A control method for reducing surface scratches of high lubrication aluminized zinc sheet

Abstract

This invention discloses a control method for reducing surface scratches on high-lubricity galvanized steel sheets. This control method reduces the surface friction coefficient of the galvanized steel sheet and improves lubricity by forming a passivation film through roller coating with an anti-fingerprint solution. At the same time, it rationally matches the galvanizing process parameters, inter-section tension control parameters, and transmission roller system operating parameters, and adds steering rollers and pressure rollers to ensure that the high-lubricity galvanized steel sheets do not experience machine stoppages or surface scratches caused by slippage between the steel sheet and the roller system during galvanizing unit production. The defective product rate due to scratches is below 0.08%, reaching a minimum of 0.03%, ensuring stable unit operation and product surface quality that meets requirements.

Description

Technical Field

[0001] This invention relates to the field of cold-rolled sheet and strip technology, and more particularly to a method for controlling surface scratches on high-lubricated galvanized steel sheets. Background Technology

[0002] The galvanizing unit at Ansteel's cold rolling mill had previously suffered from issues such as a high surface friction coefficient and poor lubrication during processing, which easily led to stamping cracks and blackening of the contact surface during stamping or bending. Customer complaints were numerous. After adjusting the composition of the anti-fingerprint solution and adding solid lubricant, the surface friction coefficient of the anti-fingerprint galvanized sheet was significantly reduced, and the lubrication during processing was significantly improved. However, due to the reduced surface friction coefficient of the galvanized sheet, the friction between the strip and the main drive roller system after the passivation section decreased sharply. This resulted in slippage between the steel sheet and the roller system, causing shutdowns and scratches on the galvanized sheet surface. The unit's operational stability was poor, and the surface quality of the steel sheet did not meet customer requirements.

[0003] Chinese Patent CN103102790A, entitled "A Lubricating Coating for Galvanized Steel Sheets, a Self-Lubricating Galvanized Steel Sheet and its Production Method," discloses that the lubricating coating is composed of a base resin, a lubricating component, and additives. The base resin is selected from one or more of aminomethyl methacrylate, epoxy resin, acrylate, vinyl acetate, and polyurethane. The lubricating component is selected from one or more of graphite, polyethylene, polyolefin wax, and polytetrafluoroethylene. The additives are colloidal SiO2 and / or silicates. The production method includes the following steps: weighing the base resin, lubricating component, and additives and mixing them evenly; coating the galvanized steel sheet with the lubricating coating using a one-step roller coating process, and then drying and curing. The main design of this patent is a technical solution for the formulation of fingerprint-resistant passivating agents, not a specific control technology for the stable control of self-lubricating galvanized sheets in the production process of galvanizing units. Furthermore, it only provides general and broad requirements for the process technology in the production process of self-lubricating galvanized sheets, without providing a control solution for the slippage and scratch defects that may occur due to the reduction of the friction coefficient of the galvanized sheet surface. Therefore, it is insufficient to support the quality stability control requirements of self-lubricating galvanized sheets in the galvanizing production line.

[0004] Chinese patent CN103911031A, entitled "A Self-Lubricating Treatment Agent Composition for Hot-Dip Galvanizing and a Self-Lubricating Galvanized Sheet and its Preparation Method," discloses a composition consisting of water, lubricant, colloidal silica, inorganic corrosion inhibitor, silane coupling agent, organic resin, and additives. The main design of this patent focuses on the technical solution for the fingerprint-resistant passivating agent formulation, rather than on specific control technology for the stable control of self-lubricating galvanized sheets during the galvanizing process. Furthermore, the patent only provides broad requirements regarding drying temperature and film thickness in the production process of self-lubricating galvanized sheets, without offering a comprehensive system of equipment and processes to address the slippage and scratch defects that may occur due to the reduced surface friction coefficient of the galvanized sheet. Therefore, it is insufficient to support the quality stability control requirements of self-lubricating galvanized sheets in galvanizing production lines. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a control method for reducing surface scratches on high-lubricity galvanized steel sheets. This control method addresses the issue that the significantly reduced friction coefficient and increased lubricity of fingerprint-resistant galvanized surfaces lead to a sharp decrease in friction between the strip and the main drive roller system after the passivation stage, resulting in slippage between the steel sheet and the roller system, causing downtime and surface scratches on the galvanized sheet. The method involves rationally matching the galvanizing process parameters, inter-stage tension control parameters, and drive roller system operating parameters, and employing servo closed-loop control on the inspection table to adjust the roller pressure and roller gap, with an error controllable within ±1g / m. 2 This significantly improves the uniformity of the zinc layer and reduces zinc consumption.

[0006] Another object of the present invention is to provide a high-lubricity aluminized zinc plate obtained by the above-described control method. This high-lubricity aluminized zinc plate forms a passivation film by roller coating with an anti-fingerprint solution, thereby reducing the surface friction coefficient of the aluminized zinc plate and improving its lubricity.

[0007] To achieve the above objectives, the present invention is accomplished through the following technical solutions.

[0008] A method for reducing surface scratches on highly lubricated aluminized zinc-coated steel sheets includes the following steps:

[0009] S1, Aluminum-zinc plating is applied to the substrate to obtain an aluminum-zinc plate; The thickness T of the finished high-lubricity aluminized zinc plate corresponds to the following unit outlet velocity V and unit outlet acceleration a: 0.30 mm≤T<0.50mm: 130 m / min≤V≤160 m / min, 5 m / s 2 ≤a<8 m / s 2 ; 0.50 mm≤T<0.80 mm: 120 m / min≤V≤140 m / min, 4 m / s2 ≤a<7 m / s 2 ; 0.80 mm≤T<1.20 mm: 100 m / min≤V≤120 m / min, 3 m / s 2 ≤a<6 m / s 2 ; 1.20 mm≤T<1.80 mm: 80 m / min≤V≤100 m / min, 2 m / s 2 ≤a<5 m / s 2 ; 1.80 mm≤T<2.50 mm: 55 m / min≤V≤80 m / min, 2 m / s 2 ≤a<4 m / s 2 ; S2, the aluminum-zinc plate is fed into the passivation section, a fingerprint-resistant solution is applied by roller, and then dried and cured to form a passivation film on the surface of the aluminum-zinc plate. The tension difference between the passivation section, the inspection section, and the exit loop section is controlled within 800 daN. When adjusting the tension, the motor load of the drive roller is ensured not to exceed 50%, resulting in a highly lubricated aluminized zinc plate. The roughness of the tail roller system is ≥4.5μm.

[0010] In the above technical solution, the fingerprint-resistant solution comprises the following components in parts by weight:

[0011] In the above technical solution, an additional pressure roller with the same axial length as the steering roller is also installed above the main drive steering roller of the inspection table. Its diameter is 40% of the diameter of the main drive steering roller. The surface of the additional pressure roller is treated with polyurethane rubber lining, and then the surface rubber layer is roughened. The steering roller and the additional pressure roller are connected to independent drive devices. After the two are synchronously traction and passivated, the strip steel enters the roll gap between the steering roller and the additional pressure roller from bottom to top. It is pressed down 5 seconds before the inspection table unit decelerates due to winding failure and rotates with the roller. It is lifted up 5 seconds after the unit re-threads the strip and speeds up to return to a stable process speed.

[0012] In the above technical solution, the thickness of the polyurethane lining layer is 15mm ≤ 20mm.

[0013] In the above technical solution, the surface friction coefficient is 0.1~0.25.

[0014] In the above technical solution, the drying and curing temperature is 80~120℃.

[0015] The high-lubricity aluminized zinc plate obtained by the above control method includes an aluminized zinc plate and a passivation film formed on the surface of the aluminized zinc plate by roller coating with an anti-fingerprint solution.

[0016] In the above technical solution, the passivation film thickness is 1.2μm~1.6μm.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: The control method of this invention reduces the surface friction coefficient of aluminized zinc sheet, improves lubricity, and reduces the defective product rate due to scratches to below 0.08%, reaching as low as 0.03%. This ensures that the high-lubricity aluminized zinc sheet does not experience machine stoppages or surface scratches caused by slippage between the steel sheet and the roller system during galvanizing, thus guaranteeing stable unit operation and product surface quality that meets requirements. Detailed Implementation

[0018] The following examples are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0019] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained commercially or prepared according to conventional methods known to those skilled in the art.

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to embodiments 1 to 5. The described embodiments are merely descriptions of the best implementation of the present invention, and not all embodiments.

[0021] Examples 1-5 A method for reducing surface scratches on highly lubricated aluminized zinc-coated steel sheets includes the following steps: S1, using a galvanizing unit to galvanize the substrate with aluminum zinc to obtain an aluminum zinc plate; The thickness T of the finished high-lubricating aluminized zinc plate corresponds to the unit outlet velocity V and the unit outlet acceleration a, as shown in Table 1.

[0022] S2, the aluminum-zinc plate is fed into the passivation section, and an anti-fingerprint solution is rolled onto it to improve the lubricity of the aluminum-zinc plate, reduce the coefficient of friction, and then dried and cured to form a passivation film. The above-mentioned fingerprint-resistant solution comprises the following components in parts by weight:

[0023] The tension adjustment method after the passivation section is optimized to form a fixed linkage tension adjustment mechanism, controlling the tension difference between the passivation section, inspection section, and exit loop section to be within 800 daN. During tension adjustment, the motor load of the drive roller is guaranteed not to exceed 50%, resulting in a high-lubricity aluminized zinc plate. To prevent slippage between the roll surface and the passivated strip, ensure stable operation of the unit, and avoid scratches on the strip surface, the surface of the main drive roll system after the passivation section is treated with tungsten carbide coating. Above the main drive steering roll of the inspection table, there is also an additional pressure roll with the same axial length as the steering roll, and its diameter is 40% of the diameter of the main drive steering roll. The surface of the additional pressure roll is treated with polyurethane (polymerization degree of 12-25) rubber lining with a thickness of 20mm. Then, the surface rubber layer is roughened. The steering roll and the additional pressure roll are connected to independent drive devices. The two synchronously pull the passivated strip from bottom to top into the roll gap between the steering roll and the additional pressure roll. Five seconds before the inspection table unit decelerates due to winding breakage, the pressure roll is pressed down and rotates with the roll until the unit resumes winding and speeding up, and then lifts up again after 5 seconds when it returns to a stable process speed.

[0024] The high-lubricating aluminized zinc-coated sheets obtained in Examples 1-5 include an aluminized zinc-coated sheet and a passivation film formed on the surface of the aluminized zinc-coated sheet by roller coating with an anti-fingerprint solution. The parameter settings for Examples 1-5 are shown in Table 1.

[0025] Table 1

[0026] The control methods in Examples 1-5 effectively avoided scratch defects caused by slippage of the finished product at the tail end. The scratch defect rate was reduced from 0.42% to 0.052% (the average scratch defect rate of Examples 1-5), a reduction of 0.368%. Based on a scrap loss of 2,200 yuan per ton of steel and an annual production of 65,000 tons of self-lubricating fingerprint-resistant products, the annual benefit from reducing scratch scrap is 526,240 yuan.

[0027] As can be seen from the above embodiments, the method for reducing surface scratches on high-lubricity galvanized steel sheets using the present invention can achieve stable control of the surface quality and friction coefficient of such products. This production method will significantly improve the efficiency of R&D and industrialization of new galvanized steel strip products.

[0028] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation. The scope of protection of the present invention should be determined by the scope defined in the claims. Other variations or modifications can be made based on the above description. Obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for controlling scratches on the surface of highly lubricated aluminized zinc-coated steel sheets, characterized in that, Specifically, the following steps are included: S1, Aluminum-zinc plating is applied to the substrate to obtain an aluminum-zinc plate; The thickness T of the finished high-lubricity aluminized zinc plate corresponds to the following unit outlet velocity V and unit outlet acceleration a: 0.30 mm≤T<0.50mm:130 m / min≤V≤160 m / min,5 m / s 2 ≤a<8 m / s 2 ; 0.50 mm≤T<0.80 mm:120 m / min≤V≤140 m / min,4 m / s 2 ≤a<7 m / s 2 ; 0.80 mm≤T<1.20 mm:100 m / min≤V≤120 m / min,3 m / s 2 ≤a<6 m / s 2 ; 1.20 mm≤T<1.80 mm:80 m / min≤V≤100 m / min,2 m / s 2 ≤a<5 m / s 2 ; 1.80 mm≤T<2.50 mm:55 m / min≤V≤80 m / min,2 m / s 2 ≤a<4 m / s 2 ; S2, the aluminum-zinc plate is fed into the passivation section, a fingerprint-resistant solution is applied by roller, and then dried and cured to form a passivation film on the surface of the aluminum-zinc plate. The tension difference between the passivation section, the inspection section, and the exit loop section is controlled within 800 daN. When adjusting the tension, the motor load of the drive roller is ensured not to exceed 50%, resulting in a highly lubricated aluminized zinc plate. The roughness of the tail roller system is ≥4.5μm.

2. The control method according to claim 1, characterized in that, The fingerprint-resistant solution comprises the following components in parts by weight: 。 3. The control method according to claim 1, characterized in that, Above the main drive steering roller of the inspection table, there is an additional pressure roller with the same axial length as the steering roller. Its diameter is 35% to 45% of the diameter of the main drive steering roller. The surface of the additional pressure roller is treated with polyurethane rubber lining, and then the surface rubber layer is roughened. The steering roller and the additional pressure roller are connected to independent drive devices. After the two are synchronously traction and passivated, the strip steel enters the roll gap between the steering roller and the additional pressure roller from bottom to top. It is pressed down 5 seconds before the inspection table unit decelerates due to winding failure and rotates with the roller. It is lifted up 5 seconds after the unit resumes winding and speeding up to return to a stable process speed.

4. The control method according to claim 3, characterized in that, 15mm≤Polyurethane lining thickness≤20mm.

5. The control method according to claim 3, characterized in that, The surface friction coefficient is 0.1~0.

25.

6. The control method according to claim 1, characterized in that, The drying and curing temperature is 80~120℃.

7. The high-lubricating aluminized zinc plate obtained by the control method according to any one of claims 1 to 6, comprising the aluminized zinc plate and a passivation film formed on the surface of the aluminized zinc plate by roller coating with an anti-fingerprint solution.

8. The high-lubricity aluminized zinc plate according to claim 7, characterized in that, The passivation film thickness is 1.2μm~1.6μm.

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