Method for nitrogen increase of nitrogen-containing steel for wind power flange through RH vacuum degassing system

A wind power flange and vacuum degassing technology, applied in the field of metallurgy, can solve the problems of inaccurate control of nitrogen content, low efficiency of nitrogen increase, poor dehydrogenation effect, etc., to improve the purity of molten steel, improve the efficiency of nitrogen increase, save The effect of secondary pollution risk of molten steel

Inactive Publication Date: 2020-07-14
建龙北满特殊钢有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problems of low nitrogen increasing efficiency, inaccurate nitrogen content control, and poor dehydrogenation effect of the existing nitrogen increasing method in the refining process of nitrogen-containing steel for wind power flanges, the present invention provides a nitrogen-containing steel for wind power flanges using RH vacuum Nitrogen increase method for degassing system

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] This embodiment provides a method for increasing nitrogen by using the RH vacuum degassing system when producing S355NL (Q355NE) steel for wind power flanges. The steps are as follows:

[0026] When the ladle leaves the LF position, the nitrogen content is 59ppm, and the target nitrogen content is 90ppm.

[0027] Step 1. When the ladle reaches the RH vacuum position, use argon with a ring flow of 2000NL / min as the lifting gas, turn on the vacuum pump, evacuate to 67MPa and keep it for 10 minutes, then use a low-pressure nitrogen pipeline to switch the argon to nitrogen, at 0.8kg of nitrogen The pressure and nitrogen ring flow rate of 2000NL / min are maintained for 5 minutes to break empty, and the total vacuum time is 15 minutes. After breaking the air, take a sample and determine the hydrogen. The measured hydrogen content is 0.85ppm. In the process of blanking sample inspection, use argon gas for soft blowing at a flow rate of 120NL / min;

[0028] When nitrogen is used as th...

Embodiment 2

[0032] This embodiment provides a method for increasing nitrogen by using the RH vacuum degassing system when producing S355NL (Q355NE) steel for wind power flanges. The steps are as follows:

[0033] The nitrogen content when the ladle leaves the LF position is 54 ppm, and the target nitrogen content is 90 ppm.

[0034] Step 1. The ladle reaches the vacuum position of RH, use 1800NL / min ring flow argon as the lifting gas, turn on the vacuum pump, evacuate to 67MPa and keep it for 12min, then use the low pressure nitrogen pipeline to switch the argon to nitrogen, at 0.6kg of nitrogen The pressure and the nitrogen ring flow rate of 1800NL / min are maintained for 5 minutes to break, and the total vacuum time is 17 minutes. After breaking the air, take a sample and determine the hydrogen. The measured hydrogen content is 0.78ppm. In the process of blank sample inspection, argon gas is used for soft blowing at a flow rate of 80NL / min;

[0035] Step 2. The nitrogen content of the air-bre...

Embodiment 3

[0038] This embodiment provides a method for increasing nitrogen by using the RH vacuum degassing system when producing S355NL (Q355NE) steel for wind power flanges. The steps are as follows:

[0039] When the ladle leaves the LF position, the nitrogen content is 60 ppm, and the target nitrogen content is 90 ppm.

[0040] Step 1. When the ladle reaches the RH vacuum position, use argon with a ring flow of 1900NL / min as the lifting gas, turn on the vacuum pump, evacuate to 67MPa and keep it for 10 minutes, and use a low-pressure nitrogen pipeline to switch the argon to nitrogen. The pressure and the nitrogen ring flow rate of 1900NL / min are maintained for 5 minutes to break, and the total vacuum time is 15 minutes. After breaking the air, take a sample and determine the hydrogen. The measured hydrogen content is 0.80ppm. In the process of blank sample inspection, argon gas is used for soft blowing at a flow rate of 100NL / min;

[0041] Step 2. The nitrogen content of the air-break sa...

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Abstract

The invention relates to a method for nitrogen increase of nitrogen-containing steel for a wind power flange through a RH vacuum degassing system, and belongs to the technical field of metallurgy. Inorder to solve the problems of low nitrogen increase efficiency, inaccurate nitrogen content control and poor dehydrogenation effects of an existing nitrogen increase method, the method for nitrogen increase of the nitrogen-containing steel for the wind power flange through the RH vacuum degassing system is provided. Argon-nitrogen pipeline switching of the RH vacuum degassing system is utilized,nitrogen serves as lifting gas, stable and quick nitrogen increase is achieved through RH vacuum position nitrogen increase and bottom nitrogen direct introduction for nitrogen increase after vacuum breaking, and then nitrogen soft blowing is used for supplementation of nitrogen increase to precisely control the nitrogen content. Argon soft blowing is utilized to ensure the dehydrogenation effect,and the hydrogen content is controlled to be smaller than or equal to 1.0 ppm. According to the method, by flexibly adjusting switching of the nitrogen and the argon, vacuumizing and soft blowing total time is controlled within 45 minutes, smooth production can be ensured, the nitrogen content of the nitrogen-containing steel for the wind power flange is controlled in an internal control range, and stable control over the performance of steel products is ensured.

Description

Technical field [0001] The invention belongs to the technical field of metallurgy, and particularly relates to a method for increasing nitrogen by using a RH vacuum degassing system for nitrogen-containing steel for wind power flanges. Background technique [0002] Generally speaking, nitrogen is a harmful element, which will increase the risk of age embrittlement of steel materials. However, for nitrogen-containing steel materials such as steel for wind power flanges, the addition of V and Nb alloys to the steel and the addition of nitrogen elements can form stable nitrides VN and NbN, and the nitrides are dispersed in the grain boundaries to produce precipitation strengthening Function, and then refine the grains and improve the strength and toughness of steel. Therefore, adding 70-110ppm of N to the steel for wind power flanges can improve the strength and toughness of the finished flange. [0003] The nitrogen content in steel is controlled by adding chromium nitride or manga...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/10C21C7/072C21C7/00
CPCC21C7/00C21C7/072C21C7/10
Inventor 王雪威白海虎陈列陶立志李军业董贵文刘光辉回磊陈福元李凯李庆斌郑福盛毛威昂孙鸿鹏王刘艳蔡宏瀚
Owner 建龙北满特殊钢有限责任公司
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