A lifting method for a double-lift rolling mill stand

Abstract

This invention discloses a lifting method for a rolling mill stand using two cranes, belonging to the technical field of lifting equipment. It is mainly used for lifting extra-long, extra-wide, and extra-heavy objects using two cranes of different specifications. The technical problem this invention aims to solve is to provide a lifting method for a rolling mill stand using two cranes, comprising: connecting a lifting tool to a first crane, a second crane, and the rolling mill stand; connecting a first and second lifting lug on the top of the lifting tool to the hooks of the first and second cranes, and connecting a third and fourth lifting lug on the bottom of the lifting tool to the mill lifting point of the rolling mill stand; lifting and erecting the rolling mill stand; transferring the rolling mill stand to the installation position; and lowering and installing the rolling mill stand. This lifting method enables the safe lifting of extra-heavy rolling mill stands by two cranes of different specifications without the need for additional reloading of cranes of the corresponding specifications, effectively reducing the construction cost of equipment installation, and the lifting tool is simple to manufacture.

Description

Technical Field

[0001] This invention relates to the field of lifting and hoisting equipment technology, and in particular to a hoisting method for a rolling mill frame using a dual-machine lifting system. Background Technology

[0002] When installing heavy equipment indoors, if the installation location cannot meet the working environment of a truck crane, overhead cranes are often used for lifting and transporting the equipment. For example, during the installation of the 18-roll mill stand (archway) of a stainless steel black pickling and rolling mill unit in a steel plant, the weight of a single mill stand was 44 tons. The installation location could not meet the working environment of a truck crane, so an overhead crane was used to lift the mill stand. At the construction site, multiple overhead cranes of different specifications are usually set up within the same span for lifting. However, due to the excessive weight of the individual mill stand, a single overhead crane cannot lift it, so at least two overhead cranes are required to work together. When adjacent overhead cranes are not... When using overhead cranes of the same specifications, i.e., one 32T overhead crane and one 16T overhead crane, although they can lift a 44-ton rolling mill stand, the center distance between the two cranes of different specifications is greater than the width of the lifting lugs of the rolling mill stand (the center distance between the 32T and 16T overhead cranes is 6944mm, which is greater than the width of the lifting lugs of the aforementioned 18-roll rolling mill stand, 2550mm). During lifting, the wire ropes on the overhead cranes that are adapted to the lifting lugs of the rolling mill stand will deviate, making it impossible to lift the rolling mill stand vertically. It cannot be guaranteed whether the lifted rolling mill stand meets the rated load range that the overhead crane can bear, resulting in certain safety hazards when lifting the rolling mill stand. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a lifting method for a rolling mill frame with two cranes, which is mainly used for lifting objects that are too long, too wide, or too heavy by two cranes of different specifications, so as to achieve the purpose of safely lifting objects of different specifications by two cranes of different specifications together when the objects being lifted are too long, too wide, or too heavy.

[0004] The present invention discloses a hoisting method for a double-lift rolling mill stand, comprising the following steps:

[0005] Step 1: Connect the hoisting equipment to the first overhead crane, the second overhead crane, and the rolling mill frame;

[0006] Both the first and second gantry cranes are equipped with wire ropes, and the lower ends of the wire ropes are equipped with hooks for hoisting. The hoisting tool includes an I-beam composed of a top plate, a web plate, and a bottom plate. The top plate is equipped with upper lifting lugs for connecting to the hooks of the first and second gantry cranes. The upper lifting lugs include a first lifting lug and a second lifting lug. The first lifting lug and the second lifting lug are respectively located at both ends of the top plate. The distance between the first lifting lug and the second lifting lug is equal to the distance between the first and second gantry cranes. The first lifting lug is connected to the hook of the first gantry crane, and the second lifting lug is connected to the hook of the second gantry crane. Below the bottom plate, there are lower lifting lugs for connecting to the rolling mill stand. The lower lifting lugs include a third lifting lug and a fourth lifting lug. The distance between the third lifting lug and the fourth lifting lug is equal to the distance between the rolling mill stand. Both the third lifting lug and the fourth lifting lug are equipped with hoisting straps, and the two hoisting straps are connected to the rolling mill hoisting points on the rolling mill stand.

[0007] The horizontal distance between the third lifting lug and the first lifting lug is X1, and the horizontal distance between the fourth lifting lug and the first lifting lug is X2; X1 and X2 are:

[0008]

[0009] X2 = X1 + L2;

[0010] Where: F1—theoretical force on the first traction machine, N; F2—theoretical force on the second traction machine, N; G1—weight of the lifting tool between the first and third lifting lugs, N. G2—The weight of the lifting equipment located between the third and second lifting lugs, in N. G3—Weight of the mill stand being hoisted, N; G—Weight of the hoisting equipment, N; L1—Horizontal distance between the hooks of the first and second gantry cranes, mm; L2—Horizontal distance between the third and fourth lifting lugs, i.e., the horizontal distance between the two mill hoisting points on the mill stand, mm; X1—Horizontal distance between the third and first lifting lugs, mm; X2—Horizontal distance between the fourth and first lifting lugs, mm.

[0011] Step 2: Lift and erect the rolling mill frame; the first and second overhead cranes simultaneously drive the lifting tools to lift the rolling mill frame off the ground and make it perpendicular to the ground;

[0012] Step 3: Transfer the mill stand to the installation position; the first and second overhead cranes simultaneously move the hoisting tools horizontally to transfer the mill stand to the installation position;

[0013] Step 4: Lower and install the rolling mill frame; the first and second overhead cranes simultaneously move the hoisting tools downwards until the rolling mill frame lands on the rolling mill base. After installing the rolling mill frame on the rolling mill base, disconnect the hoisting belt from the rolling mill frame.

[0014] Furthermore, step two also includes a safety inspection. The mill stand is lifted 100mm off the ground, and the connection between the mill stand and the lifting tools needs to be inspected.

[0015] Furthermore, the web plate has ribs on both the left and right sides with the same height as the web plate, and multiple sets of the ribs are spaced apart on the web plate along the length of the web plate.

[0016] As a preferred embodiment, both ends of the I-beam are provided with end caps for connecting the top plate and the bottom plate.

[0017] As a preferred embodiment, a side sealing plate is also provided between the two end sealing plates for connecting the two end sealing plates. The length of the side sealing plate is the same as the length of the web plate. The side sealing plate and the end sealing plate cover the I-beam to form a box girder.

[0018] Furthermore, the center of the first lifting lug and the center of the second lifting lug are 200mm away from the end of the top plate.

[0019] Furthermore, the first, second, third, and fourth lifting lugs are all made of steel plates and are welded to the I-beam with double-sided welds.

[0020] The beneficial effects of this invention are as follows: The method for lifting a rolling mill stand using a dual-machine lifting system allows for the use of readily available Q235 steel, common on construction sites, making the lifting tools inexpensive and simple to manufacture. It fully utilizes existing overhead cranes on the construction site, eliminating the need for additional cranes of the appropriate specifications, thus effectively reducing equipment installation costs. Furthermore, by connecting the first and second overhead cranes to the rolling mill stand using the lifting tools, the vertical angle between the wire ropes on the first and second overhead cranes and the rolling mill stand remains at 180° throughout the lifting process, greatly ensuring the safety of the machine. The method ensures the safe load of the overhead cranes and wire ropes, and the lifting of the mill stand will not exceed the rated lifting capacity of the lifting tools and the two overhead cranes. This effectively guarantees the installation and lifting of the equipment when using two overhead cranes of different specifications to lift the mill stand together, while reducing the safety risks during lifting operations. When using this method to transfer the mill stand, the trolleys on both overhead cranes can be directly operated for movement, which reduces the requirements for the coordination of the two overhead cranes, reduces the pressure on the crane operators, and improves the accuracy of the lifting operation. The lifting tools used in this method are designed with detailed calculations, which greatly ensures the safe implementation of the lifting operation. Attached Figure Description

[0021] Figure 1 : A schematic diagram of the structure of the hoisting tool used in this invention;

[0022] Figure 2 : Another structural schematic diagram of the hoisting tool used in this invention;

[0023] Figure 3 : A schematic diagram of the use of lifting tools to lift the mill stand using overhead crane equipment;

[0024] Figure 4 : A schematic diagram showing the connection between the hoisting tools, the overhead crane, and the rolling mill stand;

[0025] Figure 5 : A schematic diagram of the structure for lifting the rolling mill stand off the ground;

[0026] Figure 6 Schematic diagram of the structure of the transfer rolling mill stand;

[0027] Reference numerals: 1-Lifting tool; 11-Top plate; 111-First lifting lug; 112-Second lifting lug; 12-Web plate; 13-Bottom plate; 131-Third lifting lug; 132-Fourth lifting lug; 14-End sealing plate; 15-Rib plate; 16-Side sealing plate; 17-Lifting belt; 2-Tractor equipment; 21-First tractor; 22-Second tractor; 23-Wire rope; 24-Hook; 25-Locking component; 3-Rolling mill frame; 31-Rolling mill lifting point. Detailed Implementation

[0028] The present invention will be further described below.

[0029] This invention provides a lifting method for a double-machine lifting rolling mill stand, mainly used for lifting extra-long, extra-wide, and extra-heavy objects using two overhead cranes of different specifications, including the following steps:

[0030] Step 1: Connect the hoisting tool 1 to the first overhead crane 21, the second overhead crane 22, and the rolling mill frame 3;

[0031] like Figures 1-6As shown, both the first gantry crane 21 and the second gantry crane 22 are equipped with wire ropes 23, and the lower ends of the wire ropes 23 are equipped with hooks 24 for hoisting. The hoisting tool 1 includes an I-beam composed of a top plate 11, a web plate 12, and a bottom plate 13. The top plate 11 is equipped with upper lifting lugs for connecting with the hooks 24 of the first gantry crane 21 and the second gantry crane 22. The upper lifting lugs include a first lifting lug 111 and a second lifting lug 112. The first lifting lug 111 and the second lifting lug 112 are respectively located at both ends of the top plate 11. The distance between the first lifting lug 111 and the second lifting lug 112 is equal to the distance between the first gantry crane 21 and the second gantry crane 22. The distance between the two cranes 22 is equal. The first lifting lug 111 is connected to the hook 24 of the first crane 21, and the second lifting lug 112 is connected to the hook 24 of the second crane 22. The bottom plate 13 is provided with a lower lifting lug for connecting to the mill stand 3. The lower lifting lug includes a third lifting lug 131 and a fourth lifting lug 132. The distance between the third lifting lug 131 and the fourth lifting lug 132 is equal to the distance between the mill stand 3. The third lifting lug 131 and the fourth lifting lug 132 are each provided with a lifting strap 17. The two lifting straps 17 are connected to the mill lifting point 31 on the mill stand 3.

[0032] The horizontal distance between the third lug 131 and the first lug 111 is X1, and the horizontal distance between the fourth lug 132 and the first lug 111 is X2; X1 and X2 are:

[0033]

[0034] X2 = X1 + L2;

[0035] Where: F1—theoretical force on the first traction machine, N; F2—theoretical force on the second traction machine, N; G1—weight of the lifting tool between the first and third lifting lugs, N. G2—The weight of the lifting equipment located between the third and second lifting lugs, in N. G3—Weight of the mill stand being hoisted, N; G—Weight of the hoisting equipment, N; L1—Horizontal distance between the hooks of the first and second gantry cranes, mm; L2—Horizontal distance between the third and fourth lifting lugs, i.e., the horizontal distance between the two mill hoisting points on the mill stand, mm; X1—Horizontal distance between the third and first lifting lugs, mm; X2—Horizontal distance between the fourth and first lifting lugs, mm.

[0036] Specifically, taking the hoisting of the 44T rolling mill stand 3 by the first crane 21 (32T crane) and the second crane 22 (16T crane) as an example, the design and strength calculation of the hoisting tool 1 are carried out:

[0037] The lifting tool 1 is an I-beam made of Q235 steel plate with dimensions of 800*500*20*20mm. Fourteen pairs of evenly spaced web plates 12 can be welded to its web plate 12 to enhance the bending strength of the I-beam. Two end plates are welded to both sides of the I-beam. The first lifting lug 111 and the second lifting lug 112 with a hole spacing of 6944mm are welded on the top plate 11 of the I-beam, which is equal to the center distance between the two overhead cranes. The third lifting lug 131 and the fourth lifting lug 132 with a hole spacing of 2550mm are welded on the bottom plate 13 of the I-beam, which is equal to the distance between the lifting points of the rolling mill stand 3. The first lifting lug 111, the second lifting lug 112, the third lifting lug 131 and the fourth lifting lug 132 are all made of Q235 steel plate with a thickness of 30mm and a length of 400mm, with double-sided welds.

[0038] Design of hoisting tools:

[0039] Design conditions: Permanent load partial factor: 1.35; Dynamic load and other comprehensive safety factor: 1.5; Overall stability factor: Φb=0.6; Uniformly distributed load of the lifting tool's self-weight: 5.4kN / m, i.e., G=L1×5.4×10 6 N / mm; Material Q235, f=215N / mm 2 Considering the theoretical force of 32T for a 32T vehicle, the force is 31.8T, i.e., F1 = 31.8 × 10⁻⁶. 3 ×9.8N; the actual force on the 16T crane is 15T, i.e., F2 = 15 × 10 3 ×9.8N; where L1=6944mm, L2=2550mm; S=50×20mm 2 ; To conduct accounting.

[0040] Calculation of the installation positions of the third lifting lug 131 and the fourth lifting lug 132:

[0041] The distance X1 between the third lug 131 and the first lug 111:

[0042]

[0043] X1 = 856 mm;

[0044] The distance X2 between the fourth lifting lug 132 and the first lifting lug 111 is: X2 = X1 + L2 = 856 + 2550 = 3406 mm;

[0045] Maximum bending moment calculation:

[0046] M1=1.35×1.5×318×0.856=551KN·m;

[0047] M2=1.35×1.5×150×(6944-3046)=1076KN·m;

[0048] The maximum bending moment is 1076 kN·m.

[0049] W x calculate:

[0050]

[0051] Verification based on existing beam design

[0052] I-beam: 800*500*20*20mm

[0053] Moment of inertia:

[0054]

[0055]

[0056] w′ x >w x ;

[0057] The hoisting tools meet the requirements. To make the overall structure of the hoisting beam more stable, end sealing plates 14 can be set at the ends of the I-beams, and side sealing plates 16 can be set between the end sealing plates 14 to form a box beam. Take Φb=1.0 to improve the safety and stability of the hoisting process.

[0058] The overhead crane's lifting capacity allows for an overload of 25%. A 16-ton overhead crane can lift objects weighing no more than 20 tons; a 32-ton overhead crane can lift objects weighing 40 tons. In this lifting operation, the lifting gear and rigging weighed 4 tons, and the total weight of the lifting gear and frame was approximately 44 tons. The total weight is less than the rated lifting capacity of 48 tons and the maximum weight of 60 tons, therefore it meets the usage requirements.

[0059] By adding the lifting tool 1 and adjusting the positions of the third lifting lug 131 and the fourth lifting lug 132 on the lifting tool 1 for connecting to the rolling mill stand 3, the lifting of rolling mill stands 3 of different weights can be achieved. Specifically, based on the known theoretical forces of the first gantry crane 21 and the second gantry crane 22, the weight of the rolling mill stand 3 to be lifted, and the weight of the lifting tool 1 itself, the torque balance of the lifting tool 1 is calculated to determine the installation points of the third lifting lug 131 and the fourth lifting lug 132. This ensures that during the lifting of the rolling mill stand 3, the wire ropes 23 at the first lifting lug 111 and the second lifting lug 112, respectively connected to the first gantry crane 21 and the second gantry crane 22, remain vertical and do not tilt, thus preventing safety hazards during the lifting process. Specifically, as shown in the figure... As shown, by calculating the torque conservation on both sides of the third lifting lug 131, the distance between the third lifting lug 131 and the first lifting lug 111 can be obtained. Thus, the setting point of the fourth lifting lug 132 can be determined. Connect the hook 24 of the first trolley 21 to the first lifting lug 111, and connect the hook 24 of the second trolley 22 to the second lifting lug 112. Connect one of the mill lifting points 31 of the mill stand 3 to the third lifting lug 131 through the lifting belt 17, and connect the other mill lifting point 31 to the fourth lifting lug 132 through the lifting belt 17. Use the lifting tool 1 to lift the mill stand 3 between the first trolley 21 and the second trolley 22. After the connection is completed, lock it with a lock to prevent the wire rope 23 from loosening during the movement, which could lead to an unstable connection and the mill stand 3 falling. This design ensures that when using two overhead cranes of different specifications to lift the overweight rolling mill frame 3, the vertical angle between the overhead crane's wire rope 23 and the rolling mill frame 3 is 180°, greatly guaranteeing the safe load of the overhead crane and wire rope 23. Furthermore, the lifting of the rolling mill frame 3 will not exceed the rated lifting capacity of the lifting tool 1 and the two overhead cranes. Moreover, the lifting tool 1 can be directly made using existing I-beams, resulting in low manufacturing costs and simple manufacturing processes. This fully utilizes the lifting machinery available on the construction site and effectively reduces the construction cost of equipment installation.

[0060] Step Two: Lift and erect the rolling mill frame 3; the first overhead crane 21 and the second overhead crane 22 simultaneously drive the lifting tool 1 to lift the rolling mill frame 3 off the ground and make it perpendicular to the ground. Figure 4 , Figure 5As shown, after the mill stand 3 is connected to the first gantry crane 21 and the second gantry crane 22 via the hoisting tool 1, the first gantry crane 21 and the second gantry crane 22 start synchronously. The retracting wire rope 23 drives the hooks 24 of the first gantry crane 21 and the second gantry crane 22 to move upward, slowly lifting the mill stand 3 upward until it is upright, that is, perpendicular to the ground. During the uprighting process, the synchronicity between the first gantry crane 21 and the second gantry crane 22 should be ensured, and the entire mill stand 3 should rotate around the bottom of the mill stand 3 as the axis until the mill stand 3 is upright. When the mill stand 3 is fully upright, during the process of lifting it off the mill stand 3 using the first gantry crane 21 and the second gantry crane 22, the first gantry crane 21 and the second gantry crane 22 also need to slowly move towards the position where the mill stand 3 is about to be upright to ensure the perpendicularity between the wire rope 23 and the mill stand 3 throughout the process. After the mill stand 3 is stably perpendicular to the ground, the first gantry crane 21 and the second gantry crane 22 continue to lift synchronously, that is, slowly retract the wire rope 23 of the first gantry crane 21 and the second gantry crane 22 to lift the mill stand 3 off the ground.

[0061] Step 3: Transfer the mill stand 3 to the installation position; the first overhead crane 21 and the second overhead crane 22 simultaneously move the lifting tool 1 horizontally to transfer the mill stand 3 to the installation position. After confirming that the mill stand 3 is lifted correctly, as follows... Figure 6 As shown, the trolleys of the first crane 21 and the second crane 22 operate synchronously, causing the mill stand 3 to move slowly to the designated position. By using the trolleys of the first crane 21 and the second crane 22 to drive the first crane 21 and the second crane 22 to operate synchronously, the requirements for the coordination of the two cranes are lower, reducing the pressure on the crane operators and improving the accuracy of the lifting operation.

[0062] Step 4: Lowering and installing the mill stand 3; the first gantry crane 21 and the second gantry crane 22 simultaneously move the lifting tool 1 downwards until the mill stand 3 lands on the mill base. After installing the mill stand 3 on the mill base, disconnect the lifting strap 17 from the mill stand 3. After moving the mill stand 3 to the designated position, once the mill stand 3 is stable, the steel strands of the first gantry crane 21 and the second gantry crane 22 simultaneously descend until the mill stand 3 falls onto the mill base. Once the mill stand 3 is in place, initially tighten the connection between the mill stand 3 and the mill base using connecting bolts. Then, disconnect the lifting strap 17 connecting the lifting tool 1 and the mill stand 3, and remove the locks between the lifting tool 1 and the mill stand 3. Then proceed with the lifting of the next stand.

[0063] The lifting method for the double-machine lifting of the mill stand is adopted to lift the mill stand. Lifting tool 1 is fabricated; specifically, it can be made from Q235 steel commonly used on construction sites, making it inexpensive and simple to manufacture. It fully utilizes existing overhead cranes on the construction site, eliminating the need to reload overhead cranes of the appropriate specifications for lifting the mill stand 3, effectively reducing the construction cost of equipment installation. Furthermore, by using lifting tool 1 to connect the first overhead crane 21 and the second overhead crane 22 to the mill stand 3, the vertical angle between the wire ropes 23 on the first overhead crane 21 and the second overhead crane 22 and the mill stand 3 remains at 180° throughout the lifting process, greatly ensuring... The method ensures the safety load of the overhead crane and wire rope 23, and the lifting of the mill stand 3 will not exceed the rated lifting capacity of the lifting tool 1 and the two overhead cranes. This effectively guarantees the installation and lifting of the equipment when using two overhead cranes of different specifications to lift the mill stand 3 together, and reduces the safety risks during the lifting operation. When using this method to transfer the mill stand 3, the trolleys on the two overhead cranes can be directly operated to move, which reduces the requirements for the coordination of the two overhead cranes, reduces the pressure on the crane operators, and improves the accuracy of the lifting operation. The lifting tool 1 used in this method is designed with detailed calculations, which greatly ensures the safe implementation of the lifting operation.

[0064] To ensure the stability of the connection between the mill stand 3 and the lifting tool 1, and to prevent instability during the lifting of the mill stand 3 due to connection errors, step two also includes a safety inspection. When the mill stand 3 is lifted 100mm off the ground, the connection between the mill stand 3 and the lifting tool 1 needs to be inspected. After the mill stand 3 is completely lifted off the ground and stably perpendicular to the ground, the first gantry crane 21 and the second gantry crane 22 continue to lift synchronously. When the bottom of the mill stand 3 is 100mm from the ground, a safety inspection is carried out. During the inspection, the locking of the lifting belt 17 and the connection between the lifting belt 17 and the lifting lugs on the mill stand 3 need to be verified to ensure that the lifting belt 17 is locked to fix the relative position between the mill stand 3 and the lifting tool 1, and to ensure that the lifting tool 1 will not shift or tilt during the lifting of the mill stand 3, thereby ensuring the stability and safety when using the gantry crane to lift the mill stand 3.

[0065] To further enhance the bending strength of I-beams, such as Figure 1As shown, ribs 15 with the same height as the web 12 are provided on both the left and right sides of the web 12. Multiple sets of ribs 15 are spaced apart on the web 12 along its length. Specifically, the spacing between two adjacent sets of ribs 15 is determined according to the actual length of the hoisting tool 1, i.e., the length of the I-beam. By adding ribs 15 located between the top plate 11 and the bottom plate 13 and connected to the web 12, the bending strength of the entire hoisting tool 1 is enhanced. This prevents the I-beam from bending or breaking due to insufficient bending strength during use when hoisting the mill frame 3 because the mill frame 3 is too heavy, thus ensuring the safety and stability of the hoisting tool 1 during use.

[0066] To enhance the connection stability between the top plate 11, bottom plate 13, and web plate 12, and to prevent breakage or detachment of the joints between the top plate 11, bottom plate 13, and web plate 12 due to excessive stress, such as... Figure 1 , Figure 2 As shown, both ends of the I-beam are provided with end sealing plates 14 for connecting the top plate 11 and the bottom plate 13; by setting the end sealing plates 14, the ends of the top plate 11, the bottom plate 13, and the web plate 12 are connected to the same end sealing plate 14, which strengthens the connection strength between the top plate 11, the bottom plate 13, and the web plate 12, and avoids the I-beam from breaking or detaching due to excessive weight of the hoisted object, thus ensuring safety during the hoisting process.

[0067] To make the overall structure of lifting tool 1 more stable, such as Figure 2 As shown, a side sealing plate 16 is also provided between the two end sealing plates 14 for connecting the two end sealing plates 14. The length of the side sealing plate 16 is the same as the length of the web plate 12. The side sealing plate 16 and the end sealing plate 14 cover the I-beam to form a box beam. By cooperating with the end sealing plate 14 and the side sealing plate 16, the entire I-shaped hoisting tool 1 is enclosed to form a box beam to improve the safety and stability of the hoisting process.

[0068] To ensure the installation stability of the first lifting lug 111 and the second lifting lug 112, and the balance of the entire lifting tool 1 when connected using the hooks 24 of the first gantry crane 21 and the hooks 24 of the second gantry crane 22, the center of the first lifting lug 111 and the center of the second lifting lug 112 are 200mm away from the end of the top plate 11. By setting the center of the first lifting lug 111 and the second lifting lug 112 at a distance of 200mm from the end of the top plate 11, the length of the entire lifting tool 1 is extended, exceeding the horizontal distance between the hooks 24 of the first gantry crane 21 and the hooks 24 of the second gantry crane 22. This ensures the balance of the entire lifting tool 1 when connected to the first gantry crane 21 and the second gantry crane 22, and also ensures the connection stability of the first lifting lug 111 and the second lifting lug 112 with the I-beam.

[0069] To ensure the connection strength of the first lifting lug 111, the second lifting lug 112, the third lifting lug 131, and the fourth lifting lug 132 on the lifting tool 1, and to avoid safety accidents caused by breakage due to unstable connections when lifting excessively heavy equipment, the first lifting lug 111, the second lifting lug 112, the third lifting lug 131, and the fourth lifting lug 132 are all made of steel plates and are welded to the I-beam with double-sided welds.

Claims

1. A hoisting method for a double-machine lifting rolling mill stand, characterized in that, Includes the following steps: Step 1: Connect the hoisting tool (1) to the first gantry crane (21), the second gantry crane (22), and the rolling mill frame (3); Both the first gantry crane (21) and the second gantry crane (22) are equipped with wire ropes (23), and the lower ends of the wire ropes (23) are equipped with hooks (24) for hoisting. The hoisting tool (1) includes an I-beam composed of a top plate (11), a web plate (12), and a bottom plate (13). The top plate (11) is equipped with upper lifting lugs for connecting with the hooks (24) of the first gantry crane (21) and the second gantry crane (22). The upper lifting lugs include a first lifting lug (111) and a second lifting lug (112). The first lifting lug (111) and the second lifting lug (112) are respectively located at both ends of the top plate (11). The distance between the first lifting lug (111) and the second lifting lug (112) is the same as that between the first gantry crane (21). The spacing between the first and second trolleys (22) is equal. The first lifting lug (111) is connected to the hook of the first trolley (21), and the second lifting lug (112) is connected to the hook of the second trolley (22). The bottom plate (13) is provided with a lower lifting lug for connecting to the mill stand (3). The lower lifting lug includes a third lifting lug (131) and a fourth lifting lug (132). The spacing between the third lifting lug (131) and the fourth lifting lug (132) is equal to the spacing between the mill stand (3). The third lifting lug (131) and the fourth lifting lug (132) are each provided with a lifting strap (17). The two lifting straps (17) are connected to the mill lifting point (31) set on the mill stand (3). The horizontal distance between the third lug (131) and the first lug (111) is X1, and the horizontal distance between the fourth lug (132) and the first lug (111) is X2; X1 and X2 are: X2 = X1 + L2; Where: F1—theoretical force on the first traction machine, N; F2—theoretical force on the second traction machine, N; G1—weight of the lifting tool between the first and third lifting lugs, N. G2—The weight of the lifting equipment located between the third and second lifting lugs, in N. G3—Weight of the mill stand being hoisted, N; G—Gravity of the hoisting equipment, N; L1—Horizontal distance between the hooks of the first and second gantry cranes, mm; L2—Horizontal distance between the third and fourth lifting lugs, i.e., the horizontal distance between the two mill hoisting points on the mill stand, mm; X1—Horizontal distance between the third and first lifting lugs, mm; X2—Horizontal distance between the fourth and first lifting lugs, mm; Step 2: Lift and erect the rolling mill frame (3); the first gantry crane (21) and the second gantry crane (22) simultaneously drive the lifting tool (1) to lift the rolling mill frame (3) off the ground and make it perpendicular to the ground; Step 3: Transfer the mill stand (3) to the installation position; the first gantry crane (21) and the second gantry crane (22) simultaneously drive the hoisting tool (1) to move horizontally and transfer the mill stand (3) to the installation position; Step 4: Lower and install the mill frame (3); The first gantry crane (21) and the second gantry crane (22) simultaneously drive the hoisting tool (1) to move downward until the mill frame (3) falls on the mill base. After the mill frame (3) is installed on the mill base, the connection between the hoisting belt and the mill frame (3) is released.

2. The hoisting method for a double-machine lifting rolling mill stand as described in claim 1, characterized in that: Step two also includes a safety inspection. The mill frame (3) is lifted 100mm off the ground, and the connection between the mill frame (3) and the hoisting tool (1) needs to be inspected.

3. The hoisting method for a double-machine lifting rolling mill stand as described in claim 1, characterized in that: The web plate (12) has ribs (15) with the same height as the web plate (12) on both the left and right sides, and multiple sets of ribs (15) are arranged at intervals on the web plate (12) along the length direction of the web plate (12).

4. The hoisting method for a double-machine lifting rolling mill stand as described in claim 3, characterized in that: Both ends of the I-beam are provided with end caps (14) for connecting the top plate (11) and the bottom plate (13).

5. The hoisting method for a double-machine lifting rolling mill stand as described in claim 4, characterized in that: A side sealing plate (16) for connecting the two end sealing plates (14) is also provided between the two end sealing plates (14). The length of the side sealing plate (16) is the same as the length of the web plate (12). The side sealing plate (16) and the end sealing plate (14) cover the I-beam to form a box girder.

6. The hoisting method for a double-machine lifting rolling mill stand as described in claim 1, characterized in that: The center of the first lifting lug (111) and the center of the second lifting lug (112) are 200mm away from the end of the top plate (11).

7. The hoisting method for a double-machine lifting rolling mill stand as described in claim 1, characterized in that: The first lifting lug (111), the second lifting lug (112), the third lifting lug (131), and the fourth lifting lug (132) are all made of steel plates and are welded to the I-beam with double-sided welds.

Images