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Method for controlling nitrogen content of nitrogen-containing non-sulfur-containing steel grades

A control method and technology for sulfur-containing steel, applied in the direction of manufacturing converters, etc., can solve the problems of not meeting the requirements of N content, resource consumption process, low sulfur content, etc., to improve the nitrogen fixation effect, reduce the denitrification rate, and control the nitrogen content. stable effect

Inactive Publication Date: 2020-11-20
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] For nitrogen-containing and non-sulfur-containing steels, the sulfur content after LF refining treatment is very low. During the subsequent vacuum RH furnace treatment, when the lifting gas uses argon (Ar), it will lead to a very high denitrification rate. Therefore, a large amount of nitrogen-containing silk threads need to be supplemented after vacuuming, resulting in resource consumption and complicated procedures; in the prior art, although the lifting gas can be changed to nitrogen (N 2 ) to reduce the denitrification rate, but for steel types without sulfur control, the N content after vacuum RH treatment still does not meet the N content requirements of steel types

Method used

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  • Method for controlling nitrogen content of nitrogen-containing non-sulfur-containing steel grades
  • Method for controlling nitrogen content of nitrogen-containing non-sulfur-containing steel grades

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] The steel grade produced is SG02

[0015] (1) Preparation before production: purge the equipment and pipelines to ensure that they are unimpeded; turn on the N 2 Pipeline valve, then cut off the Ar pipeline valve, adjust the gas flow rate to 800NL / min, and continue to spray at this flow rate for 15 minutes; check the pipeline airtightness under normal working pressure and flow rate, and the stability of pressure, flow rate and equipment operation property; check whether N 2 -Ar switching and flow regulation control, guaranteed at N 2 When the gas circuit fails, it can switch to Ar for normal gas supply;

[0016] (2) Converter smelting: N 2 As the bottom blowing gas, the flow rate is adjusted to 600NL / min;

[0017] (3) LF furnace treatment: according to the S composition, the sulfur line is supplemented before hanging the bag, and the S content is 0.0041% at the end of smelting, and the sulfur line is fed for 50 meters, and the S content is 0.0096% when the RH furnac...

Embodiment 2

[0020] The steel grade produced is SG01

[0021] (1) Preparation before production: purge the equipment and pipelines to ensure that they are unimpeded; turn on the N 2 Pipeline valve, then cut off the Ar pipeline valve, adjust the gas flow rate to 800NL / min, and continue to spray at this flow rate for 15 minutes; check the pipeline airtightness under normal working pressure and flow rate, and the stability of pressure, flow rate and equipment operation property; check whether N 2 -Ar switching and flow regulation control, guaranteed at N 2 When the gas circuit fails, it can switch to Ar for normal gas supply;

[0022] (2) Converter smelting: N 2 As the bottom blowing gas, the flow rate is adjusted to 600NL / min;

[0023] (3) LF furnace treatment: According to the S composition, the sulfur line is supplemented before lifting the bag. The S content is 0.0048% at the end of smelting, and the sulfur line is fed for 50 meters. When the RH furnace arrives at the station, the S c...

Embodiment 3

[0026] The steel grade produced is SG04

[0027] (1) Preparation before production: purge the equipment and pipelines to ensure that they are unimpeded; turn on the N 2 Pipeline valve, then cut off the Ar pipeline valve, adjust the gas flow rate to 600NL / min, and continue to spray at this flow rate for 20 minutes; check the air tightness of the pipeline under normal working pressure and flow rate, and the stability of pressure, flow rate and equipment operation property; check whether N 2 -Ar switching and flow regulation control, guaranteed at N 2 When the gas circuit fails, it can switch to Ar for normal gas supply;

[0028] (2) Converter smelting: N 2 As the bottom blowing gas, the flow rate is adjusted to 600NL / min;

[0029] (3) LF furnace treatment: according to the S composition, the sulfur line is supplemented before hanging the bag, and the S content is 0.0043% at the end of smelting, and the sulfur line is fed for 50 meters, and the S content is 0.0098% when the R...

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Abstract

The invention discloses a method for controlling the nitrogen content of nitrogen-containing non-sulfur-containing steel grades. The method includes the following steps that (1) converter smelting iscarried out, nitrogen is used for a whole converter bottom blowing process, and nitrogen blowing treatment is carried out on molten steel; (2) LF furnace treatment is carried out, at the end of LF furnace smelting, sulfur lines are fed in a supplemented mode according to the sulfur content in the molten steel, and the sulfur mass percentage content is controlled to 0.008-0.015%; and (3) RH furnacetreatment is carried out, nitrogen is used as a vacuum lifting gas, after breaking is carried out, samples are taken to analyze the nitrogen content, and nitrogen lines are fed in a supplemented modeaccording to the nitrogen content until the required range of the nitrogen content of the steel grades is reached. It is ensured that the high sulfur content is maintained in the steel grades by feeding the sulfur lines in a supplemented mode at the end of LF smelting, the nitrogen fixation effect of the nitrogen-containing non-sulfur-containing steel grades is improved, the denitrification ratein the vacuum process is reduced, the nitrogen content in steel reaches 120-200ppm, the nitrogen content is controlled stably, and a foundation is laid for subsequent product preparation.

Description

technical field [0001] The invention relates to a method for controlling nitrogen in nitrogen-containing vacuum steel grades, in particular to a method for controlling nitrogen components in nitrogen-containing non-sulfur-controlled vacuum steel. Background technique [0002] For nitrogen-containing and non-sulfur-containing steels, the sulfur content after LF refining treatment is very low. During the subsequent vacuum RH furnace treatment, when the lifting gas uses argon (Ar), it will lead to a very high denitrification rate. Therefore, a large amount of nitrogen-containing silk threads need to be supplemented after vacuuming, resulting in resource consumption and complicated procedures; in the prior art, although the lifting gas can be changed to nitrogen (N 2 ) to reduce the denitrification rate, but for steel types without sulfur control, the N content after vacuum RH treatment still does not meet the N content requirements of the steel types. Contents of the inventio...

Claims

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Application Information

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IPC IPC(8): C21C5/28C21C7/10C21C7/00
CPCC21C5/28C21C7/10C21C7/0056
Inventor 唐前进韦士琨胡志勇赵孝章周杨
Owner NANJING IRON & STEEL CO LTD
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