A triple masking plating method for a steel strip continuous electroplating production line

Abstract

This invention discloses a triple-masking electroplating method for a continuous electroplating production line of steel strip, comprising the following steps: Step 1: The steel strip to be electroplated is continuously unwound and pulled through a copper plating unit, a nickel plating unit, and a stripping unit arranged sequentially at a preset speed; Step 2: In the copper plating unit, a triple-masking device composed of a U-shaped masking structure, a straight plate masking structure, and a rubber roller sealing structure is used to completely mask the first side of the steel strip, exposing the second side of the steel strip to the copper plating electrolyte. At the same time, a first current density is applied between the anode and the steel strip to deposit a copper plating layer on the second side. Compared with the prior art, this method achieves double-sided heterogeneous electroplating with high plating precision and a high degree of automation.

Description

Technical Field

[0001] This invention relates to the field of drug coating technology, and more particularly to a triple-masking electroplating method for a continuous electroplating production line for steel strips. Background Technology

[0002] Currently, in the field of electroplating of coil steel strips, it is often necessary to deposit different metal coatings on both sides of the steel strip (e.g., copper plating on one side and nickel plating on the other). Existing production lines mostly use a single masking technology, that is, simply using baffles or tape to shield the non-electroplated side. This method has the following drawbacks: First, the degree of automation is low, and manual intervention or offline flipping is often required when changing sides of the steel strip for electroplating, affecting continuous production; second, the sealing effect of a single masking structure is limited, and electrolyte leakage is prone to occur, leading to contamination of the non-electroplated side or the formation of miscellaneous plating; finally, the control precision of the coating thickness is poor, making it difficult to meet the process requirements of high uniformity and high consistency, and production efficiency is also constrained. Summary of the Invention

[0003] The purpose of this invention is to provide a triple-masking electroplating method for continuous electroplating production lines of steel strips, which can solve at least one of the above-mentioned technical problems. The technical solution of this invention is as follows: A triple-masking electroplating method for a continuous electroplating production line of steel strip includes the following steps: Step 1: The steel strip coil to be electroplated is continuously unwound and pulled through the copper plating unit, nickel plating unit and stripping unit arranged in sequence at a preset speed. Step 2: In the copper plating unit, a triple shielding device consisting of a U-shaped shielding structure, a straight plate shielding structure, and a rubber roller sealing structure is used to completely shield the first side of the steel strip, exposing the second side of the steel strip to the copper plating electrolyte. At the same time, a first current density is applied between the anode and the steel strip to deposit a copper plating layer on the second side. Step 3: In the nickel plating unit, a triple shielding device consisting of a U-shaped shielding structure, a straight plate shielding structure, and a rubber roller sealing structure is used to completely shield the second side of the steel strip, exposing the first side of the steel strip to the nickel plating electrolyte. At the same time, a second current density is applied between the anode and the steel strip to deposit a nickel plating layer on the first side. Step 4: In the stripping unit, selective stripping is performed on the steel strip that has completed double-sided heterogeneous electroplating in order to adjust the local coating thickness or remove defects. Step 5: Real-time detection of the thickness of each coating layer on the steel strip, and adjustment of the preset running speed, first current density and / or second current density according to the detection results, so that the thickness deviation of the copper coating and nickel coating is controlled within ±0.1μm.

[0004] Furthermore, the triple shielding devices described in steps two and three operate independently, wherein: The U-shaped shielding structure is used to wrap the upper and lower surface edge areas of the steel strip to prevent edge plating. Straight-plate shielding structures are used to shield large areas of non-electroplated surfaces; The rubber roller sealing structure is used to achieve a dynamic seal between the steel belt and the electrolyte during the dynamic movement of the belt, preventing liquid from seeping into the shielded area.

[0005] Furthermore, in step five, an online X-ray fluorescence thickness gauge or a laser interferometric thickness gauge is used to detect the coating thickness on both sides of the steel strip in real time, and the detected value is used as a feedback signal to automatically adjust the output current of the rectifier and / or the rotational speed of the traction roller through a PLC or DCS system.

[0006] Furthermore, the selective stripping described in step four employs an electrochemical stripping method, which only performs local stripping on areas exceeding the set thickness limit. During stripping, an auxiliary shielding device is used to protect areas that do not require stripping.

[0007] Furthermore, the entire electroplating process operates fully automatically on a continuous production line, requiring no manual intervention in the shielding or flipping of the steel strip, increasing production efficiency by more than 50% compared to single shielding technology.

[0008] Furthermore, the width of the steel strip is 300mm to 1500mm, the thickness is 0.1mm to 2.0mm, the preset running speed is 1m / min to 30m / min, and the first current density is 5A / dm³. 2 ~50A / dm 2 The second current density is 3A / dm³ 2 ~40A / dm 2 .

[0009] In summary, the advantages of this invention over the prior art are: This invention provides a triple-masking electroplating method for a continuous electroplating production line of steel strip. By integrating a triple-masking device on a single production line, copper plating on one side and nickel plating on the other side of the steel strip can be completed continuously without flipping or offline operation, achieving double-sided heterogeneous electroplating. The combined structure of U-shaped masking, straight plate masking, and rubber roller sealing effectively prevents electrolyte leakage, controls the coating thickness deviation within ±0.1μm, meets the requirements of high uniformity, and achieves high coating precision. The entire process operates continuously and automatically without manual intervention in masking or flipping, significantly reducing labor intensity and increasing production efficiency by more than 50% compared to single masking technology, demonstrating a high degree of automation. Attached Figure Description

[0010] Figure 1 This is a three-dimensional schematic diagram of the present invention. Detailed Implementation

[0011] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: like Figure 1 The method for triple-masking electroplating in a continuous electroplating production line for steel strip includes the following steps: Step 1: The steel strip to be electroplated is continuously unwound and pulled through a copper plating unit, a nickel plating unit, and a stripping unit arranged sequentially at a preset speed; Step 2: In the copper plating unit, a triple-masking device composed of a U-shaped masking structure, a straight-plate masking structure, and a rubber roller sealing structure is used to completely mask the first side of the steel strip, exposing the second side of the steel strip to the copper plating electrolyte. Simultaneously, a first current density is applied between the anode and the steel strip to deposit a copper plating layer on the second side; Step 3: In the nickel plating unit, a triple-masking device composed of a U-shaped masking structure... A triple shielding device, consisting of a straight plate shielding structure and a rubber roller sealing structure, completely shields the second side of the steel strip, exposing the first side of the steel strip to the nickel plating electrolyte. Simultaneously, a second current density is applied between the anode and the steel strip, depositing a nickel plating layer on the first side. Step four: In the stripping unit, selective stripping is performed on the steel strip that has undergone double-sided heterogeneous electroplating to adjust local plating thickness or remove defects. Step five: The thickness of each plating layer on the steel strip is monitored in real time, and the preset running speed, first current density, and / or second current density are adjusted based on the monitoring results to control the thickness deviation of both the copper and nickel plating layers within ±0.1 μm.

[0012] In one specific embodiment of the present invention, a triple-masking electroplating method for a continuous electroplating production line of steel strip is provided. The specific operation is as follows: A steel strip coil with a width of 600 mm and a thickness of 0.5 mm is continuously unwound and pulled through a copper plating unit, a nickel plating unit, and a stripping unit arranged sequentially at a preset speed of 15 m / min. In the copper plating unit, a triple-masking device composed of a U-shaped masking structure, a straight-plate masking structure, and a rubber roller sealing structure is used to completely mask the first side of the steel strip, exposing the second side to the copper plating electrolyte. A first current density of 25 A / dm² is applied between the anode and the steel strip, depositing a copper plating layer on the second side. Subsequently, the steel strip enters the nickel plating unit, where another identical triple-masking device is used to completely mask the second side of the steel strip, exposing the first side to the nickel plating electrolyte. A second current density of 20 A / dm² is applied, depositing a nickel plating layer on the first side. The steel strip then enters the stripping unit for selective stripping of the double-sided heterogeneous electroplated steel strip, in order to adjust the thickness of local coatings or remove defects. Throughout the process, the thickness of each coating layer on the steel strip is monitored in real time using an online X-ray fluorescence thickness gauge, and the preset travel speed, first current density, and / or second current density are adjusted according to the monitoring results, ultimately ensuring that the thickness deviation of both the copper and nickel coatings is controlled within ±0.1 μm. The triple shielding devices described in steps two and three operate independently. Specifically: the U-shaped shielding structure is used to wrap the upper and lower surface edge areas of the steel strip to prevent edge plating; the straight plate shielding structure is used to shield the non-electroplated surface over a large area; and the rubber roller sealing structure is used to achieve dynamic sealing between the steel strip and the electrolyte during dynamic movement to prevent liquid from seeping into the shielded area.

[0013] This embodiment further defines the independent operation of each component of the triple shielding device. Specifically, in the copper plating unit and the nickel plating unit, the U-shaped shielding structure is made of corrosion-resistant rubber material, with a U-shaped cross-section, tightly wrapping the upper and lower surface edges of the steel strip to prevent electrolyte from seeping into the non-plated surface from the edges; the straight shielding structure is made of polypropylene board, covering a large area of ​​the middle region of the non-plated surface; the rubber roller sealing structure consists of two silicone rollers positioned opposite each other, achieving dynamic sealing by applying a constant pressure (0.2-0.5 MPa) through a cylinder during the dynamic movement of the steel strip, preventing electrolyte from seeping into the shielded area along the steel strip surface. The three shielding structures work together to ensure that the non-plated surface is completely free from contact with the electrolyte.

[0014] In step five, an online X-ray fluorescence thickness gauge or a laser interferometric thickness gauge is used to detect the coating thickness on both sides of the steel strip in real time, and the detected value is used as a feedback signal to automatically adjust the output current of the rectifier and / or the rotation speed of the traction roller through a PLC or DCS system.

[0015] This embodiment details the specific methods for real-time detection and feedback adjustment of coating thickness. An online X-ray fluorescence thickness gauge is installed after the nickel plating unit, before the stripping unit, and after the stripping unit to detect the copper and nickel plating thicknesses on both sides of the steel strip in real time. The detection signal is transmitted to the PLC control system in the form of a 4–20 mA current signal. The PLC compares the measured thickness value with the set target value (e.g., 5 μm for copper and 8 μm for nickel) and calculates the thickness deviation. If the deviation exceeds ±0.1 μm, the PLC automatically adjusts the rectifier output current (step accuracy 0.1 A / dm²) and / or the rotational speed of the traction roller (step accuracy 0.1 m / min) according to a PID algorithm until the deviation returns to the allowable range. The entire feedback control cycle does not exceed 2 seconds.

[0016] The selective stripping described in step four uses an electrochemical stripping method, which only performs local stripping on areas exceeding the set thickness limit. During stripping, an auxiliary shielding device is used to protect areas that do not need to be stripped.

[0017] This embodiment further specifies the operational details of the stripping unit. An electrochemical stripping method is employed, using a 10% sulfuric acid solution as the electrolyte. During stripping, a steel strip is used as the anode, an inert titanium plate as the cathode, and a reverse current density of 5 A / dm² is applied. Stripping is performed only on areas exceeding the set thickness limit. To achieve localized stripping, an auxiliary shielding device (composed of movable PVC baffles) is installed in the stripping tank. Based on the coordinates of the exceeding location detected by an online thickness gauge, the control system drives the baffles to shield areas that do not require stripping, ensuring that the stripping current applies only to the excessively thick areas. The stripping time is experimentally preset to 5–10 seconds, and each stripping operation removes 0.1–0.3 μm of metal layer.

[0018] The entire electroplating process operates fully automatically on a continuous production line, requiring no manual intervention in the shielding or flipping of the steel strip, increasing production efficiency by more than 50% compared to single shielding technology.

[0019] This implementation emphasizes the fully automated operation of the entire production line. From unwinding, traction, electroplating, stripping, thickness measurement to final winding, the entire process is automatically coordinated and controlled by a central control system (DCS), requiring no manual intervention in the shielding or flipping of the steel strip. Operators only need to set process parameters (speed, current density, target coating thickness, etc.) before startup; the subsequent process is fully automated. Compared to existing production lines that use single shielding and require manual offline flipping, this invention increases production efficiency by more than 50%, with one production line capable of processing up to 12,000 square meters of steel strip per day, and reducing the number of operators from four per shift to one per shift (responsible only for monitoring).

[0020] The steel strip has a width of 300mm to 1500mm and a thickness of 0.1mm to 2.0mm. The preset running speed is 1m / min to 30m / min, and the first current density is 5A / dm³. 2 ~50A / dm 2 The second current density is 3A / dm³ 2 ~40A / dm 2 .

[0021] This embodiment provides a range of process parameters applicable to steel strips of different specifications. When the steel strip width is between 300mm and 1500mm and the thickness is between 0.1mm and 2.0mm, the preset running speed can be selected as 1m / min to 30m / min, and the first current density (copper plating) as 5A / dm², depending on the actual product requirements. 2 ~50A / dm 2 The second current density (nickel plating) is 3 A / dm. 2 ~40A / dm 2For example, for an extremely thin steel strip with a thickness of 0.2 mm and a width of 800 mm, a running speed of 25 m / min and a copper plating current density of 10 A / dm are used. 2 Nickel plating current density 8A / dm 2 This process yields a 2μm copper layer and a 3μm nickel layer. For thick steel strips with a thickness of 1.5mm and a width of 1200mm, a walking speed of 5m / min and a copper plating current density of 45A / dm are used. 2 Nickel plating current density 35A / dm 2 This allows for the acquisition of a 15μm copper layer and a 20μm nickel layer. The above parameter combinations all ensure that the coating thickness deviation is within ±0.1μm.

[0022] The foregoing has shown and described the basic principles and main features of the present invention, as well as its advantages. 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 present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A triple-masking electroplating method for a continuous electroplating production line of steel strip, characterized in that, Includes the following steps: Step 1: The steel strip coil to be electroplated is continuously unwound and pulled through the copper plating unit, nickel plating unit and stripping unit arranged in sequence at a preset speed. Step 2: In the copper plating unit, a triple shielding device consisting of a U-shaped shielding structure, a straight plate shielding structure, and a rubber roller sealing structure is used to completely shield the first side of the steel strip, exposing the second side of the steel strip to the copper plating electrolyte. At the same time, a first current density is applied between the anode and the steel strip to deposit a copper plating layer on the second side. Step 3: In the nickel plating unit, a triple shielding device consisting of a U-shaped shielding structure, a straight plate shielding structure, and a rubber roller sealing structure is used to completely shield the second side of the steel strip, exposing the first side of the steel strip to the nickel plating electrolyte. At the same time, a second current density is applied between the anode and the steel strip to deposit a nickel plating layer on the first side. Step 4: In the stripping unit, selective stripping is performed on the steel strip that has completed double-sided heterogeneous electroplating in order to adjust the local coating thickness or remove defects. Step 5: Real-time detection of the thickness of each coating layer on the steel strip, and adjustment of the preset running speed, first current density and / or second current density according to the detection results, so that the thickness deviation of the copper coating and nickel coating is controlled within ±0.1μm.

2. The triple-masking electroplating method for a continuous electroplating production line of steel strip according to claim 1, characterized in that, The triple shielding devices described in steps two and three operate independently, wherein: The U-shaped shielding structure is used to wrap the upper and lower surface edge areas of the steel strip to prevent edge plating. Straight-plate shielding structures are used to shield large areas of non-electroplated surfaces; The rubber roller sealing structure is used to achieve a dynamic seal between the steel belt and the electrolyte during the dynamic movement of the belt, preventing liquid from seeping into the shielded area.

3. The triple-masking electroplating method for a continuous electroplating production line of steel strip according to claim 1, characterized in that, In step five, an online X-ray fluorescence thickness gauge or a laser interferometric thickness gauge is used to detect the coating thickness on both sides of the steel strip in real time, and the detected value is used as a feedback signal to automatically adjust the output current of the rectifier and / or the rotation speed of the traction roller through a PLC or DCS system.

4. The triple-masking electroplating method for a continuous electroplating production line of steel strip according to claim 1, characterized in that, The selective stripping described in step four uses an electrochemical stripping method, which only performs local stripping on areas exceeding the set thickness limit. During stripping, an auxiliary shielding device is used to protect areas that do not need to be stripped.

5. The triple-masking electroplating method for a continuous electroplating production line of steel strip according to claim 1, characterized in that, The entire electroplating process operates fully automatically on a continuous production line, requiring no manual intervention in the shielding or flipping of the steel strip, increasing production efficiency by more than 50% compared to single shielding technology.

6. The triple-masking electroplating method for a continuous electroplating production line of steel strip according to claim 1, characterized in that, The width of the steel strip is 300mm-1500mm, the thickness is 0.1mm-2.0mm, the preset running speed is 1m / min-30m / min, the first current density is 5A / dm 2 ~50A / dm 2 , the second current density is 3A / dm 2 ~40A / dm 2 .

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