Continuous casting method for titanium-containing steel

Abstract

The invention provides a titanium-containing steel continuous casting method which comprises the following steps: injecting refined molten steel into a tundish through a steel ladle, distributing the molten steel into a crystallizer through the tundish, cooling and solidifying the molten steel into a blank in the crystallizer, discharging the blank out of the crystallizer, entering a secondary cooling area for cooling, and straightening through a withdrawal and straightening machine to obtain a casting blank; wherein the molten steel is molten steel containing titanium microalloyed steel; wherein the content of Ti is 0.03%-0.12%, and the content of N is smaller than or equal to 0.005%; traveling wave magnetic field electromagnetic stirring is applied to the secondary cooling area, the direction of the magnetic field is perpendicular to the throwing direction, and the following conditions are controlled: the relation between the current intensity of electromagnetic stirring and the superheat degree of tundish molten steel is controlled to be I = 18 * delta T-270; wherein I is the current intensity (A) of electromagnetic stirring, and delta T is the degree of superheat (DEG C) of the tundish molten steel. According to the method, the isometric crystal rate of the casting blank can be effectively increased, and the TiN size gt in the steel is eliminated; and inclusions of 10 microns are obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of metallurgy, in particular to a continuous casting method of titanium-containing steel. Background Art

[0002] Titanium alloyed steel is a type of alloy steel that uses steel as a matrix and improves its performance by adding titanium to the steel (its titanium content is usually between 0.12% and 2%). Unlike pure titanium alloys, titanium alloyed steel maintains the high strength characteristics of steel, while improving its high temperature stability and corrosion resistance through the addition of titanium. At the same time, titanium-containing microalloyed steel has also been developed. This type of alloy steel is a steel grade with titanium as the main microalloying element (its titanium content is usually controlled at 0.01% to 0.12%). This type of steel significantly improves the overall performance of the steel through the precipitation strengthening mechanism of titanium carbonitrides and the grain refinement effect.

[0003] With the development of my country's economy and the upgrading of its industrial structure, titanium alloyed steel / titanium-containing microalloyed steel has been widely used in key areas such as automobiles, energy, and electricity due to its high strength, high toughness, and low cost. Therefore, the production of titanium alloyed steel / titanium-containing microalloyed steel is of great significance.

[0004] The continuous casting production process of steel is as follows: ladle → tundish → crystallizer → secondary cooling → straightening → cutting → roller conveyor → ingot; specifically, the refined molten steel is transported to the continuous casting machine turntable by the ladle, and after being positioned by the turntable, it is injected into the tundish for buffering and diversion → the tundish evenly distributes the molten steel to multiple crystallizers → the molten steel quickly cools in the crystallizer and begins to solidify into continuous casting ingots → after the ingots exit the crystallizer, they enter the secondary cooling section (or secondary cooling zone) for further solidification and cooling → the straightening machine straightens the curved ingots → they are cut into appropriate lengths by the cutting mechanism.

[0005] However, with the continuous upgrading of products, the production technology and quality issues of titanium-containing microalloyed steel have become increasingly prominent. Due to the high titanium content, this steel is prone to forming large titanium nitride inclusions (>10 microns) during continuous casting and solidification. These inclusions are difficult to deform and are prone to crack defects during rolling and stamping.

[0006] Current titanium nitride control methods include: staged titanium alloying (CN202210755058.1), adding titanium alloy and heterogeneous nucleating agents (such as MgO) in two stages through RH refining to increase the heterogeneous nucleation rate of TiN; continuous casting parameter optimization (CN202111409012.6), low superheat (15-20°C), constant pulling speed, and electromagnetic stirring of the crystallizer to suppress solute segregation; composite wire feeding technology (CN202310551867.5), feeding aluminum, calcium, rare earth and other elements in sequence, preferentially fixing nitrogen or forming fine inclusions; vacuum degassing and light reduction at the end of solidification (CN201410459165.5), reducing nitrogen activity through high vacuum treatment, combined with light reduction to improve segregation.

[0007] Although the above existing technologies have achieved certain effects, they still have the following limitations:

[0008] High process complexity: Staged titanium alloying (CN202210755058.1) requires precise control of RH refining, which is cumbersome and increases costs; composite feeding (CN202310551867.5) relies on expensive elements such as rare earths or hafnium zirconium, which poses high environmental risks; insufficient control of solidification structure: existing crystallizer electromagnetic stirring (CN202111409012.6) only increases the equiaxed crystal rate to 30% to 40%. Summary of the Invention

[0009] In view of this, the present invention provides a continuous casting method for titanium-containing steel. The continuous casting method of the present invention can effectively improve the equiaxed grain ratio of the ingot, inhibit the coarsening of TiN between columnar grains, and eliminate TiN inclusions with a size greater than 10 μm in the steel.

[0010] The present invention provides a continuous casting method for titanium-containing steel, comprising the following steps:

[0011] The refined molten steel is poured into the tundish through the ladle, and then distributed to the crystallizer through the tundish. The molten steel is cooled and solidified into billet in the crystallizer, and then flows out of the crystallizer into the secondary cooling zone for cooling, and is straightened in the straightening machine to obtain the ingot.

[0012] in,

[0013] The molten steel is a titanium-containing microalloyed steel, wherein the Ti content is 0.03% to 0.12% and the N content is ≤0.005%;

[0014] The secondary cooling zone applies a traveling wave magnetic field electromagnetic stirring, the direction of the magnetic field is perpendicular to the casting direction, and the following conditions are controlled:

[0015] The relationship between the current intensity of the electromagnetic stirring and the superheat of the molten steel in the tundish is shown in formula (1):

[0016] I=18×ΔT-270 Formula (1);

[0017] In formula (1), I is the current intensity of electromagnetic stirring, in A; ΔT is the superheat of molten steel in the tundish, in °C.

[0018] Preferably, the superheat degree ΔT of the molten steel in the tundish is 15-35°C.

[0019] Preferably, the current intensity I of the electromagnetic stirring is 100-450A.

[0020] Preferably, the following conditions are also controlled: the frequency of the electromagnetic stirring is controlled to be 4 to 8 Hz.

[0021] Preferably, the water volume of the secondary cooling zone is controlled as follows: the low water volume in the front section is 1.0-1.2 L / kg; the high water volume in the back section is 1.5-1.8 L / kg;

[0022] The front section accounts for 60% to 80% of the total length of the secondary cooling zone.

[0023] Preferably, the central solid phase ratio of the front section is less than 50%, and the central solid phase ratio of the rear section is greater than or equal to 50%.

[0024] Preferably, the drawing speed of the blank in the secondary cooling zone is 0.9-1.3 m / min.

[0025] Preferably, the composition of the titanium-containing microalloyed steel is as follows, in percentage by mass:

[0026] C: 0.05%~0.3%;

[0027] Si: 0.1% to 0.4%;

[0028] Mn: 0.1%~1.0%;

[0029] Ti: 0.03%~0.12%;

[0030] P: ≤0.01%;

[0031] S: ≤0.01%;

[0032] N: ≤0.005%;

[0033] The balance is Fe and inevitable impurities.

[0034] Preferably, the superheat degree ΔT of the molten steel in the tundish is 18-35°C.

[0035] Preferably, the superheat degree ΔT of the molten steel in the tundish is 20-35°C.

[0036] The present invention provides a continuous casting method for titanium-containing steel, specifically a method for continuously casting molten steel containing titanium microalloyed steel. The method primarily controls the production of large-sized titanium nitride in the continuously cast ingot. By applying traveling-wave electromagnetic stirring in the secondary cooling zone and controlling specific electromagnetic stirring conditions, the method facilitates the disruption of columnar crystals, increases the equiaxed crystal region, and inhibits the aggregation and growth of titanium nitride precipitated between the columnar crystals. Furthermore, combined with gradient cooling control in the secondary cooling zone, the cooling of the ingot core is accelerated, preventing the aggregation and growth of liquid-precipitated titanium nitride. The method can increase the equiaxed crystal ratio from the traditional 30% to 40% to ≥55%, significantly inhibiting TiN coarsening between columnar crystals and eliminating TiN inclusions larger than 10 μm in the steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0038] Figure 1 This is the central metallographic structure diagram of the ingot obtained in Example 1 of the present invention;

[0039] Figure 2 This is the central metallographic structure diagram of the ingot obtained in Comparative Example 3. DETAILED DESCRIPTION

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0041] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0042] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] As used herein, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0044] In this document, when referring to a range, if the unit is followed only by the right endpoint, it means that the units of the left and right endpoints are the same. For example, 15-35°C means that the units of the left endpoint "15" and the right endpoint "35" are both in °C.

[0045] A continuous casting method for titanium-containing steel comprises the following steps:

[0046] The refined molten steel is poured into the tundish through the ladle, and then distributed to the crystallizer through the tundish. The molten steel is cooled and solidified into billet in the crystallizer, and then flows out of the crystallizer into the secondary cooling zone for cooling, and is straightened in the straightening machine to obtain the ingot.

[0047] in,

[0048] The molten steel is a titanium-containing microalloyed steel, wherein the Ti content is 0.03% to 0.12% and the N content is ≤0.005%;

[0049] The secondary cooling zone applies a traveling wave magnetic field electromagnetic stirring, the direction of the magnetic field is perpendicular to the casting direction, and the following conditions are controlled:

[0050] The relationship between the current intensity of the electromagnetic stirring and the superheat of the molten steel in the tundish is shown in formula (1):

[0051] I=18×ΔT-270 Formula (1);

[0052] In formula (1), I is the current intensity of electromagnetic stirring, in A; ΔT is the superheat of molten steel in the tundish, in °C.

[0053] In the present invention, the molten steel used is titanium-containing microalloyed steel; wherein the titanium content is 0.03% to 0.12%, and the nitrogen content is ≤0.005%. Titanium-containing microalloyed steel is a steel with an iron matrix and titanium as the primary microalloying element. The titanium content can specifically be 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, or 0.12%. The nitrogen content can specifically be 0.0035%, 0.0040%, or 0.0045%.

[0054] In the present invention, preferably, the molten steel containing titanium microalloyed steel comprises, in percentage by mass:

[0055] C: 0.05%~0.3%;

[0056] Si: 0.1% to 0.4%;

[0057] Mn: 0.1%~1.0%;

[0058] Ti: 0.03%~0.12%;

[0059] P: ≤0.01%;

[0060] S: ≤0.01%;

[0061] N: ≤0.005%;

[0062] The balance is Fe and inevitable impurities.

[0063] Specifically, the C content can be 0.05%, 0.07%, 0.10%, 0.15%, 0.20%, 0.25%, or 0.30%. The Si content can be 0.1%, 0.2%, 0.3%, or 0.4%. The Mn content can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1.0%. The Ti content can be 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, or 0.12%. The N content can be 0.0035%, 0.0040%, or 0.0045%.

[0064] In the present invention, the refined molten steel is poured into a tundish via a ladle, and then the molten steel is distributed into a crystallizer via the tundish, where the molten steel is cooled and solidified into a billet (specifically, the molten steel is cooled in the crystallizer to form a surface-solidified billet with a liquid core); the above process is not particularly limited and can be performed according to conventional processes in the art. In the present invention, the superheat of the molten steel in the tundish is preferably 15 to 35°C, more preferably 18 to 35°C, and even more preferably 20 to 35°C, and specifically can be 18°C, 20°C, 22°C, 25°C, 30°C, or 35°C.

[0065] In the present invention, after the molten steel is cooled and solidified into a billet in the crystallizer, it is cooled in the secondary cooling zone after exiting the crystallizer. A traveling magnetic field is applied to the electromagnetic stirring, and the direction of the magnetic field is perpendicular to the direction of the billet drawing, forcing the liquid phase to flow and break the dendrites. The following conditions are controlled: (1) The frequency of the electromagnetic stirring is controlled to be 4 to 8 Hz, specifically 4 Hz, 5 Hz, 6 Hz, 7 Hz, and 8 Hz. (2) The current intensity is controlled to be 100 to 450 A, specifically 100 A, 126 A, 150 A, 200 A, 250 A, 270 A, 300 A, 350 A, 360 A, 400 A, and 450 A. (3) The relationship between the current intensity of the electromagnetic stirring and the superheat of the molten steel in the tundish is shown in formula (1):

[0066] I=18×ΔT-270 Formula (1);

[0067] In formula (1), I is the current intensity of the electromagnetic stirring, in A (amperes); ΔT is the superheat of the molten steel in the tundish, in degrees Celsius. In the early stages of the present invention, the superheat of the molten steel was controlled to be 15-35°C, and the current intensity was generally controlled to be 100-450A. Simultaneously, the current intensity and the superheat of the molten steel were controlled to satisfy the relationship of formula (1), which is beneficial for offsetting the tendency of columnar crystal growth caused by high temperature.

[0068] In the present invention, when the billet exits the crystallizer and enters the secondary cooling zone for cooling, the water content in the secondary cooling zone is preferably controlled as follows: the low water content in the front section is 1.0-1.2 L / kg, specifically 1.0 L / kg, 1.1 L / kg, or 1.2 L / kg; the high water content in the back section is 1.5-1.8 L / kg, specifically 1.5 L / kg, 1.6 L / kg, 1.7 L / kg, or 1.8 L / kg. The front section accounts for 60%-80% of the total length of the secondary cooling zone, specifically 60%, 65%, 70%, 75%, or 80%. In the present invention, the central solid phase fraction in the front section is less than 50%, and the central solid phase fraction in the back section is ≥50%. The present invention facilitates the refinement of equiaxed grains through this gradient cooling control.

[0069] In the present invention, the continuously poured molten steel is cooled in the crystallizer and the secondary cooling zone, and is slowly bent in the bending section of the secondary cooling zone and straightened by a straightening machine. Specifically, the molten steel is rapidly cooled in the crystallizer to form a billet with a liquid core, and then the billet is pulled out of the crystallizer by a mechanism and enters the secondary cooling zone for further cooling. The speed of the billet movement is the pulling speed, and the billet cooling and movement are carried out synchronously. Among them, the pulling speed is preferably 0.9 to 1.3 m / min, specifically 0.9 m / min, 1.0 m / min, 1.1 m / min, 1.2 m / min, and 1.3 m / min. The present invention controls the superheat of the molten steel and the pulling speed as above, which is conducive to suppressing the growth of columnar crystals. After the above process, a billet is obtained.

[0070] Traditional methods rely on electromagnetic stirring in the mold and low superheat. However, the secondary cooling zone, a critical area in the middle and late stages of solidification, underutilizes the influence of liquid flow on equiaxed grain formation and solute segregation. The problem of large-sized TiN (>10μm) caused by TiN enrichment in columnar intergranular segregation remains unresolved. This continuous casting method reduces large titanium nitride inclusions, improves ingot quality, and fully meets the continuous casting requirements for titanium-containing steels.

[0071] The continuous casting method provided by this invention utilizes traveling-wave electromagnetic stirring in the secondary cooling zone and controls specific electromagnetic stirring conditions to break up columnar crystals, increase equiaxed crystal regions, and inhibit the aggregation and growth of titanium nitride precipitated between columnar crystals. Furthermore, combined with gradient cooling control in the secondary cooling zone, this accelerates cooling of the core of the ingot and prevents the aggregation and growth of liquid-precipitated titanium nitride. This method can increase the equiaxed crystal ratio from the traditional 30% to 40% to ≥55%, significantly inhibiting TiN coarsening between columnar crystals and eliminating TiN inclusions larger than 10μm in the steel.

[0072] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0073] Example 1

[0074] The refined molten steel is poured into the tundish through the ladle, and then distributed to the crystallizer through the tundish. The molten steel is cooled in the crystallizer to form a surface-solidified ingot. The ingot then leaves the crystallizer and enters the secondary cooling zone for cooling, and is straightened in the straightening machine to obtain the ingot.

[0075] in,

[0076] The molten steel is titanium-containing microalloyed steel with the following composition: Ti: 0.10%, N: 0.0035%, C: 0.05%, Si: 0.2%, Mn: 1.0%, P: ≤ 0.01%, S: ≤ 0.01%, and the balance is Fe and unavoidable impurities.

[0077] The superheat of the molten steel in the tundish is 22°C and the pulling speed is 1.1m / min.

[0078] The secondary cooling zone is subjected to traveling wave magnetic field electromagnetic stirring, with the direction of the magnetic field perpendicular to the casting direction (frequency 4 Hz, current calculated according to formula (1) is 126 A); the cooling water volume of the front section of the secondary cooling zone is 1.1 L / kg, and that of the rear section is 1.6 L / kg (the central solid phase ratio of the front section is <50%, and the central solid phase ratio of the rear section is ≥50%).

[0079] result:

[0080] The equiaxed crystal ratio of the obtained ingot is 60%; the microstructure of the metallographic center of the ingot is as follows Figure 1 As shown, the golden particles are TiN inclusions with an average size of 5.2 μm, and there are no TiN inclusions larger than 10 μm.

[0081] Example 2

[0082] The refined molten steel is poured into the tundish through the ladle, and then distributed to the crystallizer through the tundish. The molten steel is cooled in the crystallizer to form a surface-solidified ingot. The ingot then leaves the crystallizer and enters the secondary cooling zone for cooling, and is straightened in the straightening machine to obtain the ingot.

[0083] in,

[0084] The molten steel is titanium-containing microalloyed steel with the following composition: Ti: 0.05%, N: 0.003%, C: 0.05%, Si: 0.2%, Mn: 1.0%, P: ≤ 0.01%, S: ≤ 0.01%, and the balance is Fe and unavoidable impurities.

[0085] The superheat of the molten steel in the tundish is 30°C and the pulling speed is 0.9m / min.

[0086] The secondary cooling zone is subjected to traveling wave magnetic field electromagnetic stirring, with the direction of the magnetic field perpendicular to the casting direction (frequency 6 Hz, current calculated according to formula (1) is 270 A); the cooling water volume of the front section of the secondary cooling zone is 1.0 L / kg, and that of the rear section is 1.5 L / kg (the central solid phase ratio of the front section is <50%, and the central solid phase ratio of the rear section is ≥50%).

[0087] Results: The equiaxed grain ratio of the ingot was 65%. The average TiN size of the ingot center was 3.8μm by metallographic examination, and there was no TiN inclusion larger than 10μm.

[0088] Example 3

[0089] The refined molten steel is poured into the tundish through the ladle, and then distributed to the crystallizer through the tundish. The molten steel is cooled in the crystallizer to form a surface-solidified ingot. The ingot then leaves the crystallizer and enters the secondary cooling zone for cooling, and is straightened in the straightening machine to obtain the ingot.

[0090] in,

[0091] The molten steel is titanium-containing microalloyed steel with the following composition: Ti: 0.12%, N: 0.005%, C: 0.07%, Si: 0.3%, Mn: 0.6%, P: ≤ 0.01%, S: ≤ 0.01%, and the balance is Fe and unavoidable impurities.

[0092] The superheat of the molten steel in the tundish is 35°C and the pulling speed is 1.3m / min.

[0093] The secondary cooling zone is subjected to traveling wave magnetic field electromagnetic stirring, with the direction of the magnetic field perpendicular to the casting direction (frequency 8 Hz, current calculated according to formula (1) is 360 A); the cooling water volume of the front section of the secondary cooling zone is 1.2 L / kg, and that of the rear section is 1.8 L / kg (the central solid phase ratio of the front section is <50%, and the central solid phase ratio of the rear section is ≥50%).

[0094] Results: The equiaxed grain ratio of the ingot was 67%. The average TiN size of the ingot center was 6.6μm by metallographic examination, and there was no TiN inclusion larger than 10μm.

[0095] It can be seen from Examples 1-3 that the present invention can make the equiaxed grain ratio of the ingot reach above 55%, and eliminate TiN inclusions with a size of >10 μm in the steel.

[0096] Comparative Example 1

[0097] The process was carried out in accordance with Example 1, except that the superheat was 40° C., the pulling speed was 0.8 m / min, the electromagnetic stirring frequency was 8 Hz, and the current was 450 A.

[0098] Results: The equiaxed grain ratio of the ingot was 43%. The average TiN size of the ingot center was 9μm by metallographic examination, and there was no TiN inclusion larger than 10μm.

[0099] It can be seen that compared with Example 1, the equiaxed crystal ratio of the ingot obtained in Comparative Example 1 is reduced and the average TiN size is increased, which proves that the present invention controls the specific superheat and pulling speed, which is beneficial to improving the equiaxed crystal ratio.

[0100] Comparative Example 2

[0101] The process was carried out in accordance with Example 1, except that electromagnetic stirring was not applied in the second cooling zone.

[0102] Results: The equiaxed grain ratio of the ingot was 35%. The average TiN size of the ingot center was 8μm, and there were 2 TiN inclusions larger than 10μm.

[0103] It can be seen that compared with Example 1, the equiaxed crystal ratio of the ingot obtained in Comparative Example 2 is reduced, the average size of TiN is increased, and TiN inclusions >10 μm appear, which proves that the application of traveling wave electromagnetic stirring in the secondary cooling zone of the present invention is beneficial to improving the equiaxed crystal ratio and eliminating TiN inclusions with a size >10 μm.

[0104] Comparative Example 3

[0105] The process was carried out in accordance with Example 1, except that electromagnetic stirring was not applied to the second cooling zone, and a gradient cooling system was not implemented in the second cooling zone. Instead, the overall water content was controlled to be 0.8 L / kg.

[0106] Results: The equiaxed crystal ratio of the ingot is 32%; the microstructure of the metallographic center of the ingot is as follows Figure 2 As shown, the average size of TiN in the center of the ingot is 16μm by metallographic examination, and large golden TiN inclusions with a length of 50μm are found.

[0107] It can be seen that compared with Example 1, the equiaxed crystal ratio of the ingot obtained in Comparative Example 3 is significantly reduced, the average TiN size is significantly increased, and very large TiN inclusions appear, which proves that the present invention applies traveling wave electromagnetic stirring in the secondary cooling zone in combination with gradient cooling control, which can significantly improve the equiaxed crystal ratio, inhibit the coarsening of TiN between columnar grains, and eliminate TiN inclusions with a size of >10μm.

[0108] Comparative Example 4

[0109] The process was carried out in accordance with Example 1, except that the superheat was 40° C. and the current of the electromagnetic stirring was 500 A (ie, the superheat, the current, and the relationship between the superheat and the current all exceeded the scope defined in the present invention).

[0110] Results: The equiaxed grain ratio of the ingot was 37%. The average TiN size of the ingot center was 9μm, and there were 3 TiN inclusions larger than 10μm.

[0111] It can be seen that compared with Example 1, the equiaxed crystal ratio of the ingot obtained in Comparative Example 4 is reduced, the average size of TiN is increased and large particles of TiN appear, which proves that the specific conditions controlled during the second cooling of the present invention are conducive to improving the equiaxed crystal ratio of the ingot and reducing the TiN size.

[0112] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal description of the claims, or if they include equivalent structural elements that are not substantially different from the literal description of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A continuous casting method for titanium-containing steel, characterized in that: The following steps are involved: The refined molten steel is poured into the tundish through the ladle, and then distributed to the crystallizer through the tundish. The molten steel is cooled and solidified into billet in the crystallizer, and then flows out of the crystallizer into the secondary cooling zone for cooling, and is straightened in the straightening machine to obtain the ingot. in, The molten steel is a titanium-containing microalloyed steel, wherein the Ti content is 0.03% to 0.12% and the N content is ≤0.005%; The secondary cooling zone applies a traveling wave magnetic field electromagnetic stirring, the direction of the magnetic field is perpendicular to the casting direction, and the following conditions are controlled: The relationship between the current intensity of the electromagnetic stirring and the superheat of the molten steel in the tundish is shown in formula (1): I=18×ΔT-270 Formula (1); In formula (1), I is the current intensity of electromagnetic stirring, in A; ΔT is the superheat of molten steel in the tundish, in °C.

2. The continuous casting method according to claim 1, characterized in that: The superheat degree ΔT of the molten steel in the tundish is 15-35°C.

3. The continuous casting method according to claim 1, characterized in that: The current intensity I of the electromagnetic stirring is 100-450A.

4. The continuous casting method according to claim 1, characterized in that The following conditions are also controlled: the frequency of the electromagnetic stirring is controlled to be 4 to 8 Hz.

5. The continuous casting method according to claim 1, characterized in that: The water volume of the secondary cooling zone is controlled as follows: the low water volume in the front section is 1.0-1.2 L / kg; the high water volume in the rear section is 1.5-1.8 L / kg; The front section accounts for 60% to 80% of the total length of the secondary cooling zone.

6. The continuous casting method according to claim 5, characterized in that: The central solid phase ratio of the front section is less than 50%, and the central solid phase ratio of the rear section is greater than or equal to 50%.

7. The continuous casting method according to claim 1, characterized in that: The drawing speed of the billet in the secondary cooling zone is 0.9 to 1.3 m / min.

8. The continuous casting method according to claim 1, characterized in that: The composition of the titanium-containing microalloyed steel is as follows, in percentage by mass: C：0.05％～0.3％； Si: 0.1% to 0.4%; Mn: 0.1%~1.0%; Ti: 0.03%~0.12%; P：≤0.01％； S：≤0.01％； N：≤0.005％； The balance is Fe and inevitable impurities.

9. The continuous casting method according to claim 1, characterized in that: The superheat degree ΔT of the molten steel in the tundish is 18-35°C.

10. The continuous casting method according to claim 1, characterized in that: The superheat degree ΔT of the molten steel in the tundish is 20-35°C.

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