A cooling roller and an assembly method thereof

Abstract

The present invention discloses a cooling roller and an assembly method thereof. The cooling roller comprises a roller sleeve and a roller core. The roller sleeve is disposed on the outer periphery of the roller core, and the roller sleeve and the roller core are interference-fitted. The interference ratio between the inner diameter of the roller sleeve and the outer diameter of the roller core is 2 to 3.5‰. The assembly method comprises designing the interference ratio between the roller sleeve and the roller core, subjecting the roller sleeve to an aging treatment, and simultaneously performing the aging treatment and preheating. The aged, hot-fitted roller sleeve and the roller core are interference-fitted and cooled to room temperature to obtain the cooling roller. The present invention ensures the realization of prestressing of the roller sleeve by designing the interference ratio, and can achieve the same prestress throughout the roller sleeve or different prestresses at different locations along the width of the roller sleeve. The present invention combines the aging treatment of the roller sleeve with the preheating process before assembly of the roller sleeve, completely avoiding the problem of over-aging that occurs during preheating in the prior art, which involves first completing the aging treatment, then machining, and preheating before assembly.

Description

Technical Field

[0001] The invention belongs to the technical field of cooling roller preparation, and in particular relates to a cooling roller and an assembling method thereof. Background Art

[0002] Amorphous nanocrystalline alloys are a type of soft magnetic material that has developed rapidly in recent years. Compared with traditional soft magnetic materials such as electrical steel and ferrite, they have higher magnetic permeability and lower AC loss. They have been widely used in the iron cores of magnetic components such as transformers, inductors, mutual inductors, and motor stators.

[0003] Amorphous and nanocrystalline alloy ribbons are typically manufactured using planar flow technology. The principle is to rapidly solidify a molten alloy of a defined composition on the outer circumference of a rapidly rotating cooling roller, forming a continuous, thin ribbon with an amorphous structure. The process involves melting a specific ratio of raw materials in a smelting furnace into a molten alloy. The molten alloy is then poured into a nozzle pack with a slit nozzle at the bottom. The molten alloy in the nozzle pack flows out of the nozzle, spreading over the outer circumference of a rapidly rotating copper alloy cooling roller below the nozzle, forming a molten pool of defined size between the cooling roller surface and the nozzle bottom. The molten alloy is then rapidly withdrawn and cooled, while the molten alloy in the nozzle slit is continuously replenished into the pool, forming a continuous, thin ribbon with an amorphous structure. The ribbon clings to the outer surface of the cooling roller as it rotates at high speed. It is then peeled off at an appropriate location on the outer circumference of the cooling roller by high-pressure gas or mechanical means, and finally wound into a coil by a coiling device.

[0004] The cooling roller is the core component to achieve rapid solidification of alloy liquid. Figure 1 As shown, it is generally made of an annular roller sleeve and a cylindrical roller core, which are interference fitted together. A thin annular channel is formed between the inner surface of the roller sleeve and the outer circumferential surface of the roller core. High-speed cooling water flows through the channel, and the heat conducted from the outer surface of the roller sleeve to the inner surface of the roller sleeve is taken away by forced convection. The roller sleeve is usually made of copper alloys with high thermal conductivity and high strength, such as CuBe, CuNiSi, CuCrZr, etc. The diameter of the roller sleeve is generally between 400mm and 2000mm, and the thickness of the roller sleeve is generally between 5 and 30mm. The manufacturing and assembly process of the roller sleeve generally includes: copper alloy smelting, casting, multiple forging or rolling and annealing, solid solution treatment, aging treatment, machining, interference fitting, installation and use. When the roller sleeve is deformed by heat, a drum-shaped roller surface is formed on the outer surface of the roller sleeve, such as Figure 4As shown in the figure, the drum-shaped roller surface makes the distance between the roller surface and the bottom surface of the nozzle (roller nozzle spacing) uneven, and the spacing in the middle area of ​​the strip width is significantly smaller than that on both sides, so that the alloy liquid flow in the middle area of ​​the strip width is smaller than that on both sides, resulting in uneven transverse thickness of the produced strip, forming a "concave core" plate shape that is thin in the middle and thick on both sides, seriously reducing the lamination coefficient. During the strip making process, when a certain point on the roller surface enters the molten pool and contacts the high-temperature alloy liquid, the local temperature will instantly rise to about 300°C due to thermal shock. When this point leaves the molten pool, the heat is quickly transferred to the inside of the roller sleeve, and its temperature drops sharply. Therefore, under the action of periodic thermal shock, the roller surface temperature also changes periodically, as shown in the attached figure. Figure 5 As shown in the figure (the dotted line is the equilibrium temperature of the roller surface). When the roller surface just contacts the alloy liquid, the roller surface material is heated rapidly and expands. At this time, the internal stress is compressive stress. Subsequently, the heat is transferred to the inside of the roller sleeve, and the roller sleeve 1 quickly cools and contracts. At this time, it is tensile stress. The schematic diagram of the internal stress change of a certain point on the roller sleeve surface during one rotation cycle is shown as follows Figure 6 As shown. The prior art cooling roller assembly method is as follows Figure 7 As shown, the roller sleeve is first aged, then machined; the machined roller sleeve is preheated, and the preheated roller sleeve is hot-fitted to the roller core and finally installed for use. In this process, the preheating and aging treatment of the roller sleeve are carried out separately.

[0005] During the manufacturing process of amorphous alloy strip, the high-speed rotation of the cooling rollers subjects the outer circumferential surface of the roller sleeve to periodic thermal shock from the molten alloy. This results in two major issues: uneven thermal crowning of the roller sleeve and thermal fatigue caused by thermal stress on the roller surface. However, most existing technologies do not fully address these issues. For example, the uneven thermal crowning of the roller surface leads to uneven spacing between the roller nozzles, which can easily cause the manufactured strip to have a concave core. Existing technologies often machine the nozzle bottom surface into a curved surface to offset the thermal crowning of the roller surface; however, this method cannot compensate for the ever-changing thermal crowning of the roller surface. For another example, to reduce thermal fatigue of the roller surface, existing technologies often seek to increase the mechanical strength of the roller sleeve material, but the improvement is very limited. While some have considered these issues and proposed some solutions, they have introduced other problems and are limited in scope.

[0006] Chinese utility model patent CN2452652Y discloses a curved nozzle for amorphous strip spraying equipment. The nozzle bottom surface is machined into a curved shape, essentially offsetting the thermal crown of the roller surface, making the roller nozzle spacing across the strip width essentially consistent, thereby improving the strip shape. However, this method increases the amount of nozzle machining required and is prone to nozzle machining defects. Furthermore, the thermal crown of the roller surface changes continuously with strip production time and process conditions, so the pre-machined nozzle bottom curvature cannot effectively compensate for the ever-changing thermal crown of the roller surface.

[0007] U.S. Patent No. 4,537,239 discloses a method for manufacturing a CuBe2 alloy roller sleeve for amorphous alloy strip production. This method employs prestressing to avoid thermal crowning of the roller surface. The sleeve has a diameter of 15 inches (approximately 380 mm) and an initial thickness of approximately 1 / 4 inch (6.35 mm). The radial interference between the sleeve and the roll core is 0.076 cm (an interference ratio of approximately 3.94‰). The sleeve is then heated to 316°C for a predetermined period of time, after which the roll core is inserted into the sleeve. After the sleeve cools, the sleeve contracts, tightly clamping it around the roll core, creating an interference fit and generating a tensile prestress of 75,000 psi (approximately 517 MPa) within the sleeve. Because the sleeve is prestressed by internal stress, heating the sleeve during use only reduces the internal stress, without causing thermal expansion, thus eliminating the thermal crowning problem. At the same time, because the roller sleeve is always in a tensile stress state, there is no alternating internal stress, thus avoiding thermal fatigue of the roller surface and delaying its deterioration. However, this method has many shortcomings: First, a simple calculation shows that in this technical solution, after the roller sleeve is heated to the target temperature, its relative expansion is approximately 5‰, while the designed interference is as high as nearly 4‰. This results in a margin of only about 0.4mm between the outer diameter of the roller core at room temperature and the inner diameter of the roller sleeve at high temperature. If factors such as out-of-roundness, dimensional deviation, and thermal expansion differences caused by temperature unevenness between the roller core and the roller sleeve are further considered, fitting the roller core into the roller sleeve is extremely difficult, placing extremely stringent requirements on the machining accuracy of the roller core and roller sleeve, as well as the positioning accuracy of the shrink-fit equipment. Second, the roller sleeve has already undergone solid solution treatment and aging treatment before assembly. The aging strengthening effect has already optimized the mechanical properties (strength or hardness) of the roller sleeve. Therefore, the preheating temperature and hold time of the sleeves before assembly must be strictly controlled. Otherwise, the sleeves will continue to age during preheating, deteriorating their mechanical properties (known as overaging). To prevent the side effects of overaging, this technical solution can only be applied to very thin and small sleeves requiring short hold times. However, thicker and larger sleeves are now widely used, with upper thickness limits reaching 25 mm and sleeve diameters approaching 2000 mm. These large sleeves require hold times exceeding five hours after heating to temperature before assembly. If the patented solution is still used, the prolonged hold time above 300°C will inevitably cause overaging, resulting in a loss of the sleeve's originally excellent mechanical properties. Thirdly, the patented solution applies a prestress of 517 MPa to the sleeves through interference fit, which is close to 50% of the sleeve material's yield strength. To produce thick amorphous alloy strip or amorphous nanocrystalline strip with higher cooling rate requirements, sleeve materials with higher thermal conductivity are required. The mechanical properties of metal materials often change inversely with thermal conductivity, and roller sleeve materials with higher thermal conductivity have lower strength or hardness.For example, the tensile strength of low-Be copper alloy roller sleeves, which have high thermal conductivity, is only approximately 600-800 MPa. If the patent's technical solution is still used to assemble roller sleeves with higher thermal conductivity, the prestressed stress inside the sleeve will be too close to the tensile strength of the sleeve material. If macroscopic or microscopic defects such as inclusions or looseness exist within the sleeve, there is a risk of the sleeve breaking (or bursting). In other words, the patent's technical solution is only applicable to roller sleeves made of CuBe2 and is not suitable for sleeves made of materials with higher thermal conductivity.

[0008] Chinese invention patent applications CN111804733A and CN112247478A, respectively, disclose methods for assembling copper alloy roller sleeves for metal strip casting. The sleeves are designed to have an interference fit ratio of 1.8‰ or less between the sleeve and the core. Because the interference fit employed in these methods is too small to generate sufficient prestress within the sleeves, they are unsuitable for assembling sleeves used in the production of amorphous or nanocrystalline alloy strips.

[0009] Chinese invention patent application CN102582015A discloses a process for assembling a roller sleeve for amorphous strip: the sleeve is preheated to 160°C for 24 hours before being shrink-fitted onto the roller core. Because the sleeve preheating temperature used in this technique is too low, the sleeve's thermal expansion is too small, and the interference fit between the sleeve and the core must also be minimal, making it impossible to generate sufficient prestress within the sleeve. Furthermore, this assembly method only achieves an interference fit between the sleeve's wide ends and the end caps (flanges) at both ends of the core, while the entire sleeve's center region remains suspended. Consequently, after shrink-fitting, the sleeve's center region shrinks due to lack of support, resulting in a "slump" phenomenon and failing to generate the desired prestress. Summary of the Invention

[0010] In response to the above problems, the present invention discloses a cooling roller, comprising a roller sleeve and a roller core, wherein the roller sleeve is arranged on the outer periphery of the roller core, and the roller sleeve and the roller core are interference fitted; the interference ratio between the inner diameter of the roller sleeve and the outer diameter of the roller core is 2 to 3.5‰.

[0011] The roller sleeve material comprises copper alloy. After the roller sleeve is interference fitted with the roller core, the prestress formed inside the roller sleeve is 20-50% of the tensile strength of the roller sleeve material.

[0012] The cooling roller also includes support bars; the support bars are distributed on the inner surface of the roller sleeve or the outer circumferential surface of the roller core, the support bars are arranged axially along the roller core, and the height, width and spacing between adjacent support bars are not fixed.

[0013] Furthermore, the height of the support bar is less than or equal to 10 mm, the circumferential width of the support bar is 5 to 30 mm, and the circumferential spacing between adjacent support bars is 5 to 50 mm.

[0014] The present invention also discloses a method for assembling a cooling roller.

[0015] The assembly method comprises the following steps:

[0016] The roller sleeve is subjected to aging treatment, and the aging treatment and preheating are carried out simultaneously;

[0017] The heat-coated roller sleeve and roller core that have completed the aging treatment are interference-fitted and cooled to room temperature to obtain a cooling roller; wherein the interference ratio between the inner diameter of the roller sleeve and the outer diameter of the roller core is 2 to 3.5‰.

[0018] The aging treatment process is also a preheating process before the roller sleeve and roller core are assembled.

[0019] Furthermore, the aging treatment temperature is 300-550° C., and the holding time is 1-20 hours.

[0020] The assembly method further comprises performing the following operations before performing the aging treatment:

[0021] Design the interference ratio between the roller sleeve and the roller core;

[0022] The roller sleeve is machined according to the pre-designed interference ratio.

[0023] While the roller sleeve is being aged, the roller core is also being cold treated.

[0024] Furthermore, the cold treatment includes placing the roller core in a cold treatment furnace, introducing low-temperature gas, and reducing the temperature of the roller core to below -30°C.

[0025] Advantages of the present invention:

[0026] The present invention sets the interference ratio between the inner diameter of the roller sleeve and the outer diameter of the roller core between 2‰ and 3.5‰ according to different copper alloy roller sleeve materials, and sets the prestress inside the roller sleeve after assembly to 20% to 50% of the tensile strength of the roller sleeve material, thereby minimizing the thermal convexity of the roller sleeve during the belt making process and reducing cracks and pits on the roller surface caused by thermal fatigue, while also avoiding the risk of the roller sleeve being broken (bursting) due to excessive prestress.

[0027] According to the requirements for interference, the present invention designs reasonable shapes of the inner surface of the roller sleeve and the outer circumferential surface of the roller core, thereby ensuring the realization of the prestress of the roller sleeve; not only can the entire roller sleeve have the same prestress, but also different positions in the width direction of the roller sleeve can have different prestresses.

[0028] The present invention combines the aging treatment of the roller sleeve with the preheating process before the roller sleeve is assembled, which completely avoids the problem of over-aging that easily occurs during preheating in the prior art, which is to complete the aging treatment first and then perform machining and preheating before assembly. If necessary, the present invention can perform cold treatment on the roller core while preheating the roller sleeve, thereby increasing the dimensional margin between the cold roller core and the hot roller sleeve, reducing the accuracy requirements for the assembly mechanism, and allowing assembly to proceed more smoothly.

[0029] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 The figure shows a schematic cross-sectional view of the center of a cooling roller in the prior art;

[0032] Figure 2 A schematic diagram showing the interference fit state of a circular ring-shaped roller sleeve and a roller core with support strips on its outer surface in an embodiment of the present invention is shown;

[0033] Figure 3 A schematic diagram showing the interference fit state between a roller sleeve with support strips on its inner surface and a cylindrical roller core in an embodiment of the present invention is shown;

[0034] Figure 4 A schematic diagram of the deformation of the cooling roller sleeve due to heat in an embodiment of the prior art is shown;

[0035] Figure 5 A schematic diagram showing the surface temperature change of the cooling roller sleeve after the start of strip making in the prior art is shown;

[0036] Figure 6 A schematic diagram showing the change of internal stress at a certain point on the surface of a roller sleeve in one rotation cycle in the prior art is shown;

[0037] Figure 7 Shown is a flow chart of a cooling roller assembly method in the prior art;

[0038] Figure 8 A flow chart of a cooling roller assembly method according to an embodiment of the present invention is shown.

[0039] In the figure: 1. Roller sleeve; 2. Roller core.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] The present invention provides a cooling roller, comprising a roller sleeve 1 and a roller core 2. In order to achieve smooth assembly of the roller sleeve 1 and the roller core 2, avoid over-aging of the roller sleeve 1, and prevent prestress from being generated inside the roller sleeve 1, the interference ratio and prestress of the roller sleeve 1 and the roller core 2 must be designed.

[0042] The interference ratio between the roller sleeve 1 and the roller core 2 of the present invention ranges from 2.0 to 3.5‰. After the roller sleeve 1 is interference fitted with the roller core 2, the prestress (tensile stress along the circumferential direction of the roller sleeve) formed inside is 20 to 50% of the tensile strength of the roller sleeve material.

[0043] Among them, the calculation formula of interference ratio (interference amount) is:

[0044]

[0045] Wherein, d0 is the inner diameter of the roller sleeve 1 at room temperature; d1 is the outer diameter of the roller core 2 at room temperature.

[0046] For example, the cooling roller can be a combination of an annular roller sleeve 1 and a cylindrical roller core 2. The roller sleeve 1 is arranged on the outer periphery of the roller core 2. The roller sleeve 1 and the cylindrical roller core 2 are interference-fitted. A thin annular channel is formed between the inner surface of the roller sleeve 1 and the outer circumferential surface of the roller core 2. The inner surface of the roller sleeve 1 can be a flat and smooth cylindrical surface. The outer circumferential surface of the roller core 2 is distributed with a plurality of support bars extending in the axial direction (formed by the roller core 2 through machining), such as Figure 2 The support bar can also be provided on the inner surface of the roller sleeve 1 (formed by machining of the roller sleeve 1), as shown Figure 3 shown.

[0047] The support strips can be multiple axially extending strips or multiple cylinders distributed across the entire surface. The width and spacing of the support strips are not fixed, nor is their height. For example, the middle of the width of the roller sleeve 1 is often the belt-making location. To specifically eliminate thermal convexity at this location during belt making, the height of the support strips at this location on the inner surface of the roller sleeve 1 or the outer circumferential surface of the roller core 2 can be made higher than on the sides, ensuring that the height difference between the belt-making area and the flanking areas is between 0.1 and 2.0 mm. This ensures that the internal prestress of the roller sleeve in the belt-making area is greater than that on the flanking areas.

[0048] The support bars can be the same along the axial direction of the roller sleeve 1 or the roller core 2, so that the same interference is generated between the roller sleeve 1 and the roller core 2 at different axial positions, and the same prestress is generated at different axial positions inside the roller sleeve 1. For example, the support bar height does not exceed 10mm, the circumferential width is 5 to 30mm, and the circumferential spacing between adjacent support bars is 5 to 50mm. Figure 2 The support strips shown in the figure illustrate that when the sleeve 1 and core 2 are interference-fitted, the support strips on the outer circumference of the core 2 support the inner surface of the sleeve 1, generating a prestress of 200 to 500 MPa (i.e., tensile stress along the circumference of the sleeve 1) within the sleeve 1. The gaps between the support strips on the outer circumference of the core 2, together with the inner surface of the sleeve 1, form cooling water channels. High-speed cooling water flows through these channels, removing heat transferred from the outer surface of the sleeve 1 to the inner surface by forced convection.

[0049] In addition to the structure of the cooling roll, the material of the roller sleeve 1 and the internal structure of the roller core 2 also influence the performance of the cooling roll and subsequent strip production. The roller sleeve 1 can be made of, but is not limited to, copper alloys, with a thickness of 5-30 mm, an inner diameter of 400-2000 mm, and an axial width of 50-600 mm. After solution treatment and aging, the thermal conductivity ranges from 80-350 W / mK, and the tensile strength is ≥600 MPa. The internal structure of the roller core 2 must have sufficient rigidity to ensure that it does not significantly shrink when subjected to the shrinkage pressure of the roller sleeve 1 after assembly. Otherwise, if the roller core 2 undergoes significant shrinkage, the prestress generated within the roller sleeve 1 will be significantly less than the designed value.

[0050] Preferably, the roller sleeve 1 can be made of a copper alloy with a Be content of 1.7-2.1 wt%, and other elements, including but not limited to Ni, Co, Fe, Si, Al, Ti, Cr, P, Sn, Zn, and Pb, may be added with a total content not exceeding 10 wt%. After solution treatment and aging treatment, the interference ratio between the roller sleeve 1 and the roller core 2 is 2.5-3.5‰, the internal prestress of the roller sleeve 1 is 300-500 MPa, the thermal conductivity of the roller sleeve 1 material is in the range of 80-150 W / mK, and the tensile strength is ≥1000 MPa.

[0051] Preferably, the roller sleeve 1 can be made of a copper alloy with a Be content of 0.2-0.7 wt% and a total Ni and / or Co content of 0.5-2.5 wt%. Other elements, including but not limited to Ni, Co, Fe, Si, Al, Ti, Cr, P, Sn, Zn, and Pb, may be added with a total content not exceeding 10 wt%. After solution and aging treatment, the interference ratio between the roller sleeve 1 and the roller core 2 is 2.0-3.0‰, the internal prestress of the roller sleeve 1 is 180-400 MPa, the thermal conductivity of the roller sleeve 1 material is in the range of 150-300 W / mK, and the tensile strength is ≥600 MPa.

[0052] Preferably, the roller sleeve 1 can be made of a copper alloy with a Ni content of 2-10 wt%, and other elements including, but not limited to, Ni, Co, Fe, Si, Al, Ti, Cr, P, Sn, Zn, and Pb may be added, with a total content not exceeding 10 wt%. After solution treatment and aging treatment, the interference ratio between the roller sleeve 1 and the roller core 2 is 2.0-3.0‰, the internal prestress of the roller sleeve 1 is 180-400 MPa, the thermal conductivity of the roller sleeve 1 material is in the range of 100-300 W / mK, and the tensile strength is ≥600 MPa.

[0053] The present invention also provides a method for assembling a cooling roll. The invention utilizes a shrink-fit process for the interference fit between the roll sleeve 1 and the roll core 2. By presetting a reasonable interference fit and combining the aging treatment of the roll sleeve 1 with the shrink-fit process, prestress is generated within the roll sleeve 1 after assembly of the roll sleeve 1 and the roll core 2, thereby reducing thermal deformation and fatigue cracking of the roll sleeve 1 during the belt manufacturing process.

[0054] The assembly method of the cooling roller proposed by the present invention is as follows Figure 8 As shown, the specific steps include:

[0055] The roller sleeve 1 (solution treatment has been completed) and the roller core 2 are machined according to the pre-designed interference fit; illustratively, the outer surface of the roller core 2 can be machined into a gear-like shape by machining, and then each rack is equivalent to a support bar, which contacts the inner surface of the roller sleeve 1, supports the roller sleeve 1 and generates prestress inside the roller sleeve 1.

[0056] The machined roller sleeve 1 is subjected to aging treatment and preheating, that is, the aging treatment of the roller sleeve is combined with the preheating before assembly. The aging treatment process of the roller sleeve is also the preheating process before the roller sleeve and the roller core are assembled. The heating temperature is 300-550°C and the holding time is 1-20 hours. The aging treatment is to reheat the roller sleeve 1 that has completed the solid solution treatment to above 300°C and hold the temperature to precipitate the dispersion strengthening phase in the supersaturated alloy solid solution to obtain excellent mechanical properties.

[0057] The hot roller sleeve 1 and roller core 2 that have completed the aging treatment are assembled; after the temperatures of the two are consistent, the roller sleeve 1 is clamped on the roller core 2, and a predetermined tensile stress along the circumferential direction is generated inside the roller sleeve 1 to obtain a cooling roller assembly.

[0058] Install the assembled cooling roller assembly onto the belt making machine.

[0059] For example, when the interference fit is designed to be large, resulting in a small size difference between the hot roller sleeve 1 and the room temperature roller core 2, which makes assembly difficult, the roller core 2 can be cold-treated while the roller sleeve 1 is being aged, that is, the roller core 2 is placed in a cold treatment furnace, low-temperature gas is introduced and kept warm for a period of time, so that the temperature of the roller core 2 is reduced to below -30°C; the low-temperature gas can be generated by dry ice, liquid nitrogen, etc.; the cold treatment of the roller core 2 causes the roller core 2 to shrink to a certain extent, so as to increase the dimensional margin between the cold roller core 2 and the hot roller sleeve 1, reduce the requirements for the accuracy of the assembly mechanism, and make the hot assembly process go smoothly.

[0060] Preferably, for the roller sleeve 1 made of a copper alloy with a Be content of 1.7-2.1 wt%, the preheating temperature is 300-400° C. and the holding time is 1-20 hours.

[0061] Preferably, for the roller sleeve 1 made of a copper alloy with a Be content of 0.2-0.7 wt% and a total Ni and / or Co content of 0.5-2.5 wt%, the preheating temperature is 400-550° C. and the holding time is 1-20 hours.

[0062] Preferably, for the roller sleeve 1 made of copper alloy with a Ni content of 2 to 10 wt%, the preheating temperature is 400 to 500° C. and the holding time is 1 to 20 hours.

[0063] The present invention verifies through multiple embodiments and comparative examples that the cooling roller and assembly method proposed in the present invention are feasible and have better effects. The cooling rollers assembled using the conditions of Examples 1, 2, 3 and Comparative Examples 1, 2, 3 are respectively used to manufacture Fe-based amorphous alloy Fe of the same size. 79 Si9B 12 (atomic percentage) strip, the surface temperature of the cooling roller sleeve 1 changes after the strip making starts as follows Figure 7 As shown, Figure 7 The middle dashed line is the equilibrium temperature of the roller surface. The internal stress change of a certain point on the surface of the roller sleeve 1 during one rotation cycle is as follows: Figure 8 shown.

[0064] Example 1

[0065] The roller sleeve is made of CuBe2 alloy, which has a tensile strength of 1250MPa, an elastic modulus of 132GPa, a thermal conductivity of 105W / mK, and a thermal expansion coefficient of 17ppm. The inner surface of the roller sleeve is cylindrical with an inner diameter of 1191mm. The outer surface of the roller core is a gear-shaped support bar with an outer diameter of 1195mm. The designed interference ratio is 3.36‰ and the designed prestress is 443MPa.

[0066] A method for assembling a cooling roller comprises the following steps:

[0067] Machining the roller sleeve according to the pre-designed interference;

[0068] The machined roller sleeve is subjected to aging treatment and preheating. The preheating temperature is 330°C and the holding time is 8 hours. After the holding time is completed, the inner diameter of the hot roller sleeve is 1197mm. While the roller sleeve is preheating, the roller core is cold-treated at -70°C for 6 hours. The outer diameter of the roller core after cold treatment is 1193.7mm.

[0069] The preheated roller sleeve and the cold-treated roller core were assembled and cooled to room temperature to obtain a cooling roller. At this time, the actual inner diameter of the roller sleeve was 1194.9 mm, and the actual prestress inside the roller sleeve was 432 MPa.

[0070] After the assembled cooling roller is installed, the iron-based amorphous alloy Fe 79 Si9B 12 (atomic percent) of the strip.

[0071] Example 2

[0072] Roller sleeve material is CuBe 0.5 Co 2.5 Alloy, the material has a tensile strength of 750MPa, an elastic modulus of 140GPa, a thermal conductivity of 220W / mK, a thermal expansion coefficient of 18ppm, the inner surface of the roller sleeve is cylindrical, the inner diameter of the roller sleeve is 1915mm, the outer surface of the roller core is a gear-shaped support bar, the outer diameter of the roller core is 1920mm, the design interference ratio is 2.61‰, and the design prestress is 366MPa;

[0073] A method for assembling a cooling roller comprises the following steps:

[0074] Machining the roller sleeve according to the pre-designed interference;

[0075] The machined roller sleeve is subjected to aging treatment and preheating; the preheating temperature is 460°C and the holding time is 19 hours. After the holding is completed, the inner diameter of the hot roller sleeve is 1930mm; the roller core is not treated and the outer diameter of the roller core is 1920mm;

[0076] The preheated roller sleeve and the untreated roller core were assembled and cooled to room temperature to obtain a cooling roller. At this time, the actual inner diameter of the roller sleeve was 1919.7 mm, and the actual prestress inside the roller sleeve was 344 MPa.

[0077] After the assembled cooling roller is installed, the iron-based amorphous alloy Fe 79 Si9B 12 (atomic percent) of the strip.

[0078] Example 3

[0079] The roller sleeve is made of CuNiSi alloy, which has a tensile strength of 720MPa, an elastic modulus of 140GPa, a thermal conductivity of 230W / mK, and a thermal expansion coefficient of 16ppm. The inner surface of the roller sleeve is shaped with evenly distributed support blocks, and the inner diameter of the roller sleeve is 605mm. The outer surface of the roller core is cylindrical, and the outer diameter of the roller core is 606.3mm. The designed interference ratio is 2.15‰, and the designed prestress is 301MPa.

[0080] A method for assembling a cooling roller comprises the following steps:

[0081] Machining the roller sleeve according to the pre-designed interference;

[0082] The machined roller sleeve is subjected to aging treatment and preheating; the preheating temperature is 480°C and the holding time is 4 hours. After the holding is completed, the inner diameter of the hot roller sleeve is 609mm; the roller core is not treated and the outer diameter of the roller core is 606.3mm;

[0083] The preheated roller sleeve and the untreated roller core were assembled and cooled to room temperature to obtain a cooling roller. At this time, the actual inner diameter of the roller sleeve was 606.26 mm, and the actual prestress inside the roller sleeve was 292 MPa.

[0084] After the assembled cooling roller is installed, the iron-based amorphous alloy Fe 79 Si9B 12 (atomic percent) of the strip.

[0085] Comparative Example 1

[0086] The roller sleeve is made of CuBe2, which has a tensile strength of 1250MPa, an elastic modulus of 132GPa, a thermal conductivity of 105W / mK, and a thermal expansion coefficient of 17ppm. The inner surface of the roller sleeve is cylindrical with an inner diameter of 1191mm. The outer surface of the roller core is a gear-shaped support bar with an outer diameter of 1195mm. The designed interference ratio is 1.26‰ and the designed prestress is 166MPa.

[0087] A method for assembling a cooling roller comprises the following steps:

[0088] The roller sleeve after solution treatment is subjected to aging treatment, and the aging treatment time is 8 hours;

[0089] Machining the roller sleeve according to the pre-designed interference;

[0090] The machined roller sleeve is preheated to 330°C. After the heat preservation is completed, the inner diameter of the hot roller sleeve is 1197mm. The roller core is not processed and the outer diameter of the roller core is 1195mm.

[0091] The preheated roller sleeve and the untreated roller core were assembled and cooled to room temperature to obtain a cooling roller. At this time, the actual inner diameter of the roller sleeve was 1194.9 mm, and the actual prestress inside the roller sleeve was 155 MPa.

[0092] After the assembled cooling roller is installed, the iron-based amorphous alloy Fe 79 Si9B 12 (atomic percent) of the strip.

[0093] Comparative Example 2

[0094] Roller sleeve material is CuBe 0.5 Co 2.5 The material has a tensile strength of 750MPa, an elastic modulus of 140GPa, a thermal conductivity of 220W / mK, and a thermal expansion coefficient of 18ppm. The inner surface of the roller sleeve is cylindrical with an inner diameter of 1918mm. The outer surface of the roller core is a gear-shaped support bar with an outer diameter of 1920mm. The designed interference ratio is 1.04‰ and the designed prestress is 146MPa.

[0095] A method for assembling a cooling roller comprises the following steps:

[0096] The roller sleeve after solution treatment is subjected to aging treatment, and the aging treatment time is 19 hours;

[0097] Machining the roller sleeve according to the pre-designed interference;

[0098] The machined roller sleeve is preheated at a temperature of 300°C. After the heat preservation is completed, the inner diameter of the hot roller sleeve is 1928 mm. The roller core is not processed and the outer diameter of the roller core is 1920 mm.

[0099] The preheated roller sleeve and the untreated roller core were assembled and cooled to room temperature to obtain a cooling roller. At this time, the actual inner diameter of the roller sleeve was 1919.4 mm, and the actual prestress inside the roller sleeve was 102 MPa.

[0100] After the assembled cooling roller is installed, the iron-based amorphous alloy Fe 79 Si9B 12 (atomic percent) of the strip.

[0101] Comparative Example 3

[0102] The roller sleeve is made of CuNiSi, which has a tensile strength of 720MPa, an elastic modulus of 140GPa, a thermal conductivity of 230W / mK, and a thermal expansion coefficient of 16ppm. The inner surface of the roller sleeve is shaped with evenly distributed support blocks, with an inner diameter of 605.8mm. The outer surface of the roller core is cylindrical, with an outer diameter of 606.3mm. The designed interference ratio is 0.83‰, and the designed prestress is 116MPa.

[0103] A method for assembling a cooling roller comprises the following steps:

[0104] The roller sleeve after solution treatment is subjected to aging treatment, and the aging treatment time is 4 hours;

[0105] Machining the roller sleeve according to the pre-designed interference;

[0106] The machined roller sleeve is preheated at 300°C. After the heat preservation is completed, the inner diameter of the hot roller sleeve is 609mm. The roller core is not processed and the outer diameter of the roller core is 606.3mm.

[0107] The preheated roller sleeve and the untreated roller core were assembled and cooled to room temperature to obtain a cooling roller. At this time, the actual inner diameter of the roller sleeve was 606.2 mm, and the actual prestress inside the roller sleeve was 92 MPa.

[0108] After the assembled cooling roller is installed, the iron-based amorphous alloy Fe 79 Si9B 12 (atomic percent) of the strip.

[0109] The materials of the roller sleeves and their aging properties, the shapes and sizes of the roller sleeves and roller cores in the above embodiments and comparative examples are shown in Table 1. The assembly process of the roller sleeves and roller cores and the actual prestress inside the roller sleeves are shown in Table 2.

[0110]

[0111]

[0112]

[0113] To facilitate comparison of strip production results, all examples and comparative examples used identical process parameters during strip production: alloy liquid temperature of 1380±5°C, alloy liquid static pressure at the nozzle of 35±2 kPa, no curvature on the nozzle bottom, nozzle gap width of 0.40±0.02 mm, roll gap distance of 0.25±0.01 mm, cooling roll surface linear velocity of 22±1 m / s, cooling water flow rate of 150 t / h, and cooling water inlet temperature of 31±2°C. The nominal dimensions of the produced strips were: 142 mm width and 25 μm average thickness. Roll surface thermal crown was measured using a high-precision capacitive distance sensor, and strip width and transverse thickness distribution were measured using the method in accordance with the national standard GB / T 19345.1-2017. The measured data are shown in Table 3.

[0114]

[0115] As can be seen from Table 3, after adopting the technical solution of the present invention, the thermal crown of the roller surface and its difference during strip making are significantly reduced, which greatly improves the strip shape and makes the transverse thickness of the strip uniform. In particular, the concave core phenomenon is basically avoided. At the same time, the pits caused by thermal fatigue on the roller surface are eliminated or greatly reduced, which significantly improves the surface quality of the strip.

[0116] Principle of the present invention:

[0117] During the manufacturing process of amorphous and nanocrystalline strips, thermal crowning of the roller surface is caused by the thermal expansion of the roller sleeve, while cracks on the roller surface are caused by thermal fatigue resulting from periodic thermal shock to the roller surface. However, the pre-existing tensile stress within the roller sleeve can simultaneously reduce or prevent both thermal expansion and thermal fatigue during strip production. An interference fit involves making the outer diameter of the shaft core slightly larger than the inner diameter of the sleeve, using external force to squeeze the shaft core into the sleeve. When the interference fit is large, the sleeve must first be heated to expand, and then the shaft core is inserted. After the two cool down and reach the same temperature, the sleeve contracts and is tightened against the shaft core. This interference fit assembles the roller sleeve and core together, generating a predetermined prestress within the sleeve.

[0118] The present invention considers three aspects: roller sleeve prestress design, roller sleeve and roller core structure design, and roller sleeve and roller core assembly process; first, the roller sleeve prestress range is matched with the roller sleeve material: since different roller sleeve materials have different mechanical properties, the prestress range must be reasonably determined according to the mechanical properties of different materials. After determining the prestress, the roller sleeve interference is determined according to the prestress; roller sleeve and roller core structure: support bars are used that cover the inner surface of the roller sleeve or the outer circumferential surface of the roller core to ensure the realization of prestress inside the entire roller sleeve; roller sleeve and roller core assembly process: prevent the roller sleeve from being over-aged due to preheating and ensure that there is a sufficiently large dimensional margin between the hot roller sleeve and the cold roller core.

[0119] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cooling roller comprising a roller sleeve and a roller core, wherein the roller sleeve is arranged on the outer periphery of the roller core, and the roller sleeve and the roller core are interference fitted; Its characteristics are: The interference ratio between the inner diameter of the roller sleeve and the outer diameter of the roller core is 2 to 3.5‰; The cooling roller is obtained by an assembly method comprising the following steps: subjecting the roller sleeve to aging treatment, wherein the aging treatment process is also a preheating process before the roller sleeve and the roller core are assembled, and the aging treatment and preheating are carried out simultaneously; and interference fitting the hot-fitted roller sleeve and the roller core after the aging treatment is performed and the roller core is cooled to room temperature to obtain the cooling roller.

2. A cooling roller according to claim 1, characterized in that: The roller sleeve material comprises copper alloy. After the roller sleeve is interference fitted with the roller core, the prestress formed inside the roller sleeve is 20-50% of the tensile strength of the roller sleeve material.

3. The cooling roller according to claim 1, wherein: The cooling roller also includes support bars; the support bars are distributed on the inner surface of the roller sleeve or the outer circumferential surface of the roller core, the support bars are arranged axially along the roller core, and the height, width and spacing between adjacent support bars are not fixed.

4. A cooling roller according to claim 3, characterized in that: The height of the support bars is less than or equal to 10 mm, the circumferential width of the support bars is 5 to 30 mm, and the circumferential spacing between adjacent support bars is 5 to 50 mm.

5. A method for assembling a cooling roller, characterized in that: The assembly method comprises the following steps: The roller sleeve is subjected to aging treatment, and the aging treatment and preheating are carried out simultaneously; the aging treatment process is also the preheating process before the roller sleeve and the roller core are assembled; The heat-coated roller sleeve and roller core that have completed the aging treatment are interference-fitted and cooled to room temperature to obtain a cooling roller; wherein the interference ratio between the inner diameter of the roller sleeve and the outer diameter of the roller core is 2 to 3.5‰.

6. The method for assembling a cooling roller according to claim 5, wherein: The aging treatment temperature is 300-550° C., and the heat preservation time is 1-20 hours.

7. The method for assembling a cooling roller according to claim 5, wherein: The assembly method further comprises performing the following operations before performing the aging treatment: Design the interference ratio between the roller sleeve and the roller core; The roller sleeve is machined according to the pre-designed interference ratio.

8. The method for assembling a cooling roller according to claim 5, wherein: While the roller sleeve is being aged, the roller core is also cold-treated; the cold treatment includes placing the roller core in a cold treatment furnace, introducing low-temperature gas, and reducing the temperature of the roller core to below -30°C.

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