A method for processing defects of a thin-gauge galvanized collapsed coil

Abstract

The present application belongs to the technical field of galvanized coil maintenance, and specifically discloses a thin-gauge galvanized coil collapse defect processing method, which comprises the following steps: S1: adjusting the inner diameter of the galvanized steel coil collapse to ensure that the size of the inner diameter of the steel coil can make the core shaft body of the uncoiler smoothly enter; S2: using a polishing machine to polish the 3-4 cm part of the strip head, polish the zinc layer clean, and use a resistance welding machine to stitch the galvanized coil; S3: respectively reducing the inlet uncoiling tension and the straightening tension, starting the jog-type threading production, and when the strip head runs to the outlet of the tension roller 2-5 meters, the roller system of the straightening machine is fully put into operation to avoid the breakage accident caused by the tearing of the weld; S4: using the straightening machine to straighten the galvanized steel strip, cutting off all the wrinkles of the strip head clean to ensure that the strip head is flat and straight, and oiling to prevent oxidation; S5: simultaneously starting the uncoiling and coiling work, setting different uncoiling tension values, coiling tension values and straightening tension values according to different thicknesses of the steel strip to achieve a suitable steel coil winding tightness.

Description

Technical Field

[0001] This invention relates to the field of galvanized coil maintenance technology, specifically to a method for handling the collapse defect of thin-gauge galvanized coils. Background Technology

[0002] The development of cold-rolled ultra-thin galvanized coils is based on the advancement of cold-rolled ultra-thin carbon steel, which is formed through subsequent galvanizing. Cold-rolled ultra-thin carbon steel refers to ordinary carbon steel strips with a width of over 600mm and a thickness of less than 0.1mm. Its advantage lies in its thinness while maintaining a certain level of strength. Through subsequent galvanizing, chromium plating, and other coating processes, it can replace functional materials such as aluminum, copper, and stainless steel, thereby effectively reducing costs. The galvanizing process is mainly used to increase the corrosion resistance of the metal material and extend its service life.

[0003] The production process of cold-rolled ultra-thin galvanized coils involves multiple steps, from the preparation of cold-rolled hard steel coils to the final galvanizing treatment. This process includes uncoiling, trimming, welding, followed by degreasing treatment, hot air drying, and annealing. Finally, the annealed coil is immersed in a zinc bath, then cleaned with an air knife, cooled, dried with hot air, and finished to obtain the galvanized steel coil. This series of processes ensures the high quality and high performance of cold-rolled ultra-thin galvanized coils. For ease of immersion and subsequent processing, the galvanized coils are generally produced in roll form.

[0004] However, cold-rolled galvanized coils are prone to coil collapse defects during production due to factors such as drum precision, coiling tension matching, and external conditions. This results in severe coil deformation, with the core changing from a perfect circle to an ellipse. In severe cases, the core becomes flattened. This defect is called coil collapse or flattened coil. After collapse, the horizontal diameter of the coil increases, while the vertical diameter decreases. Typically, the inner diameter of a galvanized coil is 508 mm, and the expansion and contraction range of the uncoiler drum in a rework unit is 468.8–520 mm. Coil cores with a minimum inner diameter of 470 mm or higher can be directly reworked. Steel coils with an inner diameter of 470-480mm require simple treatment before rework. However, for severely collapsed coils, the inner diameter at the smallest point in the vertical direction is only 100-460mm, especially galvanized coils with a thickness of less than 0.40mm. These coils cannot be reworked and must be disposed of as scrap, resulting in significant waste. Ordinary galvanized coils are heat-treated steel coils with a minimum yield strength of 220MPa, a tensile strength of 300MPa, and a coil weight of 3-6 tons. Due to their low strength, rework is difficult, and if the rework process is not properly controlled, secondary collapse may occur. Summary of the Invention

[0005] The purpose of this invention is to provide a method for handling the collapse defect of thin-gauge galvanized coils, so as to solve the problem that collapse defects and severe coil deformation of cold-rolled galvanized coils are caused by factors such as coil precision, coil tension matching and external conditions during production.

[0006] To achieve the above objectives, the basic solution provided by this invention is: a method for handling the collapse defect of thin-gauge galvanized coils, comprising the following steps:

[0007] S1: Adjust the inner diameter of the galvanized steel coil to ensure that the inner diameter of the steel coil allows the uncoiling mandrel to enter smoothly;

[0008] S2: Use a grinder to grind the 3-4 cm section of the strip to remove the galvanized layer, and then use a resistance welding machine to sew the galvanized steel strip together.

[0009] S3: Reduce the inlet uncoiling tension to 300-500 kg, reduce the tensioning tension to 800-1200 kg, open all the tensioning rollers to the zero position, and start the inching belt threading production. When the belt head has moved to 2-5 meters from the tension roller outlet, the tensioning rollers are fully engaged to avoid belt breakage accidents caused by weld tearing.

[0010] S4: Use a straightening machine to straighten the galvanized steel strip, remove all wrinkles and defects at the strip head to ensure the strip head is straight, and apply oil to prevent oxidation;

[0011] S5: Continue threading the strip while simultaneously starting the unwinding and winding process. Set different unwinding tension, winding tension, and straightening tension values ​​according to the thickness of the galvanized steel strip to achieve the appropriate coil tightness.

[0012] The principle and beneficial effects of this invention are as follows: by processing the inner diameter of the collapsed galvanized steel coil, the collapsed galvanized steel coil can be smoothly placed on the mandrel of the uncoiler. The end of the galvanized coil is ground with a grinder so that the galvanized coil can be sewn together by a resistance welding machine. The uncoiling tension and tension leveling tension are adjusted to prevent the weld from breaking. The steel strip is straightened with a tension leveling machine to ensure that the end of the strip is straight and wrinkle-free. Different uncoiling tension values, winding tension values ​​and tension leveling tension values ​​are set to achieve the appropriate coil tightness.

[0013] Option 2, which is the preferred option of the basic option, involves the following specific steps for adjusting the inner diameter of the galvanized steel coil in S1:

[0014] First, use a steel ruler to measure the vertical inner diameter of the collapsed galvanized steel coil.

[0015] If the measured vertical inner diameter of the collapsed galvanized steel coil is less than 400 mm:

[0016] 1) Use crane slings to initially support and fix the steel coil core so that the steel coil will not sway from side to side during operation;

[0017] 2) Based on the distance between the mandrel body and the mandrel head, the jack support position was determined to avoid interference between the jack and the mandrel head when the steel coil enters the mandrel. When the distance between the end of the mandrel head and the jack is 5-10 mm, the mandrel is opened and the jack is removed.

[0018] 3) Place the jack inside the steel coil and continuously apply pressure to the jack to support the collapsed coil to a height of about 500mm.

[0019] 4) When confirming that there is no gap between the lower end of the steel coil and the upper part of the processing rack, click the mandrel retraction button, wait 1-2 seconds and then continue to move the coiling trolley forward. Repeat the action of stopping the trolley movement when the mandrel expands and moving the coiling trolley forward at the moment the mandrel retracts. This can reverse the steel coil onto the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel should be controlled within ±100 mm.

[0020] If the measured vertical inner diameter of the galvanized steel coil is between 400-470mm, press the outer diameter of the galvanized steel coil against the inner wall of the processing rack. The outer wall at the center of the galvanized steel coil gradually comes into contact with the inner wall of the processing rack. Through the weight of the galvanized steel coil itself, the inner diameter of the coil gradually collapses into an elliptical or circular shape, and the vertical inner diameter of the coil gradually increases to 490-508mm, so as to ensure that the inner diameter is large enough for the uncoiling machine mandrel to enter.

[0021] Option 3, which is the preferred option of Option 2, is based on the following condition: when the vertical inner diameter of the galvanized steel coil is measured to be between 400-470mm:

[0022] 1) Secure the treatment frame to the upper winding trolley and raise the trolley to the normal upper winding height;

[0023] 2) Move the steel coil trolley, and when the core is inserted into the mandrel, rotate the mandrel in the opposite direction to wind the steel coil onto the mandrel;

[0024] 3) Once you confirm that there is no gap between the lower end of the steel coil and the upper part of the processing rack, click the mandrel retraction button. After waiting for 1-2 seconds, continue to move the coiling trolley forward. Repeat the action of stopping the trolley movement when the mandrel expands and moving the coiling trolley forward at the moment the mandrel retracts. This can transfer the steel coil onto the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel should be controlled within ±100 mm.

[0025] Option 4, a preferred option of the basic option, includes S5: placing a paper sleeve on the mandrel, and starting the winding operation of the galvanized steel strip on the paper sleeve. The paper sleeve further strengthens the inner core of the galvanized steel coil, increasing the support strength of the repaired coil's inner core.

[0026] Option 5, which is the preferred option of Option 4, is defined in S5 as follows:

[0027] When the thickness of the galvanized steel strip is 0.25-0.33 mm, the uncoiling tension is set at 800-900 kg, the winding tension is set at 800 kg, and the straightening tension is set at 1600-1800 kg before production begins. After winding 400 meters, the winding tension is gradually increased to 1400-1500 kg.

[0028] When the thickness of the galvanized steel strip is 0.33-0.38 mm, the uncoiling tension is set at 800 kg, the winding tension is set at 1400-1500 kg, and production begins after the tensioning tension is 2000-2200 kg. After winding 400 meters, the winding tension is gradually increased to 1600-1800 kg.

[0029] Option 6, an optimal choice from Option 5, involves controlling the equipment operating speed between 100-260 m / min. When the galvanized steel strip on the uncoiler weighs between 900-1100 kg, the operating speed is reduced to 30-50 m / min. When uncoiling a collapsed galvanized steel coil, the initial section is wrinkle-free, allowing for faster equipment speed. When 900-1100 kg remains on the uncoil, indicating the core of the coil has been reached, the remaining section contains wrinkled strips. Therefore, the equipment speed is slowed down to improve wrinkle repair efficiency. Detailed Implementation

[0030] The present invention will be further described in detail below through specific embodiments:

[0031] Example

[0032] The specific implementation process of this embodiment is as follows:

[0033] First, a crane is used to lift the collapsed galvanized steel coil onto the collapse treatment rack. At this point, the collapse defect, due to its own weight, will cause the outer diameter of the steel coil to fill and press against the inner wall of the treatment rack. At the same time, the reaction force of the inner wall acts as a driving force on the outer diameter of the galvanized steel coil, which is then transmitted to the galvanized steel coil. Under the action of the reaction force, the inner diameter of the galvanized steel coil will collapse and become elliptical or even circular. Then, a steel ruler is used to measure the vertical inner diameter of the galvanized steel coil.

[0034] When the vertical inner diameter of the galvanized steel coil is between 400-470 mm, the treatment frame containing the collapsed coil is hoisted onto the upper winding trolley of the rewinding unit. The treatment frame is then fixed onto the upper winding trolley, and the trolley is raised to the normal upper winding height. The steel coil trolley is then moved, and when the core is inserted into the mandrel, the mandrel is rotated in the opposite direction to wind the steel coil onto the mandrel. Finally, when it is confirmed that there is no gap between the lower end of the galvanized steel coil and the upper part of the treatment frame, the mandrel retraction button is pressed. After waiting for 1-2 seconds, the upper winding trolley is moved forward again. The movement of the trolley is stopped when the mandrel expands and moved forward the moment the mandrel retracts.

[0035] When the vertical inner diameter of the galvanized steel coil is less than 400mm, a modified jack is installed 400mm from the end of the coil. The jack is then continuously raised and pressurized to support the vertical inner diameter of the coil to 48-508mm. The handling frame containing the collapsed coil is then hoisted onto the upper winding trolley of the uncoiler. The handling frame is then fixed onto the upper winding trolley, and the trolley is raised to the normal winding height. The coil trolley is then moved, and when the coil core is inserted into the mandrel, the mandrel is rotated in the opposite direction to lift the galvanized steel coil onto the mandrel. Roll the coil onto the mandrel and rotate it. When the distance between the mandrel head and the jack is 5-10 mm, expand the mandrel, then remove the jack. Finally, when you confirm that there is no gap between the lower end of the galvanized steel coil and the upper part of the handling frame, click the mandrel retraction button. After waiting for 1-2 seconds, continue to move the coiling trolley forward. Repeat the action of stopping the trolley movement when the mandrel expands and moving the trolley forward the moment the mandrel retracts. This can transfer the steel coil onto the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel should be controlled within ±100 mm.

[0036] Next, the zinc layer on the galvanized steel strip head is ground clean, and then welded together using a resistance welding machine. The inlet uncoiling tension is then reduced to 300-500 kg, and the leveling tension is reduced to 800-1000 kg. All rollers of the leveling machine are opened to zero, and inching threading production begins. When the strip head has traveled 2-5 m to the tension roller exit, all rollers of the leveling machine are engaged. The strip head is then threaded to the segment shear, and all wrinkles and defects are removed until the strip head is straight and wrinkle-free. A paper sleeve is then added to the mandrel of the coiler, and both the uncoiling and coiling machines are started simultaneously. The overflow edge defect at the strip head is controlled to be below 10 mm. For galvanized steel strips with a thickness between 0.25-0.33 mm, production begins after setting the uncoiling tension to 800-900 kg, the coiling tension to 800 kg, and the leveling tension to 1600-1800 kg. After winding 400 meters, gradually increase the winding tension to 1400-1500 kg. For galvanized steel strip with a thickness between 0.33-0.38 mm, set the unwinding tension to 800 kg, the winding tension to 1400-1500 kg, and the straightening tension to 2000-2200 kg before starting production. After winding 400 meters, gradually increase the winding tension to 1600-1800 kg. During the initial threading process, control the equipment speed between 100-260 m / min. After calculation by the uncoiler, when the galvanized steel strip on the uncoiler weighs between 900-1100 kg, reduce the production speed to 30-50 m / min. After the collapsed galvanized steel coil has undergone unwinding, straightening, and rewinding, the repaired galvanized steel coil is finally carried away from the rewinding unit by a trolley and arrives at the steel coil storage area.

[0037] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for handling the collapse defect of thin-gauge galvanized coils, characterized in that, Includes the following steps: S1: Adjust the inner diameter of the galvanized steel coil to ensure that the inner diameter of the steel coil allows the uncoiling mandrel to enter smoothly; S2: Use a polishing machine to polish the 3-4 cm section of the strip to remove the zinc layer, and then use a resistance welding machine to sew the galvanized steel strip together. S3: Reduce the inlet uncoiling tension to 300-500 kg, reduce the tensioning tension to 800-1200 kg, open all the tensioning rollers to the zero position, and start the inching belt threading production. When the belt head has moved to 2-5 meters from the tension roller outlet, the tensioning rollers are fully engaged to avoid belt breakage accidents caused by weld tearing. S4: Use a straightening machine to straighten the galvanized steel strip, remove all wrinkles and defects at the strip head to ensure the strip head is straight, and apply oil to prevent oxidation; S5: Continue threading the strip while simultaneously initiating uncoiling and winding operations. Set different uncoiling tension, winding tension, and straightening tension values ​​according to the thickness of the galvanized steel strip to achieve the appropriate coil tightness. When the thickness of the galvanized steel strip is 0.25-0.33 mm, the uncoiling tension is set at 800-900 kg, the winding tension is set at 800 kg, and the straightening tension is set at 1600-1800 kg before production begins. After winding 400 meters, the winding tension is gradually increased to 1400-1500 kg. When the thickness of the galvanized steel strip is 0.33-0.38 mm, the uncoiling tension is set at 800 kg, the winding tension is set at 1400-1500 kg, and production begins after the tensioning tension is 2000-2200 kg. After winding 400 meters, the winding tension is gradually increased to 1600-1800 kg.

2. The method for handling the collapse defect of thin-gauge galvanized coils according to claim 1, characterized in that, The specific steps for adjusting the inner diameter of the galvanized steel coil in S1 are as follows: First, use a steel ruler to measure the vertical inner diameter of the collapsed galvanized steel coil. If the measured vertical inner diameter of the collapsed roll is less than 400 mm: 1) Use crane slings to initially support and fix the galvanized steel coil core so that the galvanized steel coil will not sway from side to side during operation; 2) Install the modified jack 400 mm from the end of the galvanized steel coil, and continuously apply pressure to the jack to support the collapsed coil to a height of about 500 mm. 3) Hoist the treatment frame containing the collapsed coil onto the upper winding trolley of the uncoiler, fix the treatment frame on the upper winding trolley, raise the trolley to the normal upper winding height and move the steel coil trolley. When the steel coil core is inserted into the mandrel, rotate the mandrel in the opposite direction to wind the galvanized steel coil onto the mandrel and rotate the mandrel. 4) When the distance between the end of the mandrel head and the jack is 5-10 mm, expand the mandrel and remove the jack; 5) When you confirm that there is no gap between the lower end of the steel coil and the upper part of the processing rack, click the mandrel retraction button, wait 1-2 seconds and then continue to move the coiling trolley forward. Repeat the action of stopping the trolley movement when the mandrel expands and moving the coiling trolley forward at the moment the mandrel retracts. This can transfer the steel coil onto the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel should be controlled within ±100 mm. If the measured vertical inner diameter of the collapsed roll is between 400-470mm: 1) Hoist the handling frame containing the collapsed coil onto the trolley of the rewinding unit and fix it. Raise the trolley to the normal winding height. By the weight of the galvanized steel coil itself, the inner diameter of the collapsed coil gradually becomes elliptical or circular, and the vertical inner diameter of the steel coil gradually increases to 490-508mm to ensure that the inner diameter is large enough for the uncoiler mandrel to enter. 2) Next, move the steel coil trolley and rotate the mandrel in the opposite direction when the core is inserted into the mandrel to wind the steel coil onto the mandrel. The outer wall of the center of the galvanized steel coil gradually comes into contact with the inner wall of the processing rack. 3) When you confirm that there is no gap between the lower end of the galvanized steel coil and the upper part of the processing rack, click the mandrel retraction button, wait 1-2 seconds and then continue to move the upper winding trolley forward. Repeat the process of stopping the trolley movement when the mandrel expands and moving the upper winding trolley forward the instant the mandrel retracts.

3. The method for handling the collapse defect of thin-gauge galvanized coils according to claim 2, characterized in that, When the vertical inner diameter of the galvanized steel coil collapse is measured to be between 400-470 mm: 1) Secure the treatment frame to the upper winding trolley and raise the trolley to the normal upper winding height; 2) Move the steel coil trolley, and when the core is inserted into the mandrel, rotate the mandrel in the opposite direction to wind the steel coil onto the mandrel; 3) Once you confirm that there is no gap between the lower end of the steel coil and the upper part of the processing rack, click the mandrel retraction button. After waiting for 1-2 seconds, continue to move the coiling trolley forward. Repeat the action of stopping the trolley movement when the mandrel expands and moving the coiling trolley forward at the moment the mandrel retracts. This can transfer the steel coil onto the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel should be controlled within ±100 mm.

4. The method for handling the collapse defect of thin-gauge galvanized coils according to claim 1, characterized in that, S5 includes: A paper sleeve is fitted onto the mandrel, and the galvanized steel strip begins to be wound onto the paper sleeve.

5. The method for handling the collapse defect of thin-gauge galvanized coils according to claim 4, characterized in that, Control the equipment operating speed between 100-260 m / min. When the galvanized steel belt on the uncoiler weighs between 900-1100 kg, reduce the equipment operating speed to 30-50 m / min.