-11-23
BAOSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] To sum up, so far, there are no relevant reports and applications on RH vacuum equipment for ultra-low carbon stainless steel refining, making it impossible to effectively expand the decarburization advantages of RH vacuum equipment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Example 1, refining ferritic stainless steel with a carbon content of 0.03% (300ppm) and a nitrogen content of less than 150ppm.

[0036] A. The temperature of molten steel in the ladle is detected to be 1570°C; while the initial carbon content in the molten steel is 0.10%, and the initial nitrogen content of the treatment is 800ppm;

[0037] B. Keep the RH vacuum degree at 6.0kpa, and carry out the preliminary denitrification operation of RH vacuum. The vacuum time is maintained at 5 minutes. At this time, the lifting gas flow rate is controlled at 1200Nl / min;

[0038] C. After the end of the denitrification process, keep the RH vacuum at 6.0kpa and enter the forced decarburization process: control the oxygen flow rate of the top lance at 1200Nm 3 / h, properly adjust the lifting gas flow rate, control the lifting gas flow rate from 1200Nl / min to 1800Nl / min, in order to increase the liquid steel ring flow rate, thereby increasing the decarburization speed, and control t...

Embodiment 2

[0043] Example 2, refining ferritic stainless steel with a carbon content of 0.01% (100 ppm) and a nitrogen content of less than 100 ppm.

[0044] A. The temperature of molten steel in the detection ladle is 1595°C; while the initial carbon content in the molten steel is 0.10%, and the initial nitrogen content of the treatment is 800ppm;

[0045] B. Keep the RH vacuum degree at 5.5kpa, and carry out the preliminary denitrification operation of RH vacuum. The vacuum time is maintained at 10 minutes, and the lifting gas flow rate is controlled at 1400Nl / min at this time;

[0046] C. After the end of the denitrification process, keep the RH vacuum at 5.5kpa and enter the forced decarburization process: control the oxygen flow rate of the top lance at 1350Nm 3 / h, properly adjust the lifting gas flow rate, control the lifting gas flow rate from 1200Nl / min to 1800Nl / min, in order to increase the liquid steel ring flow rate, thereby increasing the decarburization speed, and control ...

Embodiment 3

[0051] Example 3, refining ferritic stainless steel with a carbon content of 0.05% (500ppm) and a nitrogen content of less than 70ppm.

[0052] A. The temperature of molten steel in the ladle is detected to be 1605°C; while the initial carbon content in the molten steel is 0.10%, and the initial nitrogen content of the treatment is 800ppm;

[0053] B. Keep the RH vacuum degree at 5.0kpa, and carry out the preliminary denitrification operation of RH vacuum. The vacuum time is maintained at 15 minutes, and the lifting gas flow rate is controlled at 1500Nl / min at this time;

[0054] C. After the end of the denitrification process, keep the RH vacuum at 5.0kpa and enter the forced decarburization process: control the oxygen flow rate of the top lance at 1500Nm 3 / h, properly adjust the lifting gas flow rate, control the lifting gas flow rate from 1200Nl / min to 1800Nl / min, in order to increase the liquid steel ring flow rate, thereby increasing the decarburization speed, and contro...

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Abstract

The invention discloses an RH vacuum refining method of ultra-low carbon stainless steel, and the method uses a unique vacuum smelting principle of a RH vacuum circulation device; during an initial stage of RH vacuum refining, the nitrogen content of an incoming material of molten steel is decreased to meet an object requirement by using the vacuum condition; a decarburization mode combining forced decarburization with free decarburization is adopted at an RH refining work station; during denitrification and decarburization, the circulation flow rate of the molten steel is changed by different vacuum degrees and the increase of the gas flow so as to reach the purpose of rapid denitrification and decarburization; finally the temperature and the component are adjusted so as to meet the component requirement for ultra-low carbon stainless steel. Therefore, with the present production condition, variety extension of steel enterprises is realized, and requirements of stainless steel in various markets are met.

Description

technical field [0001] The invention relates to the refining technology of ultra-low carbon steel, more specifically, relates to a RH vacuum refining method of ultra-low carbon stainless steel. Background technique [0002] At present, in the traditional ultra-low carbon stainless steel smelting process, VOD refining furnace (vacuumoxygen decarburization) is mainly used to carry out the refining method of oxygen blowing decarburization under vacuum. As a common refining device, the RH vacuum unit (Ruhrstahl Heraeus vacuum unit) is often used to smelt carbon steel grades represented by automobile sheets and pipeline steels. It has the advantages of fast reaction speed and high efficiency, but it has not been used For the refining of ultra-low carbon stainless steel. [0003] The Chinese patent with the application number CN98125048.3 discloses a molten steel refining process, including vacuum circulation degassing (i.e. RH treatment), which belongs to the treatment method of...

Claims

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Application Information

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IPC IPC(8): C21C7/10C21C7/068C21C7/06
Inventor 李波池和冰顾学红茅卫东
Owner BAOSHAN IRON & STEEL CO LTD
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