A coiling tending device for preventing sticking of steel

Abstract

A coiling and clamping device for preventing steel sticking comprises a frame, a hydraulic cylinder, conveying rollers, upper and lower clamping rollers, an upper pin, a lower pin, pin joint gaps between the upper and lower pins and the hydraulic cylinder, a transition plate between every two adjacent conveying rollers, a transition plate support frame, and transition plate gaps. The pin joint gaps are controlled to be ≤0.4mm. The upper end face of the transition plate is a smooth arc shape. The connection end between the transition plate support frame and the upper smooth arc-shaped transition plate is inclined. A hot metal detector is installed on the frame at a distance of 4.3–4.6m from the first upper or lower clamping roller at the steel plate entry end. This invention reduces the scrap rate from a previous monthly average of 0.34%, impact on operating rate of 0.48%, and generation of substandard products of 0.39% to a monthly average scrap rate of zero, an impact on operating rate of no more than 0.063%, and generation of substandard products of no more than 0.022%. Furthermore, it is easy to operate and requires no additional equipment.

Description

Technical Field

[0001] This invention relates to a steel rolling apparatus, specifically a coiling and clamping device for preventing steel sticking, and is more suitable for producing thin strips with a thickness of 0.8-2.0 mm and a width of 900-1500 mm on short-process production lines. Background Technology

[0002] Thin strip steel not only represents a high value-added product, leading to greater economic benefits, but also promotes steel lightweighting and energy conservation and low carbon emissions. However, one of the main challenges in thin strip steel production is the series of production quality problems caused by steel sticking to the pinch rolls.

[0003] In production practice, it has been found that steel sticking to the pinch rolls during coiling exists in three aspects: ① When the strip head enters the pinch roll, the strip head sticks to the pinch roll surface, resulting in roll wrapping, which is more common on the upper pinch roll than on the lower pinch roll; ② When the strip is being rolled in for finishing, the strip head is crushed and the tail is thrown off. The crushed part is then crushed or scraped by the pinch roll, resulting in the pinch roll sticking. Continuing production will cause roll marks on the strip; ③ When the strip head is folded, during the clamping process of the coiling pinch roll, because the linear speed of the pinch roll is greater than the speed of the strip passing through the plate, the relative sliding during clamping will cause the pinch roll to stick.

[0004] According to the applicant's statistics, from May 1, 2017 to April 30, 2018, there were 40 instances of steel sticking to the pinch rolls during coiling, resulting in 828.35 tons of scrap steel. Consequently, the casting machine experienced a reduction in speed for 5,986 minutes, 451.4 tons of casting machine breakage, 7 instances of casting machine interruption, 806 minutes of production stoppage, and 93 tons of molten steel being recycled. The total amount of scrap steel due to sticking to the pinch rolls during coiling was 1,544.63 tons.

[0005] Search results:

[0006] The August 2006 issue of *Rolling Steel*, Volume 23, No. 4, published an article by Fu Zhigang et al. entitled "Analysis and Improvement Measures for Strip Steel Wrapping Pinch Roll Accidents." The article elaborated on the data correspondence of strip steel wrapping pinch rolls from five aspects: ① the steel grade of the pinch rolls; ② the thickness of the strip head; ③ the service life and diameter of the upper and lower pinch rolls; ④ the offset of the pinch rolls; and ⑤ the pinch roll gap. Seven control measures were implemented: ① modifying the pinch roll position; ② increasing the offset of the pinch rolls; ③ regularly calibrating the side guide plates in front of the coiler; ④ regularly tightening the wear-resistant plates of the valve; ⑤ adjusting the gap between the wear-resistant plates of the valve and the pinch rolls; ⑥ improving the management system for the pinch rolls; and ⑦ shortening the replacement cycle of the pinch rolls. As a result, the number of times the rolls wrapped was reduced from an average of 6 times per month to 2 times.

[0007] The paper "Analysis of Steel Entanglement Mechanism and Improvement Measures of Pinch Rolls on Wuhan Iron and Steel CSP Line," published by Lu Changsheng et al. in the October 2015 issue of "Rolling Steel" (Volume 32, Issue 5), argues that the root cause of steel penetration and entanglement is the unreasonable structure of the pinch rolls. They suggest that by designing the pinch roll deflection angle to 17°, thin strip steel does not achieve the required plastic bending after passing through the pinch rolls, causing it to deviate upwards from the ideal winding trajectory after exiting the pinch rolls. They also suggest regularly monitoring the wear of the upper and lower pinch rolls, optimizing the pinch roll configuration, shortening the replacement cycle, and strictly controlling the hardness and surface quality of the pinch rolls to prevent steel entanglement accidents due to severe wear. However, these measures did not fundamentally eliminate the problem of steel sticking to the pinch rolls. Summary of the Invention

[0008] The present invention aims to overcome the shortcomings of the existing technology and provide a coiling and clamping device that can solve the problem of steel sticking to the clamping rollers during the coiling process after rolling of ultra-thin strip in a short process, reduce the monthly scrap rate caused by steel sticking to zero, reduce the impact on the operating rate to no more than 0.065%, and reduce the production of substandard products to no more than 0.025%, thereby achieving stable production of ultra-thin strip in a short process and preventing steel sticking.

[0009] Measures to achieve the above objectives:

[0010] A coiling and clamping device for preventing steel sticking comprises a frame, a hydraulic cylinder and conveying rollers on the frame, an upper clamping roller and a lower clamping roller on the frame, an upper pin connecting the hydraulic cylinder and the upper clamping roller, a lower pin connecting the hydraulic cylinder and the lower clamping roller, pin fit gaps between the upper and lower pins and the hydraulic cylinder, a transition plate between every two adjacent conveying rollers, a transition plate support frame on the frame connected to the transition plate, and a transition plate gap between the transition plate and its front conveying roller. The device is characterized in that: the pin fit gaps between the upper and lower pins and the hydraulic cylinder are controlled to be ≤0.4mm; the upper end face of the transition plate is a smooth arc shape; the connection end between the transition plate support frame and the upper smooth arc transition plate is inclined; and a hot metal detector is installed on the frame at a distance of 4.3–4.6m from the first upper or lower clamping roller at the steel plate entry end.

[0011] The key feature is that the maximum thickness at the center of the arc-shaped transition plate is 8 to 15 mm, and the thickness at both ends is 1 to 3 mm.

[0012] The key features are: the gap between the arc-shaped transition plate and the inlet of the conveyor roller is 1-3mm; and the center line of the thickness at the lower end of the arc-shaped transition plate is at the same horizontal level as the center line of the conveyor roller axis.

[0013] The key feature is that the inclined angle of the connecting end of the transition plate support frame and the arc transition plate is any angle within 10 to 15°.

[0014] The key point is that during production: whenever the tail of a single strip steel is removed from the hot metal detector, the pinch roll cooling water must be turned off; before that, the pinch roll cooling water is always on.

[0015] The key point is that when the tilt angle of the curved transition plate needs to be adjusted, it can be achieved by replacing the transition plate support frame or setting adjustment shims.

[0016] Function of components in this invention

[0017] The reason why the pin fit gap between the upper and lower pins of the pinch roller and the oil cylinder is controlled to ≤0.4mm is because the strip head with a thickness of ≤2.0mm is cut off by 500mm, and the thickness of the strip head at different positions is sampled and measured to analyze the surface condition and the motion state of the strip when it exits the pinch roller. (1) When the accident strip head is tongue-shaped, the actual thickness of the strip is measured at points equidistant around the tongue shape. The measurement shows that the thickness of the tip of the strip head is mostly below 1.5mm, with an error of 0.5 to 0.6mm from the target thickness. The thickness error at the bottom of both sides of the tongue is 0.3 to 0.4mm, and the strip head is wedge-shaped. As the strip head enters the pinch rolls, the peak of the reaction force exerted by the strip on the pinch rolls gradually increases with the thickness of the wedge-shaped area at the strip head. If the roll gap formed by the upper and lower pinch rolls becomes smaller at this time, the peak of the reaction force will be aggravated. According to the principle that the action force is equal to the reaction force, the pressure exerted by the pinch rolls on the strip head increases instantaneously, resulting in plastic deformation. These contact peaks that produce plastic deformation will also have a cold welding effect due to the excessive pressure. This may cause the two peaks to stick together. Therefore, in order to avoid a sharp increase in the pressure exerted by the pinch rolls on the strip when the strip head enters the pinch rolls, the pinch rolls need to have a high-precision roll gap.

[0018] The reason why the upper surface of the transition plate is designed as a smooth arc is that in the original design, the thin strip often folds and flips before the coiler, resulting in scrap steel. To ensure the smooth running of the strip on the transition plate, the transition plate implements the principle of "sinking and avoiding," hence its smooth arc shape. This effectively controls the quality of the strip head and solves the problem of steel sticking to the pinch rolls caused by poor head quality.

[0019] The reason why the connection end between the transition plate support frame and the transition plate is set as an inclined surface and the inclination angle is any angle within 10 to 15° is that when the strip head passes through the arc-shaped transition plate of the conveyor roller, the inclined arc-shaped transition plate can avoid the strip head from being obstructed and impacted by the arc-shaped transition plate inlet, thus preventing the strip head from folding defects.

[0020] The reason for installing a hot metal detector on the frame at 4.3 to 4.6m above the first upper or lower pinch roll of the steel plate is that when the tail of the strip leaves the hot metal detector, it indicates that the steel coil is about to be wound up. In order to accurately achieve the simultaneous baking of the pinch roll surface by the strip surface and oxidation by the air, without baking the pinch roll surface for too long and causing a decline in the surface quality of the pinch roll, a hot metal detector is installed. The hot metal detector is purchased.

[0021] The reason this invention controls the cooling water on the pinch rolls is that a water film forms between the pinch rolls and the cooling water, which can cause the strip head to stick. Therefore, the cooling water on the roll surface is turned on only after the strip head enters the pinch roll. When the tail of the strip is 4.3 to 4.6 meters away from the pinch roll inlet, that is, whenever the tail of a single strip leaves the hot metal detector, the cooling water on the pinch rolls is turned off. At this time, the hot strip bakes the water on the pinch roll surface, removing the water film. At the same time, the pinch roll surface is oxidized after contact with air, forming a powdery oxide layer, which further prevents the strip from sticking to the pinch roll, thereby controlling the sticking of the strip to the pinch roll.

[0022] Compared with the prior art, the present invention:

[0023] 1. This invention does not require modification of equipment; existing equipment and control systems can be used.

[0024] 2. This invention is applicable to the problem of steel sticking to the pinch rolls during the coiling process of all hot-rolled thin materials. It can reduce the scrap rate from the previous monthly average of 0.34%, the impact on the operating rate of 0.48%, and the generation of substandard products of 0.39% to a monthly average scrap rate of zero, an impact on the operating rate of no more than 0.063%, and a generation of substandard products of no more than 0.022%.

[0025] 3. This invention is simple, easy to implement, and easy to operate. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention;

[0027] Figure 2 for Figure 1 Schematic diagram of the intermediate transition plate support frame;

[0028] In the diagram: 1—Hot metal detector, 2—Conveying roller, 3—Upper smooth arc transition plate, 4—Lower pinch roller, 5—Upper pinch roller, 6—Hydraulic cylinder, 7—Frame, 8—Upper pin, 9—Lower pin, 10—Transition plate support frame, 11—Transition plate gap, 12—Pin mating clearance. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings:

[0030] A coiling and clamping device for preventing steel sticking comprises a frame 7, a hydraulic cylinder 6 and conveying rollers 2 on the frame 7, an upper clamping roller 5 and a lower clamping roller 4 on the frame 1, an upper pin 8 connecting the hydraulic cylinder 6 and the upper clamping roller 5, a lower pin 9 connecting the hydraulic cylinder 6 and the lower clamping roller 4, a pin engagement gap 12 between the upper pin 8 and the lower pin 9 and the hydraulic cylinder 6, a transition plate 3 between every two adjacent conveying rollers 2, a transition plate support frame 10 on the frame 7 connected to the transition plate 3, and a transition plate gap 11 between the transition plate 3 and its preceding conveying roller 2. It also includes a conveying roller track formed by the conveying rollers 2. The pin engagement gap between the upper pin 8 and the lower pin 9 and the hydraulic cylinder 6 is controlled at 0.4 mm. m / 0.25mm / 0.35mm / 0.30mm / 0.20mm; the upper end face of the transition plate 3 is a smooth arc shape; the connection end between the transition plate support frame 10 and the upper smooth arc transition plate 3 is inclined, and the inclination angle of the inclined surface is 10° / 12° / 15° / 11° / 14°, which makes the inclination angle of the upper smooth arc transition plate 3 correspondingly 10° / 12° / 15° / 11° / 14°; the hot metal detector 1 is bolted to the frame at 4.5m / 4.3m / 4.5m / 4.6m / 4.5m of the first upper pinch roller 5 or lower pinch roller 4 at the steel plate entry end, and the selected model is DELTA DC 3010-L.

[0031] When the tilt angle of the upper smooth arc transition plate 3 needs to be adjusted, it can be achieved by replacing the transition plate support frame 11 that is adapted to the tilt surface.

[0032] The maximum thickness at the center of the upper smooth arc transition plate 3 is 8mm / 13mm / 11mm / 12mm / 15mm, and the thickness at both ends is 1mm / 2.3mm / 1.2mm / 1.3mm / 2.8mm.

[0033] When the tail of the strip leaves the hot metal detector 1, it indicates that the steel coil is about to be wound up. In order to accurately achieve the goal of baking the surface of the pinch roll with the surface of the strip while oxidizing it with air, and to prevent the surface of the upper pinch roll 5 and the lower pinch roll 4 from being baked for too long, which would reduce the surface quality of the pinch roll.

[0034] The horizontal gap 12 of the upper smooth arc transition plate 3 near the inlet end of the conveyor roller 2 is 1.2mm / 1.8mm / 2.2mm / 1.3mm / 3mm; and the center line of the thickness of the lower end of the upper smooth arc transition plate 3 is the same horizontal line as the axis of the conveyor roller 2.

[0035] During production: Whenever the tail of a single strip steel is removed from the hot metal detector 1, the pinch roll cooling water must be turned off; before this, the pinch roll cooling water is always on.

[0036] The above embodiments are merely best examples and are not intended to limit the technical solutions of the present invention.

Claims

1. A coiling and clamping device for preventing steel sticking, comprising a frame, a hydraulic cylinder and conveying rollers on the frame, an upper clamping roller and a lower clamping roller on the frame, an upper pin connecting the hydraulic cylinder and the upper clamping roller, a lower pin connecting the hydraulic cylinder and the lower clamping roller, a pin fitting gap of ≤0.4mm between the upper and lower pins and the hydraulic cylinder, a smooth arc-shaped transition plate between each pair of adjacent conveying rollers, a transition plate support frame on the frame with a sloping end connecting to the smooth arc-shaped transition plate, and a transition plate gap between the transition plate and its front conveying roller, characterized in that: A hot metal detector is installed on the frame at a distance of 4.3 to 4.6 m from the first upper or lower pinch roller at the steel plate entry end; the upper end face is a smooth arc-shaped transition plate with a maximum thickness of 8 to 15 mm at the center and 1 to 3 mm at both ends; the center line of the thickness at the lower end of the upper smooth arc-shaped transition plate is at the same horizontal line as the axis of the conveying roller; the inclination angle of the inclined surface at the connection end between the transition plate support frame and the upper smooth arc-shaped transition plate is any angle within 10 to 15º; when the inclination angle of the upper smooth arc-shaped transition plate needs to be adjusted, it is achieved by replacing the transition plate support frame.

2. The winding and clamping device for preventing steel sticking as described in claim 1, characterized in that: During production: Whenever the tail of a single strip steel is removed from the hot metal detector, the pinch roll cooling water must be turned off; before that, the pinch roll cooling water is always on.

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