CN114941054A - Nitrogen increasing method for nitrogen-containing steel - Google Patents

Nitrogen increasing method for nitrogen-containing steel Download PDF

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Publication number
CN114941054A
CN114941054A CN202210681299.6A CN202210681299A CN114941054A CN 114941054 A CN114941054 A CN 114941054A CN 202210681299 A CN202210681299 A CN 202210681299A CN 114941054 A CN114941054 A CN 114941054A
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China
Prior art keywords
nitrogen
steel
containing steel
smelting
increasing
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Pending
Application number
CN202210681299.6A
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Chinese (zh)
Inventor
马传庆
张佩
张海霞
范斌
李金浩
戈文英
王海州
魏晨阳
李月
郑桂云
赵冠夫
梁娜
刘金玲
张利平
刘兵
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Shandong Iron and Steel Co Ltd
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Shandong Iron and Steel Co Ltd
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Priority to CN202210681299.6A priority Critical patent/CN114941054A/en
Publication of CN114941054A publication Critical patent/CN114941054A/en
Pending legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/32—Blowing from above
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/34—Blowing through the bath
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Abstract

The invention discloses a nitrogen increasing method for nitrogen-containing steel, and belongs to the technical field of ferrous metallurgy. The method for smelting the nitrogen-containing steel by adopting the duplex mode can increase the nitrogen content in the molten steel at lower cost and simultaneously ensure that the nitrogen content of the steel is stabilized at 80-150 ppm.

Description

Nitrogen increasing method for nitrogen-containing steel
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and relates to a new nitrogen increasing process for nitrogen-containing steel.
Background
Generally, nitrogen is considered one of the harmful impurities in steel. Although the solubility of nitrogen in liquid steel is low at normal pressure, these small amounts of nitrogen can cause age embrittlement of the steel, and various secondary refining techniques for reducing nitrogen in liquid steel have been developed and are being continuously improved. However, nitrogen as an alloying element may interact with other alloying elements in the steel (e.g., Mn, Cr, V, Nb, Ti, etc.) to impart many superior properties to the steel. For example, the stability of austenite is improved, the mechanical properties of steel are greatly improved, the corrosion resistance of steel is improved, and the like.
In the prior art, two ways of increasing nitrogen in the alloy are provided: (1) one is to add solid nitrogen-containing alloy: adding precious solid nitrogen-containing alloy (such as vanadium-nitrogen alloy and the like) into liquid molten steel at the later stage of refining in the steelmaking process, wherein nitrogen elements in the nitrogen-containing alloy are absorbed by the molten steel, so that the molten steel reaches a certain nitrogen content; the nitrogen increasing mode has the following defects: the steel smelting cost is high, and the nitrogen absorption stability of the steel is poor, so that the nitrogen content in the molten steel is easy to fluctuate greatly and even exceeds the standard range. (2) In the other mode, nitrogen is blown into the molten steel, and part of nitrogen elements in the nitrogen are absorbed by the molten steel, so that the molten steel reaches a certain nitrogen content; the method is economical and practical, the nitrogen element has certain solubility in the molten alloy steel, the nitrogen is cheap, the smelting cost is low, but the nitrogen blowing mode can only be adopted in the primary smelting furnace, but the nitrogen increasing amount is very limited due to the smelting environment of the primary smelting furnace, and the nitrogen increasing amount is not more than 30ppm generally.
For steel grades needing to ensure the nitrogen content, the key of nitrogen control is to ensure the stability of the nitrogen content. Therefore, the key to increase the market share and improve the benefit of the nitrogen-containing steel is that the nitrogen alloying can be realized and the production cost can be reduced.
Disclosure of Invention
In order to solve the problems, the invention provides a nitrogen increasing method for nitrogen-containing steel.
The invention provides a nitrogen increasing method for nitrogen-containing steel, which comprises the following steps: the method is particularly suitable for producing the nitrogen-containing low-alloy high-strength steel by adopting the electric furnace and the production process of bottom blowing direct-upward continuous casting blank.
Preferably, in the nitrogen increasing process, a mode of blowing nitrogen into a primary furnace is adopted, wherein the primary furnace comprises a converter or an electric furnace. Further preferably, the electric furnace adopts a whole-process bottom blowing nitrogen smelting process, the nitrogen can adopt industrial nitrogen or nitrogen with higher purity, the flow rate of the nitrogen is adjusted to be between 5 and 25L/min, the pressure is automatically controlled according to the condition of the air brick, and the smelting time is 35 to 60 min; the converter bottom blowing adopts a whole-process bottom blowing nitrogen smelting process, the nitrogen can adopt industrial nitrogen or nitrogen with higher purity, the flow rate of the nitrogen is adjusted to be 15-50L/min, the pressure is automatically controlled according to the condition of the air brick, and the smelting time is 20-40 min; the converter top blowing adopts a smelting process of whole-process or partial-time-period blowing, oxygen containing nitrogen is blown, the proportion (volume ratio) of the nitrogen is 10-30%, the flow pressure is controlled differently according to the requirements of the converter, the blowing amount is greatly increased compared with bottom blowing, and the smelting time is 20-40 min. The nitrogen increasing amount of the smelting environment of the primary smelting furnace is very limited, and the nitrogen increasing amount is not more than 30ppm generally.
Preferably, the main component of the AD powder, i.e., the steel-making promoter, added in a slag-washing manner during tapping is Al 2 O 3 And partial active Al (metal Al and AlN), the nitrogen content (mass percentage) is 6-12%, and the nitrogen content is divided into AD15 (containing active Al 15%), AD20 (containing active Al 20%) and the like according to the different active Al contents.
Further preferably, when the AD powder is added by slag washing, the active Al contained in the AD powder reacts rapidly with oxygen in the molten steel. If the AD powder is added, lime is added immediately, the speed and temperature of slagging can be rapidly increased because heat is concentrated on the surface of molten steel, and in addition, A1 in the AD powder 2 O 3 The substances generated by the reaction with the aluminum oxide are combined with CaO to generate calcium aluminate with low melting point, and the slag has good fluidity and does not need to be added with fluorite. Meanwhile, the oxygen content in steel and slag is reduced, and the desulfurization is facilitated. The washing of the calcium aluminate slag generated by the AD powder and the CaO has better capability of absorbing the inclusion.
4Al+3O 2 ＝＝＝＝Al 2 O 3
2CaO+S＝＝＝＝2CaS+O 2
Preferably, the AD powder with the nitrogen content of 6-12% is added in the tapping process to achieve an obvious nitrogen increasing effect, and the AD powder is added in a slag washing mode in the tapping process to be 2 kg/ton steel to 4 kg/ton steel, so that the nitrogen can be increased by 30-80 ppm.
2AlN＝＝＝＝2Al+N 2
Further preferably, the nitrogen is increased by a duplex mode of adding AD powder in the processes of nitrogen blowing of the primary smelting furnace and tapping, the nitrogen can be increased by 50-110ppm, and the nitrogen content of the molten steel can be stably controlled to be 80-150 ppm.
The invention has the beneficial effects that:
in the prior art, nitrogen is increased by adding a nitrogen-containing alloy, so that the cost is too high and the nitrogen content in molten steel is unstable; the nitrogen increase is carried out only in the primary smelting furnace by adopting a nitrogen blowing mode, and the nitrogen increase amount is less than or equal to 30 ppm. Compared with the prior art, the invention has the following beneficial effects:
(1) the method adopts a mode of blowing nitrogen in a primary smelting furnace (comprising an electric furnace and a converter) and a mode of carrying out slag washing duplex nitrogen increase by adopting AD powder in the tapping process, thereby solving the problem of overhigh alloy nitrogen increase cost in the current steel smelting process.
(2) For steel grades needing to ensure the nitrogen content, the key point of nitrogen control is to ensure the stability of the nitrogen content. The method of blowing nitrogen into the primary smelting furnace and adding AD powder to carry out slag washing duplex nitrogen increase in the tapping process is adopted, the problem of low nitrogen increase efficiency of blowing nitrogen into the primary smelting furnace can be effectively solved, and the nitrogen content in the nitrogen-containing steel can be stably controlled to be 80-150 ppm.
(3) The invention effectively supplements the prior steelmaking process and provides a new idea and method for smelting nitrogen-containing steel, in particular low-alloy high-strength nitrogen-containing steel without refining.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
As described in the background, currently employed nitrogen-increasing methods: the nitrogen increasing mode of the alloy is adopted, so that the cost is high and the nitrogen increasing amount is unstable; the nitrogen is increased by blowing nitrogen in the primary smelting furnace, and the nitrogen increasing efficiency is low. Based on the method, the process of blowing nitrogen in the primary smelting furnace and adding AD powder in a slag washing mode in the tapping process is adopted, so that the low steelmaking cost is realized, the nitrogen content is stably controlled, and the nitrogen increasing amount reaches 80-150 ppm.
In order to make the technical solutions of the present application more clearly understood by those skilled in the art, the technical solutions of the present application will be described in detail below with reference to specific embodiments.
The test materials used in the examples of the present invention are all conventional in the art and commercially available.
Example 1:
the production process of the direct-upward continuous casting blank by using the electric furnace and the bottom blowing is adopted to produce the nitrogen-containing low-alloy high-strength steel, under the condition that 50% of molten iron and high-quality waste steel are added into the electric furnace, nitrogen gas is used for 40 minutes for the whole bottom blowing process of the electric furnace, the nitrogen gas flow is 20L/min, 2 kg/ton of steel AD15 (containing 9% of nitrogen) is added in a slag washing duplex mode in the tapping process, and the nitrogen content in the steel can reach 100-120 ppm.
Example 2:
the production process of converter and bottom blowing direct-upward continuous casting blank forming is adopted to produce the nitrogen-containing low-alloy high-strength steel, nitrogen for converter bottom blowing industry is 30 minutes, the nitrogen flow is 40L/min, 4 kg/ton of steel AD15 (containing 9% of nitrogen) is added in a slag washing mode in the converter tapping process, and the nitrogen content in the steel can reach 100-150 ppm.
Example 3:
the production process of converter and bottom blowing direct-upward continuous casting blank forming is adopted to produce the nitrogen-containing low-alloy high-strength steel, oxygen mixed with 20% nitrogen is blown at the top of the converter for 30 minutes, 4 kg/ton of steel AD15 (containing 9% of nitrogen) is added in a slag washing mode in the converter tapping process, and the nitrogen content in the steel can reach 100-150 ppm.
Comparative example 1:
the nitrogen-containing low-alloy high-strength steel is produced by adopting an electric furnace, nitrogen is not blown into the electric furnace in the smelting process, AD15 powder is not added in the tapping process, and the nitrogen content in the steel can reach 30-50 ppm.
Comparative example 2:
the production process of the direct-up continuous casting blank by adopting the electric furnace and the bottom blowing is adopted to produce the nitrogen-containing low-alloy high-strength steel, under the condition that the electric furnace is added with 50 percent of molten iron and high-quality scrap steel, the nitrogen gas for the industrial use is blown at the bottom for 40 minutes in the whole process of the electric furnace, the flow rate of the nitrogen gas is 20L/min, AD15 powder is not added in the tapping process, and the nitrogen content in the steel can reach 70-90 ppm.
Comparative example 3:
the nitrogen-containing low-alloy high-strength steel is produced by adopting an electric furnace, nitrogen is not blown into the electric furnace in the smelting process, 2 kg/ton of AD15 (containing 9% of nitrogen) is added in the electric furnace steel tapping process only by adopting a slag washing mode, and the nitrogen content in the steel can reach 75-95 ppm.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims (9)

1. A nitrogen increasing method of nitrogen-containing steel is characterized by comprising the following steps:
and in the smelting process, nitrogen is blown by an electric furnace or a converter in cooperation with the AD powder in the tapping process in a slag washing mode to smelt the nitrogen-containing steel.
2. The nitrogen increasing method of the nitrogen-containing steel as claimed in claim 1, wherein the electric furnace adopts a whole-process bottom-blown nitrogen smelting process, the nitrogen flow is 5-25L/min, and the smelting time is 35-60 min.
3. The nitrogen increasing method for the nitrogen-containing steel as claimed in claim 1, wherein the converter adopts a full-process bottom-blown nitrogen smelting process, the nitrogen flow is 15-50L/min, and the smelting time is 20-40 min.
4. The nitrogen increasing method for the nitrogen-containing steel as claimed in claim 1, wherein the converter adopts a whole-process or partial-period top-blown smelting process, oxygen containing nitrogen is blown, the volume ratio of the nitrogen is 10-30%, and the smelting time is 20-40 min.
5. The method for increasing nitrogen content in nitrogen-containing steel as claimed in claim 1, wherein the main component of the AD powder is Al 2 O 3 And active Al, wherein the nitrogen content is 6-12%.
6. The method for increasing nitrogen content in nitrogen-containing steel as claimed in claim 1, wherein the AD powder is added in an amount of 2 kg/ton steel to 4 kg/ton steel during tapping.
7. The nitrogen-containing steel obtained by the nitrogen increasing method of the nitrogen-containing steel according to any one of claims 1 to 5.
8. The nitrogen-containing steel of claim 6, wherein the nitrogen content is 80ppm to 150 ppm.
9. The application of the nitrogen increasing method of the nitrogen-containing steel as claimed in any one of claims 1 to 5 in the production of nitrogen-containing low-alloy high-strength steel by adopting an electric furnace and a production process of bottom-blowing direct-up continuous casting blank.
CN202210681299.6A 2022-06-16 2022-06-16 Nitrogen increasing method for nitrogen-containing steel Pending CN114941054A (en)

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Application Number Priority Date Filing Date Title
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111826498A (en) * 2020-07-31 2020-10-27 唐山飞迪冶金材料有限公司 Additive for increasing strength of deformed steel bar and preparation method and application thereof
CN113337679A (en) * 2021-06-21 2021-09-03 重庆钢铁股份有限公司 Method for increasing nitrogen content in steel
CN114058788A (en) * 2021-11-19 2022-02-18 甘肃酒钢集团宏兴钢铁股份有限公司 Method for preparing micro-nitrogen deoxidizing alloy by using aluminum ash

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111826498A (en) * 2020-07-31 2020-10-27 唐山飞迪冶金材料有限公司 Additive for increasing strength of deformed steel bar and preparation method and application thereof
CN113337679A (en) * 2021-06-21 2021-09-03 重庆钢铁股份有限公司 Method for increasing nitrogen content in steel
CN114058788A (en) * 2021-11-19 2022-02-18 甘肃酒钢集团宏兴钢铁股份有限公司 Method for preparing micro-nitrogen deoxidizing alloy by using aluminum ash

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