A method for replacing rolls of a reversing rolling mill

Abstract

The present application relates to the technical field of roll body replacement, and discloses a reversible rolling mill roll replacement method, which comprises flat head alignment, and the flat head alignment method comprises the following steps: marking a first mark for determining the position of the flat head at the end of the new and old roll shafts away from the flat head, and making a circumferential second mark on the new and old roll bearing boxes; adjusting the position of the first mark of the old roll on the second mark, so that the position of the first mark of the old roll on the second mark is consistent with the position of the first mark of the new roll on the second mark; disassembling the old roll from the rolling mill through a replacement tool; and directly feeding the new roll into the installation position of the rolling mill body through the replacement tool. The method can simplify the installation steps, reduce the labor intensity, and improve the operation efficiency.

Description

Technical Field

[0001] This invention relates to the field of roll replacement technology, specifically a method for replacing rolls in a reversible rolling mill. Background Technology

[0002] Four-high reversible rolling mills are commonly used equipment in hot-rolled plate plants. However, with economic development, the capacity of these mills (such as those designed and put into operation around the 1990s) can no longer meet the requirements, especially due to their low roll changing efficiency, which leads to a further reduction in capacity. Although there are now quick roll changing devices such as hydraulic roll changing trolleys, the mills are all old-style mills, and the on-site operating space was insufficient during their design. Most of the functions of quick roll changing cannot be realized. The roll changing efficiency has improved, but it has not achieved the expected results. It still takes more than 30 minutes to change a roll each time. For example, when installing rolls with the sliding universal joint of the old-style rolls, the flat end ( The roll drive end (the part that mates with the drive shaft) and the slider position must be in a vertical position. The main drive motor aligns the flat ends of the upper and lower rolls with the vertical position for roll pulling. When placing the new roll on the roll changing trolley, the flat end needs to be lifted to a vertical position using a crane for roll installation. This allows the new roll to be clamped onto the slider-type universal joint. This requires alignment of both the new and old rolls. Especially when aligning the new roll, the rotating head needs to be slowly aligned. The new roll is heavy, has high inertia, and requires high surface roughness; secondary scratches must be prevented during the roll alignment process. This requires multiple personnel and has a low safety factor. Now, by utilizing the single-action capability of the upper and lower horizontal roll drives in the roughing mill and changing the roll joint from a slider-type universal joint to a cross-shaped universal joint, the roll changing steps and procedures have been innovated and optimized. After hoisting the new roll, it is no longer necessary to lift the flat end of the new roll to align it with the connection hole of the cross-shaped universal joint on the mill stand; it can be directly installed. Summary of the Invention

[0003] The purpose of this invention is to provide a method for changing rolls in a reversible rolling mill, which simplifies the installation process, reduces labor intensity, and improves operational efficiency.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for replacing rolls in a reversible rolling mill includes aligning the flat ends. The method for aligning the flat ends includes marking a first mark on the end of the new and old roll shafts away from the flat ends to determine the position of the flat ends, and marking a second mark on the bearing housings of the new and old rolls in the circumferential direction.

[0006] Adjust the position of the first mark on the old roll to be consistent with the position of the first mark on the second mark of the new roll;

[0007] The old rolls are removed from the rolling mill by changing the tooling;

[0008] The new rolls are fed directly into the installation position on the mill body using a tooling changer.

[0009] In a further embodiment, the mounting position of the rolling mill body includes a mounting hole at the end of a cross-shaped universal joint shaft.

[0010] In a further embodiment, the first mark includes an arrow positioned on the end of the new and old roll shafts furthest from the flat end.

[0011] In a further embodiment, the second marking includes horizontal and vertical markings on the bearing housing end face of the roll, as well as positioning bolt markings arranged in a clockwork pattern on the roll bearing housing.

[0012] In a further embodiment, the arrows correspond to the positioning bolt marks marked according to the positions corresponding to the clock face.

[0013] In a further embodiment, the disassembly steps of the old roll include: switching the rotation mode of the old roll to manual mode;

[0014] The manual method includes jogging the main drive mechanism connected to the old roll to make the first mark position of the old roll consistent with the first mark position of the new roll;

[0015] The old rolls are guided to the ground via guide rails connected to the front end of the rolling mill.

[0016] In a further embodiment, the changing fixture includes a guide rail and rollers, with the rollers rotatably connected to the guide rail. The guide rail is located on one side of the mounting position and is used to guide or guide the work roll to the mounting position of the mill body.

[0017] In a further embodiment, the replacement of the old rolls includes simultaneously performing an alignment operation on the upper and lower rolls on the mill and the flat ends of the two new rolls. After disassembly, the two new rolls are simultaneously inserted into the installation position of the mill through the same replacement fixture.

[0018] In a further embodiment, the new roll is simultaneously lifted onto the guide rail in one go using a lifting device before being inserted into the mill mounting position.

[0019] In a further embodiment, the cooling water used on the old rolls is shut off during the dismantling of the old rolls.

[0020] The beneficial effects of this invention are:

[0021] This invention primarily eliminates the need for the crane to hold the flattened head in a vertical position. Instead, the flattened head of the roll to be rolled is positioned to align with the spare roll, based on its specific characteristics. This not only saves roll changing time, reducing it from 30 minutes to just 20 minutes, but also reduces the safety risks for operators using cranes. This roll changing method is highly practical, easy to master, and has resulted in no personal injury or equipment accidents during its field application.

[0022] Before the roll is pulled, the indicator head is moved to the flat head position of the standby roll by the main drive. The position is accurately determined by the clock pointer method to indicate the position of the positioning bolts of the roll bearing box of the flat head (the part of the roll drive side that is in cross-shaped fit with the drive shaft). The bolt positions are numbered according to the clock pointer, which greatly reduces the positioning error. Attached Figure Description

[0023] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a simplified diagram of the marking positions of the rolls in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the marking positions when the upper and lower rolls are marked simultaneously in an embodiment of the present invention. Figure 1 ;

[0026] Figure 3 This is a schematic diagram of the marking positions when the upper and lower rolls are marked simultaneously in an embodiment of the present invention. Figure 2 ;

[0027] Figure 4 This is a schematic diagram of the marking positions when the upper and lower rolls are marked simultaneously in an embodiment of the present invention. Figure 3 ;

[0028] Figure 5 This is a schematic diagram of a four-roll reversible rolling mill changing rolls in related technologies;

[0029] Figure 6 This is a schematic diagram of a cross-shaped universal joint shaft in related technologies;

[0030] Figure 7 This is a schematic diagram of a cross-shaped universal joint shaft installed on a rolling mill in related technologies;

[0031] In the diagram: 1. Flat head; 11. First mark; 12. Arrow; 2. Roll bearing housing; 21. Second mark; 22. Positioning bolt mark; 3. Roll; 4. Cross-shaped universal joint; 41. Mounting hole. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] like Figure 2 As shown, a method for changing rolls in a reversible rolling mill includes, for example, changing the rolls of a reversible rolling mill. Figure 5 The alignment of the flat head 1, and the methods for aligning the flat head include as follows: Figure 1 As shown, a first mark 11 is marked on the end of the new and old roll shafts away from the flat head 1 to determine the position of the flat head 1, and a second circumferential mark 21 is made on the new and old roll bearing housings 2;

[0034] Adjust the position of the first mark 11 of the old roll on the second mark 21 so that the position of the first mark 11 of the old roll on the second mark 21 is consistent with the position of the first mark 11 of the new roll on the second mark 21.

[0035] The old rolls are removed from the rolling mill by changing the tooling;

[0036] The new roll is directly fed into its mounting position on the mill body using a tooling changer. This allows for immediate roll installation once the marked position is determined, eliminating the need for matching the new roll with the old one, thus saving labor and costs.

[0037] Based on the principles of the above method, some preferred implementation methods or structures are provided, such as... Figure 6 As shown, the mounting position on the mill body includes a mounting hole 41 at the end of the cross-shaped universal joint 4. The cross-shaped universal joint 4 is a widely used mill work roll connecting shaft developed in the past. Those skilled in the art should be able to recognize that this method is also effective for other axial mounting positions, such as redesigned universal joint shafts.

[0038] The method for determining the marking positions includes: the second marking 21 includes horizontal and vertical markings on the bearing housing end face of the roll, and positioning bolt markings 22 arranged in a clockwork pattern on the roll bearing housing 2. Selecting the positions of the positioning bolts on the roll bearing housing as markings eliminates the need for additional scales, provides clear markings for easy comparison, facilitates roll stability, and enables convenient assembly, resulting in less damage to the roll itself.

[0039] The first mark 11 includes an arrow 12 positioned on the end of the new and old roll shafts furthest from the flat end. Those skilled in the art will recognize that the mark here could also be of other shapes.

[0040] The dismantling steps for the old rolls include: switching the rotation mode of the old rolls to manual mode;

[0041] The manual method includes jogging the main drive mechanism connected to the old roll to make the position of the first mark consistent with the position of the mark on the new roll;

[0042] The old rolls are guided to the ground via guide rails connected to the front end of the rolling mill. This step can be accomplished using the existing rolling mill operating procedures, without the need for additional programs, making it simple and convenient to operate.

[0043] The positioning bolt markings corresponding to the arrows should be read according to the corresponding positions on the clock face, which makes it easier for the operator to adjust the alignment of the old work rollers.

[0044] The changing fixture includes guide rails and rollers. The rollers are rotatably connected to the guide rails, which are located on one side of the mounting position. This is used to guide or guide the work rolls to or from the mounting position on the mill body. The roll bearing housing facilitates the fixing of the rolls and allows the rolls to be lifted in one go without overturning, thus avoiding misalignment. The rollers facilitate the sliding of the roll bearing housing on the rails.

[0045] When dismantling old rolls, turn off the cooling water in the rolling mill. This makes it easier to pull out the old rolls and prevents water leakage.

[0046] The replacement of old rolls involves simultaneously aligning the upper and lower rolls on the mill with two new rolls. After disassembly, the two new rolls are inserted into their mounting positions on the mill simultaneously using the same replacement fixture. This method significantly improves work efficiency compared to installing each roll individually.

[0047] Before inserting the new roll into the mill, it is lifted onto the guide rail in one go using a hoisting device. This is to prevent the new roll body from rubbing against the ground, which could cause the arrow marked on the roll body to flip over, rendering the above method ineffective, and thus requiring a crane to flatten the roll head.

[0048] Taking the simultaneous replacement of upper and lower rolls as an example, the specific installation operation steps are as follows: Prepare the new upper and lower working rolls and inspect them, placing them on the rolling line floor. The position of the flat head 1 of the new spare roll must be clearly confirmed on-site (arrow points to the bolt position). Using the flat head indicator arrow on the spare roll operation side to correspond to the 12 fixing bolts on the roll bearing housing, we number the corresponding bolt positions. Because the bolt positions are misaligned by a 15-degree angle with the hour mark on a clock, we set the bolt positions to 12 points according to clock sequence when aligning the flat head. Each positioning bolt is a specific point. Additionally, a "vertical position" and a "horizontal position" are set as supplementary points besides the bolt positions (because these two points are easier to describe and implement). Record these points. Figure 2 As shown: the upper roller can be read as 3 o'clock position, and the lower roller can be read as 2 o'clock position; for example... Figure 3 As shown: the upper and lower rolls can be read as vertical, such as... Figure 4 As shown: the upper and lower rolls can be read as horizontal. Instruct the operator to align the old roll flattening head according to the above description. The operator has a clear reference system to complete the flattening work.

[0049] Utilize the interval time during the finishing mill rolling process. Set the automatic / manual position selector switch in the table area to manual mode.

[0050] Use the main drive speed handle of the old upper roll shaft to jog the position of the flat end of the upper roll to match the prepared roll point;

[0051] On the human-machine interface of the rolling mill, select the tracking screen and uncheck the upper and lower roll main drive speed selection. At this time, use the old lower roll main drive speed handle to jog the lower roll main drive to bring the lower roll flat head position to match the spare roll.

[0052] Turn off the cooling water for the 3kg and 12kg rolls, and manually press down and lift the upper and lower old rolls to the roll changing position;

[0053] Next, in the human-machine interface, select the operation screen and select the mode management function key. In the pop-up window, select the maintenance mode and apply it. In the old roller area, select the roller replacement mode and apply it. In the pop-up window, select the local mode (that is, the mode of conveying the upper and lower old rollers to the ground).

[0054] In the human-machine interface, select the media system and then select hydraulic station No. 3 to start a roller changing pump to assist in roller changing and provide the power in the local mode mentioned above.

[0055] After the upper and lower old rolls are in place, the bearing housing can be disassembled and the roll pulling operation can be carried out to lift the individual old rolls down and place them on the rolling line, arranging them neatly.

[0056] When hoisting a new roll, the hoisting personnel must lift it in one go to prevent the roll surface from making secondary contact with the ground, which could cause the roll body to slip and change the position of the flat end.

[0057] After placing the new roll in place, the roll can be installed in one go without using a crane to flatten the head;

[0058] Restore steel rolling conditions.

[0059] The above-mentioned roll replacement method is expected to improve economic and social benefits, and has good prospects for widespread application.

[0060] Specific benefits include: reduced roll changing time and increased production efficiency. Compared to the original roll changing procedure, each roll changing session can be shortened by 10 minutes. The roll changing cycle for the upper and lower rolls is 18,000-20,000 tons respectively. A typical factory's annual output is 2,800,000 tons, requiring more than 280 roll changes per year. Assuming a 10-minute reduction in roll changing time each time, this translates to a reduction of 2,800 minutes (46.7 hours) of roll changing time annually. The hourly capacity is 454.5 tons, the effective operating rate is 72.6%, and the profit per ton of product is 400 yuan (this profit is the average profit margin for typical steel rolling).

[0061] Direct economic benefits are calculated as A × B × C × D = E.

[0062] In the formula: A - the reduction in roll change time by the operation method:

[0063] B-Hot Rolling Mill Hourly Capacity:

[0064] C - Effective operating rate of hot-rolled plate mill;

[0065] D - Average profit per ton of steel at hot-rolled plate mills;

[0066] The E-operation method generates 46.7 × 454.5 × 72.6% × 400 = 6163783.56 = 616.38 million yuan.

[0067] Therefore, this method of changing the flat end rolls can generate 6.1638 million yuan in revenue annually. The economic benefits are very significant.

[0068] The above method is also applicable to single roll change, and is especially suitable for four-roll mills.

[0069] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.

[0070] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for changing rolls in a reversible rolling mill, comprising aligning the flat ends, characterized in that, The method for aligning the flat head includes: marking a first mark (11) on the end of the new and old roll shafts away from the flat head (1) to determine the position of the flat head, and making a second circumferential mark (21) on the new and old roll bearing housings (2). Adjust the position of the first mark (11) of the old roll on the second mark (21) so that the position of the first mark (11) of the old roll on the second mark (21) is consistent with the position of the first mark (11) of the new roll on the second mark (21); The old rolls are removed from the rolling mill by changing the tooling; The new rolls are fed directly into the installation position on the mill body using a tooling changer; The mounting position of the mill body includes the mounting hole (41) at the shaft end of the cross-shaped universal joint shaft (4). The dismantling steps of the old rolls include: switching the rotation mode of the old rolls to manual mode; The manual method includes controlling the main drive mechanism connected to the old roll to jog so that the position of the first mark (11) of the old roll is consistent with the position of the first mark (11) of the new roll; The old rolls are guided to the ground via guide rails connected to the front end of the rolling mill; The changing tooling includes a guide rail and rollers. The rollers are rotatably connected to the guide rail, which is located on one side of the mounting position and is used to guide or guide the work roll to the mounting position of the mill body. The replacement of the old rolls involves simultaneously performing alignment operations on the upper and lower rolls on the mill and the flat ends of the two new rolls. After disassembly, the two new rolls are inserted into the installation position of the mill simultaneously through the same replacement fixture.

2. The method for changing rolls in a reversible rolling mill according to claim 1, characterized in that, The first mark (11) includes an arrow (12) placed on the end of the new and old roll shafts away from the flat end.

3. The method for changing rolls in a reversible rolling mill according to claim 2, characterized in that, The second mark (21) includes horizontal and vertical marks on the bearing housing end face of the roll and positioning bolt marks (22) arranged in the form of 12 clock positions on the bearing housing (2) of the roll.

4. The method for changing rolls in a reversible rolling mill according to claim 3, characterized in that, The arrows correspond to the positioning bolt marks marked according to the positions on the clock face.

5. The method for changing rolls in a reversible rolling mill according to claim 1, characterized in that, The new roll is simultaneously hoisted onto the guide rail in one go using a lifting device before being inserted into the mill installation position.

6. A method for changing rolls in a reversible rolling mill according to any one of claims 1-5, characterized in that, When the old rolls are dismantled, the mill is shut down to use cooling water for the old rolls.

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