CN112322958A - Low-carbon aluminum-containing steel and smelting control method thereof - Google Patents
Low-carbon aluminum-containing steel and smelting control method thereof Download PDFInfo
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- 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
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
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Abstract
The application relates to the field of steel smelting, in particular to low-carbon aluminum-containing steel and a smelting control method thereof. The method comprises the following steps: controlling the end point carbon content in molten steel to be 0.08-0.12% during converter tapping; carrying out decarburization treatment on the molten steel by adopting a vacuum degassing process; adding aluminum into the molten steel for deoxidation; and after refining, performing calcium treatment on the molten steel. The carbon content in the molten steel at the end point of the converter is controlled to be 0.08-0.12%, so that the oxidizability of the molten steel and the erosion of high-temperature molten steel to a furnace lining are reduced, and the service life of the converter is prolonged. Meanwhile, the oxygen source can be brought to the natural decarburization under the subsequent vacuum degassing condition, and the condition is created for VD natural decarburization. And the carbon is lower after the decarburization is finished by adopting a VD treatment process. The deoxidation is carried out by adding aluminum, so that the deoxidation efficiency can be improved, and the deoxidation speed is high. Is beneficial to deoxidation of the refining slag. After LF treatment is finished, calcium treatment is carried out on the molten steel, so that the impurities can be denatured, calcium aluminate with low melting point is formed, and the castability of the molten steel is improved.
Description
Technical Field
The application relates to the field of steel smelting, in particular to low-carbon aluminum-containing steel and a smelting control method thereof.
Background
The smelting process is the key for ensuring the stable curve of the stopper rod in the pouring process of the molten steel. If the smelting process is unreasonable, the nozzle nodulation of the molten steel is serious in the pouring process due to the poor purity of the molten steel in the pouring process, the stopper rod curve is obviously expanded, the multi-furnace continuous pouring cannot be realized, and meanwhile, the steel quality control is greatly influenced.
At present, the conventional process mainly comprises the following steps:
patent CN201610594212 discloses a molten steel smelting process for preventing nozzle nodulation during pouring of sulfur-containing and aluminum-containing steel, which discloses: smelting molten steel by a converter or an electric furnace, entering an RH furnace, deoxidizing by using aluminum particles and calcium carbide in an LF furnace, and refining the slag to the station, wherein the slag comprises the following components in percentage by mass: CaO 50-60%, MgO 4-7%, SiO210 to 14 percent of Al2O322 to 28 percent, the T.Fe content is less than 1.5 percent, and the sulfur content is 0.2 to 0.6 percent; and adjusting the sulfur content in the slag, performing calcium treatment on the molten steel at the later stage of refining, and then adjusting the sulfur content of the molten steel. The top slag component at the end of ladle refining comprises the following components in percentage by mass: 50-65% of CaO, 4-7% of MgO and SiO29-13%, Al2O3 is 24-30%, the content of T.Fe is less than 1.0%, and the content of sulfur is 1.0-2.4%. However, the process can not completely remove the inclusions in the molten steel, and the quality of the molten steel is not pure, so that the plug rod curve is easy to obviously rise.
Patent CN201811155734 discloses a steel-making method of sulfur-containing and aluminum-containing steel, which discloses that: smelting molten steel in a converter, adding active lime, fluorite and aluminum pellets in the refining process of an LF (ladle furnace)Refining slag is prepared, and the refining slag comprises the following components in percentage by weight: 42-48% of CaO and SiO2 10～15％，Al2O3 20～25％，MgO 8～12％，FeO+MnO 0.3～0.8％，CaF22-5%, the alkalinity of refining slag is 2.5-4.0, and the later stage of LF refining is to feed calcium silicate wires into molten steel by 0.8-1.2 m/ton; adjusting sulfur in the RH process, and blowing the mixture to a casting machine for casting. However, the molten steel obtained by the treatment method has the problem that the stopper rod obviously rises during the pouring process.
Disclosure of Invention
The embodiment of the application aims to provide low-carbon aluminum-containing steel and a smelting control method thereof, and aims to solve the problems that in the existing smelting process of the low-carbon aluminum-containing steel, the pouring nozzle nodulation is serious, the stopper curve is obviously expanded, multi-furnace continuous pouring cannot be realized, and the steel quality is influenced due to the fact that the pouring performance of molten steel is poor.
In a first aspect, the application provides a smelting control method of low-carbon aluminum-containing steel, comprising the following steps:
controlling the end point carbon content in molten steel to be 0.08-0.12% during converter tapping;
carrying out decarburization treatment on the molten steel by adopting a vacuum degassing process, and adding aluminum into the molten steel according to the oxygen content in the molten steel after the decarburization treatment is finished so that the aluminum content in the molten steel is within the range of 0.020-0.030%;
refining the molten steel, and adding aluminum into the molten steel for deoxidation;
after the refining is finished, the molten steel is subjected to calcium treatment.
In another embodiment of the present application, the tapping from the converter includes: the tapping temperature is controlled to be more than or equal to 1640 ℃.
In another embodiment of the present application, the step of performing decarburization treatment on the molten steel by a vacuum degassing process includes: and carrying out vacuum treatment for 8-12 minutes at the temperature of 1580-1610 ℃.
In another embodiment of the present application, the refining of the molten steel includes: adding lime 4.5-5.5kg/t and synthetic slag 6.5-8.5kg/t into the molten steel; adding aluminum for deoxidation after the slag is melted; and the refining slag is controlled to comprise the following components in percentage by mass: 60-65% of CaO, less than or equal to 6% of SiO2, 330-35% of Al2O, 3-8% of MgO, and less than or equal to 1.0% of TFe + MnO; the alkalinity of the refining slag is more than or equal to 10.
In another embodiment of the present application, the refining of the molten steel includes: in the process of slagging and deoxidizing, inert gas is blown into the molten steel until the slag is melted, and the flow rate of the inert gas is controlled to be 30-60Nm3After the slag has melted, the flow of inert gas is reduced.
In another embodiment of the present application, the refining of the molten steel includes: in the process of slagging and deoxidizing, the temperature of the molten steel is increased to more than 1580 ℃, and the molten steel is stirred for 5 to 8 minutes.
In another embodiment of the present application, the deoxidation step of adding aluminum to molten steel includes: adding 1kg/t-1.8kg/t aluminum into the molten steel for deoxidation.
In another embodiment of the present application, the step of performing calcium treatment on the molten steel includes: 0.04 kg/t-0.06 kg/t calcium is added into the molten steel.
In another embodiment of the present application, after the step of calcium-treating the molten steel is completed, the inert gas is further blown into the molten steel for at least 30 minutes.
In a second aspect, the application provides a low-carbon aluminum-containing steel, which is prepared by smelting by the smelting control method of the low-carbon aluminum-containing steel;
the low-carbon aluminum-containing steel comprises the following chemical components in percentage by mass: c: 0.04-0.07%, Si: less than or equal to 0.08 percent, Mn: 0.15 to 0.50%, Al: 0.010-0.040%, P: less than or equal to 0.025%, S: less than or equal to 0.025 percent.
The low-carbon aluminum-containing steel and the smelting control method thereof provided by the embodiment of the application have the beneficial effects that:
by controlling the carbon content in the molten steel at the converter end point to be 0.08-0.12%, the carbon content in the molten steel is higher than that at the converter end point in the conventional art in the range. The higher end point carbon content is controlled, so that the oxidizability of molten steel and the erosion of high-temperature molten steel to a furnace lining are reduced, the service life of the converter is prolonged, an oxygen source can be brought to natural decarburization under the subsequent Vacuum Degassing (VD) condition, and strips are created for the natural decarburization of VDAnd (3) a component. The decarburization process is carried out in the molten steel by adopting the VD treatment process, and is also carried out at the interface of the steel slag, so the carbon is lower after the VD treatment under the condition of the same oxygen content in the steel. In the embodiment of the application, VD treatment is carried out on the converter tapping control molten steel with the end point carbon content of 0.08-0.12%, and the VD end carbon content can be controlled below 0.01%. During refining (LF), aluminum is added for deoxidation, so that the deoxidation efficiency can be improved, and the deoxidation speed is high. And Al is formed as a deoxidation product by deoxidation of aluminum particles2O3The fluidity of the slag can be improved when the slag enters the slag, so that the dynamic condition is improved, and the deoxidation of the refining slag is facilitated. After LF treatment is finished, calcium treatment is carried out on the molten steel, so that the impurities can be denatured, calcium aluminate with low melting point is formed, and the castability of the molten steel is improved. According to the method, through control and cooperative coordination of all process links, the molten steel with excellent castability is obtained, multi-furnace continuous casting can be realized, and steel quality is favorably provided, so that the problems that in the prior art, the molten steel casting performance is poor in the low-carbon aluminum-containing steel smelting process, the nozzle nodulation is serious in the casting process, the stopper curve is obviously expanded, multi-furnace continuous casting cannot be realized, and the steel quality is influenced are solved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
FIG. 1 is a graph of a stopper rod provided in example 1 of the present application;
FIG. 2 is a graph of a stopper rod provided in example 2 of the present application;
FIG. 3 is a graph of a stopper rod provided in example 3 of the present application;
FIG. 4 is a graph of a stopper rod provided in example 4 of the present application;
FIG. 5 is a graph of a stopper rod provided in example 5 of the present application;
FIG. 6 is a graph of a stopper rod provided in comparative example 1 of the present application;
FIG. 7 is a graph of a stopper rod provided in comparative example 2 of the present application;
FIG. 8 is a graph of a stopper rod provided in comparative example 3 of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
Referring to fig. 1, an embodiment of the present application provides a smelting control method for low-carbon aluminum-containing steel, including:
and step S1, tapping through a converter.
Further, the end point carbon content in the molten steel is controlled to be 0.08-0.12% during converter tapping.
By controlling the carbon content in the molten steel at the converter end point to be 0.08-0.12%, the carbon content in the molten steel is higher than that at the converter end point in the conventional art in the range. The higher end point carbon content is controlled, so that the oxidability of molten steel and the erosion of high-temperature molten steel to a furnace lining are reduced, and the service life of the converter is prolonged. Meanwhile, the oxygen source can be brought to the natural decarburization under the subsequent Vacuum Degassing (VD) condition, and a condition is created for the natural decarburization of VD.
Further, molten iron is directly tapped from the converter without desulfurization pretreatment.
Further optionally, the end point carbon content in the molten steel is controlled to be 0.085-0.115% during converter tapping.
Further optionally, the end point carbon content in the molten steel is controlled to be 0.09-0.11% during converter tapping.
Illustratively, the converter tapping controls the end point carbon content in the molten steel to be 0.095%, 0.10%, 0.11%, or 0.12%.
Further, the step of tapping from the converter comprises the following steps: the tapping temperature is controlled to be more than or equal to 1640 ℃.
The tapping temperature of the converter tapping is controlled to be more than or equal to 1640 ℃, so that the temperature requirement during the subsequent vacuum degassing treatment can be ensured.
Further optionally, the tapping from the converter comprises: the tapping temperature is controlled to be more than or equal to 1640 ℃.
The steel tapping temperature is controlled to be more than or equal to 1640 ℃, so that the erosion of high-temperature molten steel to a furnace lining is increased, and the service life of the converter is greatly influenced.
In the smelting of low-carbon aluminum-containing steel, the RH decarburization process is adopted as the conventional decarburization process in the field. Because the circulation gas is used for stirring in the decarbonization process of the RH furnace, the bottom blowing argon is in a closed state, and the air brick is easy to block in the RH treatment process, so that the bottom blowing effect is poor, and the treatment effect of the LF furnace is influenced. The tapping temperature is controlled to be more than or equal to 1640 ℃, the steel tapping temperature can be matched with subsequent VD (bottom blowing argon) treatment (stirring) to realize synergistic interaction, the LF bottom blowing effect can be ensured, the erosion of high-temperature molten steel to a furnace lining is increased, and the service life of the converter is greatly influenced.
Further optionally, the tapping from the converter comprises: controlling the tapping temperature to be 1640-1700 ℃.
In some examples, tapping from the converter occurs at 1650 ℃, 1660 ℃, 1670 ℃, 1680 ℃, 1690 ℃, or 1700 ℃.
Further, the step of tapping from the converter comprises the following steps: the free oxygen content in the molten steel is controlled to be 300-500 ppm.
By controlling the free oxygen content in the molten steel to be 300-500ppm during the tapping of the converter, the method can be cooperated with the subsequent VD treatment, and the subsequent vacuum decarburization treatment effect is further improved.
Further optionally, the tapping from the converter comprises: the free oxygen content in the molten steel is controlled at 310-490 ppm.
Further optionally, the tapping from the converter comprises: the free oxygen content in the molten steel is controlled to be 320-480 ppm.
In some examples, the step of tapping the converter comprises: the free oxygen content in the molten steel is controlled to be 330ppm, 340ppm, 350ppm, 360ppm, 370ppm, 380ppm, 390ppm, 400ppm, 410ppm, 420ppm, 430ppm, 440ppm, 450ppm, 460ppm or 470 ppm.
Further, after tapping, vacuum degassing treatment (VD treatment) in step S2 was performed without undergoing oxidation alloying.
And step S2, vacuum degassing treatment.
The vacuum degassing treatment is degassing treatment by using a VD (vacuum degassing) process.
And further, carrying out decarburization treatment on the molten steel by adopting a vacuum degassing process, and adding aluminum into the molten steel according to the oxygen content in the molten steel after the decarburization treatment is finished so that the aluminum content in the molten steel is within the range of 0.020-0.030%.
Because VD decarburization is a strong steel slag stirring process, the decarburization process is carried out not only in molten steel but also at a steel slag interface by adopting a VD treatment process, so that the carbon content of VD treatment is lower under the condition of the same oxygen content in steel. In the embodiment of the present application, the molten steel in step S1 (the end point carbon content in the molten steel is controlled to be 0.08% to 0.12% in converter tapping) is VD-treated, and the VD-end carbon content can be controlled to be 0.01% or less.
In the prior art, the conventional operation is to adopt an RH decarburization process. However, according to the embodiment of the present invention, the molten steel in which the end point carbon content in the molten steel is controlled to 0.08% to 0.12% in the converter tapping in step S1 is subjected to the RH decarburization process, and after the decarburization is completed, the carbon content cannot be controlled to 0.01% or less. If the RH decarburization process is combined with the oxygen blowing decarburization process, although the carbon content can be controlled to be below 0.01 percent, the service life of a vacuum groove of the RH furnace is greatly reduced, the oxygen content in steel is increased, the deoxidation difficulty of a subsequent LF refining furnace is increased, and the castability of molten steel is greatly influenced. The nozzle nodulation of molten steel is easy to be serious in the pouring process, the stopper rod curve is obviously expanded, the multi-furnace continuous pouring cannot be realized, and meanwhile, the steel quality control is greatly influenced.
Further, the method is favorable for reducing the deoxidation load of the subsequent LF refining furnace, and more importantly, the adding amount of aluminum during deoxidation of the subsequent LF furnace can be greatly reduced.
Compared with the conventional RH furnace decarburization process in the field, by adopting the scheme of the application, the use amount of the subsequent LF furnace deoxidized aluminum can be reduced by more than or equal to 0.8 kg/ton.
Further optionally, the molten steel is subjected to decarburization treatment by a vacuum degassing process, and after the decarburization treatment is finished, aluminum is added into the molten steel according to the oxygen content in the molten steel, so that the aluminum content in the molten steel is in the range of 0.022-0.029%.
Further optionally, the molten steel is subjected to decarburization treatment by a vacuum degassing process, and after the decarburization treatment is finished, aluminum is added into the molten steel according to the oxygen content in the molten steel, so that the aluminum content in the molten steel is in the range of 0.023-0.028%.
Illustratively, the molten steel is decarbonized by a vacuum degassing process, and after the decarbonization process is finished, aluminum is added into the molten steel according to the oxygen content in the molten steel, so that the aluminum content in the molten steel is 0.024%, 0.025% or 0.026%.
Further, the step of performing decarburization treatment on the molten steel by a vacuum degassing process comprises: and carrying out vacuum treatment for 8-12 minutes at the temperature of 1580-1610 ℃.
In the above temperature and time ranges, the effect of the vacuum decarburization treatment can be effectively improved, and the VD finish carbon content can be controlled to 0.01% or less.
Further optionally, the step of performing decarburization treatment on the molten steel by using a vacuum degassing process comprises: and carrying out vacuum treatment for 8.5-11.5 minutes at the temperature of 1585-1605 ℃.
Further optionally, the step of performing decarburization treatment on the molten steel by using a vacuum degassing process comprises: and carrying out vacuum treatment at the temperature of 1590-1600 ℃ for 9-11 minutes.
Illustratively, the step of subjecting the molten steel to decarburization treatment by a vacuum degassing process includes: vacuum treating at 1595 deg.C for 10 min; or vacuum treated at 1600 ℃ for 9 minutes.
And step S3, refining.
Further, the step of refining the molten steel includes: adding lime 4.5-5.5kg/t and synthetic slag 6.5-8.5kg/t into the molten steel; adding aluminum for deoxidation after the slag is melted; and the refining slag is controlled to comprise the following components in percentage by mass: CaO 60-65%, SiO2≤6％，Al2O330-35%, 3-8% of MgO, and less than or equal to 1.0% of TFe + MnO; the alkalinity of the refining slag is more than or equal to 10.
The molten steel treated in step S2 of the present application is refined, and the content of added aluminum can be greatly reduced.
In some embodiments of the present application, the amount of aluminum added for deoxidation is reduced by at least 0.8 kg/ton.
Further, the step of refining the molten steel includes: adding lime 4.6-5.4kg/t and synthetic slag 6.6-8.4kg/t into the molten steel; adding aluminum for deoxidation after the slag is melted; and the refining slag is controlled to comprise the following components in percentage by mass: CaO 60.5-64.5%, SiO2≤6％，Al2O330.5-34.5%, 3.5-7.5% MgO, and less than or equal to 1.0% of TFe + MnO; the alkalinity of the refining slag is more than or equal to 10.
And aluminum is added for deoxidation after the slag is melted, so that the deoxidation efficiency can be improved, and the deoxidation speed is high. And deoxidation with aluminium particles can form the deoxidation product Al2O3，Al2O3The fluidity of the slag is improved when the slag enters the slag, so that the dynamic condition is better, and the refining slag deoxidation is facilitated.
At present, calcium carbide deoxidizers are adopted in the conventional method for smelting low-carbon aluminum-containing steel. However, according to the embodiment of the present invention, the reaction speed of the calcium carbide type deoxidizer is slow due to the characteristics of the molten steel after the treatment in the steps S1 and S2, and the slag fluidity is deteriorated due to the formation of CaO after the deoxidation, and the deoxidation is adversely affected by the deterioration of the kinetic conditions.
Further, the step of refining the molten steel includes: in the process of slagging and deoxidizing, inert gas is blown into the molten steel until the slag is melted, and the flow rate of the inert gas is controlled to be 30-60Nm3After the slag has melted, the flow of inert gas is reduced.
Further optionally, the step of refining the molten steel comprises: in the process of slagging and deoxidizing, inert gas is blown into the molten steel until the slag is melted, and the flow rate of the inert gas is controlled to be 35-55Nm3After the slag has melted, the flow of inert gas is reduced.
Illustratively, the step of refining the molten steel comprises: in the process of slagging and deoxidizing, inert gas is blown into the molten steel until the slag is melted, and the flow rate of the inert gas is controlled to be 40Nm3/h、45Nm3/h、50Nm3H or 55Nm3/h。
Alternatively, argon is selected as the inert gas.
By controlling the flow rate of the inert gas within the above range, the deoxidation and the desulfurization can be accelerated and white slag can be produced quickly.
Further, the step of refining the molten steel includes: in the process of slagging and deoxidizing, the temperature of the molten steel is increased to more than 1580 ℃, and the molten steel is stirred for 5 to 8 minutes.
In the process of slagging and deoxidizing, the molten steel is heated to more than 1580 ℃ and stirred for 5 to 8 minutes, so that the deoxidation and the desulfurization can be further accelerated, and white slag can be rapidly produced.
Further optionally, the step of refining the molten steel comprises: in the process of slagging and deoxidizing, the molten steel is heated to 1580 to 1600 ℃ and stirred for 6 to 8 minutes.
Illustratively, during the deoxidation of the slag, the molten steel is heated to 1590 ℃ and stirred for 7 minutes.
The molten steel is heated and the temperature is increased, strong stirring is carried out when the temperature reaches more than 1580 ℃, so that the deoxidation and desulfurization among steel slag can be accelerated, the floating removal of impurities is promoted under a better dynamic condition, and the castability of the molten steel is improved.
Further, the step of adding aluminum to the molten steel for deoxidation comprises: adding 1kg/t-1.8kg/t aluminum into the molten steel for deoxidation.
By adopting the process disclosed by the application and matching, the deoxidation effect is good, the addition amount of aluminum is greatly reduced, and the addition amount can be controlled within the range of 1kg/t-1.8 kg/t.
Further, the step of adding aluminum to the molten steel for deoxidation comprises: adding 1.1kg/t-1.7kg/t aluminum into the molten steel for deoxidation.
Further optionally, the step of adding aluminum to the molten steel for deoxidation comprises: adding 1.2kg/t-1.6kg/t aluminum into the molten steel for deoxidation.
Illustratively, the step of adding aluminum to the molten steel for deoxidation comprises: 1.2kg/t, 1.3kg/t, 1.4kg/t, 1.5kg/t or 1.6kg/t of aluminum is added to the molten steel to deoxidize.
Further, after the slag is melted, a small amount of slag surface compound deoxidizer can be used for slag maintenance in the middle and later periods of refining. Such as calcium carbide deoxidizers.
Further, after aluminum is added into the molten steel for deoxidation in the step, a sample 1 is taken from the molten steel for detection, and a basis is provided for further adjustment of molten steel components and temperature in the subsequent step.
Since the components and the temperature in the molten steel are relatively stable after aluminum is added into the molten steel for deoxidation, sampling 1 at the stage can improve the accuracy of subsequent adjustment of the components of the molten steel.
Step S4, after the refining is completed, the molten steel is subjected to calcium treatment.
Further, the step of calcium treatment of the molten steel comprises: 0.04 kg/t-0.06 kg/t calcium is added into the molten steel.
After LF treatment is finished, calcium treatment is carried out on the molten steel, so that the impurities can be denatured, calcium aluminate with low melting point is formed, and the castability of the molten steel is improved.
Further optionally, the step of calcium treating the molten steel comprises: 0.045 kg/t-0.055 kg/t calcium is added into the molten steel.
Illustratively, the step of calcium treating the molten steel comprises: 0.05kg/t calcium was added to the molten steel.
Alternatively, the calcium added above may be optionally added to a pure calcium wire.
Further, after the step of calcium-treating the molten steel is completed, the inert gas is blown into the molten steel for at least 30 minutes.
Soft argon blowing is carried out for more than or equal to 30 minutes after the calcium treatment is finished, so that floating removal of inclusions can be further promoted, and castability of molten steel is improved.
Illustratively, after the step of calcium-treating the molten steel is completed, the inert gas is further blown into the molten steel for 40 minutes.
Argon is selected as the inert gas.
Further, the argon blowing is soft argon blowing commonly used in the field.
Further, the low-carbon aluminum-containing steel prepared by the method comprises the following chemical components in percentage by mass: c: 0.04-0.07%, Si: less than or equal to 0.08 percent, Mn: 0.15 to 0.50%, Al: 0.010-0.040%, P: less than or equal to 0.025%, S: less than or equal to 0.025 percent.
Some embodiments of the application also provide a low-carbon aluminum-containing steel, which is prepared by adopting the smelting control method of the low-carbon aluminum-containing steel provided by the previous embodiment;
the low-carbon aluminum-containing steel comprises the following chemical components in percentage by mass: c: 0.04-0.07%, Si: less than or equal to 0.08 percent, Mn: 0.15 to 0.50%, Al: 0.010-0.040%, P: less than or equal to 0.025%, S: less than or equal to 0.025 percent.
The features and properties of the present invention are further described in detail below with reference to examples:
example 1
The control requirements of the components of a finished product of a certain steel grade are as follows: c: 0.04-0.07%, Si: less than or equal to 0.08 percent, Mn: 0.15-0.25%, Als: 0.010-0.025%, P: less than or equal to 0.025%, S: 0.025 percent.
The method comprises the following specific steps: controlling the end point carbon of the converter according to 0.08 percent, controlling the tapping temperature to be more than or equal to 1640 ℃, carrying out VD treatment, keeping the high vacuum time for 8 minutes, ending VD, determining oxygen, and adjusting Al to be 0.025 percent. Then, LF treatment is carried out, 5.5kg/t lime is added into LF, and 8.5kg/t synthetic slag is added. And the refining slag is controlled to comprise the following components in percentage by mass:CaO 60-65％，SiO2≤6％，Al2O330-35%, 3-8% of MgO, and less than or equal to 1.0% of TFe + MnO; the alkalinity of the refining slag is more than or equal to 10. After the slag is melted, 0.5kg/t of aluminum particles are added through a storage bin, 0.8kg/t of aluminum particles are manually fed, argon is blown from the bottom in the process, and the flow of the argon is controlled to be 30Nm3H is used as the reference value. Heating to 1580 deg.C, strong stirring and quickly making white slag. And (3) sampling 1, detecting, wherein the temperature is more than or equal to 1580 ℃ before sampling 1, stirring for 5 minutes, feeding 0.04kg of pure calcium line after the LF furnace treatment is finished, and the soft argon blowing time is more than or equal to 30 minutes.
Example 2
The control requirements of the components of a finished product of a certain steel grade are as follows: c: 0.05 to 0.07%, Si: less than or equal to 0.08 percent, Mn: 0.35 to 0.50%, Al: 0.025 to 0.040%, P: less than or equal to 0.025%, S: 0.025 percent.
The method comprises the following specific steps: controlling the end point carbon of the converter according to 0.12 percent, controlling the tapping temperature to be more than or equal to 1640 ℃, carrying out VD treatment, carrying out high vacuum time for 12 minutes, finishing VD, determining oxygen, adjusting Al to 0.025 percent, carrying out LF treatment, adding lime into LF for 4.5kg/t, and controlling the composition of the refining slag to comprise the following components in percentage by mass: CaO 60-65%, SiO2≤6％，Al2O330-35%, 3-8% of MgO, and less than or equal to 1.0% of TFe + MnO; the alkalinity of the refining slag is more than or equal to 10. After the slag is melted, 0.4kg/t of aluminum particles are added through a storage bin, 0.6kg/t of aluminum particles are manually fed, argon gas is blown at the bottom in the process, and the flow of the argon gas is controlled to be 60Nm3H is used as the reference value. The temperature is more than or equal to 1580 ℃ before sampling 1, stirring is carried out for 8 minutes, 0.06kg of pure calcium line is fed after LF furnace treatment is finished, and the soft argon blowing time is more than or equal to 30 minutes.
Example 3
The process was substantially the same as in example 1, except that VD was stopped to control the oxygen content and that Al was adjusted to 0.020%.
Example 4
The procedure was repeated in substantially the same manner as in example 1, except that VD was terminated with oxygen and Al was adjusted to 0.030%.
Example 5
The procedure was as in example 1 except that 0.8kg/t of the aluminum pellets were charged through the hopper and 1.0kg/t of the aluminum pellets were manually charged.
Comparative example 1
Substantially the same as in example 1, except that: the VD process is replaced with the RH process.
Comparative example 2
Substantially the same as in example 1, except that: after the VD treatment is finished, Al is adjusted to 0.010%.
Comparative example 3
Substantially the same as in example 1, except that: during LF treatment, the aluminum particles are replaced by calcium carbide deoxidizers.
The molten steel obtained in examples 1 to 5 and comparative examples 1 to 3 was poured by a casting machine, and the stopper curves were generated on the same scale interface by the same software during the pouring. The specific stopper rod curve is shown in the attached figures 1-8 of the specification.
If no nozzle nodulation exists in the pouring process, the stable curve of the stopper rod indicates that the pouring performance of the molten steel is good. If the nozzle nodulation is serious and the stopper rod curve obviously rises in the pouring process, the method indicates that the pouring performance of the molten steel is poor, continuous pouring cannot be realized, and the quality of the steel is influenced.
As can be seen from the drawings 1 to 5, the stopper rod obtained by the methods of the embodiments 1 to 5 of the present application has a stable curve, so that the method of the embodiments of the present application can effectively improve the pouring performance of molten steel, realize multi-furnace continuous pouring, and is beneficial to providing steel quality. As can be seen from fig. 6 to 8, the molten steels obtained in comparative examples 1 to 3 were poured by a casting machine, and the clogging was severe and the rising of the stopper rod curve was significant. Therefore, the molten steel obtained by smelting according to the methods provided by the comparative examples 1 to 3 is poor in pouring performance, cannot be continuously poured and has influence on the quality of steel.
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 (10)
1. A smelting control method of low-carbon aluminum-containing steel is characterized by comprising the following steps:
controlling the end point carbon content in molten steel to be 0.08-0.12% during converter tapping;
carrying out decarburization treatment on molten steel by adopting a vacuum degassing process, and adding aluminum into the molten steel according to the oxygen content in the molten steel after the decarburization treatment is finished so that the aluminum content in the molten steel is within the range of 0.020-0.030%;
refining the molten steel, and adding aluminum into the molten steel for deoxidation;
after the refining is finished, the molten steel is subjected to calcium treatment.
2. The method for controlling the smelting of a low-carbon aluminum-containing steel according to claim 1,
the converter tapping step comprises the following steps: the tapping temperature is controlled to be more than or equal to 1640 ℃.
3. The method for controlling the smelting of a low-carbon aluminum-containing steel according to claim 1,
the step of decarbonizing molten steel by adopting a vacuum degassing process comprises the following steps: and carrying out vacuum treatment for 8-12 minutes at the temperature of 1580-1610 ℃.
4. The method for controlling the smelting of a low-carbon aluminum-containing steel according to claim 1,
the step of refining the molten steel comprises: adding lime 4.5-5.5kg/t and synthetic slag 6.5-8.5kg/t into the molten steel; adding aluminum for deoxidation after the slag is melted; and the refining slag is controlled to comprise the following components in percentage by mass: CaO 60-65%, SiO2≤6％，Al2O330-35%, 3-8% of MgO, and less than or equal to 1.0% of TFe + MnO; the alkalinity of the refining slag is more than or equal to 10.
5. The method of claim 4, wherein the step of refining the molten steel comprises: in the process of slagging and deoxidizing, inert gas is blown into the molten steel until the slag is melted, and the flow rate of the inert gas is controlled to be 30-60Nm3H, in the melting of slagThen, the flow rate of the inert gas is adjusted to be low.
6. The method for controlling smelting of a low-carbon aluminum-containing steel according to claim 4,
the step of refining the molten steel comprises: in the process of slagging and deoxidizing, the temperature of the molten steel is increased to more than 1580 ℃, and the molten steel is stirred for 5 to 8 minutes.
7. The method for controlling smelting of a low carbon aluminum-containing steel according to any one of claims 1 to 6,
the step of adding aluminum to molten steel for deoxidation comprises the following steps: adding 1kg/t-1.8kg/t aluminum into the molten steel for deoxidation.
8. The method for controlling smelting of a low carbon aluminum-containing steel according to any one of claims 1 to 6,
the step of performing calcium treatment on the molten steel comprises the following steps: 0.04 kg/t-0.06 kg/t calcium is added into the molten steel.
9. The method for controlling smelting of a low carbon aluminum-containing steel according to any one of claims 1 to 6,
after the step of calcium treatment of the molten steel is finished, inert gas is blown to the molten steel for at least 30 minutes.
10. A low-carbon aluminum-containing steel is characterized by being prepared by adopting the smelting control method of the low-carbon aluminum-containing steel of any one of claims 1 to 9;
the low-carbon aluminum-containing steel comprises the following chemical components in percentage by mass: c: 0.04-0.07%, Si: less than or equal to 0.08 percent, Mn: 0.15 to 0.50%, Al: 0.010-0.040%, P: less than or equal to 0.025%, S: less than or equal to 0.025 percent.
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