A cored wire for improving the deformation ability of inclusions in steel, method and application thereof

Abstract

The present invention discloses a cored wire, method and application thereof for improving the deformation ability of inclusions in steel, wherein the cored wire comprises a wire core and a coated outer skin; the core powder forming the wire core comprises the following components by mass content in terms of the total amount: Na2CO3 45‑70wt%, K2CO3 20‑40wt%, the remainder being CaC2, and inevitable impurities. The method for improving the deformation ability of inclusions in steel of the present invention and its application comprise LF furnace refining, VD furnace process and continuous casting process, wherein in the VD furnace process, the cored wire is fed into the ladle. The present invention obtains a stable ultra-low melting point easily deformable inclusion component by feeding the cored wire, which is of great significance for promoting the improvement of the quality of high-end wire products.

Description

Technical Field

[0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a cored wire for improving the deformation ability of inclusions in steel, and further discloses a method for improving the deformation ability of inclusions in steel and an application thereof. Background Art

[0002] Radial tires, also known as steel wire tires, are composed of two or three layers of steel wire rings placed crosswise and attached to the cord carcass. The carcass meridian is connected from one bead to the other, much like the meridian of the earth. The structure of radial tires generally requires steel wire as the main buffer and belt, so its advantages are durability and puncture resistance, large load capacity, good shock absorption performance, not easy to deform during driving, can reduce fuel consumption, good economy, and heat dissipation performance is more suitable for high temperature or high speed environment. At the same time, because radial tires have extremely high requirements for stability, life, safety, etc., strict requirements are also placed on the quality of steel. However, the diameter of steel used for tire meridians is generally about 0.2mm, and the wire breakage rate per 100 kilometers is required not to be higher than 1 time. However, due to the presence of large-sized non-deformable inclusions in the steel, it is easy to cause wire breakage during the drawing process, which makes the production of the product extremely difficult. Therefore, how to overcome the adverse effects of inclusions in steel and obtain tire radial steel with better tensile properties plays a key role in the production of radial tires.

[0003] At present, the measures reported to control plastic inclusions in steel mainly include: (1) avoiding the addition of aluminum-containing raw materials during the entire steelmaking process, and not using aluminum-containing alloys for deoxidation treatment to reduce Al2O3 brittle inclusions in steel; (2) low-basicity pre-melted slag is usually used to control inclusions to obtain plastic inclusions during LF refining and VD refining. However, due to the high total oxygen content in steel, although most of the inclusions in steel are plastic inclusions, there are still a small number of large-sized brittle inclusions, which causes the wire breakage rate of tire radial steel to increase, and still cannot completely solve the problem of easy wire breakage.

[0004] For example, Chinese patent CN111155024A discloses a method for controlling ultra-low melting point plastic inclusions in cord steel. The method controls the oxygen content in the molten steel, first deoxidizes the steel through a manganese alloy, and then adds an appropriate amount of carbon powder to assist in deoxidation during the steel tapping process; after the steel tapping is completed, SiC or silicon particles are added to the surface of the ladle to cover the molten steel surface to prevent air oxidation; although the method requires the MnO component content in the inclusions to be ≥20%, due to the high content of Si and C elements in the tire radial steel, the MnO component will be reduced, resulting in unstable content control, and the CaO component is easy to enter the molten steel, so that the inclusions are converted into a SiO2-CaO-MnO system, resulting in a narrow industrial production control window and greater difficulty.

[0005] For example, Chinese patent CN106555025A discloses a low inclusion production method for cord steel. Among the inclusions in the steel, CaO-SiO-Al2O3 inclusions account for 82% of the total number of inclusions, and MnO-SiO2-Al2O3 inclusions account for 18% of the total number. For MnO-SiO2-Al2O3 inclusions, the inclusion components with good deformation ability are distributed in the low melting point area of ​​manganese aluminum garnet (3MnO-Al2O3-3SiO2) and its surroundings, and the phase composition of Al2O3 in this area is 15%-30%. This method can greatly improve the cleanliness of molten steel, minimize the content of inclusions, and reduce the production cost per ton of steel. However, the composition range of the low melting point zone of inclusions is narrow, and it is difficult to ensure that the composition of inclusions can be accurately controlled in this low melting point area; in addition, although the melting point of this type of inclusions is low, due to the high content of components such as CaO and Al2O3 in the inclusions, the deformation ability of the inclusions during wire rod rolling and drawing is poor.

[0006] Therefore, developing a method to improve inclusions in steel, by effectively improving the deformation capacity of inclusions, thereby reducing the risk of steel being easily broken during the drawing process, has positive significance for steel smelting, especially the production of tire radial steel. Summary of the invention

[0007] Therefore, the object of the present invention is to provide a cored wire that improves the deformation ability of inclusions in steel, which can be used to improve the inclusions in steel to improve its tensile properties;

[0008] The second object of the present invention is to provide a method for improving the deformation ability of inclusions in steel, which can reduce the melting point of inclusions, improve the deformation ability of inclusions, and effectively reduce the harm of steel production during the drawing process;

[0009] The third object of the present invention is to provide a radial tire steel having better tensile properties.

[0010] The present invention provides a cored wire for improving the deformation ability of inclusions in steel, comprising a wire core and a sheath;

[0011] The core powder forming the wire core includes the following components by weight based on the total amount: Na2CO3 45-70wt%, K2CO3 20-40wt%, the balance being CaC2, and inevitable impurities.

[0012] Specifically, the contents of CaC2, K2CO3 and Na2CO3 satisfy the following relationship:

[0013]

[0014] Preferably,

[0015] The ratio of Na2CO3, K2CO3 and CaC2 should satisfy formula (1)-(2), as shown in formula (3). Formula (3) is simplified to obtain formula (4), that is, Na2CO3: 45-70%, K2CO3: 20-40% in the cored wire, and the balance is CaC2. At the same time, their mass percentage exist and Within the range, preferably As shown in formula (4);

[0016] CaC2+3Na2CO3=3Na2O+CaO+5CO(g) (1)

[0017] CaC2+3K2CO3=3K2O+CaO+5CO(g) (2)

[0018]

[0019]

[0020] in, are the mass percentages of CaC2, K2CO3, and Na2CO3 in the cored wire, respectively; The molar masses of CaC2, K2CO3 and Na2CO3 are 64g / mol, 138g / mol and 106g / mol respectively.

[0021] Specifically, the particle size distribution of the core powder is as follows: 35-45% of 3-5 mm particles; 35-45% of 1-3 mm particles; and the rest are 0.1-1 mm particles;

[0022] Preferably, the particle size distribution of the core powder is as follows: 3-5 mm particles account for 40%; 1-3 mm particles account for 40%; and the rest are 0.1-1 mm particles.

[0023] Specifically, the nominal size of the cored wire is The core wire weight is 160-200g / m.

[0024] The present invention also discloses a method for preparing a cored wire for improving the deformation ability of inclusions in steel, comprising the following steps:

[0025] (1) mixing the raw material components according to the selected ratio to obtain core powder for later use;

[0026] (2) The steel strip is loaded on the rack, the rewinder is turned on, and the rolling speed is adjusted to start the forming process;

[0027] (3) Adding core powder after the steel strip is rolled;

[0028] (4) The steel strip after adding the core powder is subjected to coating forming treatment to obtain the steel strip.

[0029] The invention also discloses a method for improving the deformation ability of inclusions in steel, comprising the step of adding the cored wire for improving the deformation ability of inclusions in steel to improve wire feeding during steel refining.

[0030] Specifically, the feeding speed of the cored wire is controlled to be ξ=0.20×W 0.344 / [δ×(1-δ / D Mg )];

[0031] Where, ξ: feeding speed / m·s -1 ; W: weight of molten steel in ladle / t; δ: thickness of core wire iron sheet / mm; D Mg : core wire diameter / mm;

[0032] Preferably, the feeding amount of the cored wire is controlled to be 5-6.25 m / ton of steel;

[0033] The wire feeding speed has a great influence on the wire feeding effect and directly affects the core powder recovery rate. In order to improve the recovery rate, it is hoped that the core powder has a longer residence time in the molten steel so that when the fed cored wire reaches the bottom of the ladle, the iron sheet just melts and releases the core powder.

[0034] Specifically, the wire feeding step adopts double argon bottom blowing, and the wire feeding position is controlled to be on the other side perpendicular to the center line of the double permeable brick.

[0035] Specifically, the method for improving the deformation ability of inclusions in steel comprises the following steps:

[0036] (1) LF furnace refining: steel is tapped into a ladle, and reducing slag is refined and alloying operations are performed;

[0037] (2) Vacuum degassing in VD furnace;

[0038] (3) After the VD breaks the vacuum, the cored wire is added for wire feeding;

[0039] (4) After feeding the wire, bottom blowing is carried out and the continuous casting billet is cast.

[0040] Specifically, in step (1), the binary basicity CaO / SiO2 of the pre-molten slag is controlled to be 1.0-1.5.

[0041] Specifically, in step (2), the vacuum degree is controlled to be ≤67Pa, and the processing period is 25-40min.

[0042] The invention also discloses improved molten steel obtained by the method for improving the deformation ability of inclusions in steel.

[0043] The invention also discloses tire meridian steel prepared from the improved molten steel.

[0044] The cored wire for improving the deformation ability of inclusions in steel of the present invention is prepared by uniformly mixing Na2CO3, K2CO3 and CaC2 to form cored powder, and reacting CaC2+3Na2CO3=3Na2O+CaO+5CO(g); CaC2+3K2CO3=3K2O+CaO+5CO(g) in high-temperature molten steel. On the one hand, CO gas can stir the molten steel near the cored wire, so that the core powder can fully react with the inclusions in the steel, thereby achieving the purpose of plasticizing and modifying the inclusions in the steel. On the other hand, the addition of alkali metal oxides can greatly reduce the melting point of the inclusions, thereby stably controlling the melting point of the inclusions to be below 1350°C, so that this type of inclusions maintains plasticity during the process of blanking, rolling and drawing, thereby improving the drawing performance of the tire radial steel.

[0045] The method for improving the deformation ability of inclusions in steel and its application of the present invention selects the wire feeding position as the other side perpendicular to the center line of the double permeable brick, and adopts the double argon bottom blowing method, so that the molten steel flow field brings the core wire into the deep of the molten steel, improves the absorption efficiency of the molten steel to the core wire, and at the same time, the flow rate of the fluid above the bottom blowing nozzle is the largest, forming an asymmetric loop flow on the longitudinal section where the nozzle is located, further improving the uniformity of the reaction between the alkali metal oxide and the molten steel inclusions. From the velocity distribution at the top of the ladle, the loop flow formed by the two nozzles intersects in the middle area, prompting the respective flows to turn, forming a flow roughly perpendicular to the direction of the line connecting the two nozzles, and the flow stream turns to a downward flow after reaching the ladle wall, ultimately accelerating the flow and uniform behavior of the molten steel inside the ladle.

[0046] It is very important to modify inclusions so that they have excellent deformation ability during drawing deformation and reduce the harm of inclusions in steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 The feeding position of the cored wire in the industrial production of the present invention, wherein: (a) the flow field of molten steel in the ladle; (b) the wire feeding and bottom blowing position;

[0049] Figure 2The composition distribution of SiO2-Al2O3-MnO inclusions in the continuous casting billet described in Example 1, wherein: (a) SiO2-Al2O3-MnO-Na2O; (b) SiO2-Al2O3-MnO-K2O;

[0050] Figure 3 The composition distribution of SiO2-Al2O3-CaO inclusions in the continuous casting slab described in Example 1, wherein: (a) SiO2-Al2O3-CaO-K2O; (b) SiO2-Al2O3-CaO-Na2O;

[0051] Figure 4 The morphology of the SiO2-Al2O3-MnO-Na2O inclusions and the surface scanning images of each element described in Example 1, wherein: (a) SiO2-Al2O3-MnO-Na2O inclusion morphology; (b) Na element; (c) O element; (d) Al element; (e) Si element; (f) Mn element;

[0052] Figure 5 The morphology of the SiO2-Al2O3-MnO-K2O inclusions and the scanning images of each element surface described in Example 1, wherein: (a) SiO2-Al2O3-MnO-K2O inclusion morphology; (b) K element; (c) Si element; (d) Al element; (e) Mn element; (f) O element;

[0053] Figure 6 The morphology of SiO2-Al2O3-MnO-Na2O inclusions after drawing described in Example 1;

[0054] Figure 7 is the composition distribution of inclusions in the continuous casting slab in Comparative Example 1, wherein (a)

[0055] SiO2-Al2O3-MnO-K2O inclusions; (b) SiO2-Al2O3-CaO-Na2O inclusions;

[0056] Figure 8 The morphology of the SiO2-Al2O3-MnO inclusions and the surface scanning images of each element described in Comparative Example 1, wherein: (a) SiO2-Al2O3-MnO inclusion morphology; (b) O element; (c) Si element; (d) Mn element; (e) Al element;

[0057] Fig. 9 This is the morphology of the SiO2-Al2O3-MnO inclusions after drawing described in Comparative Example 1. DETAILED DESCRIPTION

[0058] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0059] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the materials or instruments used, they are all conventional products that can be purchased.

[0060] Example 1

[0061] The cored wire for improving the deformation ability of inclusions in steel of this embodiment comprises a wire core and a sheath covered with the wire core; the core powder forming the wire core is prepared according to the raw material components. The core powder of the wire core described in this embodiment includes the following components by weight based on the total amount: Na2CO3 45wt%, K2CO3 40wt%, the balance CaC2 15wt%, and inevitable impurities.

[0062] The method for preparing a cored wire for improving the deformation ability of inclusions in steel described in this embodiment comprises the following steps:

[0063] (1) mixing the raw material components according to the ratio selected above, forming particles by die casting, and mixing the materials evenly to obtain core powder for later use; wherein the particle size distribution of the core powder is: 3-5 mm particles account for 40%; 1-3 mm particles account for 40%; and the rest are 0.1-1 mm particles;

[0064] (2) Place the steel strip loading rack into the unwinding reel, insert one end into the reel preparation reel of the rewinding machine, start the rewinding machine, adjust the rolling speed and start the machine to form the cored wire, with a thickness of 0.6 mm and a width of 60 mm;

[0065] (3) After the steel strip is rolled and formed, core powder is added, and the powder feeding amount and speed are adjusted to match the belt speed;

[0066] (4) The steel strip after adding the core powder is subjected to a coating forming process to obtain a cored wire. The nominal size of the cored wire is φ15 mm and the core wire weight is 180 g / m.

[0067] The method for improving the deformation ability of inclusions in steel described in this embodiment comprises the following steps:

[0068] (1) LF furnace refining: The converter / arc furnace is tapped into a ladle, and pre-melted slag is added into the ladle for primary refining of the molten steel, wherein the binary basicity of the pre-melted slag is CaO / SiO2 of 1.25; the content of each component of the steel grade is: C: 0.8%, Si: 0.2%, Mn: 0.5%, Al: 0.002%, Cr: 0.03%, and the content of alloy elements is controlled in the later stage of primary refining according to the chemical composition requirements of the steel grade;

[0069] (2) subjecting the 120 tons of primary refined molten steel to vacuum degassing treatment, with a vacuum degree of 5 Pa and a treatment cycle of 35 min;

[0070] (3) After the VD breaks the vacuum, the cored wire is added for feeding. The feeding speed of the cored wire is calculated according to the following formula:

[0071] ξ=0.20×W 0.344 / [δ×(1-δ / D Mg )]

[0072] In the above formula, ξ is the feeding speed / m·s -1 ; W is the weight of molten steel in the ladle / t; δ is the thickness of the core wire iron sheet / mm; D Mg is the core wire diameter / mm;

[0073] According to calculation, the feeding amount of the cored wire is 5.5 m / ton steel, the feeding speed is 1.80 m / s, and double argon bottom blowing is used for 15 min to obtain secondary refined molten steel; the feeding position is the other side perpendicular to the center line of the double permeable brick, such as Figure 1 As shown, this position is the descending flow of molten steel. The molten steel flow field can be used to bring the cored wire into the deep of molten steel, thereby improving the absorption efficiency of the molten steel to the cored wire. At the same time, the mixing time is also the shortest, which is beneficial to the uniformity of the reaction between the cored wire and the molten steel.

[0074] (4) The secondary refined molten steel is fed into a wire and then transported to a continuous casting turntable for casting to obtain a continuous casting billet.

[0075] The continuous casting ingot was cut and polished, and the inclusions were observed using a scanning electron microscope.

[0076] The composition distribution of inclusions in the continuous casting slab obtained in this embodiment is as follows: Figure 2 and Figure 3 As shown in Figure 1, the inclusions are divided into two categories, and the composition range of the two types of inclusions falls in the low melting point area in the phase diagram, indicating that almost all of the inclusions are low melting point inclusions, and low melting point inclusions have excellent deformation ability during hot working. The surface scanning images of the inclusions and each element are shown in Figure 1. Figure 4 and Figure 5 As shown in Figure 2, the morphology of SiO2-Al2O3-MnO-Na2O inclusions after drawing is as follows: Figure 6As shown, the results show that the steel treated in this embodiment has a strong deformation capacity. The steel produced is subjected to radial tire wire drawing, and the average wire breakage rate during the wire drawing process is 2 times per 500 kilometers.

[0077] Example 2

[0078] The cored wire for improving the deformation ability of inclusions in steel of this embodiment comprises a wire core and a sheath covered with the wire core; the core powder forming the wire core is prepared according to the raw material components. The core powder of the wire core described in this embodiment includes the following components by weight based on the total amount: Na2CO3 62wt%, K2CO3 23wt%, the balance CaC2 15wt%, and inevitable impurities.

[0079] The method for preparing a cored wire for improving the deformation ability of inclusions in steel described in this embodiment comprises the following steps:

[0080] (1) mixing the raw material components according to the ratio selected above, forming particles by die casting, and mixing the materials evenly to obtain core powder for later use; wherein the particle size distribution of the core powder is: 3-5 mm particles account for 45%; 1-3 mm particles account for 35%; and the rest are 0.1-1 mm particles;

[0081] (2) Place the steel strip loading rack into the unwinding reel, insert one end into the reel preparation reel of the rewinding machine, start the rewinding machine, adjust the rolling speed and start the machine to form the cored wire, with a thickness of 0.5 mm and a width of 58 mm;

[0082] (3) After the steel strip is rolled and formed, core powder is added, and the powder feeding amount and speed are adjusted to match the belt speed;

[0083] (4) The steel strip after adding the core powder is subjected to a coating forming process to obtain a cored wire. The nominal size of the cored wire is φ14 mm and the core wire weight is 160 g / m.

[0084] The method for improving the deformation ability of inclusions in steel and its application described in this embodiment include the following steps:

[0085] (1) LF furnace refining: The converter / arc furnace is tapped into a ladle, and pre-melted slag is added into the ladle for primary refining of the molten steel, wherein the pre-melted slag has a binary basicity of CaO / SiO2 of 1.0; the content of each component of the steel grade is: C: 0.8%, Si: 0.2%, Mn: 0.5%, Al: 0.002%, Cr: 0.03%. In the later stage of primary refining, the content of various alloy elements is controlled according to the chemical composition requirements of the steel grade;

[0086] (2) subjecting the above 120 tons of primary refined molten steel to vacuum degassing treatment, with a vacuum degree of 5 Pa and a treatment cycle of 25 min;

[0087] (3) After the VD breaks the vacuum, the cored wire is added for feeding. The feeding speed of the cored wire is calculated according to the following formula:

[0088] ξ=0.20×W 0.344 / [δ×(1-δ / D Mg )]

[0089] In the above formula, ξ is the feeding speed / m·s -1 ; W is the weight of molten steel in the ladle / t; δ is the thickness of the core wire iron sheet / mm; D Mg is the core wire diameter / mm;

[0090] According to calculation, the feeding amount of the cored wire is 6.25 m / ton steel, the feeding speed is 2.15 m / s, and double argon bottom blowing is used for 15 min to obtain secondary refined molten steel; the feeding position is the other side perpendicular to the center line of the double permeable brick, such as Figure 1 As shown, this position is the descending flow of molten steel. The molten steel flow field can be used to bring the cored wire into the deep of molten steel, thereby improving the absorption efficiency of the molten steel to the cored wire. At the same time, the mixing time is also the shortest, which is beneficial to the uniformity of the reaction between the cored wire and the molten steel.

[0091] (4) The secondary refined molten steel is fed into a wire and then transported to a continuous casting turntable for casting to obtain a continuous casting billet.

[0092] The continuous casting ingot was cut and polished, and the inclusions were observed using a scanning electron microscope.

[0093] The results show that the composition range of inclusions in the continuous casting billet obtained in this embodiment falls in the low melting point area in the phase diagram, indicating that almost all inclusions are low melting point inclusions, and low melting point inclusions have excellent deformation ability during hot working. The plastic inclusions after drawing have strong deformation ability. The steel produced is subjected to radial wire drawing of tires, and the average wire breakage rate is 3 times per 500 kilometers during the wire drawing process.

[0094] Example 3

[0095] The cored wire for improving the deformation ability of inclusions in steel of this embodiment comprises a wire core and a sheath covered with the wire core; the core powder forming the wire core is prepared according to the raw material components. The core powder of the wire core described in this embodiment includes the following components by weight based on the total amount: Na2CO3 57wt%, K2CO3 26.75wt%, the balance CaC2 16.25wt%, and inevitable impurities.

[0096] The method for preparing a cored wire for improving the deformation ability of inclusions in steel described in this embodiment comprises the following steps:

[0097] (1) mixing the raw material components according to the ratio selected above, forming particles by die casting, and mixing the materials evenly to obtain core powder for later use; wherein the particle size distribution of the core powder is: 35% of the particles are 3-5 mm; 45% of the particles are 1-3 mm; and the rest are particles of 0.1-1 mm;

[0098] (2) Place the steel strip loading rack into the unwinding reel, insert one end into the reel preparation reel of the rewinding machine, start the rewinding machine, adjust the rolling speed and start the machine to form the cored wire, with a thickness of 0.7 mm and a width of 62 mm;

[0099] (3) After the steel strip is rolled and formed, core powder is added, and the powder feeding amount and speed are adjusted to match the belt speed;

[0100] (4) The steel strip with the core powder added is subjected to a coating forming process to obtain a cored wire. The nominal size of the cored wire is φ16 mm and the core wire weight is 200 g / m.

[0101] The method for improving the deformation ability of inclusions in steel and its application described in this embodiment include the following steps:

[0102] (1) LF furnace refining: The converter / arc furnace is tapped into a ladle, and pre-melted slag is added into the ladle for primary refining of the molten steel, wherein the binary basicity of the pre-melted slag is CaO / SiO2 of 1.5; the content of each component of the steel grade is: C: 0.8%, Si: 0.2%, Mn: 0.5%, Al: 0.002%, Cr: 0.03%. In the later stage of primary refining, the content of various alloy elements is controlled according to the chemical composition requirements of the steel grade;

[0103] (2) subjecting the 120 tons of primary refined molten steel to vacuum degassing treatment, with a vacuum degree of 5 Pa and a treatment cycle of 40 minutes;

[0104] (3) After the VD breaks the vacuum, the cored wire is added for feeding. The feeding speed of the cored wire is calculated according to the following formula:

[0105] ξ=0.20×W 0.344 / [δ×(1-δ / D Mg )]

[0106] In the above formula, ξ is the feeding speed / m·s -1 ; W is the weight of molten steel in the ladle / t; δ is the thickness of the core wire iron sheet / mm; D Mg is the core wire diameter / mm;

[0107] According to calculation, the feeding amount of the cored wire is 5 m / ton steel, the feeding speed is 1.55 m / s, and double argon bottom blowing is used for 15 min to obtain secondary refined molten steel; the feeding position is the other side perpendicular to the center line of the double permeable brick, such as Figure 1As shown, this position is the descending flow of molten steel. The molten steel flow field can be used to bring the cored wire into the deep of molten steel, thereby improving the absorption efficiency of the molten steel to the cored wire. At the same time, the mixing time is also the shortest, which is beneficial to the uniformity of the reaction between the cored wire and the molten steel.

[0108] (4) The secondary refined molten steel is fed into a wire and then transported to a continuous casting turntable for casting to obtain a continuous casting billet.

[0109] The continuous casting ingot was cut and polished, and the inclusions were observed using a scanning electron microscope.

[0110] The results show that the composition range of inclusions in the continuous casting billet obtained in this embodiment falls in the low melting point area in the phase diagram, indicating that almost all inclusions are low melting point inclusions, and low melting point inclusions have excellent deformation ability during hot working. The plastic inclusions after drawing have strong deformation ability. The steel produced is subjected to radial wire drawing of tires, and the average wire breakage rate is 3 times per 500 kilometers during the wire drawing process.

[0111] Comparative Example 1

[0112] The steelmaking method described in this comparative example is the same as that in Example 1, except that the alkali metal oxide cored wire treatment described in Example 1 is not performed.

[0113] The continuous casting slab was cut and polished and the inclusions were observed by scanning electron microscope. The composition analysis of SiO2-Al2O3-MnO-K2O and SiO2-Al2O3-CaO-Na2O inclusions is shown in Figure 7 As shown, the results show that in the phase diagram, some inclusions are low-melting point plastic inclusions, and some are high-melting point brittle inclusions; Figure 8 It is the morphology of SiO2-Al2O3-MnO inclusions and the scanning images of each element surface. Fig. 9 This is the morphology of SiO2-Al2O3-MnO inclusions after drawing. The results show that the deformation ability is very poor. The steel is subjected to radial wire drawing for tires. The average wire breakage rate is 12 times per 500 kilometers during the wire drawing process.

[0114] Comparative Example 2

[0115] The steelmaking method described in this comparative example is the same as that in Example 1, the only difference being that the composition of the alkali metal oxide cored wire is 80% Na2CO3 and 20% K2CO3.

[0116] The obtained continuous casting billet was cut and polished, and the inclusions were observed by scanning electron microscope. The inclusions were SiO2-Al2O3-Na2O and SiO2-Al2O3-K2O, which did not contain CaO and were brittle inclusions with high melting point. The deformation ability of the inclusions after drawing was very poor. The steel was subjected to radial wire drawing for tires, and the average wire breakage rate was 8 times per 500 kilometers during the wire drawing process.

[0117] Comparative Example 3

[0118] The steelmaking method described in this comparative example is the same as that in Example 1, the only difference being that the feeding rate of the alkali metal oxide cored wire is 1.0 m / s.

[0119] The obtained continuous casting billet was cut and polished, and the inclusions were observed by scanning electron microscope. The inclusions were SiO2-Al2O3-CaO and SiO2-Al2O3-MnO, and the inclusions did not contain Na2O and K2O. The yield of alkali metal cored wire was extremely low, and the continuous casting billet showed high melting point brittle inclusions; the deformation ability of the inclusions after drawing was very poor. The steel was subjected to radial wire drawing for tires, and the average wire breakage rate was 9 times per 500 kilometers during the wire drawing process.

[0120] Comparative Example 4

[0121] The steelmaking method described in this comparative example is the same as that in Example 1, the only difference being that the composition of the alkali metal oxide cored wire is 70% Na2CO3, 20% K2CO3, and 10% CaC2.

[0122] The obtained continuous casting billet was cut and polished, and the inclusions were observed by scanning electron microscope. The inclusions were SiO2-Al2O3-Na2O and SiO2-Al2O3-K2O, and the CaO content in the inclusions was less than 3%, which was a high melting point brittle inclusion; the inclusions after drawing had very poor deformation ability, and the steel was subjected to radial wire drawing for tires, and the average wire breakage rate was 7 times per 500 kilometers during the wire drawing process.

[0123] Obviously, the above embodiments and comparative examples are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the protection scope of the invention.

Claims

1. A cored wire for improving the deformation ability of inclusions in steel, characterized in that: Including wire core and sheath; The core powder forming the wire core includes the following components by weight based on the total amount: Na2CO3 45-70wt%, K2CO3 20-40wt%, the balance being CaC2, and inevitable impurities; The contents of CaC2, K2CO3 and Na2CO3 satisfy the following relationship: in, They are the mass percentages of CaC2, K2CO3 and Na2CO3 in the cored wire respectively.

2. The cored wire for improving the deformation ability of inclusions in steel according to claim 1, characterized in that:

3. The cored wire for improving the deformation ability of inclusions in steel according to claim 1 or 2, characterized in that: The particle size distribution of the core powder is as follows: the content of 3-5 mm particles is 35-45%; the content of 1-3 mm particles is 35-45%; and the rest are 0.1-1 mm particles.

4. The cored wire for improving the deformation ability of inclusions in steel according to claim 3, characterized in that: The particle size distribution of the core powder is as follows: 3-5 mm particles account for 40%; 1-3 mm particles account for 40%; and the rest are 0.1-1 mm particles.

5. The cored wire for improving the deformation ability of inclusions in steel according to claim 1 or 2, characterized in that: The nominal size of the cored wire is The core wire weight is 160-200g / m.

6. A method for preparing a cored wire for improving the deformation ability of inclusions in steel according to any one of claims 1 to 5, characterized in that: The steps include: (1) mixing the raw material components according to the selected ratio to obtain core powder for later use; (2) The steel strip is loaded on the rack, the rewinder is turned on, and the rolling speed is adjusted to start the forming process; (3) Adding core powder after the steel strip is rolled; (4) The steel strip after adding the core powder is subjected to coating forming treatment to obtain the steel strip.

7. A method for improving the deformation ability of inclusions in steel, characterized in that: The method comprises the step of adding the cored wire according to any one of claims 1 to 5 to improve wire feeding during steel refining.

8. The method for improving the deformation ability of inclusions in steel according to claim 7, characterized in that: The feeding speed of the cored wire is controlled to be ξ=0.20×W 0.344 / [δ×(1-δ / D Mg )]; Where, ξ: feeding speed / m·s -1 ; W: weight of molten steel in ladle / t; δ: thickness of core wire iron sheet / mm; D Mg : Core wire diameter / mm.

9. The method for improving the deformation ability of inclusions in steel according to claim 8, characterized in that: The feeding amount of the cored wire is controlled to be 5-6.25 m / ton of steel.

10. The method for improving the deformation ability of inclusions in steel according to claim 7 or 8, characterized in that: The feeding line adopts double argon bottom blowing, and the feeding line position is controlled to be on the other side perpendicular to the center line of the double permeable brick.

11. The method for improving the deformation ability of inclusions in steel according to any one of claims 7 to 9, characterized in that: The steps include: (1) LF furnace refining: steel is tapped into a ladle, and reducing slag is refined and alloying operations are performed; (2) Vacuum degassing in VD furnace; (3) After the VD breaks the vacuum, the cored wire is added for wire feeding; (4) After feeding the wire, bottom blowing is carried out and the continuous casting billet is cast.

12. The method for improving the deformation ability of inclusions in steel according to claim 11, characterized in that: In the step (1), the binary basicity CaO / SiO2 of the pre-melted slag is controlled to be 1.0-1.5; In the step (2), the vacuum degree is controlled to be ≤67Pa, and the processing period is 25-40min.

13. Improved molten steel obtained by the method for improving the deformation ability of inclusions in steel as claimed in any one of claims 7 to 12.

14. Tire meridian steel prepared from the improved molten steel according to claim 13.

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