Collapse coil defect disposal method for thin-gauge galvanized coil

Abstract

The invention belongs to the technical field of galvanized coil maintenance, and particularly discloses a thin-gauge galvanized coil collapse defect disposal method which comprises the steps that S1, the inner diameter of a collapsed galvanized steel coil is adjusted so as to ensure that the inner diameter of the steel coil can enable a mandrel body of an uncoiling machine to enter smoothly; s2, a polishing machine is used for polishing the position, 3-4 cm away from the belt head part, of the belt head part, a zinc layer is polished to be clean, and a resistance welding machine is used for sewing the galvanized coil; s3, the inlet uncoiling tension and the withdrawal and straightening tension are reduced respectively, inching type strip threading production is started, and when the strip head runs to a tension roller outlet by 2-5 m, all roller systems of a withdrawal and straightening machine are put in, so that the strip breaking accident after a welding seam is torn is avoided; s4, the galvanized steel strip is straightened through a withdrawal and straightening machine, the wrinkle defects of the strip head are completely cut off, so that it is guaranteed that the strip head is straight, and oil is applied to prevent oxidation; and S5, uncoiling and coiling work is started at the same time, and different uncoiling tension values, coiling tension values and withdrawal and straightening tension values are set according to the steel belts with different thicknesses so as to achieve the proper coil tightness of the steel coil.

Description

Technical Field

[0001] The invention relates to the technical field of galvanized coil maintenance, and in particular to a method for handling coil collapse defects of thin-gauge galvanized coils. Background Art

[0002] The production of cold-rolled ultra-thin galvanized coils is based on the development of cold-rolled ultra-thin carbon steel, which is formed through subsequent galvanizing treatment. Cold-rolled ultra-thin carbon steel refers to ordinary carbon steel strip with a width of more than 600mm and a thickness of less than 0.1mm. Its advantage is that it is thin and has a certain strength. Through subsequent galvanizing, chromium and other coating treatments, it can replace functional materials such as aluminum, copper, and stainless steel, thereby effectively reducing costs. The galvanizing treatment is mainly to increase the corrosion resistance of metal materials and extend their service life.

[0003] The production process of cold-rolled ultra-thin galvanized coils includes multiple steps, from the preparation of cold-rolled hard steel coils to the final galvanizing treatment. This process includes uncoiling, cutting heads and tails, welding, and then degreasing liquid treatment, hot air drying, annealing, and finally the annealed steel coils are placed in a zinc pot for soaking, air knife purging, cooling, hot air drying, and smoothing to obtain galvanized steel coils. This series of processes ensures the high quality and high performance of cold-rolled ultra-thin galvanized coils. In order to facilitate soaking and subsequent processing, the galvanized coils are generally made into rolls.

[0004] However, cold-rolled galvanized coils are prone to coil collapse defects due to factors such as coil accuracy, coiling tension matching, and external conditions during production. The coil shape is severely deformed, and the coil core changes from a perfect circle to an ellipse. In severe cases, the coil core of the steel coil is flattened. This defect is called coil collapse or flat coil. After coil collapse, the coil diameter in the horizontal direction increases and the coil diameter in the vertical direction decreases. Under normal circumstances, the inner diameter of the galvanized coil is 508mm, and the coil expansion and contraction range of the unwinder of the repair unit is 468.8~520mm. The minimum inner diameter of the coil core is above 470mm and can be directly repaired. Steel coils with an inner diameter of 470-480mm need to be simply treated before they can be repaired. However, when the coil collapses seriously, the inner diameter of the smallest coil diameter in the vertical direction is only 100-460㎜, especially the galvanized coils with a thickness of less than 0.40㎜. They cannot be repaired and can only be disposed of as scrap, which is a serious 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. They are difficult to repair due to their low strength. If the process control of the repaired steel coils is not in place, secondary coil collapse may occur. Summary of the invention

[0005] The purpose of the present invention is to provide a method for dealing with the coil collapse defect of thin-gauge galvanized coils, so as to solve the problem that the cold-rolled galvanized coils are affected by factors such as coil accuracy, coiling tension matching, external conditions, etc. during production, resulting in coil collapse defects and serious coil deformation.

[0006] To achieve the above object, the basic scheme provided by the present invention is: a method for treating the defect of thin-gauge galvanized coil collapse, 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 is large enough for the mandrel of the unwinder to enter smoothly;

[0008] S2: Use a polishing machine to grind 3-4 cm of the head part to clean the galvanized layer, and use a resistance welding machine to sew the galvanized steel strip;

[0009] S3: Reduce the entrance unwinding tension to 300-500kg, reduce the tension and straightening tension to 800-1200kg, open all the rollers of the straightening machine to zero position, start the inching belt threading production, and when the belt head runs to 2-5 meters from the tension roller outlet, all the rollers of the straightening machine are put into operation to avoid the accident of belt breaking after the weld is torn;

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

[0011] S5: Continue threading the strip and start the coiling work at the same time. According to the different thicknesses of the galvanized steel strip, set different uncoiling tension values, coiling tension values ​​and straightening tension values ​​to achieve the appropriate coil tightness.

[0012] The principle and beneficial effects of the present invention are as follows: by processing the collapsed inner diameter of the galvanized steel coil, the collapsed galvanized steel coil can be smoothly placed on the core shaft of the uncoiler, using a polishing machine to grind the galvanized coil head so that the galvanized coil can be sewn by a resistance welding machine, adjusting the uncoiling tension and the straightening tension to prevent the weld from being broken, using a straightening machine to straighten the steel strip to ensure that the strip head is straight and wrinkle-free, and setting different uncoiling tension values, coiling tension values ​​and straightening tension values ​​to achieve a suitable steel coil tightness.

[0013] Scheme 2 is the preferred basic scheme. The specific steps for adjusting the inner diameter of the collapsed galvanized steel coil in S1 are as follows:

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

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

[0016] 1) Use a crane sling to initially support and fix the steel coil core so that the steel coil will not shake left and right during operation;

[0017] 2) According to the distance between the mandrel shaft and the shaft head, the jack support position is determined to avoid interference between the jack and the shaft head when the steel coil enters the mandrel. When the distance between the mandrel shaft head end and the jack is 5-10mm, expand the mandrel and remove the jack;

[0018] 3) Place the jack on the inner core of the steel coil and continuously apply pressure to the jack to support the collapsed coil to a height of about 500mm;

[0019] 4) When it is confirmed that there is no gap between the lower end of the steel coil and the upper part of the disposal rack, click the mandrel retraction button, wait for 1-2 seconds and then continue to move the roll-up trolley forward. Repeat the action of stopping the trolley when the mandrel expands and moving the roll-up trolley forward at the moment the mandrel retracts. The steel coil can be transported back to the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel can be controlled within ±100㎜;

[0020] If the vertical inner diameter of the collapsed galvanized steel coil is measured to be between 400-470mm, press the outer diameter of the galvanized steel coil against the inner wall of the handling rack, and the outer wall at the center of the galvanized steel coil gradually fits with the inner wall of the handling rack. Through the gravity of the galvanized steel coil itself, the inner diameter of the steel coil gradually collapses into an elliptical or circular shape, 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 core shaft to enter.

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

[0022] 1) Fix the disposal rack on the winding trolley and raise the trolley to the normal winding height;

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

[0024] 3) When it is confirmed that there is no gap between the lower end of the steel coil and the upper part of the disposal rack, click the mandrel retraction button, wait for 1-2 seconds and continue to move the coiling trolley forward, repeat the action of stopping the trolley when the mandrel expands, and moving the coiling trolley forward at the moment the mandrel retracts. The steel coil can be transported back to the mandrel, and the deviation between the center line of the steel coil and the center line of the mandrel can be controlled within ±100㎜.

[0025] Scheme 4 is the preferred basic scheme, S5 includes: a paper sleeve is set on the core shaft, and the galvanized steel strip starts to be rolled on the paper sleeve. The paper sleeve can further strengthen the inner core of the galvanized steel coil to increase the support force of the repaired steel coil inner core.

[0026] Scheme 5 is the preferred option of Scheme 4. In S5:

[0027] When the thickness of the galvanized steel strip is 0.25-0.33 mm, the unwinding tension is set to 800-900 kg, the coiling tension is set to 800 kg, and the production starts after the tension is 1600-1800 kg. After 400 meters of coiling, the coiling tension is gradually increased to 1400-1500 kg.

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

[0029] Option 6, which is the preferred option of Option 5, controls the equipment running speed between 100-260m / min. When the galvanized steel strip on the unwinding machine is between 900-1100kg, reduce the equipment running speed to 30-50m / min. When the collapsed galvanized steel coil is unwinded, the front section of the steel strip is a wrinkle-free steel strip, so the equipment running speed can be increased. When the unwinding steel coil has 900-1100kg left, it means that the unwinding has reached the inner core of the steel coil, and the rear section of the steel strip is a steel strip with wrinkle defects, so the equipment running speed is slowed down to improve the efficiency of repairing the wrinkles of the steel strip. DETAILED DESCRIPTION

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

[0031] Example

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

[0033] First, use a crane to lift the collapsed galvanized steel coil to the collapsed coil disposal rack. At this time, the collapsed coil defect will be affected by its own gravity, filling the outer diameter of the steel coil and pressing it against the inner wall of the disposal 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 and is 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 an ellipse or even a circle. Then use a steel ruler to measure the inner diameter of the galvanized steel coil in the vertical direction:

[0034] When the inner diameter of the galvanized steel coil in the vertical direction is between 400-470㎜, lift the handling rack with the collapsed coil to the coiling trolley of the unwinder of the rewinding unit, then fix the handling rack on the coiling trolley, raise the trolley to the normal coiling height, then move the steel coil trolley, rotate the mandrel in the opposite direction when the coil core is inserted into the mandrel, and roll 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 handling rack, click the mandrel retraction button, wait for 1-2s and then continue to move the coiling trolley forward, repeat the trolley movement when the mandrel expands, and move the coiling trolley forward at the moment the mandrel retracts;

[0035] When the inner diameter of the galvanized steel coil in the vertical direction is less than 400mm, install the modified jack at 400mm from the end of the galvanized steel coil, and then continuously increase the pressure on the jack to support the inner diameter of the galvanized steel coil in the vertical direction to 48-508mm, then hoist the disposal frame with the collapsed coil to the coiling trolley of the uncoiler, then fix the disposal frame on the coiling trolley, raise the trolley to the normal coiling height, and then move the steel coil trolley. When the steel coil core is inserted into the mandrel, rotate the mandrel in the opposite direction to put the galvanized steel coil on the uncoiler. Roll onto the mandrel and rotate the mandrel. When the distance between the end of the mandrel shaft and the jack is 5-10mm, expand the mandrel and remove the jack. 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 disposal rack, click the mandrel retraction button, wait for 1s-2s and then continue to move the roll-up trolley forward. Repeat the action of stopping the trolley when the mandrel expands and moving the roll-up trolley forward at the moment the mandrel retracts. The steel coil can be transported back to the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel can be controlled within ±100mm.

[0036] Then, the galvanized steel strip head is repaired and polished to clean the zinc layer, and then the resistance welding machine is used to weld and sew. Then, the entrance unwinding tension is reduced to 300-500kg, and the tension and straightening tension is reduced to 800-1000kg. The roller system of the tension and straightening machine is all opened to zero position, and the inching belt threading production is started. When the belt head runs to 2-5m from the tension roller outlet, the roller system of the tension and straightening machine is fully invested. Then, the belt head is threaded to the segmented shear, and all the wrinkle defects of the belt head are cut off until the belt head is straight and wrinkle-free. Then, a paper sleeve is added to the mandrel of the coiler, and the unwinder and coiler are started at the same time. The overflow edge defect of the head is controlled below 10mm. For galvanized steel strips with a thickness of 0.25-0.33mm, the unwinding tension is given to 800-900kg, the coiling tension is given to 800kg, and the tension and straightening tension is 1600-1800kg. After that, production begins. After 400 meters of coiling, the coiling tension will be gradually increased to 1400-1500kg; for galvanized steel strips with a thickness of 0.33-0.38mm, the uncoiling tension is set to 800kg, the coiling tension is set to 1400-1500kg, and the tension is 2000-2200kg before production begins. After 400m of coiling, the coiling tension will be gradually increased to 1600-1800kg. In the early threading process, the equipment running speed is controlled between 100-260m / min. After calculation by the uncoiling machine, when the galvanized steel strip on the uncoiling machine reaches between 900-1100kg, the production speed is slowed down to 30-50m / min. After the collapsed galvanized steel coil is uncoiled, straightened, and re-coiled, the repaired galvanized steel coil is finally taken away from the re-coiling unit by a trolley and reaches the steel coil storage area.

[0037] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for treating the defect of thin-gauge galvanized coil collapse, characterized in that: The following steps are involved: S1: Adjust the inner diameter of the galvanized steel coil to ensure that the inner diameter of the steel coil is large enough for the mandrel of the unwinder to enter smoothly; S2: Use a polishing machine to grind 3-4 cm of the head part to clean the zinc layer, and use a resistance welding machine to sew the galvanized steel strip; S3: Reduce the entrance unwinding tension to 300-500kg, reduce the tension and straightening tension to 800-1200kg, open all the rollers of the straightening machine to zero position, start the inching belt threading production, and when the belt head runs to 2-5 meters from the tension roller outlet, all the rollers of the straightening machine are put into operation to avoid the accident of belt breaking after the weld is torn; S4: Use a straightening machine to straighten the galvanized steel strip, remove all wrinkles and defects at the strip head to ensure that the strip head is straight, and apply oil to prevent oxidation; S5: Continue threading the strip, and start uncoiling and coiling at the same time. According to the different thicknesses of the galvanized steel strip, set different uncoiling tension values, coiling tension values ​​and straightening tension values ​​to achieve the appropriate coil tightness.

2. A method for treating the collapse defect of a thin-gauge galvanized coil 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 vertical inner diameter of the collapsed roll is less than 400 mm: 1) Use a crane sling to initially support and fix the galvanized steel coil core so that the galvanized steel coil will not shake left and right during operation; 2) According to the distance between the mandrel shaft and the shaft head, the jack support position is determined to avoid interference between the jack and the shaft head when the steel coil enters the mandrel. When the distance between the mandrel shaft head end and the jack is 5-10mm, expand the mandrel and remove the jack; 3) Place the jack on the inner core of the steel coil and continuously apply pressure to the jack to support the collapsed coil to a height of about 500mm; 4) When it is confirmed that there is no gap between the lower end of the steel coil and the upper part of the disposal rack, click the mandrel retraction button, wait for 1-2 seconds and then continue to move the roll-up trolley forward. Repeat the action of stopping the trolley when the mandrel expands and moving the roll-up trolley forward at the moment the mandrel retracts. The steel coil can be transported back to the mandrel. The deviation between the center line of the steel coil and the center line of the mandrel can be controlled within ±100㎜; If the vertical inner diameter of the collapsed coil is measured to be between 400-470mm, press the outer diameter of the galvanized steel coil against the inner wall of the disposal rack, and the outer wall of the center of the galvanized steel coil gradually fits with the inner wall of the disposal rack. Through the gravity 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 core shaft to enter.

3. A method for treating the collapse defect of a thin-gauge galvanized coil according to claim 2, characterized in that: When the vertical inner diameter of the collapsed galvanized steel coil is measured to be between 400-470mm: 1) Fix the disposal rack on the winding trolley and raise the trolley to the normal winding height; 2) Move the steel coil trolley, and when the coil core is inserted into the mandrel, rotate the mandrel in the opposite direction to roll the steel coil onto the mandrel; 3) When it is confirmed that there is no gap between the lower end of the steel coil and the upper part of the disposal rack, click the mandrel retraction button, wait for 1-2 seconds and continue to move the coiling trolley forward, repeat the action of stopping the trolley when the mandrel expands, and moving the coiling trolley forward at the moment the mandrel retracts. The steel coil can be transported back to the mandrel, and the deviation between the center line of the steel coil and the center line of the mandrel can be controlled within ±100㎜.

4. A method for treating the collapse defect of a thin-gauge galvanized coil according to claim 1, characterized in that: S5 includes: A paper sleeve is placed on the core shaft, and the galvanized steel strip begins to be rolled up on the paper sleeve.

5. A method for treating the collapse defect of a thin-gauge galvanized coil according to claim 4, characterized in that: In S5: When the thickness of the galvanized steel strip is 0.25-0.33 mm, the unwinding tension is set to 800-900 kg, the coiling tension is set to 800 kg, and the production starts after the tension is 1600-1800 kg. After 400 meters of coiling, the coiling tension is gradually increased to 1400-1500 kg. When the thickness of the galvanized steel strip is 0.33-0.38㎜, the uncoiling tension is set to 800kg, the coiling tension is set to 1400-1500kg, and the production starts after the straightening tension reaches 2000-2200kg. After coiling 400 meters, the coiling tension is gradually increased to 1600-1800kg.

6. A method for treating the defect of thin-gauge galvanized coil collapse according to claim 5, characterized in that: Control the equipment running speed between 100-260m / min. When the galvanized steel strip on the uncoiler reaches between 900-1100kg, reduce the equipment running speed to 30-50m / min.