Cold forging steel smelting method capable of reducing aluminum source consumption and application of cold forging steel smelting method

Abstract

The invention discloses a cold forging steel smelting method capable of reducing aluminum source consumption and application of the cold forging steel smelting method, and relates to the technical field of steel smelting. Comprising the following steps: adding slag into molten steel in a converter tapping process, adding an aluminum source after converter tapping is finished, and refining the molten steel to obtain refined molten steel after the aluminum source is molten. The aluminum source is added after converter tapping is finished, in the converter tapping process, part of oxygen in molten steel can be consumed by carbon, part of oxygen can be discharged under the action of bottom blowing argon, and therefore aluminum loss in the converter tapping process can be reduced. Meanwhile, the oxygen content in the molten steel is low, the accuracy of the adding amount of aluminum is improved, and the difficulty of steel temperature quality stable control is lowered.

Description

Technical Field

[0001] The present invention relates to the technical field of steel smelting, and in particular to a smelting method of cold heading steel capable of reducing aluminum source consumption and application thereof. Background Art

[0002] In the process of molten steel smelting, the addition of aluminum plays an important role in adjusting the composition of molten steel. Aluminum can not only adjust the aluminum element composition in the molten steel so that the aluminum content in the molten steel meets the requirements of the steel grade, but also deoxidize during the smelting process, reduce the oxygen content in the molten steel, and ensure the quality of refined molten steel. Therefore, adding aluminum in the steelmaking process is a necessary steelmaking process for most grades of steel.

[0003] However, the raw material composition of each batch of molten steel is different, and the control method of the converter smelting process is different, resulting in large differences in the elemental composition of each batch of molten steel at the end of the converter. In particular, the acid-soluble aluminum content of low-carbon cold heading steel is higher, and the aluminum loss is more unstable. When aluminum is added for refining and deoxidation, the aluminum consumption is large, and it is difficult to control the stability of the molten steel quality by fixing the aluminum addition.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a smelting method of cold heading steel with reduced aluminum source consumption and application thereof.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a method for smelting cold heading steel with reduced aluminum source consumption, comprising adding slag to molten steel during the process of tapping from a converter, adding an aluminum source at the end of tapping from the converter, and refining the molten steel to obtain refined molten steel after the aluminum source is melted.

[0008] In an optional embodiment, the mass ratio of the aluminum source added at the end of steel tapping from the converter to the molten steel is 400-450 kg:120 t.

[0009] Preferably, the aluminum source includes any one of aluminum iron or aluminum particles.

[0010] Preferably, during the process of tapping steel from the converter, the mass ratio of the added slag to the molten steel is 480-520 kg:120 t.

[0011] In an optional embodiment, when the aluminum source is melted, the flow rate of the bottom blowing argon gas is 30 to 40 m 3 / h, stirring time is 4 to 5 minutes.

[0012] Preferably, after the aluminum source is melted and before the molten steel is refined, the argon stirring is turned off, and the molten steel is oxygenated, and aluminum wire is fed into the molten steel according to the oxygen content in the molten steel until the theoretical mass percentage of Als in the molten steel is 0.05-0.06%.

[0013] Preferably, after feeding the aluminum wire, the bottom blowing of argon is turned on, and the flow rate of the bottom blowing argon is 60-70m 3 / h, stirring time is 2 to 3 minutes.

[0014] In an optional embodiment, the refining includes sending the molten steel to a LF furnace for LF refining, the temperature of the molten steel when taking the refined sample 1 for LF refining is 1600-1610°C, and the LF refining time before taking the refined sample 1 is 10-12 minutes.

[0015] In an optional embodiment, LF refining includes: after the molten steel arrives at the LF furnace, slag is added to the molten steel again, then the molten steel is heated by electricity, and argon gas stirring is turned on for refining.

[0016] In an optional implementation, the power transmission when the molten steel is heated by electricity is at levels 7 to 9, and is adjusted to levels 2 to 4 after 2 to 3 minutes.

[0017] Preferably, the argon flow rate during the LF refining process is 50-70 m 3 / h, after the power supply time exceeds 10min, adjust the argon flow rate to 28~32m 3 / h.

[0018] Preferably, the slag added during the LF refining process includes at least one of lime, synthetic slag and aluminum slag.

[0019] Preferably, during the LF refining process, the mass ratio of the added lime to the molten steel is 480-520 kg:120 t; the mass ratio of the added synthetic slag to the molten steel is 280-320 kg:120 t; the mass ratio of the added aluminum slag to the molten steel is 180-220 kg:120 t.

[0020] In an optional embodiment, aluminum wire is fed according to the component content in the refined sample 1 until the theoretical mass percentage of Als in the molten steel is 0.05%, and then the argon flow rate is adjusted to 50-60m 3 / h and stir for 2 to 7 minutes.

[0021] Preferably, after the aluminum wire fed after refining sample 1 is melted, fluorite and / or lime are added to make the refined slag into white, smooth and non-brittle gypsum slag.

[0022] In an optional embodiment, the method further includes taking a refined sample 2 after obtaining the gypsum slag, feeding an aluminum wire according to the component content in the refined sample 2 until the mass percentage of Als in the molten steel is 0.025-0.035%, and feeding a calcium wire until the mass percentage of Ca in the molten steel is 0.0015-0.0020%.

[0023] In an optional embodiment, the element composition of the refined molten steel, by mass percentage, includes C: 0.04% ~ 0.06%, Si: 0 ~ 0.08%, Mn: 0.16 ~ 0.19%, P <0.025%, S <0.012%, Als: 0.025 ~ 0.035%, and the balance is Fe and unavoidable impurities.

[0024] In a second aspect, the present invention provides an application of a method as described in any one of the aforementioned embodiments in reducing the cost of steel smelting.

[0025] The present invention has the following beneficial effects:

[0026] The present invention provides a cold heading steel smelting method and application thereof for reducing aluminum source consumption. By adding aluminum source at the end of converter steel tapping, part of oxygen in molten steel will be consumed by carbon during converter steel tapping, and part of oxygen will be discharged under the action of bottom blowing argon gas, thereby reducing aluminum loss during converter steel tapping. At the same time, the oxygen content in molten steel is low, and the accuracy of aluminum addition is increased, which is conducive to reducing the difficulty of stable control of steel temperature quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a dot plot of the aluminum loss amount when the aluminum source is added at different times during the converter steelmaking process provided in Experimental Example 1 of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0030] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0031] The oxygen content in the molten steel at the end of the converter is relatively high, and the molten steel needs to be deoxidized during the LF refining process. The existing method of deoxidizing molten steel is mainly to add aluminum to the molten steel, and remove the oxygen in the molten steel by reacting with aluminum to form aluminum oxide. However, since the composition of the molten steel at the end of the converter is inconsistent for each batch of molten steel, and the operation of the steel tapping process is inconsistent, such as different steel tapping times, it is easy to increase the loss of the added aluminum. After adding according to the theoretical calculated value, the deoxidation effect of the molten steel cannot be guaranteed. Therefore, the inventor proposes the following solution.

[0032] In a first aspect, the present invention provides a method for smelting cold heading steel with reduced aluminum source consumption, comprising adding slag to molten steel during the process of tapping from a converter, adding an aluminum source at the end of tapping from the converter, and refining the molten steel to obtain refined molten steel after the aluminum source is melted.

[0033] The inventor has found that by adding an aluminum source at the end of the converter tapping, part of the oxygen in the molten steel will react with carbon and manganese and be consumed during the converter tapping process, and part of the oxygen will be discharged under the action of the bottom blowing argon gas during the tapping process, so that after the converter tapping is completed, the oxygen content in the molten steel is slightly lower than before the tapping. Adding an aluminum source at this time can not only reduce the consumption of the aluminum source, but also reduce the aluminum loss during the converter tapping process. At the same time, the oxygen content in the molten steel is low, and the accuracy of the aluminum addition is increased, which is conducive to reducing the difficulty of stable control of steel temperature quality.

[0034] In an optional embodiment, the mass ratio of the aluminum source added at the end of the converter tapping to the mass ratio of the molten steel is 400-450 kg: 120 t. The aluminum source added at the end of the converter tapping serves as a pre-deoxidation agent so that most of the oxygen in the molten steel is quickly converted into aluminum oxides. Therefore, the mass of the aluminum source added at the end of the converter tapping can be adjusted according to the oxygen content in the molten steel.

[0035] Preferably, the aluminum source includes any one of aluminum iron or aluminum particles.

[0036] Preferably, during the process of tapping steel from the converter, the mass ratio of the added slag to the molten steel is 480-520 kg:120 t.

[0037] Preferably, the slag added during the converter steelmaking process is lime. Depending on the type of steel, the slag added during the converter steelmaking process may also include other types of slag, such as synthetic slag.

[0038] In an optional embodiment, when the aluminum source is melted, the flow rate of the bottom blowing argon gas is 30 to 40 m 3 / h, stirring time is 4 to 5 minutes.

[0039] Since the molten steel from the converter is decarburized, when its carbon content is low enough, the temperature of the molten steel is high, and the melting rate of aluminum in the molten steel is very fast. Therefore, after the steel is tapped, adjusting the flow rate of the bottom blowing argon gas and the stirring time within the above range can achieve rapid melting of the aluminum source, which is beneficial to the combination of aluminum and oxygen in the molten steel to produce deoxidation.

[0040] Preferably, after the aluminum source is melted and before the molten steel is refined, the argon stirring is turned off, and the molten steel is oxygenated, and aluminum wire is fed into the molten steel according to the oxygen content in the molten steel until the theoretical mass percentage of Als in the molten steel is 0.05-0.06%.

[0041] After the aluminum source is melted and before the molten steel undergoes LF refining, sampling is required at the argon station to provide a basis for the weight of each raw material added in the subsequent refining process. The oxygen content in the molten steel obtained after sampling at the argon station is the oxygen content obtained by oxygen determination. The content of aluminum added during the refining process is calculated based on the oxygen content determined by oxygen at the argon station.

[0042] Since aluminum will first react with oxygen in molten steel, only when the oxygen content is reduced will there be surplus aluminum to be dissolved in the molten steel in the form of acid-fused aluminum. Therefore, feeding aluminum wire into the molten steel according to the oxygen content in the molten steel until the theoretical mass percentage of Als in the molten steel is 0.05-0.06% means first calculating the mass of aluminum required for the oxygen in the molten steel according to the oxygen content of the argon station oxygen, and the mass of aluminum required for the molten steel to theoretically contain 0.05-0.06% of acid-fused aluminum Als. The sum of the above two masses of aluminum is the mass of aluminum wire required to be fed at this time.

[0043] Preferably, after feeding the aluminum wire, in order to ensure that the aluminum is melted into the molten steel, the bottom blowing of argon is turned on, and the flow rate of the bottom blowing argon is 60-70m 3 / h, stirring time is 2 to 3 minutes.

[0044] In an optional embodiment, the refining includes sending the molten steel to a LF furnace for LF refining, the temperature of the molten steel when taking the refined sample 1 for LF refining is 1600-1610°C, and the LF refining time before taking the refined sample 1 is 10-12 minutes.

[0045] During the 10-12 minutes of refining before taking refined sample 1, the slag melted and reacted with the molten steel to generate oxidized aluminum oxide in the molten steel. More aluminum oxide was generated in the early stage of refining. As the refining time increased, the amount of aluminum oxide generated became less and less. After 12 minutes, basically no aluminum oxide was generated. Therefore, the LF refining time before taking refined sample 1 was 10-12 minutes.

[0046] The power transmission gear controls the temperature rise time. When the power transmission gear is gear 8, the temperature rises by 4°C per minute; when the power transmission gear is gear 4, the temperature rises by 6°C per minute; when the power transmission gear is gear 3, the temperature rises by 7°C per minute; when the power transmission gear is gear 2, the temperature rises by 8°C per minute. Those skilled in the art can adjust the power transmission gear as needed to ensure that the power transmission of 10 to 12 minutes can meet the molten steel temperature reaching above 1600°C.

[0047] By raising the temperature of the molten steel to 1600-1610°C before taking refined sample 1, the higher temperature is conducive to the reaction between aluminum and oxygen, so as to reduce the oxygen content in the molten steel; at the same time, deoxidation through higher molten steel temperature in the early stage of refining provides sufficient time for the subsequent floating of aluminum oxide inclusions, thereby ensuring the quality of the refined molten steel while ensuring steelmaking efficiency.

[0048] In an optional embodiment, LF refining includes: after the molten steel arrives at the LF furnace, slag is added to the molten steel again, then the molten steel is heated by electricity, and argon gas stirring is turned on for refining.

[0049] During the steelmaking process, some slag is added when the converter is tapping steel, and the remaining slag is added after the molten steel reaches the LF furnace, which is conducive to the full melting of the slag. After the molten steel reaches the LF furnace and the remaining slag is added, the temperature of the molten steel can be raised to 1600-1610℃ by sending electricity to heat the molten steel to ensure the refining effect.

[0050] In an optional implementation, in order to ensure that the temperature of the molten steel can reach the above range, the power supply power of the molten steel during power supply and temperature increase is 7 to 9 levels, and is adjusted to 2 to 4 levels after 2 to 3 minutes.

[0051] Preferably, LF refining is started after the molten steel arrives at the LF furnace. While the molten steel is heated by electricity, argon is blown from the bottom of the LF furnace for stirring. The argon flow rate during the LF refining process is 50-70 m 3 / h, after the power supply time exceeds 10min, adjust the argon flow rate to 28~32m 3 / h.

[0052] First, use a large amount of argon gas stirring to accelerate the reaction between aluminum and oxygen and the melting of the slag. When the power supply time exceeds 10 minutes, the oxygen in the molten steel almost reacts with aluminum to form aluminum oxide. Therefore, the argon gas can be adjusted to a small amount, which is conducive to the floating of aluminum oxide in the molten steel and ensure the quality of the refined molten steel.

[0053] Preferably, the slag added during the LF refining process includes at least one of lime, synthetic slag and aluminum slag.

[0054] Preferably, during the LF refining process, the mass ratio of the added lime to the molten steel is 480-520 kg:120 t; the mass ratio of the added synthetic slag to the molten steel is 280-320 kg:120 t; the mass ratio of the added aluminum slag to the molten steel is 180-220 kg:120 t.

[0055] In an optional embodiment, aluminum wire is fed according to the component content in the refined sample 1 until the theoretical mass percentage of Als in the molten steel is 0.05%, and then the argon flow rate is adjusted to 50-60m 3 / h and stir for 2 to 7 minutes.

[0056] By controlling the argon stirring time and flow rate in the early stage of LF, molten steel that meets the quality requirements of the steel grade can be obtained, and the theoretical mass percentage of acid-soluble aluminum in the molten steel of refined sample 2 is controlled to 0.05%, so that refining can be completed directly after feeding the calcium wire without supplementing the aluminum wire.

[0057] After the above operation, the oxygen content in the refined sample 1 of the molten steel fluctuates within a small range, so the calculated value of Als can be controlled at a point value, which is conducive to controlling the addition of aluminum. After feeding the aluminum wire, the argon stirring is increased to allow the aluminum wire to melt quickly in the molten steel.

[0058] Preferably, after the aluminum wire fed after refining sample 1 is melted, fluorite and / or lime are added to make the refined slag into white, smooth and non-brittle gypsum slag. Gypsum slag refers to the steel slag with a white and smooth surface and the slag is not fragile.

[0059] At present, in the refining process of cold heading steel, the slag is often thin or thick during refining. The reason is that the amount of aluminum supplemented in the argon station is too much or too little. When the aluminum supplemented in the argon station increases, more aluminum oxide is produced, the slag of the LF furnace is thinner, and the amount of lime added increases; when the aluminum supplemented in the argon station decreases, the slag of the LF furnace is thicker, and the amount of fluorite added is more.

[0060] In order to reduce the amount of aluminum source and ensure the castability of molten steel, the present invention increases the viscosity of the slag when the slag is added to the LF furnace for the first time, so that the fluidity of the slag is poor. From the time the molten steel enters the station to the time when the refined sample 2 is taken, the oxidation of aluminum in the molten steel can be reduced, and the generation of aluminum oxide can be reduced. However, before the LF furnace is used to take the refined sample 2, the slag needs to be diluted to maintain the fluidity of the molten steel. After taking the refined sample 2, the argon flow rate is maintained at 15m 3 / h or less, the acid-soluble aluminum will not be burned due to exposure of molten steel.

[0061] Preferably, the mass ratio of fluorite to molten steel is 80-150kg:120t. The mass of fluorite can also be adjusted according to actual conditions. When the steel slag becomes transparent glass slag, it means that the amount of fluorite added is too much and lime needs to be added for adjustment; when the steel slag becomes rough limestone slag, it means that the amount of fluorite added is too little and fluorite needs to be added for adjustment.

[0062] In an optional embodiment, after obtaining the gypsum slag, the refined sample 2 is taken, and the aluminum wire is fed according to the component content in the refined sample 2 until the mass percentage of Als in the molten steel is 0.025% to 0.035%, and the calcium wire is fed until the mass percentage of Ca in the molten steel is 0.0015% to 0.0020%. If the calcium content is too high, it will not only waste costs, but also accelerate the erosion of the continuous casting stopper rod; when the calcium content is less than 0.0015%, the molten steel is prone to being unable to be pulled out during continuous casting.

[0063] Since the oxygen content of the molten steel in refined sample 2 is relatively low, when aluminum wire is fed into the molten steel at this time, the aluminum will almost be converted into acid-fused aluminum Als and melted in the molten steel, as long as it is adjusted to the required range of the steel grade.

[0064] In an optional embodiment, the element composition of the refined molten steel, by mass percentage, includes C: 0.04% ~ 0.06%, Si: 0 ~ 0.08%, Mn: 0.16 ~ 0.19%, P <0.025%, S <0.012%, Als: 0.025 ~ 0.035%, and the balance is Fe and unavoidable impurities.

[0065] In a second aspect, the present invention provides an application of a method as described in any one of the aforementioned embodiments in reducing the cost of steel smelting.

[0066] Example 1

[0067] This embodiment provides a smelting method for cold heading steel with reduced aluminum source consumption, wherein the element composition of the cold heading steel is C: 0.04% to 0.06%, Si: 0 to 0.08%, Mn: 0.16 to 0.19%, P < 0.025%, S < 0.012%, Als: 0.025 to 0.035%, and the remainder is Fe and unavoidable impurities. The amount of molten steel tapped from the converter is 120 tons.

[0068] The specific smelting method is as follows:

[0069] When the converter is halfway through tapping, that is, when the 60th ton of steel is tapped, 500 kg of lime slag is added to the molten steel for washing; when the converter is finished tapping, 450 kg of aluminum iron is added to the molten steel, and the bottom blowing argon is adjusted to 30 m 3 / h stirring for 4 minutes, quickly melt the aluminum and iron on the surface of the molten steel, then turn off the argon, take oxygen samples at the argon station, and obtain the mass percentage of acid-soluble aluminum in the molten steel at this time is 0.045%. Calculated by increasing the acid-soluble aluminum by 0.001% every 5 meters, then feed 50m of aluminum wire to make the theoretical mass percentage of Als in the molten steel 0.055%. During the aluminum wire feeding process, turn on the bottom blowing of argon and control the argon flow rate to 60m 3 / h and stir for 2.5min.

[0070] After the molten steel arrives at the LF furnace, add 500kg of lime, 300kg of synthetic slag and 200kg of aluminum slag; the power supply adopts 8-speed arc starting, and after stable, it switches to 4-speed temperature increase. The argon flow rate is 50m 3 / h synchronous stirring. When the power supply is more than 10min, adjust the argon flow rate to 30m 3 / h and take refined sample 1.

[0071] The temperature of the molten steel of refined sample 1 is 1610℃, and the mass percentage of Als is 0.038%. According to the refined sample 1, the aluminum wire is fed for 60m, so that the theoretical mass percentage of Als in the molten steel is 0.05%. During the aluminum wire feeding process, the argon flow rate is 60m 3 / h, stirring time 3min, during and after stirring, observe the fluidity of the steel slag, add 150kg of fluorite, and the slag picked up by the slag sticking rod is white, smooth and not easy to break gypsum slag, then adjust the argon flow rate to 30m 3 / h and take refined sample 2.

[0072] The molten steel temperature of refined sample 2 is 1600℃, the mass percentage of Als is 0.034%, and the calcium is 0.0003%. There is no need to feed aluminum wire. The calcium is increased by 1ppm for every 10 meters of calcium wire. The calcium wire is fed for 170m to make the mass percentage of calcium in the molten steel reach 0.0020%. Refined molten steel is obtained by soft blowing for 12 minutes.

[0073] In this embodiment, the argon station feeds 50 m of aluminum wire and the LF feeds 60 m of aluminum wire.

[0074] Comparative Example 1

[0075] This comparative example provides a smelting method for cold heading steel. The element composition of the cold heading steel is the same as that of Example 1. The specific smelting method is as follows:

[0076] When the converter tapped 1 / 6 of the steel, that is, when the steel was tapped to the 20th ton, 450kg of aluminum iron was added. When the steel was tapped to the 1 / 2, that is, when the steel was tapped to the 60th ton, 500kg of lime slag was added to the molten steel for washing. From the start of adding aluminum iron to 4 minutes after the slag was added, the bottom blowing argon was adjusted to 30m 3 / h, melt the aluminum iron quickly, then turn off the argon, take oxygen samples at the argon station, and obtain the mass percentage of acid-soluble aluminum in the molten steel at this time is 0.018%, calculated based on 0.001% increase in acid-soluble aluminum per 5 meters, and then feed 185m of aluminum wire to make the theoretical mass percentage of Als in the molten steel 0.055%. During the aluminum wire feeding process, turn on the bottom blowing argon and control the argon flow rate to 60m 3 / h and stir for 2.5min.

[0077] After the molten steel arrives at the LF furnace, add 500kg of lime, 300kg of synthetic slag and 200kg of aluminum slag; the power supply adopts 8-speed arc starting, and after stable, it switches to 4-speed temperature increase. The argon flow rate is 50m 3 / h synchronous stirring. When the power supply is more than 10min, adjust the argon flow rate to 30m 3 / h and take refined sample 1.

[0078] The temperature of the molten steel of refined sample 1 is 1610℃, and the mass percentage of Als is 0.032%. According to the refined sample 1, the aluminum wire is fed for 90m, so that the theoretical mass percentage of Als in the molten steel is 0.05%. During the aluminum wire feeding process, the argon flow rate is 60m 3 / h, stirring time 3min, during and after stirring, observe the fluidity of the steel slag, add 150kg of lime, add 80kg of fluorite, and the slag picked up by the slag sticking rod is white, smooth and not easy to break gypsum slag, then adjust the argon flow rate to 30m 3 / h and take refined sample 2.

[0079] The molten steel temperature of refined sample 2 is 1600℃, the mass percentage of Als is 0.031%, and the calcium is 0.0002%. There is no need to feed aluminum wire. The calcium is increased by 1ppm for every 10 meters of calcium wire. The calcium wire is fed for 170m to make the mass percentage of calcium in the molten steel reach 0.0019%. Refined molten steel is obtained by soft blowing for 12 minutes.

[0080] In this comparative example, the argon station is fed with 185 m of aluminum wire, and the LF is fed with 90 m of aluminum wire.

[0081] Comparative Example 2

[0082] This comparative example provides a smelting method for cold heading steel. The element composition of the cold heading steel is the same as that of Example 1. The specific smelting method is as follows:

[0083] When the converter is 1 / 3 of the steel being tapped, i.e., when the 40th ton of steel is tapped, 450kg of ferroaluminum is added. When the converter is 1 / 2 of the steel being tapped, i.e., when the 60th ton of steel is tapped, 500kg of lime slag is added to the molten steel for washing. From the start of adding ferroaluminum to 4 minutes after the slag is added, the bottom blowing of argon is adjusted to 30m 3 / h, melt the aluminum iron quickly, then turn off the argon, take oxygen samples at the argon station, and obtain the mass percentage of acid-soluble aluminum in the molten steel at this time is 0.021%. Calculated by increasing the acid-soluble aluminum by 0.001% every 5 meters, then feed 170m of aluminum wire to make the theoretical mass percentage of Als in the molten steel 0.055%. During the aluminum wire feeding process, turn on the bottom blowing argon and control the argon flow rate to 60m 3 / h and stir for 2.5min.

[0084] After the molten steel arrives at the LF furnace, add 500kg of lime, 300kg of synthetic slag and 200kg of aluminum slag; the power supply adopts 8-speed arc starting, and after stable, it switches to 4-speed temperature increase. The argon flow rate is 50m 3 / h synchronous stirring. When the power supply is more than 10min, adjust the argon flow rate to 30m 3 / h and take refined sample 1.

[0085] The temperature of the molten steel of refined sample 1 is 1610℃, and the mass percentage of Als is 0.035%. According to the refined sample 1, the aluminum wire is fed for 75m, so that the theoretical mass percentage of Als in the molten steel is 0.05%. During the aluminum wire feeding process, the argon flow rate is 60m 3 / h, stirring time 3min, during and after stirring, observe the fluidity of the steel slag, add 90kg of fluorite, and the slag picked up by the slag sticking rod is white, smooth and not easy to break gypsum slag, then adjust the argon flow rate to 30m 3 / h and take refined sample 2.

[0086] The molten steel temperature of refined sample 2 is 1600℃, the mass percentage of Als is 0.033%, and the calcium is 0.0003%. There is no need to feed aluminum wire. The calcium is increased by 1ppm for every 10 meters of calcium wire. The calcium wire is fed for 170m to make the mass percentage of calcium in the molten steel reach 0.0019%. Refined molten steel is obtained by soft blowing for 12 minutes.

[0087] In this comparative example, the argon station is fed with 170 m of aluminum wire, and the LF is fed with 75 m of aluminum wire.

[0088] Comparative Example 3

[0089] This comparative example provides a smelting method for cold heading steel. The element composition of the cold heading steel is the same as that of Example 1. The specific smelting method is as follows:

[0090] When the converter is 2 / 3 of the steel out, that is, when the 80th ton of steel is out, 450kg of aluminum iron and 500kg of lime slag are added for washing. From the beginning of adding aluminum iron to 4 minutes after the slag is added, the bottom blowing argon is adjusted to 30m 3 / h, melt the aluminum iron quickly, then turn off the argon, take oxygen samples at the argon station, and obtain the mass percentage of acid-soluble aluminum in the molten steel at this time, which is 0.025%. Calculated by increasing the acid-soluble aluminum by 0.001% every 5 meters, then feed 150m of aluminum wire to make the theoretical mass percentage of Als in the molten steel 0.055%. During the aluminum wire feeding process, turn on the bottom blowing argon and control the argon flow rate to 60m 3 / h and stir for 2.5min.

[0091] After the molten steel arrives at the LF furnace, add 500kg of lime, 300kg of synthetic slag and 200kg of aluminum slag; the power supply adopts 8-speed arc starting, and after stable, it switches to 4-speed temperature increase. The argon flow rate is 50m 3 / h synchronous stirring. When the power supply is more than 10min, adjust the argon flow rate to 30m 3 / h and take refined sample 1.

[0092] The temperature of the molten steel of refined sample 1 is 1610℃, and the mass percentage of Als is 0.037%. According to the refined sample 1, the aluminum wire is fed for 65m, so that the theoretical mass percentage of Als in the molten steel is 0.05%. During the aluminum wire feeding process, the argon flow rate is 60m 3 / h, stirring time 3min, during and after stirring, observe the fluidity of the steel slag, add 100kg of fluorite, and the slag picked up by the slag sticking rod is white, smooth and not easy to break gypsum slag, then adjust the argon flow rate to 30m 3 / h and take refined sample 2.

[0093] The molten steel temperature of refined sample 2 is 1600℃, the mass percentage of Als is 0.033%, and the calcium is 0.0003%. There is no need to feed aluminum wire. The calcium is increased by 1ppm for every 10 meters of calcium wire. The calcium wire is fed for 170m to make the mass percentage of calcium in the molten steel reach 0.0019%. Refined molten steel is obtained by soft blowing for 12 minutes.

[0094] In this comparative example, the argon station is fed with 150 m of aluminum wire, and the LF is fed with 65 m of aluminum wire.

[0095] Comparative Example 4

[0096] This comparative example provides a smelting method for cold heading steel. The element composition of the cold heading steel is the same as that of Example 1. The specific smelting method is as follows:

[0097] When the steel is tapped to 5 / 6, that is, when the steel is tapped to 100 tons, 500 kg of lime slag is added to the molten steel for washing. When the converter is tapped to 2 / 3, that is, when the steel is tapped to 80 tons, 450 kg of aluminum iron is added. Stir for 4 minutes after adding aluminum iron, and adjust the bottom blowing argon to 30m 3 / h, melt the aluminum iron quickly, then turn off the argon, take oxygen samples at the argon station, and obtain the mass percentage of acid-soluble aluminum in the molten steel at this time is 0.033%. Calculated by increasing the acid-soluble aluminum by 0.001% every 5 meters, then feed 110m of aluminum wire to make the theoretical mass percentage of Als in the molten steel 0.055%. During the aluminum wire feeding process, turn on the bottom blowing argon and control the argon flow rate to 60m 3 / h and stir for 2.5min.

[0098] After the molten steel arrives at the LF furnace, add 500kg of lime, 300kg of synthetic slag and 200kg of aluminum slag; the power supply adopts 8-speed arc starting, and after stable, it switches to 4-speed temperature increase. The argon flow rate is 50m 3 / h synchronous stirring. When the power supply is more than 10min, adjust the argon flow rate to 30m 3 / h and take refined sample 1.

[0099] The temperature of the molten steel of refined sample 1 is 1610℃, and the mass percentage of Als is 0.035%. According to the refined sample 1, the aluminum wire is fed for 75m, so that the theoretical mass percentage of Als in the molten steel is 0.05%. During the aluminum wire feeding process, the argon flow rate is 60m 3 / h, stirring time 3min, during and after stirring, observe the fluidity of the steel slag, add 120kg of fluorite, and the slag picked up by the slag sticking rod is white, smooth and not easy to break gypsum slag, then adjust the argon flow rate to 30m 3 / h and take refined sample 2.

[0100] The molten steel temperature of refined sample 2 is 1600℃, the mass percentage of Als is 0.034%, and the calcium is 0.0003%. There is no need to feed aluminum wire. The calcium is increased by 1ppm for every 10 meters of calcium wire. The calcium wire is fed for 170m to make the mass percentage of calcium in the molten steel reach 0.0019%. Refined molten steel is obtained by soft blowing for 12 minutes.

[0101] In this comparative example, the argon station is fed with 110 m of aluminum wire, and the LF is fed with 75 m of aluminum wire.

[0102] Comparative Example 5

[0103] This comparative example provides a smelting method for cold heading steel. The element composition of the cold heading steel is the same as that of Example 1. The specific smelting method is as follows:

[0104] At the end of steel tapping, that is, when the steel tapping reaches 120 tons, 500kg of lime slag is added to the molten steel for washing. When the converter taps 5 / 6 of the steel, that is, when the steel tapping reaches 100 tons, 450kg of aluminum iron is added. Stir for 4 minutes after adding aluminum iron, and adjust the bottom blowing argon to 30m 3 / h, melt the aluminum iron quickly, then turn off the argon, take oxygen samples at the argon station, and obtain the mass percentage of acid-soluble aluminum in the molten steel at this time is 0.042%. Calculated by increasing the acid-soluble aluminum by 0.001% every 5 meters, then feed 65m of aluminum wire to make the theoretical mass percentage of Als in the molten steel 0.055%. During the aluminum wire feeding process, turn on the bottom blowing argon and control the argon flow rate to 60m 3 / h and stir for 2.5min.

[0105] After the molten steel arrives at the LF furnace, add 500kg of lime, 300kg of synthetic slag and 200kg of aluminum slag; the power supply adopts 8-speed arc starting, and after stable, it switches to 4-speed temperature increase. The argon flow rate is 50m 3 / h synchronous stirring. When the power supply is more than 10min, adjust the argon flow rate to 30m 3 / h and take refined sample 1.

[0106] The temperature of the molten steel of refined sample 1 is 1610℃, and the mass percentage of Als is 0.036%. According to the refined sample 1, the aluminum wire is fed for 70m, so that the theoretical mass percentage of Als in the molten steel is 0.05%. During the aluminum wire feeding process, the argon flow rate is 60m 3 / h, stirring time 3min, during and after stirring, observe the fluidity of the steel slag, add 140kg of fluorite, the slag picked up by the slag sticking rod is white, smooth and not easy to break gypsum slag, then adjust the argon flow rate to 30m 3 / h and take refined sample 2.

[0107] The molten steel temperature of refined sample 2 is 1600℃, the mass percentage of Als is 0.035%, and the calcium is 0.0003%. There is no need to feed aluminum wire. The calcium is increased by 1ppm for every 10 meters of calcium wire. The calcium wire is fed for 170m to make the mass percentage of calcium in the molten steel reach 0.0019%. Refined molten steel is obtained by soft blowing for 12 minutes.

[0108] In this comparative example, the argon station is fed with 65 m of aluminum wire, and the LF is fed with 70 m of aluminum wire.

[0109] Test Example 1

[0110] Taking 120t steel as an example, the same mass of aluminum source is added to the same molten steel composition at the steel output of 20t, 40t, 60t, 80t, 100t and 120t respectively. After the aluminum is fully melted, the molten steel is sampled at the argon station to obtain the Als content in the molten steel. Figure 1 And the results are shown in Table 1.

[0111] Table 1

[0112] Argon station aluminum wire / m LF furnace aluminum wire / m Total amount of aluminum wire / m Example 1 50 60 110 Comparative Example 1 185 90 275 Comparative Example 2 170 75 245 Comparative Example 3 150 65 215 Comparative Example 4 110 75 185 Comparative Example 5 65 70 135

[0113] Depend on Figure 1It can be seen that as the amount of steel tapping decreases, the amount of aluminum source added is converted into less Als, which means that more aluminum is used for deoxidation, and the aluminum loss is less, which is beneficial to reduce the consumption of aluminum. As shown in Table 1, by controlling the timing of adding aluminum iron during the steel tapping process, the total amount of aluminum wire added can be reduced.

[0114] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for smelting cold heading steel with reduced aluminum source consumption, characterized in that: The method includes adding slag into molten steel during the process of tapping steel from the converter, adding an aluminum source when the tapping steel from the converter is finished, and refining the molten steel to obtain refined molten steel after the aluminum source is melted.

2. The method according to claim 1, characterized in that The mass ratio of the aluminum source added at the end of the converter tapping to the molten steel is 400-450kg:120t; Preferably, the aluminum source includes any one of aluminum iron or aluminum particles; Preferably, during the process of tapping steel from the converter, the mass ratio of the added slag to the molten steel is 480-520 kg:120 t; Preferably, during the process of tapping steel from the converter, the slag added includes lime.

3. The method according to claim 1, characterized in that When the aluminum source is melted, the flow rate of bottom blowing argon is 30-40m 3 / h, stirring time is 4 to 5 minutes; Preferably, after the aluminum source is melted and before the molten steel is refined, the argon stirring is turned off, and the molten steel is oxygenated, and aluminum wire is fed into the molten steel according to the oxygen content in the molten steel until the theoretical mass percentage of Als in the molten steel is 0.05-0.06%; Preferably, after feeding the aluminum wire, the bottom blowing of argon is turned on, and the flow rate of the bottom blowing argon is 60-70m 3 / h, stirring time is 2 to 3 minutes.

4. The method according to claim 1, characterized in that: The refining includes sending the molten steel to a LF furnace for LF refining. When taking the refined sample 1 for the LF refining, the temperature of the molten steel is 1600-1610° C., and the LF refining time before taking the refined sample 1 is 10-12 minutes.

5. The method according to claim 4, characterized in that The LF refining includes: when the molten steel arrives at the LF furnace, slag is added to the molten steel again, then the molten steel is heated by electricity, and argon gas is turned on for stirring and refining.

6. The method according to claim 5, characterized in that The power supply for molten steel during heating is 7-9, and it is adjusted to 2-4 after 2-3 minutes. Preferably, the argon flow rate of the LF refining process is 50-70m 3 / h, after the power supply time exceeds 10min, adjust the argon flow rate to 28~32m 3 / h; Preferably, the slag added during the LF refining process includes at least one of lime, synthetic slag and aluminum slag; Preferably, in the LF refining process, the mass ratio of the added lime to the molten steel is 480-520kg:120t; the mass ratio of the added synthetic slag to the molten steel is 280-320kg:120t; the mass ratio of the added aluminum slag to the molten steel is 180-220kg:120t.

7. The method according to claim 4, characterized in that Feed aluminum wire according to the component content in the refined sample 1 until the theoretical mass percentage of Als in the molten steel is 0.05%, and then adjust the argon flow rate to 50-60m 3 / h stirring for 2 to 7 minutes; Preferably, after the aluminum wire fed to the refined sample 1 is melted, fluorite and / or lime are added to make the refined slag into white, smooth and non-brittle gypsum slag.

8. The method according to claim 7, characterized in that The method also includes taking a refined sample 2 after obtaining the gypsum slag, feeding an aluminum wire according to the component content in the refined sample 2 until the mass percentage of Als in the molten steel is 0.025% to 0.035%, and feeding a calcium wire until the mass percentage of Ca in the molten steel is 0.0015% to 0.0020%.

9. The method according to claim 1, characterized in that: The element composition of the refined molten steel, measured by mass percentage, includes C: 0.04% to 0.06%, Si: 0 to 0.08%, Mn: 0.16 to 0.19%, P < 0.025%, S < 0.012%, Als: 0.025 to 0.035%, and the remainder is Fe and unavoidable impurities.

10. Use of the method according to any one of claims 1 to 9 in reducing steel smelting costs.

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