CN115558742A - Deoxidation method after vacuum decarburization - Google Patents
Deoxidation method after vacuum decarburization Download PDFInfo
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- CN115558742A CN115558742A CN202211180462.7A CN202211180462A CN115558742A CN 115558742 A CN115558742 A CN 115558742A CN 202211180462 A CN202211180462 A CN 202211180462A CN 115558742 A CN115558742 A CN 115558742A
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- 238000000034 method Methods 0.000 title claims abstract description 51
- 238000005261 decarburization Methods 0.000 title claims abstract description 50
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 219
- 239000010959 steel Substances 0.000 claims abstract description 219
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 84
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 84
- 239000002893 slag Substances 0.000 claims abstract description 59
- 238000007664 blowing Methods 0.000 claims abstract description 47
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 35
- 239000001301 oxygen Substances 0.000 claims abstract description 35
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 35
- 238000003723 Smelting Methods 0.000 claims abstract description 33
- 230000000694 effects Effects 0.000 claims description 27
- 239000007788 liquid Substances 0.000 claims description 12
- 238000005070 sampling Methods 0.000 claims description 6
- 238000006392 deoxygenation reaction Methods 0.000 claims description 4
- 238000005187 foaming Methods 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 238000006477 desulfuration reaction Methods 0.000 abstract description 3
- 230000023556 desulfurization Effects 0.000 abstract description 3
- 238000004904 shortening Methods 0.000 abstract description 2
- 230000009286 beneficial effect Effects 0.000 abstract 1
- 239000002245 particle Substances 0.000 description 13
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 11
- 229910052799 carbon Inorganic materials 0.000 description 11
- 230000008569 process Effects 0.000 description 9
- CYUOWZRAOZFACA-UHFFFAOYSA-N aluminum iron Chemical compound [Al].[Fe] CYUOWZRAOZFACA-UHFFFAOYSA-N 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 238000007670 refining Methods 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 230000004048 modification Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- 238000009489 vacuum treatment Methods 0.000 description 4
- 238000009835 boiling Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000010079 rubber tapping Methods 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
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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
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
-
- 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
- C21C7/0006—Adding metallic additives
-
- 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)
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- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention particularly relates to a deoxidation method after vacuum decarburization, belonging to the field of steel smelting. A deoxidation method after vacuum decarburization comprises the following steps: carrying out vacuum decarburization on the smelting molten steel to obtain decarburized molten steel; adding a first aluminum deoxidizer with a first preset amount into the decarburized molten steel in a vacuum state to obtain first deoxidized molten steel; the first deoxidized molten steel is subjected to first bottom blowing at a first preset flow rate to obtain second deoxidized molten steel; adding a second aluminum deoxidizer with a second preset amount into the second deoxidized molten steel to obtain third deoxidized molten steel; and blowing the third deoxidized molten steel through a second bottom blowing at a second preset flow rate to obtain final deoxidized molten steel. The method can reduce the dissolved oxygen in the molten steel to below 5ppm within 5min, and reduce the FeOOwt% and MnOwt% in the slag to below 1.0wt%, thereby saving a large amount of processing time for the next procedure and directly carrying out desulfurization treatment, being beneficial to shortening the overall production period, improving the production efficiency and reducing the production cost.
Description
Technical Field
The invention belongs to the field of steel smelting, and particularly relates to a deoxidation method after vacuum decarburization.
Background
The VD refining process is one of the common vacuum refining means in the field of steelmaking, and the principle of the VD refining process is that a steel ladle filled with molten steel is placed in a vacuum tank, inert gas is blown to the bottom in a vacuum state, so that the molten steel and steel slag are strongly stirred and shaken, and the molten steel is refined in the process. When low-carbon steel and ultra-low-carbon steel are produced, in order to achieve the purposes of good decarburization effect and quick decarburization, the oxygen content in molten steel and steel slag before vacuum treatment needs to be kept at a certain level, for example, the oxygen activity in the molten steel is more than 250ppm, the FeOOwt% and the MnOwt% in the slag are more than 10%, and the like, and after decarburization is finished, the molten steel and the steel slag still contain a large amount of oxygen.
In the prior art, two methods are generally adopted for controlling the oxygen content; one is that the oxygen content in the molten steel and steel slag is controlled to a relatively low level before the vacuum treatment, and the treatment method not only causes low decarburization efficiency, but also has an adverse effect on the stable control of the final carbon content of the molten steel; and secondly, adding a deoxidizing agent after the decarburization is finished and the air is broken, stirring and then entering the next process.
Disclosure of Invention
The application aims to provide a deoxidation method after vacuum decarburization, so as to solve the technical problems that in the prior art, when deoxidation is carried out after vacuum decarburization, the deoxidation effect and the deoxidation efficiency are poor.
The embodiment of the invention provides a deoxidation method after vacuum decarburization, which comprises the following steps:
carrying out vacuum decarburization on the smelting molten steel to obtain decarburized molten steel;
adding a first aluminum deoxidizer with a first preset amount into the decarburized water in a vacuum state to obtain first deoxidized molten steel;
the first deoxidized molten steel is subjected to first bottom blowing at a first preset flow rate to obtain second deoxidized molten steel;
adding a second aluminum deoxidizer with a second preset amount into the second deoxidized molten steel to obtain third deoxidized molten steel;
the third deoxidized molten steel is subjected to second bottom blowing at a second preset flow rate to obtain final deoxidized molten steel;
wherein:
the first bottom blowing can expose the liquid level of the first deoxidized molten steel, and the exposed area is more than or equal to one half of the radius of the liquid level of the molten steel;
the second bottom blowing is capable of surging and foaming the slag of the third deoxidized molten steel.
Optionally, the first predetermined amount of reduced pure aluminum satisfies the following relation:
1000Alwt％*Q+0.001125a 0 Q+[65.9+1373*(FeOwt％+MnOwt％)]*R 2 h；
wherein:
q is the mass of the decarburized molten steel and has a unit of t;
a 0 the oxygen activity of the molten steel before the vacuum decarburization is expressed in ppm;
h is the thickness of the steel slag in the steel ladle, and the unit is m;
r is the radius of the ladle and is m.
Optionally, the first aluminum deoxidizer has a particle size of 30-50mm, a density of the first aluminum deoxidizer is greater than that of pure aluminum, and an aluminum content of the first aluminum deoxidizer is 30-90%.
Optionally, the first preset flow rate is 1.0-1.9NL/min t steel, and the time of the first bottom blowing is 1-3min.
Optionally, the second predetermined amount of reduced pure aluminum satisfies the following relation:
37.7+784.8*(FeOwt％+MnOwt％)*R 2 h；
wherein:
h is the thickness of the steel slag in the steel ladle, and the unit is m;
r is the radius of the ladle and is m.
Optionally, the granularity of the second aluminum deoxidizer is 8-15mm, and the aluminum content of the second aluminum deoxidizer is more than or equal to 99%.
Optionally, the second preset flow rate is 0.2-0.5NL/min t steel, and the time of the second bottom blowing is 1-2min.
Optionally, the method further comprises the following steps:
and respectively sampling and detecting the smelting molten steel and the steel slag to obtain the components of the smelting molten steel and the mass percentage content of FeO and MnO in the steel slag.
Optionally, the method further comprises the following steps:
and detecting the smelting molten steel to obtain the initial oxygen activity.
Optionally, the method further comprises the following steps:
and after the final deoxidized molten steel is obtained, the vacuum decarburization is broken, and the final deoxidation is carried out for oxygen determination to obtain the final oxygen activity.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
according to the deoxidation method after vacuum decarburization provided by the embodiment of the invention, the liquid level of decarburized molten steel is exposed by adopting first bottom blowing at a first preset flow rate, the exposed area is more than or equal to one half of the radius of the liquid level of the molten steel, and the granularity and the density of a first aluminum deoxidizer are controlled by adding the first aluminum deoxidizer, so that the decarburized molten steel can directly enter decarburized water, and the decarburized molten steel is well deoxidized under the strong stirring action of the first bottom blowing, so that the oxygen content in the decarburized water is rapidly reduced; then, under the vacuum state, adding a second aluminum deoxidizer, controlling the granularity and the aluminum content of the deoxidizer, and performing second bottom blowing at a second preset flow rate to keep the steel slag in a state of high-temperature boiling, good foaming and continuous surging, so that the second aluminum deoxidizer stays in the steel slag, fully contacts with the steel slag and quickly deoxidizes the steel slag; through the operation, the double deoxidation of the decarburized water and the steel slag is realized, and the deoxidation effect and efficiency are effectively improved.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
Fig. 1 is a flow chart of a method provided by an embodiment of the invention.
Detailed Description
The present invention will be specifically explained below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented thereby. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, 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 invention belongs. If there is a conflict, the present specification will control. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. For example, room temperature may refer to a temperature in the interval of 10 to 35 ℃.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
according to an exemplary embodiment of the present invention, there is provided a vacuum decarburization followed by deoxidation, including the steps of:
s1, carrying out vacuum decarburization on the smelting molten steel to obtain decarburized molten steel.
S2, adding a first aluminum deoxidizer with a first preset amount into the decarburized water in a vacuum state to obtain first deoxidized molten steel.
And S3, the first deoxidized molten steel is subjected to first bottom blowing at a first preset flow rate to obtain second deoxidized molten steel.
And S4, adding a second aluminum deoxidizer in a second preset amount into the second deoxidized molten steel to obtain third deoxidized molten steel.
And S5, blowing the third deoxidized molten steel through a second bottom blowing at a second preset flow rate to obtain final deoxidized molten steel.
Wherein:
the first bottom blowing can expose the liquid level of the first deoxidized molten steel, and the exposed area is more than or equal to one half of the radius of the liquid level of the molten steel;
the second bottom-blowing is capable of causing the slag of the third deoxidized molten steel to surge and foam.
According to the deoxidation method after vacuum decarburization provided by the embodiment of the invention, through the steps S2-S3, the first bottom blowing with the first preset flow rate is adopted, so that the liquid level of the decarburized molten steel is exposed, the exposed area is more than or equal to one half of the radius of the liquid level of the molten steel, and the granularity and the density of the first aluminum deoxidizer are controlled by adding the first aluminum deoxidizer, so that the decarburized molten steel can directly enter the decarburized molten steel, the decarburized molten steel is well deoxidized under the strong stirring action of the first bottom blowing, and the oxygen content in the decarburized molten steel is rapidly reduced; then, under the vacuum state, through the steps S4-S5, adding a second aluminum deoxidizer, controlling the granularity and the aluminum content of the deoxidizer, and performing second bottom blowing at a second preset flow rate to keep the steel slag in a state of high-temperature boiling, good foaming and continuous surging, so that the second aluminum deoxidizer stays in the steel slag, fully contacts with the steel slag and quickly deoxidizes the steel slag; through the operation, the double deoxidation of the decarburized water and the steel slag is realized, and the deoxidation effect and efficiency are effectively improved.
The vacuum decarburization was performed by using VD.
The first aluminum deoxidizer and the first aluminum deoxidizer may be any aluminum-containing deoxidizer known in the art.
The gas used for the first bottom-blowing and the gas used for the second bottom-blowing are both inert gases, and preferably argon gas.
As an alternative embodiment, the first predetermined amount of reduced pure aluminum satisfies the following relation:
1000Alwt％*Q+0.001125a 0 Q+[65.9+1373*(FeOwt％+MnOwt％)]*R 2 h；
wherein:
q is the mass of the decarburized molten steel and has a unit of t;
a 0 the oxygen activity of the molten steel before the vacuum decarburization is expressed in ppm;
h is the thickness of the steel slag in the steel ladle, and the unit is m;
r is the radius of the ladle and is m.
In an alternative embodiment, the first aluminum deoxidizer has a particle size of 30 to 50mm, a density greater than that of pure aluminum, and an aluminum content of 30 to 90%.
The reason why the particle size of the first aluminum deoxidizer is controlled is that: less than 30mm will be involved in the slag to affect dissolution into the molten steel, and more than 50mm will affect the melting rate and slow down the deoxidation efficiency.
As an alternative embodiment, the first predetermined flow rate is 1.0-1.9NL/min t steel and the first bottom blowing time is 1-3min.
The reason why the first preset flow rate is controlled is that: at the flow rate, the first bottom blowing can fully and effectively disperse steel slag, so that the liquid level of the first deoxidized molten steel is fully exposed, and the exposed area is more than or equal to one half of the radius of the liquid level of the molten steel.
The reason why the first bottom-blowing time is controlled is that: the first aluminum deoxidizer can be fully contacted and deoxidized with the first deoxidized molten steel within the time.
As an alternative embodiment, the second predetermined amount of reduced pure aluminum satisfies the following relation:
37.7+784.8*(FeOwt％+MnOwt％)*R 2 h；
wherein:
h is the thickness of the steel slag in the steel ladle, and the unit is m;
r is the radius of the ladle and is m.
As an alternative embodiment, the grain size of the second aluminum deoxidizer is 8-15mm, and the aluminum content of the second aluminum deoxidizer is more than or equal to 99%.
The reason why the particle size of the second aluminum deoxidizer is controlled is that: less than 8mm will be taken away by gas, increase the loss, more than 15mm will prolong the melting rate in the slag, slow down slag deoxidation efficiency.
As an alternative embodiment, the second predetermined flow rate is 0.2-0.5NL/min t steel and the second bottom blowing time is 1-2min.
The reason why the second preset flow rate is controlled is that: under the vacuum condition, the steel slag keeps high-temperature boiling, and at the flow rate, the steel slag can continuously surge and fully foam, so that the contact area with the second aluminum deoxidizer is effectively increased.
As an optional implementation manner, the method further comprises the following steps:
s0, respectively sampling and detecting the smelting molten steel and the steel slag to obtain the components of the smelting molten steel and the mass percentage content of FeO and MnO in the steel slag.
As an optional implementation manner, the method further comprises the following steps:
and S0.1, detecting the smelting molten steel to obtain the initial oxygen activity.
As an optional implementation manner, the method further comprises the following steps:
and S6, after the final deoxidized molten steel is obtained, the vacuum decarburization is broken, and the final deoxidation is carried out for oxygen determination to obtain the final oxygen activity.
The deoxidation method after vacuum decarburization provided by the invention has the following advantages and effects: (1) The molten steel and the steel slag can be well deoxidized in a short time, the treatment time is properly prolonged in VD, a large amount of treatment time is saved for the next refining process, the next refining process can be directly subjected to desulfurization treatment, the overall production period is favorably shortened, the production efficiency is improved, and the production cost is reduced; (2) The control method is simple, and operation difficulty and newly-added equipment are not increased; (3) The oxygen content in the molten steel and the steel slag is rapidly removed, and meanwhile, the heat loss, secondary oxidation pollution, corrosion to steel ladle refractory and other hazards caused by long-time stirring with high bottom blowing strength in the subsequent refining are reduced.
The present application will be described in detail below with reference to examples, comparative examples, and experimental data.
Example 1
The steel is SPHC, smelting is carried out by adopting a converter, the converter capacity is 210t, the target carbon content is 0.015wt%, the fluctuation range is 0.013-0.017wt%, the carbon content is required to be less than 0.01wt% after vacuum decarburization, the aluminum content is target to be 0.02wt%, and the fluctuation range is 0.015-0.025wt%.
A deoxidation method after vacuum decarburization comprises the following steps:
s0, respectively sampling and detecting the smelting molten steel and the steel slag to obtain the components of the smelting molten steel and the mass percentages of FeO and MnO in the steel slag, wherein the mass percentages of FeO and MnO in the steel slag are respectively 15wt% and 1wt%.
S0.1, detecting the smelting molten steel to obtain initial oxygen activity, a 0 Was 400ppm.
S1, carrying out vacuum decarburization on the smelting molten steel to obtain decarburized molten steel.
Wherein the thickness h of the steel slag in the steel ladle for smelting the molten steel is 0.1m, and the radius of the steel ladle slag line is 2m.
S2, adding a first aluminum deoxidizer in a first preset amount into the decarburized molten steel to obtain first deoxidized molten steel.
Wherein: the first aluminum deoxidizer is made of steel grit aluminum with the granularity of 30-50mm, the aluminum content of the first aluminum deoxidizer is 80wt%, and the first preset amount of the deoxidizer is calculated as follows: 1000 × 0.02wt% 210+0.001125 × 400 + 210+
[65.9+1373 (15.1 wt% +0.9 wt%) ]22 + 0.1=250.7kg, so the addition of steel grit aluminum is 250.7/80% =313kg.
And S3, blowing the first deoxidized molten steel through a first bottom blowing at a first preset flow rate to obtain second deoxidized molten steel.
Wherein: the first preset flow rate was 1.5NL/min t steel and the time for the first bottom blow was 2min.
And S4, adding a second aluminum deoxidizer in a second preset amount into the second deoxidized molten steel to obtain third deoxidized molten steel.
Wherein: the second aluminum deoxidizer adopts pure aluminum particles with the granularity of 9mm, and the second preset amount of converted pure aluminum is calculated as follows: 37.7+784.8 (15 wt% +1 wt%). 22 + 0.1=87.9kg, so the addition amount of pure aluminum particles is 88kg.
And S5, blowing the third deoxidized molten steel through a second bottom blowing at a second preset flow rate to obtain final deoxidized molten steel.
Wherein: the second preset flow rate was 0.3NL/min t steel and the time of the first bottom blow was 2min.
And S6, after the final deoxidized molten steel is obtained, vacuum decarburization and air breaking are carried out, final deoxidation is carried out, and oxygen determination is carried out, so that the final oxygen activity is obtained.
Example 2
The steel grade is SMMB, smelting is carried out by adopting a converter, the converter capacity is 100t, the target carbon content is 0.02wt%, the fluctuation range is 0.017-0.022wt%, the carbon content is required to be less than 0.012wt% after vacuum decarburization, the aluminum content is required to be 0.03wt%, and the fluctuation range is 0.015-0.025wt%.
A deoxidation method after vacuum decarburization comprises the following steps:
s0, respectively sampling and detecting the smelting molten steel and the steel slag to obtain the components of the smelting molten steel and the mass percentages of FeO and MnO in the steel slag, wherein the mass percentages of FeO and MnO in the steel slag are respectively 13.2wt% and 0.8wt%.
S0.1, detecting the smelted molten steel to obtain initial oxygen activity, a 0 It was 281ppm.
S1, carrying out vacuum decarburization on the smelting molten steel to obtain decarburized molten steel.
Wherein the thickness h of the steel slag in the steel ladle for smelting the molten steel is 0.08m, and the radius of the steel ladle slag line is 1.5m.
S2, adding a first aluminum deoxidizer in a first preset amount into the decarburized molten steel to obtain first deoxidized molten steel.
Wherein: the first aluminum deoxidizer adopts aluminum iron with the granularity of 30-50mm, the aluminum content of the aluminum iron is 30wt%, and the first preset amount of the aluminum iron deoxidizer calculated by the method is as follows: 1000 + 0.03wt% 100+0.001125 + 281 + 100+ [65.9+1373 (13.2 wt% +0.8 wt%) ] + 1.52 + 0.08=108.1kg, so that the addition amount of aluminum iron is 108.1/30% =360kg.
And S3, blowing the first deoxidized molten steel through a first bottom blowing at a first preset flow rate to obtain second deoxidized molten steel.
Wherein: the first preset flow rate was 1.1NL/min t steel and the time for the first bottom blow was 1.5min.
And S4, adding a second aluminum deoxidizer in a second preset amount into the second deoxidized molten steel to obtain third deoxidized molten steel.
Wherein: the second aluminum deoxidizer adopts pure aluminum particles with the particle size of 13mm, and the second preset amount of the deoxidizer is calculated to be the deoxidizer with the pure aluminum: 37.7+784.8 (13.2 wt% +0.8 wt%) + 1.52 + 0.08=57.5kg, so the amount of pure aluminum particles added is 58kg.
And S5, blowing the third deoxidized molten steel through a second bottom blowing at a second preset flow rate to obtain final deoxidized molten steel.
Wherein: the second preset flow rate was 0.5NL/min t steel and the time of the first bottom blow was 2min.
And S6, after the final deoxidized molten steel is obtained, vacuum decarburization is carried out, air breaking is carried out, final deoxidation is carried out, and oxygen determination is carried out, so that the final oxygen activity is obtained.
Example 3
The steel type YT2 is smelted by adopting an electric furnace, the furnace capacity of the electric furnace is 150t, the target carbon content is less than or equal to 0.006wt%, the fluctuation range is less than or equal to 0.008wt%, the carbon content is required to be less than 0.003wt% after vacuum decarburization, the aluminum content is required to be 0.03wt%, and the fluctuation range is 0.015-0.045wt%.
A deoxidation method after vacuum decarburization comprises the following steps:
s0, respectively sampling and detecting the smelting molten steel and the steel slag to obtain the components of the smelting molten steel and the mass percentage of FeO and MnO in the steel slag, wherein the mass percentage of FeO and MnO in the steel slag are respectively 18.2wt% and 1.8wt%.
S0.1, detecting the smelting molten steel to obtain initial oxygen activity, a 0 It was 556ppm.
S1, carrying out vacuum decarburization on the smelting molten steel to obtain decarburized molten steel.
Wherein the thickness h of the steel slag in the steel ladle for smelting the molten steel is 0.02m, and the radius of a steel ladle slag line is 1.75m.
And S2, adding a first aluminum deoxidizer in a first preset amount into the decarburized water to obtain first deoxidized molten steel.
Wherein: the first aluminum deoxidizer adopts aluminum iron with the granularity of 30-50mm, the aluminum content of the aluminum iron is 80wt%, and a first preset amount of reduced pure aluminum is calculated as follows: 1000 x 0.03wt% 150+0.001125 x 556 x 150+ [65.9+1373 (18.2 wt% +1.8 wt%) ]x1.752 x 0.02=158.9kg, so that the addition of aluminum iron is 158.9/80% =199kg.
And S3, blowing the first deoxidized molten steel through a first bottom blowing at a first preset flow rate to obtain second deoxidized molten steel.
Wherein: the first preset flow rate was 1.9NL/min t steel and the time of the first bottom blow was 3min.
And S4, adding a second aluminum deoxidizer in a second preset amount into the second deoxidized molten steel to obtain third deoxidized molten steel.
Wherein: the second aluminum deoxidizer adopts pure aluminum particles with the granularity of 8mm, and the second preset amount of the deoxidizer is calculated to be: 37.7+784.8 (18.2 wt% +1.8 wt%) + 1.752 + 0.02=47.3kg, so the addition amount of pure aluminum particles is 47kg.
And S5, blowing the third deoxidized molten steel through a second bottom blowing at a second preset flow rate to obtain final deoxidized molten steel.
Wherein: the second preset flow rate was 0.2NL/min t steel and the time for the first bottom blow was 2min.
And S6, after the final deoxidized molten steel is obtained, vacuum decarburization and air breaking are carried out, final deoxidation is carried out, and oxygen determination is carried out, so that the final oxygen activity is obtained.
Comparative example 1
The steel is SPHC, smelting is carried out by adopting a converter, the converter capacity is 210t, the target carbon content is 0.015wt%, the fluctuation range is 0.013-0.017wt%, and the carbon content is required to be less than 0.01wt% after vacuum decarburization.
A deoxygenation method comprising the steps of:
s1, taking a slag sample from converter tapping, and inspecting to obtain 15wt% and 1wt% of FeO and MnO in the slag respectively.
S2, determining oxygen before VD vacuum treatment, and determining the oxygen activity a of molten steel 0 Was 401ppm.
S3, carrying out normal vacuum decarburization by VD.
And S4, breaking the air after the VD decarburization is finished, adding 320kg of 80wt% of steel grit aluminum and 50kg of pure aluminum particles after breaking the air, and stirring for 1min at the bottom blowing flow rate of 2.5 NL/min.
Comparative example 2
The steel is SPHC, smelting is carried out by an electric furnace, the furnace volume of the electric furnace is 100t, the target carbon content is 0.015wt%, the fluctuation range is 0.013-0.017wt%, and the carbon content is required to be less than 0.01wt% after vacuum decarburization.
A deoxygenation method comprising the steps of:
s1, taking a slag sample from electric furnace tapping, and inspecting to obtain slag with FeO and MnO contents of 25.6wt% and 3.5wt%, respectively.
S2, determining oxygen before VD vacuum treatment, and determining the oxygen activity a of molten steel 0 Is 566ppm.
S3, carrying out normal vacuum decarburization by VD.
And S4, breaking the air after the decarburization by VD is finished, adding 350kg of 80wt% of steel grit aluminum and 50kg of pure aluminum particles after the air is broken, and stirring for 1.5min, wherein the bottom blowing flow rate is 3NL/min t steel.
Examples of the experiments
The deoxidized molten steels provided in examples 1 to 3 and comparative examples 1 to 2 were examined, and the specific results are shown in the following table.
As can be seen from the above table, the deoxidation effect and efficiency of the deoxidation method after vacuum decarburization provided in examples 1-3 are significantly higher than those of comparative examples 1-2, which can reduce the dissolved oxygen in molten steel to less than 5ppm within 5min, and reduce FeOOwt% + MnOwt% to less than 1wt%, thereby saving a lot of processing time for the next process, and can directly perform desulfurization treatment, effectively shortening the overall production cycle, improving the production efficiency, and reducing the production cost. The comparative example can not rapidly realize steel slag deoxidation, generally needs at least 10min, and has obvious disadvantages.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. A deoxidation method after vacuum decarburization is characterized by comprising the following steps:
carrying out vacuum decarburization on the smelting molten steel to obtain decarburized molten steel;
adding a first aluminum deoxidizer with a first preset amount into the decarburized molten steel in a vacuum state to obtain first deoxidized molten steel;
the first deoxidized molten steel is subjected to first bottom blowing at a first preset flow rate to obtain second deoxidized molten steel;
adding a second aluminum deoxidizer with a second preset amount into the second deoxidized molten steel to obtain third deoxidized molten steel;
the third deoxidized molten steel is subjected to second bottom blowing at a second preset flow rate to obtain final deoxidized molten steel;
wherein:
the first bottom blowing can expose the liquid surface of the first deoxidized molten steel, and the exposed area is more than or equal to one half of the radius of the liquid surface of the molten steel;
the second bottom blowing is capable of surging and foaming the slag of the third deoxidized molten steel.
2. The method of claim 1, wherein the first predetermined amount of reduced pure aluminum satisfies the following relationship:
1000Alwt％*Q+0.001125a 0 Q+[65.9+1373*(FeOwt％+MnOwt％)]*R 2 h；
wherein:
q is the mass of the decarburized molten steel and has a unit of t;
a 0 the oxygen activity of the molten steel before the vacuum decarburization is expressed in ppm;
h is the thickness of the steel slag in the steel ladle, and the unit is m;
r is the radius of the ladle and is m.
3. The method of claim 1, wherein the first aluminum deoxidizer has a grain size of 30 to 50mm, a density higher than that of pure aluminum, and an aluminum content of 30 to 90%.
4. The vacuum decarburization deoxygenation method of claim 1, wherein the first preset flow rate is 1.0 to 1.9NL/min t steel, and the first bottom blowing time is 1 to 3min.
5. The method of claim 1, wherein the second predetermined amount of reduced pure aluminum satisfies the following relationship:
37.7+784.8*(FeOwt％+MnOwt％)*R 2 h；
wherein:
h is the thickness of the steel slag in the steel ladle, and the unit is m;
r is the radius of the ladle and is m.
6. The method of claim 1, wherein the second aluminum deoxidizer has a grain size of 8 to 15mm and an aluminum content of not less than 99%.
7. The vacuum decarburization deoxygenation method of claim 1, wherein the second preset flow rate is 0.2-0.5NL/min t steel, and the second bottom blowing time is 1-2min.
8. The method of claim 1, further comprising the steps of:
and respectively sampling and detecting the smelting molten steel and the steel slag to obtain the components of the smelting molten steel and the mass percentage content of FeO and MnO in the steel slag.
9. The method of claim 1, further comprising the steps of:
and detecting the smelting molten steel to obtain the initial oxygen activity.
10. The method of claim 1, further comprising the steps of:
and after the final deoxidized molten steel is obtained, the vacuum decarburization is broken, and the final deoxidation is carried out for oxygen determination to obtain the final oxygen activity.
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