A method for inhibiting the segregation of alloy elements in the center of super austenitic stainless steel billets

Abstract

The present invention provides a method for suppressing the segregation of alloy elements in the center of a super austenitic stainless steel billet, and relates to the technical field of continuous casting production of super austenitic stainless steel billets. The present invention reduces the central enrichment of alloy elements by feeding a staggered and coordinated vibrating stainless steel strip into the super austenitic stainless steel liquid, strengthens the dilution effect of the steel strip on the alloy elements in the center of the molten steel, effectively solves the serious problem of central segregation of alloy elements in super austenitic stainless steel, improves the internal quality of the ingot, and provides a technical guarantee for the preparation of high-quality super austenitic stainless steel products. The method of the present invention is suitable for the continuous casting production of super austenitic stainless steel billets with a side length of 150 to 250 mm. In addition, the present invention uses a low-alloy stainless steel outer skin to wrap the super austenitic stainless steel inner core to prevent excessive oxidation of alloy elements, thereby further improving the quality of the billet.

Description

Technical Field

[0001] The invention relates to the technical field of continuous casting production of super austenitic stainless steel billets, and in particular to a method for inhibiting the segregation of alloy elements in the center of a super austenitic stainless steel billet. Background Art

[0002] In recent years, with the rapid development of the country's equipment manufacturing industry, the demand for high-end materials in related industries has become increasingly strong. Super austenitic stainless steel has a rich content of alloys such as Cr, Ni, and Mo. Its corrosion resistance in highly corrosive environments is significantly better than that of ordinary austenitic stainless steel and is not inferior to that of nickel-based alloys. It also has significant cost advantages and is a key material urgently needed in the fields of energy conservation and environmental protection, marine engineering, petrochemicals, etc. However, the rich alloy content of super austenitic stainless steel leads to serious solute redistribution during the solidification process of the molten steel. Alloy elements are easily enriched in the center, and the central segregation of alloy elements in the billet is extremely serious, which aggravates the problems of inclusion and cracking in the billet, increases the difficulty of subsequent heat treatment processes, and seriously reduces the yield rate of super austenitic stainless steel billets. It is the most difficult variety of stainless steel to prepare.

[0003] Feeding a steel strip into a continuous casting crystallizer can change the traditional solidification pattern of continuous casting, which proceeds from the surface to the inside, and reduce the concentration of alloying elements in the center of the molten steel. Chinese Patent Publication No. CN112059132A discloses a method for improving the solidification quality of ingots by feeding a stainless steel strip containing boron, magnesium, and rare earth elements into the crystallizer. The method uses an alloy powder containing boron, magnesium, and rare earth elements as an intermediate layer, and two layers of super austenitic stainless steel strip as outer layers to produce a stainless steel strip containing boron, magnesium, and rare earth elements. During the continuous casting process, one or two of the stainless steel strips containing boron, magnesium, and rare earth elements are fed into the crystallizer. A casting nozzle equipped with a strip feeding zone is used to insert the end of the stainless steel strip containing boron, magnesium, and rare earth elements into the strip feeding zone. A vibration device is activated to generate non-sinusoidal vibrations in the strip, and the strip is then fed into the molten steel. While this patent reduces the center segregation of alloying elements in super austenitic stainless steel billets to a certain extent, the effect is limited. Summary of the Invention

[0004] The object of the present invention is to provide a method for suppressing the central segregation of alloy elements in a super austenitic stainless steel billet, which can further reduce the central segregation of alloy elements in the super austenitic stainless steel billet.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for suppressing the segregation of alloy elements in the center of a super austenitic stainless steel billet, comprising the following steps:

[0007] Wind four stainless steel belts onto the belt wheel respectively, and pass each stainless steel belt through the belt feeding guide trough, electromagnetic vibrator and slag discharger feeding area in sequence;

[0008] Start the straightening machine. After the continuous casting process stabilizes, control the strip feeding system to feed four stainless steel strips on both sides of the submerged nozzle at the same time, so that the cross-sections of the four stainless steel strips are centrally symmetrically distributed about the center of the cross-section of the crystallizer, and the vertical center lines of the four stainless steel strips are parallel to the vertical center line of the crystallizer. Turn on the electromagnetic vibrator to make the two stainless steel strips on the same side vibrate in an alternating and coordinated manner.

[0009] Preferably, the drawing speed of the drawing and leveling machine is 0.3-1.0 m / min.

[0010] Preferably, the distance l between two stainless steel strips on the same side is 0.2D-0.4D, and the distance L between two adjacent stainless steel strips on the opposite side is 0.2-0.4D, where D is the side length of the stainless steel billet, mm.

[0011] Preferably, each stainless steel strip has the same strip feeding ratio and feeding speed, and the strip feeding ratio of each stainless steel strip satisfies Among them, α is the steel strip feeding ratio, ΔT is the steel liquid superheat, which is 30~50℃, and the value of K3 is 0.004~0.012; the steel strip feeding speed meets Among them, v is the feeding speed of the steel strip, m / s, and the value of K4 is 0.003~0.010.

[0012] Preferably, each stainless steel strip is composed of an inner core and an outer skin, wherein the outer skin is wrapped around the inner core and has a uniform thickness, and the thickness of the outer skin is 0.5 to 1.5 mm.

[0013] Preferably, the four stainless steel strips have the same size, and the width of the inner core meets Thickness meets Among them, w is the width of the inner core, mm; d is the thickness of the inner core, mm; l is the distance between two adjacent stainless steel strips, mm; ΔT is the superheat of the molten steel, which is 30~50℃; the value of K1 is 0.9~2.2; the value of K2 is 0.6~2.0.

[0014] Preferably, the composition of the cast steel liquid is, in percentage by mass: C≤0.04%, Mn≤5.00%, Cr: 19.0-26.0%, Ni: 17.0-26.0%, Mo: 2.0-8.0%, N: 0.15-0.58%, Cu: 0.20-1.20%, and the remainder is Fe and other inevitable impurity elements.

[0015] Preferably, the types of alloying elements in the inner core and outer skin of the stainless steel strip are the same as the types of alloying elements in the cast molten steel, the mass content of each alloying element in the inner core is 80-100% of the corresponding alloying element content in the cast molten steel, and the mass content of Mn, Cr, Ni, and Mo elements in the outer skin is not higher than 20% of the corresponding alloying element content in the cast molten steel.

[0016] Preferably, the electromagnetic vibrator drives the two stainless steel strips on the same side to alternately and cooperatively perform sinusoidal vibration, the amplitude of the stainless steel strips is 0.1-1 mm, and the vibration frequency is 30-100 Hz.

[0017] Preferably, during the strip feeding process, the narrow side of the steel strip faces the water nozzle.

[0018] The present invention provides a method for suppressing the segregation of alloy elements in the center of a super austenitic stainless steel billet, comprising the following steps: winding four stainless steel strips onto steel strip rotating wheels respectively, and sequentially passing each stainless steel strip through a strip feeding guide groove, an electromagnetic vibrator, and a strip feeding area of ​​a slag discharger; starting a tension leveler, and after a continuous casting process stabilizes, controlling the strip feeding system to simultaneously feed the four stainless steel strips on both sides of an immersed water nozzle, so that the cross sections of the four stainless steel strips are centrally symmetrically distributed about the center of a cross section of a crystallizer, and the vertical center lines of the four stainless steel strips are parallel to the vertical center line of the crystallizer; and starting the electromagnetic vibrator to cause two stainless steel strips on the same side to vibrate in a staggered and coordinated manner.

[0019] By feeding staggered, coordinated vibrating stainless steel strips into the super austenitic stainless steel melt, the present invention reduces the central enrichment of alloying elements and enhances the strip's dilution effect on the alloying elements in the center of the molten steel. This effectively solves the severe central segregation of alloying elements in super austenitic stainless steel, improves the internal quality of the ingot, and provides a technical guarantee for the production of high-quality super austenitic stainless steel products. The method of the present invention is suitable for the continuous casting of super austenitic stainless steel billets with a side length of 150 to 250 mm.

[0020] Furthermore, the super austenitic stainless steel strip in CN112059132A is in direct contact with the high-temperature environment above the crystallizer, and the rich alloy elements in the stainless steel strip are inevitably oxidized. The present invention uses a low-alloy stainless steel outer skin to wrap the super austenitic stainless steel inner core to prevent excessive oxidation of the alloy elements and further improve the quality of the square billet. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of the tape feeding device used in the present invention;

[0022] Figure 2 It is the structural diagram of the slag discharger;

[0023] Figure 1 and Figure 2 In the figure, 1-steel belt wheel; 2-stainless steel belt; 3-feeding belt guide groove; 4-electromagnetic vibrator; 5-feeding belt area of ​​slag discharger; 6-crystallizer; 7-column; 8-nut; 9-crossbeam;

[0024] Figure 3 This is a schematic diagram of the staggered coordinated vibration law of two stainless steel strips on the same side of the present invention. DETAILED DESCRIPTION

[0025] The present invention provides a method for suppressing the segregation of alloy elements in the center of a super austenitic stainless steel billet, comprising the following steps:

[0026] Wind four stainless steel belts onto the belt wheel respectively, and pass each stainless steel belt through the belt feeding guide trough, electromagnetic vibrator and slag discharger feeding area in sequence;

[0027] Start the straightening machine. After the continuous casting process stabilizes, control the strip feeding system to feed four stainless steel strips on both sides of the submerged nozzle at the same time, so that the cross-sections of the four stainless steel strips are centrally symmetrically distributed about the center of the cross-section of the crystallizer, and the vertical center lines of the four stainless steel strips are parallel to the vertical center line of the crystallizer. Turn on the electromagnetic vibrator to make the two stainless steel strips on the same side vibrate in an alternating and coordinated manner.

[0028] In order to facilitate those skilled in the art to better understand the technical solution of this application, Figure 1 and Figure 2 The scheme of this application is described. Figure 1 This is a schematic diagram of the structure of the tape feeding device used in the present invention. Figure 1 As shown, the present invention coils four stainless steel strips on the steel strip rotating wheel 1 respectively, and passes each stainless steel strip through the strip feeding guide groove 3, the electromagnetic vibrator 4 and the strip feeding area 5 of the slag discharger in sequence. Figure 2 The schematic diagram of the structure of the slag discharger is shown in Figure 2. Figure 2 As shown, the present invention preferably uses a special-shaped crystallizer 6 with columns and a special-shaped slag discharger. The crossbeam 9 is fixed to the columns 7 by nuts 8. Mold slag is arranged around the feed zone 5, but not inside. Two slag dischargers are used symmetrically on both sides of the submerged nozzle. Each slag discharger has two feed zones. The feed zones are 1.2-1.4w long and 1.4-1.6d wide. Where w is the width of the stainless steel core, mm; d is the thickness of the core, mm.

[0029] In the present invention, the cross-sections of the four stainless steel strips are arranged symmetrically about the center of the cross-section of the crystallizer, and the vertical centerlines of the four stainless steel strips are parallel to the vertical centerline of the crystallizer. Specifically, two stainless steel strips are arranged on each side of the submerged nozzle.

[0030] In the present invention, the distance l between two stainless steel strips on the same side and the distance L between two adjacent stainless steel strips on the opposite side are independently preferably 0.2D to 0.4D, more preferably 0.25D to 0.35D; where D is the side length of the stainless steel billet, in mm. In the present invention, the side length of the stainless steel billet is preferably 150 to 250 mm.

[0031] In the present invention, each stainless steel strip consists of an inner core and an outer skin. The outer skin is wrapped around the inner core and has a uniform thickness. The thickness of the outer skin is preferably 0.5-1.5 mm, more preferably 0.8-1.2 mm, and further preferably 0.9-1.0 mm.

[0032] In the present invention, the four stainless steel strips preferably have the same size, and the width of the inner core satisfies Thickness meets Where w is the width of the inner core, mm; d is the thickness of the inner core, mm; l is the distance between two adjacent stainless steel strips, mm; ΔT is the superheat of the molten steel, which is 30-50°C; K1 is 0.9-2.2; K2 is 0.6-2.0. More preferably, ΔT is 35-45°C; K1 is 1.2-1.6; K2 is 1.0-1.5.

[0033] In the present invention, the types of alloying elements in the inner core and outer skin of the stainless steel strip are the same as the types of alloying elements in the cast steel liquid. The mass content of each alloying element in the inner core is preferably 80-100% of the corresponding alloying element content in the cast steel liquid, and the mass content of Mn, Cr, Ni, and Mo elements in the outer skin is preferably not higher than 20% of the corresponding alloying element content in the cast steel liquid.

[0034] In the present invention, the composition of the cast steel liquid is preferably: C≤0.04%, Mn≤5.00%, Cr: 19.0-26.0%, Ni: 17.0-26.0%, Mo: 2.0-8.0%, N: 0.15-0.58%, Cu: 0.20-1.20%, and the balance is Fe and other inevitable impurity elements.

[0035] The present invention adopts a stainless steel outer skin with low alloy content to wrap a super austenitic stainless steel inner core to prevent excessive oxidation of alloy elements.

[0036] In the present invention, the drawing speed of the drawing and leveling machine during the continuous casting process is preferably 0.3 to 1.0 m / min, more preferably 0.5 to 0.8 m / min, and further preferably 0.6 to 0.7 m / min.

[0037] In the present invention, each stainless steel strip has the same strip feeding ratio and feeding speed, and the strip feeding ratio of each stainless steel strip satisfies Among them, α is the steel strip feeding ratio, ΔT is the steel liquid superheat, which is 30~50℃, and the value of K3 is 0.004~0.012; the steel strip feeding speed meets Where v is the feeding speed of the steel strip, m / s, and K4 is 0.003 to 0.010. In the present invention, the steel strip feeding ratio is defined as: (cross-sectional area of ​​the steel strip inner core × steel strip feeding speed) / (cross-sectional area of ​​the square billet × casting speed)

[0038] During the feeding process, the narrow side of the steel strip is preferably facing the nozzle.

[0039] During the continuous casting process, the electromagnetic vibrator drives the two stainless steel strips on the same side to vibrate in a staggered and coordinated manner. Figure 3 The amplitude of the stainless steel strip is preferably 0.1 to 1 mm, more preferably 0.3 to 0.8 mm, and even more preferably 0.5 to 0.6 mm; the vibration frequency is preferably 30 to 100 Hz, more preferably 40 to 80 Hz, and even more preferably 60 to 70 Hz.

[0040] The present invention reduces the central enrichment of alloy elements by feeding stainless steel strips with staggered coordinated vibration into the super austenitic stainless steel liquid, strengthens the dilution effect of the steel strips on the alloy elements in the center of the molten steel, effectively solves the serious problem of central segregation of alloy elements in super austenitic stainless steel, improves the internal quality of the ingot, and provides technical support for the preparation of high-quality super austenitic stainless steel products.

[0041] The method for suppressing the central alloy element segregation of super austenitic stainless steel billets provided by the present invention is described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0042] Comparative Example 1

[0043] Super austenitic stainless steel continuous casting billets were produced on a billet continuous casting machine with a mold size of 180 mm × 180 mm × 800 mm. Casting commenced with a casting speed of 0.35 m / min and a molten steel superheat of 40°C. The steel composition (wt%) was: C: 0.04, Mn: 3, Cr: 24, Ni: 22, Mo: 7, N: 0.5, Cu: 1.1, with the remainder being Fe. After the continuous casting process was completed, a sample taken from the center of the billet cross section revealed a Mo segregation of 2.25.

[0044] Comparative Example 2

[0045] Using a conventional strip feeding process, two uncoated stainless steel strips are produced. The width w of the strips is 20 mm, and the thickness d is 3 mm. The distance L between the strips is 0.35D = 63 mm. The alloying element composition (wt%) of the stainless steel strips is: C: 0.04, Mn: 2.5, Cr: 21, Ni: 21, Mo: 7, N: 0.4, Cu: 1.1, with the remainder being Fe and other unavoidable impurities. The two stainless steel strips are coiled onto a strip reel and sequentially passed through a strip feeding guide trough, an electromagnetic vibrator, and a slag discharger, awaiting use. The strip feeding guide trough, electromagnetic vibrator, and slag discharger are symmetrically located on both sides of the submerged nozzle, and the slag discharger contains only one strip feeding zone, which is located in the center of the slag discharger.

[0046] Super austenitic stainless steel continuous casting billets were produced on a billet continuous caster with a mold size of 180 mm × 180 mm × 800 mm. Casting commenced with a casting speed of 0.35 m / min and a molten steel superheat of 40°C. The molten steel composition (wt%) was: C: 0.04, Mn: 3, Cr: 24, Ni: 22, Mo: 7, N: 0.5, Cu: 1.1, with the remainder being Fe.

[0047] After the continuous casting process stabilized, the strip feeding system was controlled to simultaneously and symmetrically feed two stainless steel strips to either side of the submerged nozzle. The electromagnetic vibrator was activated to vibrate the strips. The feed ratio of the strips satisfied α = 0.01, the feed speed satisfied v = 0.03 m / s, the amplitude of the strips vibrated to 0.3 mm, and the frequency was 50 Hz. After the continuous casting process concluded, a sample taken from the center of the billet cross section revealed a Mo segregation of 1.62, a 28% reduction compared to the center segregation in the control.

[0048] Comparative Example 3

[0049] Make four stainless steel strips without outer skin, the width of the stainless steel strips meets The thickness of the stainless steel strip meets Where ΔT is the superheat of the molten steel, K1 is 1.02, and K2 is 1.12. The distance l between two stainless steel strips on the same side is 0.3D = 54 mm, and the distance L between two adjacent strips on opposite sides is 0.35D = 63 mm. The composition (wt%) of the stainless steel strips is: C: 0.04, Mn: 2.5, Cr: 21, Ni: 21, Mo: 7, N: 0.4, Cu: 1.1, with the remainder being Fe and other unavoidable impurities. Four stainless steel strips are coiled onto two steel strip reels and passed sequentially through the strip feed guide trough, electromagnetic vibrator, and slag discharger, ready for use.

[0050] Super austenitic stainless steel continuous casting billets were produced on a billet continuous caster with a mold size of 180 mm × 180 mm × 800 mm. Casting commenced with a casting speed of 0.35 m / min and a molten steel superheat of 40°C. The molten steel composition (wt%) was: C: 0.04, Mn: 3, Cr: 24, Ni: 22, Mo: 7, N: 0.5, Cu: 1.1, with the remainder being Fe.

[0051] After the continuous casting process is stable, the strip feeding system is controlled to feed four stainless steel strips simultaneously and symmetrically on both sides of the submerged nozzle, and the electromagnetic vibrator is turned on to make the two stainless steel strips on the same side vibrate in an alternating and coordinated manner. The feeding ratio of the stainless steel strips meets Feeding speed meets The K3 value was 0.0045, and the K4 value was 0.0039. The stainless steel strips on the same side were alternately vibrated in a sinusoidal manner, with an amplitude of 0.3 mm and a frequency of 50 Hz. After the continuous casting process, a sample taken from the center of the cross-section of the continuous casting strand revealed a Mo element segregation of 1.42, a 37% reduction compared to the center segregation in Comparative Example 1.

[0052] Example 1

[0053] Make four stainless steel strips, the width of the stainless steel strip core meets The thickness of the stainless steel strip core meets Where ΔT is the superheat of the molten steel, K1 is 1.02, and K2 is 1.12. The distance l between two stainless steel strips on the same side is 0.3D = 54 mm, and the distance L between two adjacent stainless steel strips on opposite sides is 0.35D = 63 mm. The stainless steel outer skin thickness is 1 mm, and the stainless steel core composition (wt%) is: C: 0.04, Mn: 2.5, Cr: 21, Ni: 21, Mo: 7, N: 0.4, Cu: 1.1, with the remainder being Fe and other unavoidable impurities. The stainless steel outer skin composition (wt%) is: C: 0.04, Mn: 0.5, Cr: 2, Ni: 2, Mo: 1.1, N: 0.4, Cu: 1.1, with the remainder being Fe. The four stainless steel strips are respectively coiled on two steel strip runners and passed through the feed guide trough, electromagnetic vibrator, and slag discharger in sequence, ready for use.

[0054] Super austenitic stainless steel continuous casting billets were produced on a billet continuous caster with a mold size of 180 mm × 180 mm × 800 mm. Casting commenced with a casting speed of 0.35 m / min and a molten steel superheat of 40°C. The molten steel composition (wt%) was: C: 0.04, Mn: 3, Cr: 24, Ni: 22, Mo: 7, N: 0.5, Cu: 1.1, with the remainder being Fe.

[0055] After the continuous casting process is stable, the strip feeding system is controlled to feed four stainless steel strips simultaneously and symmetrically on both sides of the submerged nozzle, and the electromagnetic vibrator is turned on to make the two stainless steel strips on the same side vibrate in an alternating and coordinated manner. The feeding ratio of the stainless steel strips meets Feeding speed meets The K3 value was 0.0045, and the K4 value was 0.0039. The stainless steel strips on the same side were alternately vibrated in a sinusoidal manner, with an amplitude of 0.3 mm and a frequency of 50 Hz. After the continuous casting process, a sample taken from the center of the cross-section of the continuous casting strand revealed a Mo element segregation of 1.31, a 42% reduction compared to the center segregation in Comparative Example 1.

[0056] Compared with Comparative Example 1, Comparative Example 2 adopts the traditional continuous casting crystallizer feeding process to effectively reduce the central segregation of alloy elements in the super austenitic stainless steel billet. Comparative Example 3 increases the number of steel strip streams to 4 on the basis of the traditional continuous casting crystallizer feeding process, and makes the steel strips on the same side staggered and oscillate, and the central segregation of alloy elements in the super austenitic stainless steel billet is further reduced. After increasing the number of steel strip streams, making the same side staggered and coordinated oscillation and wrapping the stainless steel skin, the central segregation of alloy elements in the super austenitic stainless steel billet is further reduced. This shows that the present invention has a significant effect on improving the center quality of the super austenitic stainless steel billet.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for inhibiting the segregation of alloy elements in the center of a super austenitic stainless steel billet, characterized in that: The following steps are involved: Wind four stainless steel belts onto the belt wheel respectively, and pass each stainless steel belt through the belt feeding guide trough, electromagnetic vibrator and slag discharger feeding area in sequence; Start the straightening machine. After the continuous casting process stabilizes, control the strip feeding system to feed four stainless steel strips simultaneously on both sides of the submerged nozzle, so that the cross sections of the four stainless steel strips are centrally symmetrically distributed about the center of the cross section of the crystallizer, and the vertical center lines of the four stainless steel strips are parallel to the vertical center line of the crystallizer. Turn on the electromagnetic vibrator to make the two stainless steel strips on the same side vibrate in an alternating and coordinated manner. The distance between two stainless steel belts on the same side l 0.2 D ~0.4 D , the distance between two adjacent stainless steel belts on the opposite side L is 0.2~0.4D, among which, D is the side length of the stainless steel billet, mm; Each stainless steel strip has the same strip feeding ratio and feeding speed. The strip feeding ratio of each stainless steel strip meets ,in, α is the steel strip feeding ratio, is the superheat of molten steel, which is 30~50℃, K The value of 3 is 0.004~0.012; the feeding speed of the steel strip meets ,in, v is the feeding speed of the steel strip, m / s, K The value of 4 is 0.003~0.010; Each stainless steel strip consists of an inner core and an outer skin, the outer skin is wrapped around the inner core and has a uniform thickness of 0.5-1.5 mm; The four stainless steel strips have the same size, and the width of the inner core meets , thickness meets ;in, w is the width of the inner core, mm; d is the thickness of the inner core, mm; l is the distance between two adjacent stainless steel strips, mm; is the superheat of molten steel, which is 30~50℃; K The value of 1 is 0.9~2.2; K The value of 2 is 0.6~2.

0.

2. The method according to claim 1, characterized in that The drawing speed of the drawing and leveling machine is 0.3-1.0 m / min.

3. The method according to claim 1, characterized in that Calculated in percentage by mass, the composition of the cast steel liquid is: C≤0.04%, Mn≤5.00%, Cr: 19.0~26.0%, Ni: 17.0~26.0%, Mo: 2.0~8.0%, N: 0.15~0.58%, Cu: 0.20~1.20%, and the balance is Fe and other inevitable impurity elements.

4. The method according to claim 1 or 3, characterized in that The types of alloying elements in the inner core and outer skin of the stainless steel strip are the same as the types of alloying elements in the cast molten steel, the mass content of each alloying element in the inner core is 80-100% of the corresponding alloying element content in the cast molten steel, and the mass content of Mn, Cr, Ni, and Mo elements in the outer skin is not higher than 20% of the corresponding alloying element content in the cast molten steel.

5. The method according to claim 1, wherein The electromagnetic vibrator drives the two stainless steel strips on the same side to perform sinusoidal vibration in an alternating and coordinated manner. The amplitude of the stainless steel strips is 0.1-1 mm, and the vibration frequency is 30-100 Hz.

6. The method according to claim 1, characterized in that During the feeding process, the narrow side of the steel strip faces the water nozzle.

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