Bionic roller sleeve and application thereof in continuous casting process

Abstract

The invention belongs to the technical field of metallurgical continuous casting equipment, and particularly relates to a bionic roller sleeve and application thereof in a continuous casting process, the bionic roller sleeve is characterized in that a pine cone scale-shaped micro groove bionic structure is etched on the surface of the roller sleeve through laser, the overall dimension length L is 1200-2400 mm, the width M is 50-150 mm, the groove depth h is 0.1-0.3 mm, the spacing n is 0.5-1.0 mm, an included angle of 10-20 degrees is formed between the flow guide direction and the movement direction of a casting blank, and the flow guide direction and the movement direction of the casting blank are different. A WC-Co gradient coating is arranged on the surface of the roller sleeve, and the total thickness of the coating is 150-250 microns. The surface layer of the WC-Co gradient coating is a WC-10Co layer; the transition layer is a WC-15Co layer; and the matrix bonding layer is a WC-20Co layer. The method has the beneficial effects that the pine cone scale-shaped micro-groove structure is prepared on the surface of the roller sleeve through the laser etching technology, the gradient WC-Co coating is combined, the coverage area and uniformity of a cooling water film are enhanced through the capillary effect, the surface temperature fluctuation of a casting blank is remarkably reduced, the transverse crack defect is restrained, and the method is suitable for high-precision continuous casting production of silicon steel, high-strength steel and the like.

Description

Technical Field

[0001] This invention belongs to the technical field of metallurgical continuous casting equipment, and particularly relates to a biomimetic roller sleeve and its application in the continuous casting process. Background Technology

[0002] Continuous casting is short for continuous steel casting. In the production of various steel products in steel plants, there are two methods for solidifying molten steel into shape: the traditional ingot casting method and the continuous casting method. Continuous casting technology, which emerged in Europe and America in the 1950s, is an advanced technology that directly pours molten steel into shape. Compared with traditional methods, continuous casting technology has significant advantages such as greatly improving metal yield and billet quality, and saving energy. The continuous casting process involves transporting a ladle containing refined molten steel to a turret. After the turret rotates to the pouring position, the molten steel is poured into the tundish, and then the tundish distributes the molten steel to various crystallizers through the nozzle. The crystallizer is one of the core pieces of equipment in the continuous casting machine; it shapes the casting and allows it to solidify rapidly. The straightening machine and the crystallization vibration device work together to pull the casting out of the crystallizer. After cooling and electromagnetic stirring, it is cut into slabs of a certain length.

[0003] Transverse cracks are prone to occur in continuously cast billets, which restricts the improvement of steel quality. The main reason is closely related to the local thermal stress caused by uneven cooling. Traditional cooling roller sleeves have the following defects: Uneven water film coverage: The smooth roller surface is prone to cooling water film breakage, forming "dry spots" in local areas, with a temperature gradient >100℃ / m; Short roller sleeve life: Under high temperature and high pressure environment, ordinary coatings (such as chrome plating) are easy to peel off, with an average service life of only 6~8 months; Difficult crack control: The coexistence of edge undercooling and core high temperature results in a transverse crack incidence rate of ≥1.5%. 4) Technical bottlenecks exist: There is a lack of biomimetic structural design to actively regulate water film distribution; Existing coating materials are difficult to balance high hardness and thermal shock resistance.

[0004] Chinese invention patent CN100576540C discloses a semiconductor device and its manufacturing method, including forming trenches for forming fin-type active regions. The trenches are wavy, increasing the current velocity flowing in the gate and reducing leakage current in the storage electrode. This solution uses wavy trenches, but the tilt angle is fixed, making it unsuitable for adapting to the dynamics of water flow at different pulling speeds. Chinese invention patent CN101152776A discloses a dual-gradient composite coating, where the coating on the substrate surface consists of multiple sub-coatings. This dual-gradient coating is prepared on the surface of solid materials such as metals, inorganic non-metals, polymers, and their composites. This solution proposes the concept of gradient coatings but does not incorporate biomimetic structural design.

[0005] Chinese invention patent CN115157406A discloses a method for manufacturing fiberboard for E0-grade electrostatic spraying, including wood peeling → chipping → wood chip screening → washing → pre-cooking → cooking → hot grinding → adding waterproofing agent → applying E0-grade high-temperature resistant and high-strength adhesive and reinforcing agent → drying and sorting → laying and forming → pre-pressing → hot pressing → cooling and tempering → sanding and cleaning → inspection and grading → packaging and warehousing. This method utilizes electrostatic spraying to enhance water film adhesion, but the equipment is complex and energy-intensive. Existing technologies do not mention the biomimetic structure of pine cone scales or the synergistic optimization of gradient coating and capillary effect. Summary of the Invention

[0006] The purpose of this invention is to provide a biomimetic roller sleeve and its application in the continuous casting process, overcoming the shortcomings of the prior art. By using laser etching technology to prepare a pinecone-scale microgroove structure on the surface of the roller sleeve, combined with a gradient WC-Co coating, the capillary effect is used to enhance the coverage area and uniformity of the cooling water film, reduce the temperature fluctuation of the billet surface, and suppress transverse crack defects. It is suitable for high-precision continuous casting production of silicon steel, high-strength steel, etc.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] One technical solution is a biomimetic roller sleeve with a pine cone-scale-like microgroove biomimetic structure laser-etched on its surface. The outer dimensions are: length L = 1200-2400 mm, width M = 50-150 mm, groove depth h = 0.1-0.3 mm, spacing n = 0.5-1.0 mm, and the flow direction is at an angle of 10°-20° with the billet movement direction. The roller sleeve surface is coated with a WC-Co gradient coating with a total coating thickness of 150 μm-250 μm.

[0009] Furthermore, the surface layer of the WC-Co gradient coating is a WC-10Co layer with a thickness of 50-80 μm; the transition layer is a WC-15Co layer with a thickness of 60-90 μm; and the substrate bonding layer is a WC-20Co layer with a thickness of 40-80 μm.

[0010] Furthermore, the distribution area of ​​the pine cone-shaped microgroove biomimetic structure in the effective cooling area where the roller sleeve contacts the billet is not less than 80% of the cooling area.

[0011] Furthermore, the geometric model of the pine cone scale-like microgroove biomimetic structure is based on the spiral arrangement of pine cone scales, establishing an inclination angle-spacing mapping relationship:

[0012]

[0013] Where θ is the scale inclination angle of 20°~45°, and d is the distance from the roller end in mm.

[0014] Furthermore, the WC-Co gradient coating is applied using supersonic flame spraying with a kerosene-oxygen mixture as fuel, a spraying speed of 750-800 m / s, and a porosity of ≤1%; the laser remelting power is 2-3 kW, and the scanning speed is 1-1.5 m / s.

[0015] Technical Solution Two: Application of a biomimetic roller sleeve in continuous casting process, wherein a capillary pressure gradient is formed along the flow direction in the biomimetic structure of the pine cone scale-like microgroove, ΔP≥50Pa, driving the cooling water to spread in a directional manner, with a water film thickness uniformity CV value of 8% and a heat flux density fluctuation ≤5%.

[0016] Furthermore, the cooling water pressure is 0.3~0.8MPa, the flow rate is 20~50L / min, and the water temperature difference is ≤5℃.

[0017] Furthermore, the cooling water contains 0.1-0.25% nano-SiO2 by weight, and the surface tension of the water film under normal operating conditions is 28-35 mN / m.

[0018] Furthermore, the cooling water contains 0.1-0.25% nano-SiO2 by weight, and the surface tension of the water film under normal operating conditions is 28-35 mN / m.

[0019] The flow rate and pressure of the cooling water are adjusted in real time based on infrared thermal image feedback of the billet surface to maintain a temperature gradient ≤50℃ / m, and the direction of the temperature gradient change is consistent with the direction of billet movement.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1) A pine cone-shaped microgroove structure is prepared on the surface of the roller sleeve by laser etching technology. Combined with a gradient WC-Co coating, the capillary effect is used to enhance the coverage area and uniformity of the cooling water film, significantly reduce the surface temperature fluctuation of the billet, and suppress transverse crack defects. It is suitable for high-precision continuous casting production of silicon steel, high-strength steel and other materials.

[0022] 2) Excellent cooling performance, the surface temperature uniformity of the billet is improved to ±10℃, and the temperature difference between the edge and the core is ≤30℃; the water film coverage is increased from 60% to 95%, the cooling efficiency is increased by 25%, the capillary effect drives the water film coverage area to increase by 40%, and the temperature fluctuation is reduced from ±30℃ to ±10℃.

[0023] 3) Breakthroughs have been achieved in the quality of roller sleeves. Overcooling at the edges of silicon steel has been eliminated, and the magnetic strength B50 has increased by 0.1T (from 1.7T to 1.8T). The straightening crack rate of high-strength steel has decreased from 1.2% to 0.15%, and the flaw detection pass rate is ≥99.5%. The hardness of the gradient WC-Co coating is ≥HRC65, and the service life has been extended to 24 months. The incidence of transverse cracks has been reduced by 90%, and overcooling at the edges has been completely eliminated.

[0024] 4) Good economic benefits: the replacement cycle of roller sleeves is extended to 24 months, and the maintenance cost per ton of steel is reduced by 40%; due to the reduction of cracks, the grinding cost per ton of steel is reduced by 60%; it is suitable for various continuous casting processes such as slab, billet, and thin slab, and the casting speed range is 0.5~3.0m / min. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the pine cone scale arrangement structure according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the distribution of pine cone scales on the roller sleeve according to an embodiment of the present invention. For clarity, the pine cone scales are enlarged.

[0027] Figure 3 These are images of pine cone scale structures in nature, representing embodiments of the present invention.

[0028] In the figure: 1-roller sleeve, 2-pine cone scale-like microgroove biomimetic structure. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0032] To further describe the present invention, specific embodiments are provided below, which will more clearly demonstrate the advantages and various effects of the present invention. Those skilled in the art should understand that these specific embodiments are illustrative of the invention and not intended to limit it.

[0033] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0034] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0035] See Figure 1 This is a schematic diagram of an embodiment of the biomimetic roller sleeve of the present invention. A pine cone-scale-like microgroove biomimetic structure 2 is laser-etched onto the surface of the roller sleeve 1. The outer dimensions are: length L = 1200-2400 mm, width M = 50-150 mm, groove depth h = 0.1-0.3 mm, and spacing n = 0.5-1.0 mm. The flow direction forms an angle of 10°-20° with the casting billet movement direction. The roller sleeve surface is coated with a WC-Co gradient coating with a total thickness of 230 μm-300 μm. The surface layer of the WC-Co gradient coating is a WC-10Co layer with a thickness of 30-50 μm; the transition layer is a WC-15Co layer with a thickness of 80-100 μm; and the substrate bonding layer is a WC-20Co layer with a thickness of 120-150 μm. In this embodiment, the WC-Co gradient coating was applied using supersonic flame spraying with a kerosene-oxygen mixture as fuel. The spraying speed was 750-800 m / s, and the porosity was ≤1%. The laser remelting power was 2-3 kW, and the scanning speed was 1-1.5 m / s. The gradient coating distribution is shown in Table 1.

[0036] Table 1

[0037]

[0038] See Figure 2 To achieve reliable cooling, the pinecone-scale microgroove biomimetic structure 2 should cover at least 80% of the cooling area on the roller sleeve 1, and should ideally be distributed across the mounting sections at both ends of the roller sleeve and non-contact areas. See [link / reference]. Figure 3 The geometric model of the pine cone scale-like microgroove biomimetic structure 2 is based on the spiral arrangement of pine cone scales, establishing an inclination angle-spacing mapping relationship:

[0039]

[0040] Where θ is the scale inclination angle of 20°~45°, and d is the distance from the roller end (mm).

[0041] The spiral tilt angle of pine cone scales in nature: The tilt angle of each "scale" (θ, between 20 and 45 degrees) is not fixed, but related to its distance (d, in millimeters) from both ends of the roller sleeve. The closer / farther it is from the roller end, the angle will change in a regular way (for example, the farther away it is, the larger the angle). This arrangement allows the cooling water to flow more smoothly along the spiral grooves and prevents water accumulation.

[0042] Example 1

[0043] Take the continuous casting of silicon steel thin slabs as an example.

[0044] Process parameters:

[0045] Steel grade: 30Q130 non-oriented silicon steel;

[0046] Billet dimensions: 100mm × 1200mm;

[0047] Roller sleeve grooves: inclination angle 25°, depth 0.2mm, spacing 0.7mm;

[0048] Cooling water: pressure 0.5 MPa, containing 0.1% nano-SiO2, surface tension of the water film at 25℃ is 29 mN / m, flow rate 30 L / min, water temperature difference 5℃. The flow rate and pressure of the cooling water are adjusted in real time based on infrared thermal image feedback of the billet surface to maintain a temperature gradient ≤50℃ / m. The direction of the temperature gradient is consistent with the direction of billet movement.

[0049] Technical effects:

[0050] Edge quality: No grain boundary oxidation caused by undercooling, edge crack rate reduced from 0.8% to 0%;

[0051] Roller sleeve life: After 18 months of continuous use, the coating wear is ≤10μm.

[0052] Energy consumption: Cooling water consumption per ton of steel reduced by 20%.

[0053] Example 2

[0054] Taking the continuous casting of Q460C high-strength steel square billets as an example.

[0055] Process parameters:

[0056] Billet dimensions: 150mm × 150mm;

[0057] Groove design: Inclination angle θ is 40°, depth is 0.25mm, and the spacing is dynamically adjustable (0.6~1.0mm).

[0058] Cooling control: Linked with an infrared thermal imaging feedback system, the water temperature difference is ≤3℃. At 25℃ ambient temperature, the water film surface tension is 30 mN / m, and the flow rate is 30 L / min. The cooling water flow rate and pressure are adjusted in real-time based on infrared thermal imaging feedback from the billet surface, maintaining a temperature gradient of 35℃ / m. The direction of the temperature gradient is consistent with the direction of billet movement.

[0059] Technical effects:

[0060] Crack control: The straightening crack rate decreased from 1.2% to 0.1%, and the flaw detection pass rate was 99.8%.

[0061] Microstructure uniformity: Bainite content increased from 85% to 92%, and hardness fluctuation across the entire cross section was ≤ HRC2;

[0062] Energy consumption: Cooling water consumption per ton of steel decreased by 23%.

[0063] Example 3

[0064] Take the continuous casting of 304 stainless steel thin strip as an example.

[0065] Process parameters:

[0066] Billet thickness: 50mm;

[0067] Coating optimization: Adding 0.5% Cr3C2 to the surface layer improves corrosion resistance;

[0068] Pulling speed: 2.5m / min (high-speed mode).

[0069] Technical effects:

[0070] Surface quality: No oxide scale warping, roughness Ra≤1.0μm;

[0071] Energy consumption: Cooling water consumption per ton of steel decreased by 18%.

[0072] Example 4

[0073] Take the continuous casting of thick slab billets for X80 pipeline steel as an example.

[0074] Process parameters:

[0075] Billet dimensions: 250mm × 2000mm;

[0076] Trench design: regional tilt angle adjustment (35° at the edge, 20° at the core);

[0077] Cooling strategy: Increase water flow at the edges by 20% to suppress center segregation.

[0078] Technical effects:

[0079] Segregation index: C segregation decreased from 1.5 to 1.1, and Mn segregation decreased from 1.3 to 1.05;

[0080] Energy consumption: Cooling water consumption per ton of steel reduced by 20%.

[0081] Cost: The processing cost per ton of steel is reduced by ¥30 due to the reduction in flame cleaning.

[0082] Example 5

[0083] Take the continuous casting of high-temperature alloy irregular billets as an example.

[0084] Process parameters:

[0085] Steel grade: GH4169 nickel-based alloy;

[0086] Roller sleeve coating: 2% Y2O3 added to gradient WC-Co to improve thermal shock resistance;

[0087] Cooling medium: deionized water + 0.05% antioxidant.

[0088] Technical effects:

[0089] Heat-affected zone control: No γ' phase coarsening on the surface, grain size maintained at level 8;

[0090] Crack suppression: The hot crack rate decreased from 2.5% to 0.3%;

[0091] Extreme operating conditions: At a casting temperature of 1550℃, the roller sleeve does not deform and has a service life of ≥2000 hours.

[0092] Those skilled in the art should recognize that the above embodiments are merely illustrative of the invention and not intended to limit it, but are similarly limited to the scope of the invention. Variations and modifications to the above embodiments will fall within the protection scope of the claims. It should be understood that the endpoints and values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of various ranges, the endpoint values ​​of various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0093] It should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Additionally, the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone.

[0094] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A biomimetic roll cover, characterized in that, The surface of the roller sleeve is etched by laser to have pinecone-shaped micro-groove biomimetic structure, the outer dimension size L is 1200-2400mm, the width M is 50-150mm, the groove depth h is 0.1-0.3mm, the interval n is 0.5-1.0mm, the flow direction forms an angle of 10-20° with the movement direction of the casting blank, the surface of the roller sleeve is provided with WC-Co gradient coating, and the total thickness of the coating is 150-250μm.

2. A biomimetic roller cover according to claim 1, characterized in that The surface layer of the WC-Co gradient coating is a WC-10Co layer with a thickness of 50-80μm, the transition layer is a WC-15Co layer with a thickness of 60-90μm, and the base bonding layer is a WC-20Co layer with a thickness of 40-80μm.

3. The biomimetic roll cover according to claim 1, characterized in that The distribution area of the pinecone-shaped micro-groove biomimetic structure on the effective cooling area of the roller sleeve contacting the casting blank is not less than 80% of the cooling area.

4. The biomimetic roll cover according to claim 1, characterized in that The geometric model of the pinecone-shaped micro-groove biomimetic structure is based on the pinecone scale spiral arrangement rule, and the inclination-interval mapping relationship is established as follows: Wherein, θ is the scale inclination angle, 20°-45°, and d is the distance from the roller end, mm.

5. The biomimetic roll cover according to claim 1, characterized in that The WC-Co gradient coating is prepared by supersonic flame spraying, the fuel is kerosene-oxygen mixed gas, the spraying speed is 750-800m / s, the porosity is ≤1%, the laser remelting power is 2-3kW, and the scanning speed is 1-1.5m / s.

6. Use of a biomimetic roll cover according to any one of claims 1 to 5 in a continuous casting process, characterized in that, The pinecone-shaped micro-groove biomimetic structure forms a capillary pressure gradient along the flow direction, ΔP≥50Pa, drives the directional spreading of the cooling water, the water film thickness uniformity CV value is 8%, and the heat flow density fluctuation is ≤5%.

7. Use of a biomimetic roll cover according to claim 6 in a continuous casting process, characterized in that The pressure of the cooling water is 0.3-0.8MPa, the flow is 20-50L / min, and the water temperature difference is ≤5℃.

8. Use of a biomimetic roll cover according to claim 7 in a continuous casting process, characterized in that 0.1-0.25% of nano-SiO2 is added to the cooling water by weight percentage, and the water film surface tension at normal temperature is 28-35mN / m.

9. Use of a biomimetic roll cover according to claim 7 in a continuous casting process, characterized in that The flow and pressure of the cooling water are based on the infrared thermal image feedback of the casting blank surface, and are adjusted in real time to maintain the temperature gradient ≤50℃ / m, and the direction of the temperature gradient change is consistent with the movement direction of the casting blank.

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