Method for reducing steel adhesion of medium-high carbon steel plate blank

Abstract

The invention discloses a method for reducing steel adhesion of a medium-high carbon steel slab. The method comprises the step that the steel bonding probability of the medium-high carbon steel plate blank is reduced mainly by controlling the hydrogen content of molten steel to be 5 ppm or below. According to investigation and analysis, it is found that zero returning of bonded steel of a casting machine is related to the hydrogen content of the molten steel, and when the hydrogen content of the molten steel is larger than 5 ppm, the probability of slab steel bonding is large, so that the probability of medium-high carbon steel slab steel bonding is reduced by controlling the hydrogen content of the molten steel to be 5 ppm or below.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for reducing steel sticking in medium- and high-carbon steel slabs. Background Art

[0002] There is a slab continuous casting machine in the No. 1 Steelmaking Plant of Shaoguan Iron and Steel Co., Ltd. At present, there are three main process routes for 50LF steel, namely, converter-argon station-casting machine, converter-LF furnace-casting machine, converter-LF furnace-RH furnace-casting machine. In the first two process routes, the original production process does not require high hydrogen and phosphorus content in molten steel, so there are no specific requirements for molten iron silicon, iron-steel ratio, use of cooling materials, and use of slag materials. As long as the molten steel composition is qualified and the molten steel can be pulled out, it is fine. However, among the steels with higher quality requirements, such as 50LF steel, which is aluminum-free steel with a higher carbon content, the liquidus temperature of the molten steel is 1490℃. Compared with steels with a carbon content of 0.15-0.22%, the temperature of the molten steel in the continuous casting process is lower, so when the continuous casting returns to zero due to sticking steel, it is very easy to have dead flow, which seriously affects the production process and the quality of the steel plate. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the above technical background and provide a method for reducing steel sticking in medium and high carbon steel slabs.

[0004] The embodiment of the present invention provides a method for reducing steel sticking of medium-high carbon steel slabs, which comprises: mainly controlling the hydrogen content of molten steel to be below 5ppm to reduce the probability of steel sticking of medium-high carbon steel slabs.

[0005] The present invention has the following beneficial effects.

[0006] The present invention provides a method for reducing steel sticking of medium-high carbon steel slabs, which comprises: mainly controlling the hydrogen content of molten steel to be below 5ppm to reduce the probability of steel sticking of medium-high carbon steel slabs. Through investigation and analysis, it is found that the steel sticking zero return of the casting machine is related to the hydrogen content of molten steel. When the hydrogen content of molten steel is greater than 5ppm, the probability of steel sticking of the slab is very high. Therefore, in the present invention, the probability of steel sticking of medium-high carbon steel slabs is reduced by controlling the hydrogen content of molten steel to be below 5ppm. DETAILED DESCRIPTION

[0007] 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.

[0008] A method for reducing steel sticking in medium- and high-carbon steel slabs provided by an embodiment of the present invention is described in detail below.

[0009] The embodiment of the present invention provides a method for reducing steel sticking of medium-high carbon steel slabs, which comprises: mainly controlling the hydrogen content of molten steel to be below 5ppm to reduce the probability of steel sticking of medium-high carbon steel slabs.

[0010] During the rolling process of medium and high carbon steel slabs, the slabs adhere to the rollers and then adhere to the surface of the subsequent strip steel. Repeated detachment and adhesion eventually cause problems such as spot-line pit-shaped steel adhesion defects on the surface of the strip steel along the entire length, affecting the surface quality. If the surface of the steel adhesion defects after hot rolling is repaired, it will affect the cold rolling operability of the subsequent engineering and increase the production cost. The inventor found through investigation and analysis that the zero return of steel adhesion in the casting machine is related to the hydrogen content of molten steel. When the hydrogen content of molten steel is greater than 5ppm, the probability of steel adhesion is very high. For this reason, in the embodiment of the present invention, the probability of steel adhesion of medium and high carbon steel slabs is reduced by controlling the hydrogen content of molten steel below 5ppm.

[0011] In some optional embodiments, controlling the hydrogen content of molten steel to below 5 ppm includes: in the converter smelting process, controlling the appropriate iron-steel ratio and the timing of adding cold material during the converter smelting process, shortening the steel flow time and reducing the exposed area of ​​the molten steel surface when tapping the converter, controlling the timing and material level of slag washing lime feeding to reduce the increased hydrogen content of the molten steel, and in the LF refining process, deoxidizing and desulfurizing the molten steel to reduce the inclusion content in the molten steel.

[0012] In some optional embodiments, during the converter smelting process, controlling a suitable iron-steel ratio includes: when the silicon content of the molten iron is in the range of 0.45-0.55%, controlling the iron-steel ratio to be 840-870 kg / t.

[0013] The iron-steel ratio refers to the ratio of the amount of molten iron invested in the steelmaking process to the steel output. Reducing the iron-steel ratio can reduce the comprehensive energy consumption per ton of steel in steel enterprises. Under the same crude steel output, the comprehensive energy consumption of enterprises can be reduced. Therefore, reducing the iron-steel ratio is an important means for steel enterprises to reduce the comprehensive energy consumption per ton of steel. The method for reducing the sticking of medium and high carbon steel slabs provided by the embodiment of the present invention, during the converter smelting process, comprehensively considers the silicon content and molten iron temperature in the molten iron, as well as the later converter smelting control and dephosphorization requirements, and controls the iron-steel ratio according to the molten iron temperature and the silicon content of the molten iron as follows: When the silicon content of the molten iron is in the range of 0.45-0.55%, the iron-steel ratio is controlled at 840-870kg / t. This is because: the molten iron temperature is the physical heat of smelting, and the silicon content of the molten iron is the chemical heat of smelting. The higher the heat, the more conducive it is to melting scrap steel, but the less conducive it is to dephosphorization. At present, in order to reduce the production cost of molten iron, the quality of molten iron will be poor, mainly because the average silicon content is 0.481%, compared with the optimal silicon value of 0.30%-0.40%, there is a high consumption of slag and cooling materials. For this reason, for the silicon content of molten iron at 0.45-0.55%, the iron-steel ratio is controlled and adjusted to 840-870kg / t. If it is lower than 840kg / t, that is, less scrap steel is added, there will be excess temperature. The smelting process needs to increase cooling materials to control the temperature during dephosphorization. The materials containing water enter the molten steel, resulting in a high hydrogen content. If it is higher than 870kg / t, that is, more scrap steel is added, the temperature will be insufficient. In the later stage of smelting, it is necessary to blow after heating, which increases slag consumption and iron loss. The materials containing water enter the molten steel, resulting in a high hydrogen content. Specifically, Shaoguan Iron and Steel is located in a southern coastal province, and the air humidity is above 80% all year round, causing the material to absorb water and re-moisten, containing water, so the less slag is used, the better.

[0014] In some optional embodiments, during the converter smelting process, controlling the timing of adding materials includes: adding cold-solidified pellets during the 0-600 second period of oxygen blowing in the converter, and adding only sintered ore or no sintered ore after 600 seconds. On the basis of controlling the appropriate iron-steel ratio, a certain amount of cold-solidified pellets needs to be added, because: during the converter smelting process, if there is a suitable surplus temperature, oxygen blowing and adding dephosphorization slag such as lime are started, and after the silicon in the molten iron is completely oxidized, 1.5-3 tons of cold-solidified pellets or cooling materials such as iron ore are added at this time, which can extend the time of low-temperature dephosphorization, so that the phosphorus content can be more surely removed to the qualified range. If the molten iron temperature is low and there is no surplus temperature to add cooling materials such as cold-solidified pellets or iron ore, will phosphorus not be removed to the qualified range? Not necessarily, but low splashing will easily occur because the molten iron temperature is low, and the dephosphorization slag added by oxygen blowing is not well smelted at the beginning, and it is difficult to form foam slag with good air permeability, so the oxygen blown in is blocked and discharged unevenly, which looks like a volcanic eruption, with groups of lava pouring out of the furnace mouth. Therefore, in order to ensure good slag smelting and smooth dephosphorization, the amount of scrap steel added is generally calculated according to the molten iron conditions to make it have a certain surplus temperature, so as to add some cooling materials such as cold-solidified pellets or iron ore in the early stage of smelting, so as to smoothly and accurately remove phosphorus in the molten iron to the qualified range.

[0015] Controlling a reasonable iron-steel ratio can effectively reduce the consumption of converter slag and cooling materials. However, since cold-solidified pellets are only 350 yuan / ton and sintered ore is 1,200 yuan / ton, cold-solidified pellets are processed from recycled iron oxide and have a high water content. Excessive use can easily lead to high hydrogen content in molten steel. Therefore, the amount of cold-solidified pellets should be reduced as much as possible. So we studied the effect of adding cold-solidified pellets on hydrogenation in molten steel. The carbon content of molten iron is generally 4.0%-4.5%. We found that when the converter smelting starts from decarburization by oxygen blowing to when the carbon content in molten steel is above 1%, adding cold-solidified pellets has no obvious effect on hydrogenation in molten steel. This is mainly because the carbon-oxygen reaction is violent and the gas can be discharged in time. However, when the carbon content in molten steel is less than 1%, especially less than 0.4%, the hydrogenation in molten steel is obvious after adding cold-solidified pellets. Therefore, while ensuring the quality of molten steel, we can reduce costs and control the timing of adding cold-solidified pellets in converter smelting. Cold-solidified pellets can be added during the period of 0-600 seconds of oxygen blowing, and only sintered ore can be added after 600 seconds. The ideal situation is not to add any cooling materials after 600 seconds.

[0016] In summary, controlling the iron-steel ratio according to the molten iron conditions is the key to reducing hydrogen increase in molten steel.

[0017] In some optional embodiments, when the converter is tapping, shortening the steel flow tapping time includes: reducing the steel molten steel's absorption of gas during the tapping process by increasing the diameter of the tapping port to reduce the tapping time. By increasing the diameter of the tapping port, the tapping time is reduced from an average of 4.2 minutes / furnace to 3.1 minutes / furnace, thereby reducing the steel molten steel's gas absorption during the tapping process. Originally, the inner diameter of the tapping port of our factory's converter was 19 cm. After the equipment was improved, it was replaced with a tapping port with an inner diameter of 21 cm. After the change, the tapping time was significantly reduced, compared with the original average reduction of 4.2-3.1=1.1 minutes. In the statistical data on nitrogen increase in the tapping process, we also found that after the tapping time was reduced, the molten steel gained less nitrogen, indicating that reducing the tapping time is effective in reducing the absorption of gas by molten steel.

[0018] In some optional embodiments, when tapping steel from a converter, reducing the exposed area of ​​the molten steel surface includes: reducing the exposed area of ​​the molten steel surface by optimizing tapping deoxidation and reducing the argon gas flow rate at the bottom of the ladle.

[0019] In some optional embodiments, optimizing steel tapping and deoxidation includes: adding 300 kg of slag-washed lime after tapping 10 tons of molten steel, spreading it on the surface of the molten steel to form protection and reduce exposure of the molten steel, and adding alloy when 1 / 2 of the steel is tapped; reducing the flow rate of argon gas blown at the bottom of the ladle includes: controlling the flow rate of argon gas blown at the bottom of the ladle to 5-8 cubic meters / hour to reduce exposure of the molten steel.

[0020] In some optional embodiments, controlling the timing and level of loading slag-washed lime includes: controlling the time from the lime burned in the roasting plant to the converter for use within 2 hours, and adopting a method of small batches and multiple loading silos to reduce the time the lime is damp. This is mainly because Shaoguan Iron and Steel is located on the southeast coast, with high air humidity, which is above 80% all year round, especially during the period of the return of the south in the early Qingming Festival, when the air humidity is as high as above 95%. Previously, it was not noticed that the dampness of lime had a relationship with the increase of hydrogen in molten steel. Later, it was found in the production process that the hydrogen content of molten steel would be higher when the lime in the later stage of the silo was used. Our investigation found that only 300 kilograms of slag was used for a furnace, and the cycle of a furnace of steel was 33 minutes. If a silo is filled with lime, it will take 10000 / 300*33=1100 minutes=18.3 hours to use it up. So after the lime was loaded into the silo, we took lime samples for water testing in different time periods and found that the longer the lime was placed in the silo, the higher the water content in the lime. Therefore, based on actual production conditions, we load lime into the silo while ensuring the minimum amount required for production. Since our own lime plant is very close to the steel plant, it only takes 25 minutes from loading to loading into our silo, so we can control the delivery of a batch of lime within 2 hours, loading 1-1.5 tons each time, which can effectively improve the problem of high hydrogen content caused by lime absorbing water and becoming damp.

[0021] In some optional embodiments, the molten steel is subjected to deoxidation and desulfurization treatment to reduce the inclusion content in the molten steel: the acid-soluble aluminum content of the molten steel out of the LF furnace is controlled to be 0.006%-0.015%, the sulfur content is less than 0.010%, and the calcium content is 0.0006%-0.0010%.

[0022] After the converter is finished tapping, due to the high silicon content in the molten iron, the slag increases, the oxygen blowing amount increases, and the carbon-oxygen product of the converter molten steel will be relatively high, which will naturally increase the difficulty of tapping and LF furnace deoxidation, as well as increase the inclusions in the molten steel. In addition to easily causing water blockage, inclusions such as alumina and iron sulfide are also likely to cause surface cracks in the ingot, as well as the precipitation of inclusions during the solidification process of the ingot, causing steel sticking in the crystallizer. Therefore, the LF furnace also needs to deoxidize and desulfurize the molten steel, and control the acid-soluble aluminum content of the molten steel out of the LF furnace to be between 0.006% and 0.015%. In medium and high carbon steel, due to the high carbon content of the molten steel, the fluidity of the molten steel is relatively good, and the oxygen content in the molten steel is low. Relatively speaking, it is relatively easy to desulfurize, so the acid-soluble aluminum only needs to be present but not too much, greater than 0.006% is enough. Of course, acid-soluble aluminum can refine the grains in steel, which is good for quality. A proper amount of acid-soluble aluminum is good for quality, but not for cost. Therefore, in order to reduce waste, we control the upper limit of acid-soluble aluminum within 0.015% and the sulfur content is less than 0.010%. Regarding LF desulfurization, I will not say much about the LF furnace desulfurization process, which is relatively conventional. At the same time, high sulfur in molten steel affects the quality of slabs. We have counted the actual production and found that among the plates with quality problems, relatively speaking, there are more furnaces with sulfur greater than 0.010%. Therefore, we require the LF furnace to remove sulfur to within 0.010% to avoid quality problems such as corner cracks and edge cracks in the casting. Regarding the control of calcium content in molten steel, the calcium content is between 0.0006% and 0.0010%. Generally, calcium wire does not need to be fed to slab molten steel. However, there is a small probability that the stopper rod will rise (molten steel cannot be pulled out), resulting in unqualified casting quality. Therefore, adding a small amount of calcium to the molten steel can eliminate the risk of stopper rod rising.

[0023] In summary, acid-soluble aluminum is used to deoxidize molten steel and refine grains. If it is too high, it is a waste, but if it is lower than 0.006%, deoxidation may be poor. Sulfur greater than 0.010% may cause cracks. If the calcium content is too high after calcium treatment, it is a waste, but if it is too low, the molten steel may not be pulled out.

[0024] In some optional implementations, the process further includes: controlling the pulling speed to be 0.05 m / min slower than the normal furnace to reduce the chance of the slab sticking to the steel. The purpose of reducing the pulling speed is to allow the molten steel to have more time to discharge hydrogen during the solidification process. However, if the speed is reduced by more than 0.2 m / min, the quality of the slab will be significantly affected.

[0025] The present invention will be further described below in conjunction with the embodiments.

[0026] Example 1

[0027] A method for reducing steel sticking in medium- and high-carbon steel slabs comprises the following steps:

[0028] During converter smelting, the silicon content of hot metal is 0.45%, and the iron-steel ratio is controlled to 870kg / t. The timing of adding cold solid pellets is controlled to add 1.5 tons within 300 seconds of oxygen blowing, and no cooling material is needed afterwards.

[0029] During the steel-tapping process of the converter, the following measures are taken: First, by increasing the diameter of the steel-tapping port, the steel-tapping time is reduced from an average of 4.2 minutes / furnace to 3 minutes / furnace, thereby reducing the air intake of molten steel during the steel-tapping process; second, the steel-tapping deoxidation is optimized. After 10 tons of molten steel are tapped from the converter, 300 kg of slag-washed lime is added and spread on the surface of the molten steel to form a protection to reduce the exposure of the molten steel; alloy is added when the steel is tapped to 1 / 2; third, argon gas is blown from the bottom of the ladle at a flow rate of 5 cubic meters / hour, as small as possible to reduce the exposure of the molten steel; fourth, the timing and level of slag-washed lime loading are controlled. The time from the lime burned in the roasting plant to the use in the converter is controlled within 2 hours. At the same time, the storage capacity of the converter and LF lime silos is controlled at 1-1.5 tons to ensure that it is sufficient. The method of small batches and multiple loading silos is adopted to reduce the time the lime is exposed to moisture.

[0030] After the molten steel arrives at the LF furnace, it is deoxidized and desulfurized: the acid-soluble aluminum of the LF molten steel is controlled at 0.015%, the sulfur content is controlled at less than 0.010%, and the calcium is 0.0010% through calcium treatment.

[0031] Example 2

[0032] A method for reducing steel sticking in medium- and high-carbon steel slabs comprises the following steps:

[0033] During converter smelting, the silicon content of hot metal is 0.48%, and the iron-steel ratio is controlled to 860kg / t. The timing of adding cold solid pellets is controlled to add 2 tons within 300 seconds of oxygen blowing, and no cooling material is needed afterwards.

[0034] During the steel-tapping process of the converter, the following measures are taken: First, by increasing the diameter of the steel-tapping port and reducing the steel-tapping time to 3.1 minutes, the steel-tapping process is reduced by absorbing air from the molten steel. Second, the steel-tapping deoxidation is optimized. After 10 tons of molten steel are tapped from the converter, 300 kg of slag-washed lime is added and spread on the surface of the molten steel to form a protection to reduce the exposure of the molten steel. When the steel is tapped to 1 / 2, alloy is added. Third, argon gas is blown from the bottom of the ladle at a flow rate of 6 cubic meters per hour, as small as possible to reduce the exposure of the molten steel. Fourth, the timing and level of loading the slag-washed lime are controlled. The time from the lime burned in the roasting plant to the use in the converter is controlled within 2 hours. At the same time, the storage capacity of the converter and LF lime silos is controlled at 1-1.5 tons to ensure that it is sufficient. The method of small batches and multiple loading silos is adopted to reduce the time the lime is exposed to moisture.

[0035] After the molten steel arrives at the LF furnace, it is deoxidized and desulfurized: the acid-soluble aluminum of the LF molten steel is controlled at 0.012%, the sulfur content is controlled at less than 0.010%, and the calcium is 0.0008% through calcium treatment.

[0036] Example 3

[0037] A method for reducing steel sticking in medium- and high-carbon steel slabs comprises the following steps:

[0038] During converter smelting, the silicon content of hot metal is 0.52%, and the iron-steel ratio is controlled to 850kg / t. The timing of adding cold solid pellets is controlled to add 2.5 tons within 300 seconds of oxygen blowing, and no cooling material is needed afterwards.

[0039] During the steel-tapping process of the converter, the following measures are taken: First, by increasing the diameter of the steel-tapping port, the steel-tapping time is reduced to 3.2 minutes, reducing the air intake of molten steel during the steel-tapping process; second, the steel-tapping deoxidation is optimized. After 10 tons of molten steel are tapped from the converter, 300 kg of slag-washed lime is added and spread on the surface of the molten steel to form a protection to reduce the exposure of the molten steel. Alloy is added when the steel is tapped to 1 / 2; third, argon gas is blown from the bottom of the ladle at a flow rate of 7 cubic meters per hour, as small as possible to reduce the exposure of the molten steel; fourth, the timing and level of slag-washed lime loading are controlled. The time from the lime burned in the roasting plant to the use in the converter is controlled within 2 hours. At the same time, the storage capacity of the converter and LF lime silos is controlled at 1-1.5 tons to ensure that it is sufficient. The method of small batches and multiple loading silos is adopted to reduce the time the lime is exposed to moisture.

[0040] After the molten steel arrives at the LF furnace, it is deoxidized and desulfurized: the acid-soluble aluminum of the LF molten steel is controlled at 0.009%, the sulfur content is controlled at less than 0.010%, and the calcium is 0.0007% through calcium treatment.

[0041] Example 4

[0042] A method for reducing steel sticking in medium- and high-carbon steel slabs comprises the following steps:

[0043] During converter smelting, the silicon content of hot metal is 0.55%, and the iron-steel ratio is controlled to 840kg / t. The timing of adding cold-solidified pellets is controlled to add 3 tons within 300 seconds of oxygen blowing, and no cooling material is needed afterwards.

[0044] During the steel-tapping process of the converter, the following measures are taken: First, by increasing the diameter of the steel-tapping port, the steel-tapping time is reduced to 3.3 minutes, reducing the air intake of molten steel during the steel-tapping process; second, the steel-tapping deoxidation is optimized. After 10 tons of molten steel are tapped from the converter, 300 kg of slag-washed lime is added and spread on the surface of the molten steel to form a protection to reduce the exposure of the molten steel. Alloy is added when the steel is tapped to 1 / 2; third, argon gas is blown from the bottom of the ladle at a flow rate of 8 cubic meters per hour, as small as possible to reduce the exposure of the molten steel; fourth, the timing and level of slag-washed lime loading are controlled. The time from the lime burned in the roasting plant to the use in the converter is controlled within 2 hours. At the same time, the storage capacity of the converter and LF lime silos is controlled at 1-1.5 tons to ensure that it is sufficient. The method of small batches and multiple loading silos is adopted to reduce the time the lime is exposed to moisture.

[0045] After the molten steel arrives at the LF furnace, it is deoxidized and desulfurized: the acid-soluble aluminum of the LF molten steel is controlled at 0.006%, the sulfur content is controlled at less than 0.010%, and the calcium is reduced to 0.0006% through calcium treatment.

[0046] Comparative Example 1

[0047] The steps are similar to those in Example 1, except that the cold-solidified pellets are added 300 seconds after the oxygen blowing starts and are added 100 seconds after the oxygen blowing starts. Because scrap steel and molten iron are added before the converter smelting, there will be scrap steel floating on the surface of the molten iron. The scrap steel is generally 26 tons or more. When the blowing starts for 100 seconds, the scrap steel has not been melted, and the cold-solidified pellets are added. This will affect the oxygen blowing effect. Some oxygen is used to melt the cooling material, some oxygen is used to melt the scrap steel, and only some oxygen is used to react with the molten iron element to reduce the silicon burning speed in the early stage. Therefore, we usually add the cold-solidified pellet cooling material after melting the scrap steel, according to the flame situation in the furnace, and see that the scrap steel has been melted, the silicon has been burned, and the carbon monoxide curve begins to appear.

[0048] Comparative Example 2

[0049] The steps are similar to those in Example 1, except that the cold-solidified pellets are added at 300 seconds after the oxygen blowing starts, but are added at 500 seconds after the oxygen blowing starts. This operation does not affect the terminal temperature control, but will affect the dephosphorization effect. In theory, low temperature is conducive to dephosphorization, so the effect of adding the cold-solidified pellets earlier is better than adding them later, that is, when the phosphorus content of the molten iron is 0.100%, 2 tons of cold-solidified pellets are added at the beginning of 300 seconds, and the phosphorus content of the molten steel can be reduced to 0.025% at the end of the smelting, but 2 tons of cold-solidified pellets are added at 500 seconds, and the phosphorus content of the molten steel can only be reduced to 0.030% at the end of the smelting.

[0050] Comparative Example 3

[0051] The steps are similar to those in Example 1, except that the speed is not reduced during the continuous casting and steel drawing process. When the hydrogen content of the molten steel is less than 5ppm when measured at the refining station, there is no need to reduce the speed. However, if it is greater than 5ppm, the molten steel may easily stick in the crystallizer without reducing the speed, resulting in steel leakage. The solution provided in the embodiment of the present invention mainly controls the hydrogen content of the molten steel to not exceed the standard through converter smelting + LF refining, so under normal circumstances, there is no need to reduce the speed. However, abnormal situations are inevitable during the operation process, such as excessive addition of converter cold material, operating errors, too strong terminal oxygen content of the molten steel, or slag, etc. In the case of abnormal molten steel, in order to reduce the chance of steel sticking, the pulling speed is slowed down by 0.05 m / min compared with the normal furnace during continuous casting and steel drawing to ensure that the steel does not stick.

[0052] 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 reducing steel sticking in medium and high carbon steel slabs, characterized in that: It includes: The probability of steel sticking in medium and high carbon steel slabs is mainly reduced by controlling the hydrogen content of molten steel below 5ppm.

2. The method according to claim 1, characterized in that Controlling the hydrogen content of molten steel below 5ppm includes: controlling the appropriate iron-steel ratio and the timing of adding cold material during the converter smelting process; shortening the steel flow time and reducing the exposed area of ​​the molten steel surface during the converter tapping process; controlling the timing and level of slag washing lime feeding to reduce the hydrogen content of the molten steel; and deoxidizing and desulfurizing the molten steel in the LF refining process to reduce the inclusion content in the molten steel.

3. The method according to claim 2, characterized in that During converter smelting, controlling the appropriate iron-steel ratio includes: when the silicon content of molten iron is in the range of 0.45-0.55%, controlling the iron-steel ratio to 840-870 kg / t.

4. The method according to claim 2, characterized in that: During the converter smelting process, controlling the timing of adding cold material includes: adding cold solidified pellets during the period of 0-600 seconds when the converter is blowing oxygen, and adding only sintered ore or no sintered ore after 600 seconds.

5. The method according to claim 2, characterized in that: When tapping steel from a converter, shortening the steel tapping time includes: reducing the steel tapping time by increasing the tapping port diameter, thereby reducing the absorption of gas by the molten steel during the tapping process.

6. The method according to claim 2, characterized in that When steel is tapped from a converter, reducing the exposed area of ​​the molten steel surface includes: reducing the exposed area of ​​the molten steel surface by optimizing the deoxidation of the steel and reducing the argon gas flow rate at the bottom of the ladle.

7. The method according to claim 6, characterized in that Optimizing steel-making deoxidation includes: adding 300 kg of slag-washed lime after 10 tons of molten steel is tapped, spreading it on the surface of the molten steel to form protection and reduce the exposure of the molten steel, and adding alloy when 1 / 2 of the steel is tapped; reducing the argon gas flow rate at the bottom of the ladle includes: controlling the argon gas flow rate at the bottom of the ladle at 5-8 cubic meters / hour to reduce the exposure of the molten steel.

8. The method according to claim 2, characterized in that: Controlling the timing and level of loading slag-washed lime includes: controlling the time from lime burned in the roasting plant to the converter to be used within 2 hours, and adopting the method of small batches and multiple loading bins to reduce the time the lime is exposed to moisture.

9. The method according to claim 2, characterized in that: The molten steel is deoxidized and desulfurized to reduce the inclusion content in the molten steel: the acid-soluble aluminum content of the molten steel leaving the LF furnace is controlled at 0.006%-0.015%, the sulfur content is less than 0.010%, and the calcium content is 0.0006%-0.0010%.

10. The method according to claim 2, characterized in that Also includes: The pulling speed is controlled to be 0.05 m / min slower than the normal furnace.