Split-type rolling mill housing assembly method

Abstract

The present invention relates to the technical field of the installation of rolling mill housings, and particularly to a method for assembling split rolling mill housings, which includes the following steps: A leveling support is arranged in the roll changing pit area, and the top elevation of the leveling support is flush with the foundation elevation of the roll grinding area; Then, an assembly platform is arranged on the leveling support and the foundation of the roll grinding area. The top surface of the convex part of the assembly platform is directly attached to the housing, and the concave surface is used for measuring the clearance between the beam and column and cold-fitting the positioning key; Hoist each component and level and align it; Install the connecting bolts, and cold-fit the positioning keys at the positions near the four corners of the window on the bottom and top surfaces of the housing; The surface of the assembly platform is a convex part and a concave surface with a concave-convex structure, which is convenient for measuring the clearance between the lower beam and column and installing the positioning key during the assembly of the housing; After assembly, the weight of the housing is transmitted to the continuous finger walls on both sides through the assembly platform and the leveling support, with stable force, and there is no need to set up a roof support frame in the basement, further saving construction costs and being time-saving and labor-saving.

Description

Technical Field

[0001] The present invention relates to the technical field of rolling mill housing installation, and particularly to an assembly method for a split rolling mill housing. Background Art

[0002] In the installation project of rolling mill equipment, rolling mill housings with a product width of less than 4300 mm are mostly designed as integral structures. For rolling mill housings with a product width of more than 4800 mm, due to their large size and heavy weight, their manufacturing, transportation, and installation are very difficult, and they are mostly designed as split structures. After the split rolling mill housings are delivered to the project site, an assembly platform needs to be set up on site, and then each component is assembled on the assembly platform. The existing assembly methods usually have the following problems: 1. For the assembly platform, there is currently no unified and standardized method, and it is usually set up rather arbitrarily, mostly in the form of an integral temporary support, with a large size and a large amount of steel used. The production, installation, and disassembly of the platform require a lot of labor; 2. The top surface of the assembly platform is mostly designed as a flat surface, which directly fits with the housing. It is very inconvenient to measure the beam-column fitting clearance and install the positioning key on the lower surface during the housing assembly; 3. The assembly platform is usually set on one side of the roll changing area of the rolling mill, and the lower part is supported on the basement roof with a large column spacing. Since the weight of the assembled rolling mill housing is often too large and exceeds the design strength of the roof, temporary supports often need to be set in the basement to protect the roof, which is time-consuming and laborious. Summary of the Invention

[0003] The present invention aims to solve the above problems, and thus provides an assembly method for a split rolling mill housing that reduces the amount of steel used in the assembly platform and facilitates the measurement of beam-column fitting clearance and the installation of positioning keys.

[0004] The technical solution adopted by the invention to solve the above problems is as follows:

[0005] An assembly method for a split rolling mill housing includes the following steps:

[0006] S1. Set up the assembly platform: In the roll changing pit area, leveling supports are set on the continuous retaining walls on both sides of the transverse center line of the rolling mill, and the top elevation of the leveling supports is flush with the foundation elevation of the roll grinding area. Then, an assembly platform is set on the leveling supports and the foundation of the roll grinding area. The assembly platform includes a cushion layer made of H-shaped steel, and box girders are spacedly arranged on the cushion layer as convex parts. The top surface of the convex parts directly fits with the housing. The gap between the convex parts serves as a concave surface for measuring the beam-column fitting clearance and cold-fitting the positioning key;

[0007] S2. Hoist each component: Hoist the inlet side column, upper crossbeam, lower crossbeam, and outlet side column onto the assembly platform in sequence, and complete the assembly and leveling and alignment of each component;

[0008] S3. Install the connecting bolts: The two sides of the frame are respectively connected by two groups of connecting bolts. One group of connecting bolts is used to fasten the upper crossbeam, the entrance-side column, and the exit-side column, and the other group of connecting bolts is used to fasten the lower crossbeam, the entrance-side column, and the exit-side column. When the connecting bolts are inserted, nuts are put on one end. After being completely inserted in place, nuts are installed on the other end for fastening. After fastening, the part of the bolt rod protruding from the nut is cut.

[0009] S4. Install the positioning keys: Cold-install the positioning keys at the positions near the four corners of the window on the bottom and top surfaces of the frame. Before installation, use the prefabricated liquid nitrogen container to place and cool the positioning keys.

[0010] Preferably, in step S2, the entrance-side column, the upper crossbeam, the lower crossbeam, and the exit-side column need to be hoisted by a crane. When the crane's trolley runs, the speed is reduced by the method of manual turning of the handwheel. The running speed of the trolley is 1 mm / s. When the crane's trolley runs at the lowest speed to assemble the components of the frame, for the components with a fit clearance of less than 0.2 mm, it is still not easy to meet the requirements. Often, due to the too fast hoisting speed, the mating surfaces of the components are knocked, which also affects the safety of the equipment and the operators. By manually turning the handwheel to reduce the running speed of the trolley, component collision can be avoided, and the safety of the equipment and the operators can be ensured.

[0011] Preferably, the connecting bolts in step S3 include inner small bolts and outer large bolts. An extension section is added to the bolt rod of the large bolt. The outer diameter of the extension section is the same as the diameter of the bolt rod of the large bolt, and the outer wall is provided with threads. A connecting part is provided on the extension section. A threaded groove is provided at the end of the bolt rod of the large bolt. The connecting part is threadedly connected in the threaded groove. When the bolts are fastened, a hydraulic tensioner is used for fastening. The connection position of the hydraulic tensioner is located at one end of the extension section of the large bolt or the end of the bolt rod of the small bolt. After fastening, the extension section is removed, and the part of the bolt rod of the large bolt protruding from the nut is cut. When using bolts with specifications of M250 - M350 to connect the split structures of each frame, the original factory bolts are usually not long enough and cannot be stretched by a hydraulic tensioner, and secondary lengthening is required. The secondary processing in the factory is difficult. Using the extension section for connection is simple and convenient, and it is easy to connect and disassemble.

[0012] Preferably, the process of fastening with a hydraulic tensioner includes

[0013] S31: Raise the pressure to 25% of the rated working pressure of the hydraulic tensioner, tighten the nut, and mark the position of the nut on the frame;

[0014] S32: Raise the pressure to 40% of the rated working pressure of the hydraulic tensioner, and at the same time use a dial indicator to detect the elongation of the bolt, and confirm that the elongation length is between 7.5 mm and 7.95 mm;

[0015] S33: Boost the pressure for the third time to 100% of the rated working pressure of the hydraulic tensioner, and use the dial indicator to detect the bolt elongation again. Confirm that the elongation length is between 9 mm and 10 mm.

[0016] S34: Rotate the large bolt nut by 300° and the small bolt nut by 330°.

[0017] Preferably, in step S4, the liquid nitrogen container is a rectangular trough box without an upper cover, and the upper cover is covered with a cotton quilt. The rectangular trough box is made by welding 3 - 5 mm steel plates. The side walls and bottom plate of the rectangular trough box are both double-layer structures, and the thickness of the sandwich between the double steel plates is 25 mm. It is simple to manufacture, has a low manufacturing cost and good heat insulation effect, improves the cooling efficiency and quality of the locating key, and can reduce the consumption and cost of liquid nitrogen at the same time.

[0018] The present invention adopting the above technical solution, compared with the prior art, its prominent features are:

[0019] This method adopts an assembly platform with modular assembly. The surface of the assembly platform is composed of convex parts and concave surfaces with a concave-convex structure, which is convenient for measuring the clearance between the lower side beam columns and installing the locating key during the assembly of the mill housing; the leveling bracket and the assembly platform have a simple structure, are convenient for disassembly and assembly, and the installation structure is standardized, reducing the consumption of steel and labor; the weight of the assembled mill housing is transmitted to the continuous finger walls on both sides through the assembly platform and the leveling bracket, with stable force, and there is no need to set up a roof support frame in the basement, further saving the construction cost and being time-saving and labor-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram during the assembly of the split mill housing according to the embodiment of the present invention;

[0021] Figure 2 It is a schematic structural diagram of the split mill housing according to the embodiment of the present invention;

[0022] Figure 3 It is a schematic structural diagram of the large bolt and the extension section according to the embodiment of the present invention;

[0023] Figure 4 It is a schematic structural diagram of the assembly platform according to the embodiment of the present invention;

[0024] Figure 5 It is a schematic side view structural diagram of the assembly platform according to the embodiment of the present invention;

[0025] Figure 6 It is a schematic structural diagram of the leveling bracket according to the embodiment of the present invention;

[0026] Figure 7 It is a schematic top view structural diagram of the leveling bracket according to the embodiment of the present invention;

[0027] Figure 8Schematic diagram of the position of the assembly platform according to the embodiment of the present invention.

[0028] In the figure: 1. Continuous supporting wall; 2. Foundation of the roller grinding area; 3. Leveling support; 301. Column; 302. Connecting cross beam; 303. Cross tension bar; 4. Cushion layer; 5. Box girder; 6. Housing; 601. Inlet side column; 602. Outlet side column; 603. Upper cross beam; 604. Lower cross beam; 7. Connecting bolt; 701. Small bolt; 702. Large bolt; 7021. Extension section; 8. Positioning key; A. Transverse center line of the rolling mill. Specific embodiments

[0029] The present invention will be further described below in conjunction with embodiments. The purpose is only to better understand the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0030] As Figures 1 to 8 shown, a split housing assembly method for a rolling mill includes the following steps:

[0031] S1. Set up the assembly platform: In the roll change pit area, set up a leveling support 3 on the continuous supporting walls 1 on both sides of the transverse center line A of the rolling mill. The top elevation of the leveling support 3 is flush with the elevation of the foundation 2 of the roller grinding area; then set up an assembly platform on the leveling support 3 and the foundation 2 of the roller grinding area. The assembly platform includes a cushion layer 4 made of H-shaped steel, and box girders 5 are arranged at intervals on the cushion layer 4 as convex parts. The top surface of the convex parts is directly attached to the housing 6; the gaps between the convex parts are used as concave surfaces for measuring the clearance between beams and columns and cold-fitting the positioning keys 8.

[0032] The leveling support 3 includes two sets of column supports arranged symmetrically on the left and right. The two sets of column supports are connected by a cross tension bar 303. Each set of column supports includes 6 columns 301. The 6 columns 301 are arranged in two columns, with 3 in each column. Connecting cross beams 302 are arranged between the 3 columns in each column and between the two columns of columns 301 to connect the 6 columns 301 into a whole. The connecting cross beams 302 are arranged in two layers, respectively located at the top and at half of the column 301. The top surface elevation of the connecting cross beam 302 located at the top layer is flush with the top of the column 301, and the top of the column 301 is flush with the elevation of the foundation 2 of the roller grinding area. Among them, the columns 301 and the connecting cross beams 302 are made of H-shaped steel, and the cross tension bar 303 is made of angle steel.

[0033] S2, Hoisting of each component: Hoist the inlet-side column 601, upper crossbeam 603, lower crossbeam 604, and outlet-side column 602 onto the assembly platform in sequence, and complete the assembly and leveling and alignment of each component; among them, the allowable deviation for the horizontality adjustment is 0.03 / 1000, and the allowable deviation for the perpendicularity over the entire height is 0.2. After adjustment, use a hydraulic jack for adjustment, an electronic level, and a square level for inspection. The paint film on the measurement points of each component should be scraped off for measurement to ensure the measurement accuracy.

[0034] The inlet-side column 601, upper crossbeam 603, lower crossbeam 604, and outlet-side column 602 need to be hoisted using a crane. When the crane's trolley runs, the speed is reduced by manually turning the handwheel. The trolley running speed is 1 mm / s; reducing the trolley running speed by manually turning the handwheel can avoid component collisions and ensure the safety of the equipment and operators.

[0035] Reducing the speed by manually turning the handwheel is a method well-known to those skilled in the art. That is, the active transmission structure of the crane's trolley is driven by a motor to drive the reducer, which in turn drives the trolley. By continuously manually turning the motor cooling fan blade to drive the motor, the motor runs at an ultra-low speed, making the crane running speed 1 mm / s.

[0036] S3, Installing the connecting bolts 7: On both sides of the housing 6, they are respectively connected by two groups of connecting bolts 7. One group of connecting bolts 7 is used to fasten the upper crossbeam 603 and the inlet-side column 601 and the outlet-side column 602, and the other group of connecting bolts 7 is used to fasten the lower crossbeam 604 and the inlet-side column 601 and the outlet-side column 602; when the connecting bolts 7 are inserted, a nut is put on one end, and the screw thread of the screw rod protrudes 10 mm from the nut. After being completely inserted in place, a nut is installed on the other end for fastening. After fastening, the part of the screw rod of the connecting bolt 7 that protrudes from the nut is cut.

[0037] Furthermore, the connecting bolt 7 includes an inner small bolt 701 and an outer large bolt 702. The screw rod of the large bolt 702 is provided with an extension section 7021. The outer diameter of the extension section 7021 is the same as the diameter of the screw rod of the large bolt 702, and the outer wall is provided with a thread. A connecting part is provided on the extension section 7021. A thread groove is provided at the end of the screw rod of the large bolt 702, and the connecting part is threadedly connected in the thread groove; when the bolt is fastened, a hydraulic tensioner is used for fastening. The connection position of the hydraulic tensioner is located at one end of the extension section 7021 of the large bolt 702 or the end of the screw rod of the small bolt 701; after fastening, the extension section 7021 is removed, and the part of the screw rod of the large bolt 702 that protrudes from the nut is cut; the process of fastening with the hydraulic tensioner includes,

[0038] S31: Raise the pressure to 350 BAR (25% of the rated value), tighten the nut, and mark the position of the nut on the housing 6;

[0039] S32: Boost the pressure to 600 BAR (40% of the rated value), and at the same time use a dial indicator to detect the elongation of the bolts, and confirm that the elongation length is between 7.5 mm and 7.95 mm;

[0040] S33: Boost the pressure to 1400 BAR (100% of the rated value) for the third time, the maximum tightening force reaches 3000 t, and use a dial indicator to detect the elongation of the bolts again, and confirm that the elongation length is between 9 mm and 10 mm;

[0041] S34: Rotate the nut of the large bolt 702 by 300°, and rotate the nut of the small bolt 701 by 330°.

[0042] Two sets of connecting bolts 7 are provided. One set of bolts (2 large bolts 702 and 2 small bolts 701 each) is used to fasten the upper cross beam 603 and the inlet side column 601 and the outlet side column 602, and the other set of bolts (2 large bolts 702 and 2 small bolts 701 each) is used to fasten the lower cross beam 604 and the inlet side column 601 and the outlet side column 602; when the connecting bolts 7 are tightened, the tightening sequence is as follows: first tighten one large bolt 702 at the lower right corner and one small bolt 701 at the upper left corner of the lower cross beam 604 and the inlet side column 601 and the outlet side column 602; then tighten one large bolt 702 at the upper left corner and one small bolt 701 at the lower right corner of the upper cross beam 603 and the inlet side column 601 and the outlet side column 602; then tighten one large bolt 702 at the lower left corner and one small bolt 701 at the upper right corner of the upper cross beam 603 and the inlet side column 601 and the outlet side column 602; finally tighten the remaining connecting bolts 7 of the lower cross beam 604 and the inlet side column 601 and the outlet side column 602.

[0043] During cutting, use the cutting saw for the root of the protruding column with the publication number CN102837067B, which can realize the root cutting of the protruding column, directly cut the part of the large bolt 702 screw rod exposed from the nut at the root, and improve the cutting speed and the forming quality of the cutting section.

[0044] S4, installation of the positioning key 8: Cold-install the positioning key 8 at the positions near the four corners of the window on the bottom and top surfaces of the housing 6. Before installation, use the prefabricated liquid nitrogen container to place and cool the positioning key 8; the liquid nitrogen container is a rectangular trough box without an upper cover, and the upper cover is covered with a cotton quilt. The rectangular trough box is made of 3-5 mm steel plates by welding. The side walls and the bottom plate of the rectangular trough box are both double-layer structures, and the thickness of the sandwich between the double-layer steel plates is 25 mm; it is simple to manufacture, has a low manufacturing cost and good heat insulation effect.

[0045] The beneficial effects of the present invention are as follows: By using the leveling support 3 and the assembly platform, the amount of steel used is reduced, and the labor required for manufacturing, installation and disassembly is decreased; The top surface of the assembly platform is designed as a concave-convex surface, which is convenient for measuring the fitting clearance between various components during the assembly of the housing 6 and for installing the positioning key 8; The assembly platform is arranged in the center of the roll-changing area of the rolling mill. The self-weight of the housing 6 is transmitted to the formal continuous supporting walls on both sides of the transverse center line A of the rolling mill in the basement through the load of the assembly platform, so that there is no need to set up temporary supports in the basement to protect the roof, saving the costs and labor for manufacturing and installing the temporary supports; During hoisting, by manually turning the shaft to reduce the speed, the requirement for the fitting clearance of the components of the housing 6 below 0.2 mm is met, and at the same time, the safety of the equipment and operators is ensured; By adding the extension section 7021, the length of the screw part is increased, avoiding the problems of too long manufacturing length and reduced performance of the bolts, and it is easy to disassemble and assemble.

[0046] The above are only the preferred and feasible embodiments of the present invention, and do not limit the scope of the rights of the present invention. Any equivalent changes made by using the content of the specification and drawings of the present invention are included in the scope of the rights of the present invention.

Claims

1. A method for assembling a split housing of a rolling mill, characterized in that, The steps are as follows: S1. Set up the assembly platform: In the roll-changing pit area, leveling brackets are set on the continuous retaining walls on both sides of the transverse center line of the rolling mill. The top elevation of the leveling brackets is flush with the foundation elevation of the roll grinding area. Then, an assembly platform is set on the leveling brackets and the foundation of the roll grinding area. The assembly platform includes a cushion layer made of H-shaped steel, and box girders are spaced on the cushion layer as convex parts. The top surface of the convex parts is directly attached to the housing. The gap between the convex parts serves as a concave surface for measuring the clearance between beams and columns and for cold-fitting the locating keys. S2. Hoist each component: Hoist the inlet-side column, upper crossbeam, lower crossbeam, and outlet-side column onto the assembly platform in sequence, and complete the assembly and leveling and alignment of each component. S3. Install the connecting bolts: The two sides of the housing are respectively connected by two groups of connecting bolts. One group of connecting bolts is used to fasten the upper crossbeam to the inlet-side column and the outlet-side column, and the other group of connecting bolts is used to fasten the lower crossbeam to the inlet-side column and the outlet-side column. When the connecting bolts are inserted, nuts are put on one end. After being completely inserted, nuts are installed on the other end for fastening. After fastening, the part of the bolt rod protruding from the nut is cut. S4. Install the locating keys: Cold-fit the locating keys at the positions near the four corners of the window on the bottom and top surfaces of the housing. Before installation, use a prefabricated liquid nitrogen container to place and cool the locating keys.

2. The split housing assembly method of a rolling mill according to claim 1, wherein: In step S2, the inlet-side column, upper crossbeam, lower crossbeam, and outlet-side column need to be hoisted by a crane. When the crane trolley runs, the speed is reduced by the method of manual handwheeling, and the trolley running speed is 1 mm / s.

3. The split type rolling mill housing assembling method according to claim 1, wherein: The connecting bolts in step S3 include inner small bolts and outer large bolts. An extension section is added to the bolt rod of the large bolt. The outer diameter of the extension section is the same as the diameter of the bolt rod of the large bolt, and the outer wall is provided with threads. A connecting part is provided on the extension section. A threaded groove is provided at the end of the bolt rod of the large bolt. The connecting part is threadedly connected in the threaded groove. When the bolts are tightened, a hydraulic tensioner is used for tightening. The connection position of the hydraulic tensioner is located at one end of the extension section of the large bolt or the end of the bolt rod of the small bolt. After tightening, the extension section is removed, and the part of the bolt rod of the large bolt protruding from the nut is cut.

4. The split type rolling mill housing assembly method according to claim 3, characterized in that: The tightening process of the hydraulic tensioner includes S31: Raise the pressure to 25% of the rated working pressure of the hydraulic tensioner, tighten the nut, and mark the position of the nut on the housing. S32: Raise the pressure to 40% of the rated working pressure of the hydraulic tensioner. At the same time, use a dial indicator to detect the elongation of the bolt, and confirm that the elongation length is between 7.5 mm and 7.95 mm. S33: Raise the pressure for the third time to 100% of the rated working pressure of the hydraulic tensioner. Use the dial indicator to detect the elongation of the bolt again, and confirm that the elongation length is between 9 mm and 10 mm. S34: Rotate the nut of the large bolt by 300° and the nut of the small bolt by 330°.

5. The split type rolling mill housing assembly method according to claim 1, characterized in that: In step S4, the liquid nitrogen container is a rectangular trough box without a top cover, and the top cover is covered with a cotton-padded quilt. The rectangular trough box is made of 3-5 mm steel plates by welding. The side walls and bottom plate of the rectangular trough box are both double-layer structures, and the thickness of the sandwich between the double-layer steel plates is 25 mm.

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