A method for factory assembly of ultra-heavy-duty large-size rolling mill stands

Abstract

A method for assembling an ultra-heavy, large-size rolling mill stand in a factory, relating to the field of heavy machinery assembly technology, is disclosed. The rolling mill stand includes two rail supports, two frames, and an upper crossbeam. The assembly method includes the following steps: S1, Site preparation: Based on the external dimensions and weight of the rolling mill stand, an assembly site with sufficient lifting and assembly capabilities is selected; S2, Constructing an assembly foundation platform: A modular support foundation is constructed at the foundation of the assembly site, formed by layering individual supports. This assembly method enables flexible, modular construction of the assembly foundation platform across regions, improves the overall rigidity of the modular assembly foundation, enhances the assembly accuracy of the rolling mill stand, and solves the problem of difficulty in adjusting the ultra-heavy mill stand into position after installing the upper crossbeam in traditional rolling mill stand assembly processes. This results in a rolling mill stand assembly process characterized by flexible layout and high rigidity.

Description

Technical Field

[0001] This invention relates to the field of heavy machinery assembly technology, specifically a method for assembling ultra-heavy-duty large-size rolling mill stands in a factory. Background Technology

[0002] The rolling mill stand is the "skeleton" of the rolling mill equipment, consisting of rail base 1, stand one 2, stand two 3, and upper crossbeam 4. A schematic diagram of the rolling mill stand assembly is shown below. Figure 1 As shown. During operation, the mill stand needs to withstand rolling forces of up to tens of thousands of tons, and its assembly accuracy directly determines the operating performance of the entire mill system. For large mills, in-plant trial assembly of the mill stand is a crucial link between "parts manufacturing" and "on-site installation." It can verify the rationality of the design, the machining accuracy of each part, the assembly accuracy of the mill stand, and identify hidden defects before on-site installation by the user.

[0003] This example uses the assembly process of the company's 5600 ultra-large and ultra-heavy rolling mill stand in the factory. The assembled 5600 rolling mill stand weighs approximately 900 tons, with each stand weighing over 400 tons and exceeding 16 meters in height. For the assembly of ultra-heavy rolling mill stands, due to the limited space in the factory, if conventional fixed assembly foundation platforms such as concrete foundation platforms are used, separate site planning, design, and pouring of the assembly foundation are required, which has disadvantages such as high construction costs, poor layout flexibility, and insufficient versatility.

[0004] Large rolling mill stands often employ a modular structure. Compared to integral stands, modular stands have more components, more mating surfaces, and higher assembly precision requirements. In this example, the components of the rolling mill stand are quite heavy and large in size, making hoisting difficult, especially stands 1-2 and 2-3. Therefore, in designing the hoisting process for each component of the stand, it is necessary to rationally plan the assembly path of each component and formulate a clear assembly process flow to ensure that the hoisting process of each component is smooth and accurate, free from scratches and bumps, and that the assembly precision meets the design requirements.

[0005] In summary, these ultra-heavy rolling mill stand parts are characterized by their heavy weight and large size, which brings difficulties to the assembly platform layout, assembly process planning, and assembly accuracy assurance in the rolling mill stand assembly process design. Therefore, it is necessary to propose an in-factory assembly method for ultra-heavy large-size rolling mill stands to achieve efficient, accurate, and high-precision in-factory assembly of large rolling mill stands. Summary of the Invention

[0006] The purpose of this invention is to propose a factory assembly method for ultra-heavy-duty large-size rolling mill stands, which overcomes the challenge of efficient and high-precision pre-assembly of ultra-heavy-duty rolling mill stands in limited spaces. It realizes the flexible cross-regional modular construction of the assembly foundation platform, improves the overall rigidity of the combined assembly foundation, enhances the assembly accuracy of the rolling mill stand, and solves the problem of difficulty in adjusting the ultra-heavy-duty stand into place after installing the upper beam in the traditional rolling mill stand assembly process. This makes the rolling mill stand assembly process flexible in layout, high in rigidity, smooth and accurate in assembly, high in assembly accuracy, and comprehensive in accuracy testing items.

[0007] The technical solution adopted in this invention is: a method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory. The rolling mill stand includes two rail supports, two frames, and an upper crossbeam. The assembly method includes the following steps:

[0008] S1. Site preparation: Based on the external dimensions and weight of the rolling mill stand, select an assembly site with sufficient lifting and assembly capacity.

[0009] S2. Constructing the assembly foundation platform: Construct a modular support foundation at the foundation of the assembly site. The modular support foundation is formed by arranging individual supports layer by layer. After each layer of supports is arranged, a heavy object is placed on top of it and held for a preset time to eliminate uneven gaps. Four casting bases are suspended on the modular support foundation. The center line of the installation position of the rolling mill stand is marked and laid out. An adjustment device is placed on the casting base to form the assembly foundation platform.

[0010] S3. Lifting the rail bases: Lift the two rail bases onto the adjustment device, and use the adjustment device to adjust the levelness, height difference, coplanarity and inner spacing of the two rail bases. After the adjustment is completed, fix the rail bases on the assembly base platform.

[0011] S4. Pressure application to eliminate gaps after rail seat hoisting: Place a heavy object on the rail seat to apply pressure, simulating the pressure of assembling two frames. After maintaining the pressure for a preset time, remove the heavy object.

[0012] S5. Hoisting the two frames: Hoist the two frames onto the rail base in sequence, adjust the fit accuracy of the contact surface between the frame and the rail base, connect and fix the two frames to the rail base respectively, and use a jack support device to provide auxiliary support under the two frames.

[0013] S6. Hoisting the upper crossbeam: Use the frame spacing adjustment tool to adjust the spacing between the upper inner sections of the two frames, then hoist the upper crossbeam between the two frames, and connect and fix it after adjustment;

[0014] S7. Post-assembly inspection and adjustment: Use a laser tracker to inspect the various assembly accuracy indicators of the rolling mill stand, use a feeler gauge to check the contact between the two stands and the rail base mating surfaces, and make adjustments according to the inspection results until the assembly accuracy is qualified.

[0015] As a preferred embodiment, in step S2, the combined support foundation is composed of supports of uniform size stacked in a three-layer structure. The number and specifications of the supports are selected according to the specifications of the rolling mill frame, so as to realize the modular construction and reuse of the assembly foundation platform.

[0016] As a preferred embodiment, the combined support foundation in step S2 is divided into two groups with a spacing, forming a gap between the two groups of combined support foundations for placing the jack support device.

[0017] As a preferred option, the casting base in step S2 is set to four pieces, which are respectively arranged on the basis of the combined support at the positions of the two rail seats.

[0018] As a preferred embodiment, in step S3, when adjusting the inner gap between the two rail seats using the adjustment device, the actual gap between the two rail seats is 2-3mm larger than the dimensions on the drawing, so as to facilitate the subsequent assembly of the two frames.

[0019] As a preferred embodiment, in step S5, the jack support device includes a support and a jack installed on the support, with the jack supporting the bottom of each frame.

[0020] As a preferred embodiment, in step S6, the frame spacing adjustment fixture includes a support rod, with four sets of adjusting screws at each end of the support rod for abutting the frame. Each set of adjusting screws can be rotated in or out axially on the support rod to expand the inner spacing of the two frames outward by 1-2 mm before the upper crossbeam is hoisted. A support ring is provided on the support rod to enhance stability and resistance to deformation.

[0021] As a preferred embodiment, the front end of the adjusting set screw is made of copper, or a shim is added between the adjusting set screw and the frame to prevent damage to the surface of the frame during adjustment.

[0022] As a preferred embodiment, in step S7, a laser tracker is used to detect various assembly accuracy indicators of the rolling mill stand, including: using a laser tracker to detect the levelness of the bottom surfaces of the two stands, the parallelism and asymmetry center deviation of the windows of the two stands, the perpendicularity of the side surfaces of the windows of the two stands to the horizontal plane of the rail seat, and the tilt of the side surfaces of the windows of the two stands.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. Assembly process of ultra-heavy-duty large-size rolling mill stand in the factory

[0025] A systematic process flow suitable for the assembly of ultra-heavy rolling mill stands in a factory is proposed. It integrates and innovates the process flow including: the construction of combined support foundations, the construction of high-rigidity assembly foundation platforms, pressure-based gap elimination methods, high-precision adjustment of rail seats, the method of stabilizing ultra-heavy and large-size mill stands, the application of mill stand spacing adjustment tooling to assemble the upper beam, and comprehensive inspection of assembly accuracy. This forms a set of high-precision assembly solutions for ultra-heavy rolling mill stands in a factory.

[0026] The advantages of the proposed assembly process are as follows: the assembly foundation layout is flexible and reusable, the overall rigidity is significantly enhanced, and the accuracy and stability are good; the assembly process is safe and smooth, realizing high-precision assembly of ultra-heavy rolling mill stands in the factory; the assembly accuracy detection indicators are comprehensive and reliable, which can verify the accuracy of the rolling mill stand structural design in advance, identify defects in parts processing and assembly, and reduce the user's on-site installation risks and overall costs.

[0027] 2. Method for constructing a high-rigidity assembly foundation platform for rolling mill stands

[0028] A modular, combined support foundation was designed, using a cast base and adjustment device to enhance the rigidity and precision of the assembly foundation platform. This enables the assembly platform to be quickly assembled, reused, and moved across regions, solving the problems of large footprint, long construction period, and poor adaptability associated with traditional fixed assembly foundations in factories. This significantly improves site utilization and assembly economy.

[0029] A phased, multi-stage pressure reduction method was proposed, which involves applying pressure three times during the construction of the modular support foundation and after the rail seat is installed. This method applies heavy objects to simulate the load on the mill frame and actively eliminates uneven gaps on the contact surface. It solves the problem of platform deformation and force flow obstruction caused by uneven gaps in the assembly of ultra-heavy mill frames using traditional modular assembly foundations. This improves the overall rigidity and precision stability of the mill frame assembly system and provides a reliable foundation for subsequent high-precision testing such as laser tracking.

[0030] 3. Efficient Assembly Method for Upper Crossbeams of Ultra-Heavy Rolling Mill Stands Based on Stand Spacing Adjustment Fixtures

[0031] In traditional rolling mill stand assembly methods, a certain distance is often pre-set during the hoisting of the stands. After the upper crossbeam is assembled, the stands are then horizontally pushed into place. For the ultra-heavy stands in this example, the traditional method is difficult to achieve horizontal pushing. To address this assembly problem of ultra-heavy stands, an innovative stand spacing adjustment fixture was designed. This fixture, by adjusting the set screws, allows for fine-tuning of the spacing between the upper inner spans of the two stands before the upper crossbeam is hoisted. This method breaks away from the traditional assembly process of "pre-reserving stand spacing - hoisting the upper crossbeam - horizontally pushing the stand." No pre-reserved spacing is needed during stand hoisting; the stands can be installed in one step. After the upper crossbeam is installed, there is no need for horizontal pushing, simplifying the assembly process and solving the problem of difficulty in horizontally pushing the heavy stands into place after the upper crossbeam is assembled, which is a common issue in traditional methods. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the rolling mill stand assembly.

[0034] Figure 2 This is a schematic diagram of the overall assembly of an ultra-heavy rolling mill stand in the factory.

[0035] Figure 3 This is a schematic diagram of the combined support foundation in this invention;

[0036] Figure 4 This is a schematic diagram of the adjustment device in this invention;

[0037] Figure 5 This is a schematic diagram of the pressure application and gap elimination of the first layer of the combined support foundation of the present invention;

[0038] Figure 6 This is a schematic diagram of the pressure application and gap elimination of the second-layer combined support foundation of the present invention;

[0039] Figure 7 This is a schematic diagram of the rail mounting reference in this invention;

[0040] Figure 8 This is a schematic diagram showing the pressure applied to eliminate gaps after the rail seat in this invention has been adjusted and installed;

[0041] Figure 9 This is a schematic diagram of the frame jack support device in this invention;

[0042] Figure 10This is a schematic diagram illustrating the adjustment of the internal spacing of the machine frame using the machine frame spacing adjustment fixture in this invention;

[0043] Figure 11 This is a schematic diagram of the frame spacing adjustment fixture in this invention.

[0044] Figure 12 This is a schematic diagram of the adjustment device in this invention.

[0045] Reference numerals in the attached drawings: 1. Rail base; 2. Frame 1; 3. Frame 2; 4. Upper crossbeam; 5. Frame spacing adjustment fixture; 6. Double-headed stud connector; 7. Adjustment device; 8. Casting base; 9. Combined support foundation; 10. Jack support device; 11. Foundation; 12. Weight; 13. Support rod; 14. Support ring; 15. Adjusting screw; 16. Eye bolt; 17. Vertical plate; 18. Cover plate; 19. Adjusting screw; 20. Upper slide; 21. Base. Detailed Implementation

[0046] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0047] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," etc., used in the specification and claims of this patent application do not express a limitation on quantity, but rather indicate the presence of at least one; the terms "first," "second," and "third," as used herein, should not be considered as a limitation on the order of components, but are merely for distinguishing different components; the terms "comprising," "including," etc., indicate that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0048] To more clearly describe the factory assembly method of this ultra-heavy-duty large-size rolling mill stand, in conjunction with the attached... Figure 1-12 This embodiment is described as follows:

[0049] like Figure 1-12 As shown, a method for assembling an ultra-heavy, large-size rolling mill stand in a factory is illustrated using the assembly process design of a 5600 rolling mill stand as an example. The method includes the construction of the rolling mill stand assembly foundation platform, pressure-based gap elimination methods, assembly process flow of the stand rail base, stand, and upper crossbeam, and stand assembly accuracy inspection, specifically including the following steps:

[0050] Step S1: Assembly site preparation

[0051] Taking into account the overall dimensions of the two rail bases 1, the two frames (Frame 1 2, Frame 2 3), and the upper crossbeam 4, a suitable assembly site with appropriate area and lifting height should be selected. The selection of the assembly site must ensure that the lifting capacity meets the assembly requirements, and that the levelness and load-bearing capacity of the assembly foundation platform meet the assembly requirements. Before assembly, the surfaces of all components should be carefully cleaned and kept clean.

[0052] Step S2: Construct the basic platform for rolling mill stand assembly.

[0053] Rolling mill stand assembly base platform, such as Figure 3 As shown, at the foundation 11 of the assembly site, supports of different quantities and specifications are hoisted and stacked according to the structural dimensions of the frame and the actual location of the assembly site to form a combined support foundation 9. Each support is neatly placed, leveled, and reasonably spaced. The combined support foundation 9 adopts a three-layer structure. After the first layer of supports is arranged from bottom to top, a heavy object 12 is placed on top to apply pressure and eliminate gaps. Figure 5 As shown, after maintaining pressure for the preset time, remove the weight 12 and begin hoisting the second layer of supports. After the arrangement is complete, apply pressure again to eliminate gaps, as shown. Figure 6 As shown, after holding for a period of time, remove the weight 12 and proceed with the subsequent assembly steps.

[0054] Then, four cast bases 8 are suspended above the combined support foundation 9. The four cast bases 8 are arranged on the combined support foundation 9, corresponding to the positions of the two rail supports 1. The alignment of each cast base 8 is adjusted to ensure that the horizontality and spacing of the cast bases 8 meet the assembly requirements. According to the rolling mill stand design drawings, the center lines of the two rail supports 1 and the stand installation positions are marked and laid out. After marking, according to... Figure 2 and Figure 4 As shown, several adjustment devices 7 are placed above the casting base 8. The adjustment devices 7 are arranged neatly, adjusted to be horizontal, and reasonably spaced. After the adjustment devices 7 are set up, an assembly base platform is formed.

[0055] The structure of the adjusting device 7 is as follows: Figure 12As shown, the main structure consists of a lifting eye screw 16, a vertical plate 17, a cover plate 18, an adjusting screw 19, an upper slide 20, and a base 21. The vertical plate 17 is welded to the base 21, and the lifting eye screw 16 is mounted on the vertical plate 17. The upper slide 20 is slidably mounted on the upper side of the base 21. The adjusting screw 19 passes laterally through a vertical groove at the upper end of the vertical plate 17. Two rings are fixed to the head of the adjusting screw 19, which are engaged on both sides of the vertical groove to restrict the lateral movement of the adjusting screw 19. The upper end of the vertical groove is closed by the cover plate 18. The threaded portion of the adjusting screw 19 engages with the threaded hole on the side of the upper slide 20, allowing the adjusting screw 19 to rotate laterally, driving the upper slide 20 to slide along the inclined surface of the base 21. The adjusting screw 19 rises and falls synchronously within its vertical groove, achieving height adjustment using the upper slide 20.

[0056] The modular support foundation 9 can be used to construct assembly foundations by combining different quantities and specifications of supports according to different rolling mill stand models. This allows for flexible arrangement of high-rigidity and high-reliability rolling mill stand assembly foundation platforms of different specifications, eliminating the need for additional fixed assembly foundations. After the rolling mill stand assembly task is completed, each support can be moved elsewhere without occupying work space. When reused, it can be quickly and flexibly transported to the work site, enabling cross-regional arrangement of rolling mill stand assembly foundations. The application of the casting base 8 enhances the rigidity of the stand assembly foundation platform and improves the assembly accuracy of the stand. The pressure-based gap elimination method can eliminate gaps between the contact surfaces of the assembly foundation platform and the rail seat before stand assembly, further enhancing the rigidity of the assembly foundation platform and improving the final assembly accuracy of the stand.

[0057] The combined support foundation 9 is divided into two groups with a spacing between them, forming a gap between the two groups of combined support foundations 9 for placing the jack support device 10.

[0058] Step S3, Lifting Rail Base

[0059] The two rail bases 1 are adjusted and installed onto the adjustment device 7 of the assembly base platform, with the inner side of the two rail bases 1 and the mating surface of the frame as reference A. Figure 7 As shown, adjust and widen the actual distance between the two rail supports 1 to be 2-3mm larger than the design dimensions on the drawing. Use the mating surface of the two rail supports 1 in the height direction with the frame as reference B, as shown... Figure 7 As shown, the two rail bases are aligned to be level, equal in height, and coplanar using a high-precision adjustment device 7, a straightedge, and a level. The inner sides of the two rail bases 1 are adjusted to be coplanar, and the levelness, coplanarity, and inner spacing of the two rail bases 1 are verified using a laser tracker to facilitate the subsequent assembly and adjustment of the two machine frames. After the rail bases 1 are assembled and adjusted, they are securely fixed with pressure plates, bolts, etc.

[0060] Step S4: Apply pressure to eliminate gaps after adjusting and installing the rail base.

[0061] After the assembly base platform is built and the two rail bases 1 are adjusted, uneven gaps exist between the contact surfaces. If the subsequent assembly of the heavy frame and upper crossbeam 4 is carried out directly, the assembly base platform will deform, and the gaps will block the force flow, resulting in uneven internal load distribution, thus causing the final assembly accuracy of the frame to deviate from the ideal state. Figure 8 As shown, pressure is applied again to eliminate gaps. After the rail base 1 is installed, a heavy object is placed on top to apply pressure, simulating the pressure on the rail base 1 and the assembly platform during the assembly of the rolling mill stand. After maintaining the pressure for a period of time, the heavy object is removed and subsequent assembly is carried out.

[0062] The above methods can eliminate internal gaps in advance, stabilize and compact the assembly base platform, improve overall rigidity, and ensure that the gravity of the frame and the upper crossbeam 4 is evenly transmitted to the ground inside the assembly base platform after assembly. This reduces the impact of gaps between the rail base and the contact surfaces of each adjustment device, as well as between the contact surfaces inside the assembly base platform, on the assembly accuracy of the frame.

[0063] Step S5: Hoisting the two frames

[0064] Install frame 1 (2) and frame 2 (3) onto rail base 1 in sequence. Ensure both frames are flush against the groove positioning surface of rail base 1, guaranteeing uniform contact. After adjusting the orientation, securely fix both frames to rail base 1 using connectors (double-headed stud connectors 6). Use a jack support device 10, consisting of a support and a jack, to further support the two frames securely. Figure 9 As shown. Due to the large weight and oversized dimensions of each frame, a safety officer must inspect the lifting points and lifting equipment on-site before lifting. During the lifting process, a designated person must direct the operation, lifting slowly to ensure a safe and reliable process, with no scratches on any contact surfaces and no collisions between any parts.

[0065] Step S6: Hoist the upper crossbeam

[0066] After the two frames are hoisted, use the adjusting screws on the tooling 5 to widen the gap between the upper inner sections of the two frames by 1-2mm compared to the design gap. Figure 2 and Figure 10 As shown. Then, try lifting the upper crossbeam 4 to ensure that the lifting posture is stable. Then, lift the upper crossbeam 4 onto the two frames. After adjustment, use the connecting parts to tighten it securely, and use a feeler gauge to check the contact between the upper crossbeam 4 and the frame.

[0067] When installing the upper crossbeam 4, the method of adjusting the spacing between the inner sections of the two frames using the frame spacing adjustment tool 5 is adopted. There is no need to reserve the spacing between the two frames, and the frame and the rail base 1 can be assembled in one step. This solves the problem that it is difficult to push the ultra-heavy frame into place horizontally after reserving the spacing in the traditional method.

[0068] Frame spacing adjustment fixture 5 Figure 11As shown, the main structure consists of a support rod 13, a support ring 14, and adjusting screws 15. Four sets of adjusting screws 15 are respectively arranged at both ends of the support rod 13 to abut against the frame. Each set of adjusting screws 15 can be screwed forward or backward in the axial direction of the support rod 13. A support ring 14 is arranged on the support rod 13 to enhance stability and resistance to deformation.

[0069] The frame spacing can be adjusted by ejecting the adjusting screw 15. The contact area between the front end of the adjusting screw 15 and the frame is made of copper. A shim can be added between the adjusting screw 15 and the frame during adjustment to prevent dents or scratches on the frame surface. Sufficient wrench space is provided between the adjusting screw 15 and the support rod 13 for easy operation. The symmetrically arranged support rings 14 on the support rod 13 improve the stability and deformation resistance of the rod and provide lifting restraints, facilitating the lifting of the frame spacing adjustment fixture.

[0070] Step S7: Post-assembly inspection and adjustment

[0071] After the upper crossbeam is assembled, a laser tracker is used to check the levelness of the bottom surfaces of the two stands, the center deviation of the parallelism and asymmetry of the two stand windows, the perpendicularity of the sides of the two stand windows relative to the horizontal plane of the rail base, and the inclination of the sides of the two stand windows. If the indicators fail the test, the stand assembly is adjusted according to the laser tracker test results until the assembly accuracy is qualified. A feeler gauge is used to check the contact between the two stands and the rail base 1 mating surfaces. Through the above assembly accuracy testing and adjustment, the processing quality, assembly accuracy, and design defects of the rolling mill stand parts can be verified, laying the foundation for smooth on-site installation by the rolling mill user.

[0072] Step S8, Disassembly

[0073] After all the assembly accuracy indicators of the frame are tested and qualified, the upper crossbeam 4, frame 2 3, frame 1 2, two rail bases 1 and the assembly base platform are removed in sequence. The components of the combined support base 9, the cast base 8, the adjustment device 7 and other parts are properly stored for use in the next assembly task.

[0074] The factory assembly method for ultra-heavy-duty large-size rolling mill stands proposed in this invention ensures the smooth and reliable assembly process of the stands in the factory. The accuracy testing and adjustment of the stand assembly allows for effective verification of the design, processing, and assembly indicators of the rolling mill stands, guaranteeing the quality of on-site installation and reducing the risk of parts needing to be returned to the factory for repair. Furthermore, this invention can provide guidance for the design of factory assembly processes for ultra-heavy-duty large-size rolling mill stands.

[0075] The parts not described in detail in the above embodiments are existing technologies.

[0076] It should be noted that although the present invention has been described through the above embodiments, the present invention may have many other embodiments. Without departing from the spirit and scope of the present invention, those skilled in the art can obviously make various corresponding changes and modifications to the present invention, but all such changes and modifications should fall within the scope of protection of the appended claims and their equivalents.

Claims

1. A method for factory assembly of an ultra-heavy-duty large-size rolling mill stand, the rolling mill stand comprising two rail bases (1), two frames, and an upper crossbeam (4), characterized in that, The assembly method includes the following steps: S1. Site preparation: Based on the external dimensions and weight of the rolling mill stand, select an assembly site with sufficient lifting and assembly capacity. S2. Constructing the assembly base platform: Construct a combined support foundation (9) on the foundation (11) of the assembly site. The combined support foundation (9) is formed by arranging individual supports layer by layer. After each layer of supports is arranged, a heavy object (12) is placed on top of it and held for a preset time to eliminate uneven gaps. Four casting bases (8) are suspended on the combined support foundation (9). The center line of the installation position of the rolling mill frame is marked and laid out. An adjustment device (7) is placed on the casting base (8) to form the assembly base platform. S3, hoisting the rail base: hoist the two rail bases (1) onto the adjustment device (7), and use the adjustment device (7) to adjust the levelness, height difference, coplanarity and inner spacing of the two rail bases (1). After the adjustment is completed, fix the rail bases (1) on the assembly base platform. S4. Pressure is applied after the rail seat is hoisted to eliminate gaps: a heavy object (12) is placed on the rail seat (1) to apply pressure, simulating the pressure of assembling two frames. After the pressure is maintained for a preset time, the heavy object (12) is removed. S5. Hoisting the two frames: Hoist the two frames onto the rail base (1) in sequence. After adjusting the fit accuracy of the contact surface between the frame and the rail base (1), connect and fix the two frames to the rail base (1) respectively, and use a jack support device (10) to support the two frames from below. S6. Hoisting the upper crossbeam: Use the frame spacing adjustment tool (5) to adjust the spacing between the upper inner sections of the two frames, then hoist the upper crossbeam (4) between the two frames, and connect and fix it after the adjustment is completed. S7. Post-assembly inspection and adjustment: Use a laser tracker to inspect the various assembly accuracy indicators of the mill stand, use feeler gauges to check the contact between the two stands and the rail seat (1), and adjust according to the inspection results until the assembly accuracy is qualified. The frame spacing adjustment fixture (5) used includes a support rod (13). Four sets of adjusting screws (15) are respectively configured at both ends of the support rod (13) to abut against the frame. Each set of adjusting screws (15) can be rotated in or out in the axial direction of the support rod (13) to open the inner gap of the upper part of the two frames outward by 1-2mm before the upper crossbeam (4) is hoisted. A support ring (14) is configured on the support rod (13) to enhance stability and resistance to deformation.

2. The method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory according to claim 1, characterized in that: In step S2, the combined support foundation (9) is made up of supports of uniform size stacked in three layers. The number and specifications of the supports are selected according to the specifications of the rolling mill frame in order to realize the modular construction and reuse of the assembly foundation platform.

3. The method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory according to claim 1, characterized in that: In step S2, the combined support foundation (9) is divided into two groups with a spacing between them, forming a gap between the two groups of combined support foundations (9) for placing the jack support device (10).

4. The method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory according to claim 1, characterized in that: In step S2, the casting base (8) is set to four pieces, which are respectively arranged on the combined support foundation (9) at the positions of the two rail seats (1).

5. The method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory according to claim 1, characterized in that: In step S3, when adjusting the inner gap of the two rail seats (1) using the adjustment device (7), the actual gap between the two rail seats (1) is 2-3mm larger than the size in the drawing, so as to facilitate the subsequent assembly of the two frames.

6. The method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory according to claim 1, characterized in that: In step S5, the jack support device (10) includes a support and a jack installed on the support, with the jack supporting the bottom of each frame.

7. The method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory according to claim 1, characterized in that: The front end of the adjusting screw (15) is made of copper, or a pad is added between the adjusting screw (15) and the frame to prevent damage to the surface of the frame during adjustment.

8. A method for assembling an ultra-heavy-duty large-size rolling mill stand in a factory according to claim 1, characterized in that, In step S7, a laser tracker is used to detect various assembly accuracy indicators of the rolling mill stand, including: using a laser tracker to detect the levelness of the bottom surface of the two stands, the parallelism and asymmetry center deviation of the two stands windows, the perpendicularity of the side of the two stands windows to the horizontal plane of the rail seat, and the tilt of the side of the two stands windows.

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