Electrochemical-based online rust formation and stabilization treatment method and equipment for steel plate surface

Abstract

The present invention discloses an electrochemical-based online rusting and stabilization treatment method and equipment for steel plate surfaces. The electrochemical treatment method is used to perform surface treatment on weathering steel plates to complete the rusting process of the weathering steel plates that would otherwise take 3 to 6 months to complete under natural conditions. An environmentally friendly protective coating is then applied to the surface of the rust layer of the steel plates to further lock the rust layer, thereby achieving a non-sticky rust-free environment for human bodies and enhancing user experience. The electrochemical-based online rusting and stabilization treatment method and equipment for steel plate surfaces of the present invention have the significant advantage of using a special design of the steel plate surface online rusting and stabilization treatment equipment to save space, and can complete 10 to 40 minutes of continuous online treatment of weathering steel plates at a speed of 100 meters per minute within a production line range of 10 to 20 meters.

Description

Technical Field

[0001] The present invention belongs to the field of weathering steel surface treatment, and in particular relates to an electrochemical-based online rusting and stabilization treatment method and equipment for steel plate surfaces, which is mainly used for online rusting and stabilization treatment of rust layers on steel plate surfaces in a limited space. Background Art

[0002] Compared with carbon steel, weathering steel has good resistance to atmospheric corrosion. The main reason is that after long-term atmospheric exposure, a stable and dense protective rust layer is formed on the surface of weathering steel, which hinders the entry of corrosive media. The rust layer formed on the surface of carbon steel is often loose and contains a large number of microcracks, which has poor protection for the substrate.

[0003] At present, under natural environment, it takes 4 years or more for weathering steel to form a stable protective rust layer. Before the formation of the stabilized rust layer, weathering steel often has uneven rust color, rust dripping, rust slag flying, etc., which affect the surrounding environment and appearance. However, after 4 years or more, when the surface rust layer is stable, weathering steel can show a dark brown or coffee color with a strong sense of heaviness, which has a strong retro artistic atmosphere and is deeply loved by people; and this color can remain unchanged for many years, which can well hinder the further penetration of corrosive media and prevent the occurrence of corrosion.

[0004] The existing technology mainly focuses on the rapid rusting and rust layer stabilization solution formulation, for example: Application No. 86103534 discloses a method for rapid formation of weather-resistant anti-rust film for steel. The technical solution disclosed in the patent document is actually an optimization of the existing method in Japan, using tannin extract to replace the more expensive tannic acid. Publication No. CN103173754A discloses a method for preparing a rust layer stabilization treatment agent for the surface of weather-resistant steel, which is composed of 25-45% alkyd varnish, 4-12% copper pyrophosphate, 2-10% barium chromate, 1-14% Fe3O4, 20-50% Fe2O3, 1-10% solvent oil and 0.5-5% dispersant. Although the above technical solution has been applied on a small scale in China, it is often used for on-site treatment of processed weather-resistant steel products, which has great limitations, as follows:

[0005] (1) The treatment process usually takes at least 1 to 2 days, because it requires complex pre-treatment such as degreasing and cleaning, and it also requires multiple sprayings of special liquid medicines and then water spraying, which makes the treatment process time-consuming and laborious;

[0006] (2) The rusting effect has certain requirements on the technical level of the construction workers. If the construction workers' technical level is not enough, it will easily cause problems such as uneven rust color and flow, affecting the appearance;

[0007] (3) The above technology has certain requirements for the site environment during construction. It requires a special site to stack samples. On-site construction of large buildings is likely to pollute the surrounding environment, and special equipment is required for construction;

[0008] (4) After rusting, the rust layer is far from stable, resulting in corrosion still occurring and a small amount of rust still flowing and polluting the environment; even after the rust layer is stable, the human body will get rusty when touched, affecting the final product experience.

[0009] In comparison, there are not many technologies for rusty products; for example, Chinese patent CN207512973U discloses a structure of a weather-resistant steel plate. Although the product involved in the patent document is a weathering steel product with a rust layer, it must be painted on the basis of the rust plate. Publication number CN103459670A discloses a steel with a rust layer that has excellent corrosion resistance even without coating, especially in severe corrosion environments with high atmospheric salt spray content such as coastal areas. However, in the technical solution disclosed in the technology, the material does not have a stable rust layer when it is first put into service, but the rust layer is naturally generated and gradually stabilized in the natural environment. Therefore, the problems of uneven color and instability before stabilization, as well as yellow rust and rust residue falling are not solved.

[0010] In general, the reason why there are no mature related rust-bearing products at present is, on the one hand, because of the contradiction between fast rusting time, production efficiency and production line length; the existing fast rusting technology can compress the fast rusting time to 1 hour at most, as described in application number CN201810620156.8; but even if the fast rusting treatment time is compressed to the limit of 30 minutes, it is difficult to achieve continuous online processing of products. Calculated at the existing hot-rolled strip speed of as low as 10 meters / minute, a production line of up to 300 meters is required to complete product processing; if the hot-rolled strip is at the conventional 45 meters / minute speed, the required production line length will reach an astonishing 1,350 meters; due to the thickness specification, conventional hot-rolled strip, especially hot-rolled products with a thickness of more than 6mm, are often difficult to save space by adopting a vertical production line layout in the form of a loop; the main user of rust-bearing weathering steel plates is weathering steel bridges, and the product specifications used are mostly medium-thick hot-rolled steel plates with a thickness of more than 6mm. This means that to achieve online treatment of steel plates before they leave the factory with rust, at least 300 meters of land is needed, which is almost impossible to achieve; or the speed needs to be slowed down to 1 meter per minute or even lower, which will seriously affect production efficiency. On the other hand, although the existing fast rusting technology almost does not involve toxic and harmful chemical media, it almost always requires the use of corrosive media to convert the iron atoms on the surface of the treated steel plate into combined ferrous or ferric ions; these corrosive media will not only cause the treated steel plate to rust quickly, but also cause the surrounding production equipment to rust quickly, seriously shortening the equipment life and increasing equipment investment.

[0011] Based on this, a new manufacturing method and production equipment are expected, which can automatically and continuously generate a uniform and stable rust layer on the surface of weathering steel plates in batches within a limited space, thereby solving the contradiction between rusting time, production efficiency and production line space, while ensuring that the surface of the weathering steel has a stable rust layer, so that the human body does not stick to the rust when touched. Summary of the invention

[0012] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide an electrochemical-based online rusting and stabilization treatment method and equipment for steel plate surface, which adopts an electrochemical treatment method to carry out surface treatment of weathering steel plates, complete the rusting process of weathering steel plates that takes 3 to 6 months to complete in a natural environment, and further lock the rust layer by applying an environmentally friendly protective coating on the surface of the rust layer of the steel plate, so as to achieve non-stick rust when touched by the human body and enhance the user experience; the significant advantage of the electrochemical-based online rusting and stabilization treatment method and equipment for steel plate surface of the present invention is that the special design of the online rusting and stabilization treatment equipment for steel plate surface is adopted to save space, and 10 to 40 minutes of continuous online treatment of weathering steel plates with a running speed of 100 meters / minute can be completed within a production line range of 10 to 20 meters.

[0013] To achieve the above object, the present invention adopts the following technical solution:

[0014] The first aspect of the present invention provides an electrochemical-based online rusting and stabilization treatment method for the surface of a steel plate, which uses an electrochemical method to complete the rusting treatment of the steel plate online, so that a uniform rust layer is generated on the surface of the steel plate, and then a protective coating is sprayed on the surface of the steel plate online. The protective coating is used to lock the rust layer, thereby achieving continuous rusting and stabilization treatment of the steel plate at a rate of 10-100 meters / minute in a limited space of 10-20 meters.

[0015] Preferably, the treatment method uses an electrochemical-based online rusting and stabilization treatment device for the steel plate surface to treat the steel plate, and specifically comprises the following steps:

[0016] S1, incoming materials, after the continuous strip steel is cross-cut into steel plates of uniform length, the steel plates are conveyed online via conveyor rollers to the fixed brackets in the incoming material area of ​​the online rusting and stabilization treatment equipment for the steel plates, and the steel plates are fixed by the fixed brackets;

[0017] S2, side-standing, the fixed support and the steel plate are lifted and rotated 90° along the conveying track driven by the conveying mechanism until the upper surface of the steel plate contacts the water-absorbing barrier of the previous fixed support, completing the side-standing operation of the steel plate;

[0018] S3, electrolytic oxidation, the steel plate after side standing enters the electrolytic oxidation zone of the treatment area, the electrolytic oxidation device is started, and the iron atoms on the surface of the steel plate lose electricity under the action of the external anode potential and become Fe 2+ ions, completing the electrolytic oxidation process;

[0019] S4, squeezing, the steel plate treated in step S3 enters the squeezing and wetting area of ​​the treatment area, and squeezes out the excess conductive liquid in the water-absorbing interlayer of the front and rear fixed brackets of the steel plate by reducing the distance between the front and rear fixed brackets of the steel plate. After squeezing, the distance between the front and rear fixed brackets of the steel plate is restored, and compressed air is passed to accelerate the volatilization of the conductive liquid on the surface of the steel plate;

[0020] S5, wetting, after no obvious droplets remain on the surface of the steel plate, spray water on the surface of the steel plate to clean the water-absorbing interlayers on both sides of the steel plate and wet the surface of the steel plate;

[0021] S6, drying, repeating the squeezing and wetting actions several times until rust is generated on the surface of the steel plate and turns yellow or yellow-brown, and then the steel plate enters the drying area, and the volatilization of water in the steel plate and the rust layer is accelerated by radiation heating or hot air baking;

[0022] S7, coating and curing, after all the water in the steel plate and the rust layer has evaporated, the fixed bracket and the steel plate are driven by the transmission mechanism to enter the flattening area, and water-based paint is sprayed on the surface of the steel plate, and the paint is accelerated to cure by air drying to form a protective coating;

[0023] S8, laying flat, after the protective coating on the surface of the steel plate is cured, the steel plate is slowly laid flat together with the fixed bracket under the drive of the conveying mechanism, and the steel plate is received by the conveying rack;

[0024] S9, feeding, after the steel plate is caught by the conveying rack, the fixed bracket releases the steel plate, and the steel plate and the conveying rack are conveyed to the conveying roller, and then the steel plate is sent away, and the conveying rack returns, and during the conveying process of the steel plate, water-based paint continues to be sprayed on the surface of the steel plate and accelerated curing through air drying.

[0025] Preferably, in step S3, the conductive liquid used in the electrolytic oxidation process is a salt solution containing potassium ions or sodium ions, and the electrolysis current is 20 to 1000 A / m 2 , the electrolysis time is 0.5 to 25 min; and / or

[0026] In step S4, the method of reducing the distance between the front and rear fixed brackets of the steel plate is that the front fixed bracket of the steel plate moves forward at a low speed or remains stationary, and the rear fixed bracket of the steel plate continues to move forward; and / or

[0027] In the step S7 and the step S9, the water-based paint adopts water-based acrylic acid, water-based alkyd resin, water-based polyester or styrene acrylic emulsion and modified paint thereof.

[0028] Preferably, the waste liquid generated in the electrochemical-based on-line rusting and stabilization treatment method for the steel plate surface is collected by a recycling tank for the on-line rusting and rust layer stabilization treatment of the steel plate; and / or

[0029] After the step S9 is completed, the fixed bracket rotates downward and is transported to the incoming material area through the conveying mechanism for the next processing.

[0030] Preferably, in the electrochemical-based online rusting and stabilization treatment method for the steel plate surface, reducing acid is regularly added to the recycling tank to convert the waste liquid into Fe 3+ Oxidants.

[0031] Preferably, the average walking speed V of the steel plate in the treatment area is:

[0032]

[0033] Among them, V0 is the traveling speed of the steel plate before the side stand, the unit is m / min;

[0034] a is the length of the steel plate along the direction of incoming material travel, in meters;

[0035] d is the distance between the steel plates after side erection, in m.

[0036] The second aspect of the present invention provides an electrochemical-based online rusting and stabilization treatment device for steel plate surfaces, which is used to complete the electrochemical-based online rusting and stabilization treatment method for steel plate surfaces described in the first aspect of the present invention, and includes an equipment body, a conveying device, a plurality of fixed brackets, an electrolytic oxidation device, a plurality of spraying mechanisms, a plurality of purge mechanisms, a drying mechanism, a recycling tank, and a conveying rack;

[0037] The conveying device comprises a conveying track and a conveying mechanism arranged on the equipment body; the conveying track is arranged vertically with the bottom of the equipment body, and the conveying track is sequentially provided with a material incoming area, a side standing area, a processing area, a flattening area, a material outgoing area and a circulation area;

[0038] The fixed bracket is used to support and lock the steel plate, and drives the steel plate to move along the conveying track under the action of the conveying mechanism; the steel plate on the fixed bracket in the processing area is connected to the electrolytic oxidation device, so that the iron atoms on the surface of the steel plate on the fixed bracket lose electrons and become ferrous ions;

[0039] The electrolytic oxidation device is arranged above the conveyor track processing area and is used to perform electrolytic oxidation treatment on the steel plate after being side-stacked;

[0040] The multiple groups of spray mechanisms are arranged above the processing area and the flattening area of ​​the conveying track and above the circulation area of ​​the conveying track, and are used to spray the fixed brackets and / or steel plates on the processing area, the flattening area and the circulation area;

[0041] The multiple groups of purge mechanisms are arranged above the processing area of ​​the conveying track, and are used to purge the steel plates on the conveying track after spraying treatment;

[0042] The drying mechanism is arranged above the conveyor track processing area and is used to dry the steel plate to be sprayed;

[0043] The recycling tank is arranged below the conveying track and is used to collect waste liquid flowing down from the steel plate and the fixed bracket;

[0044] The conveyor frame is arranged in the discharging area and is used for conveying the processed steel plate to the conveyor roller.

[0045] Preferably, the fixing bracket comprises an electrode plate, locking mechanisms disposed at both ends of the electrode plate, and water-absorbing barriers symmetrically disposed on both sides of the electrode plate;

[0046] The locking mechanism is used to fix the steel plate on the electrode plate.

[0047] Preferably, the electrode plate is made of corrosion-resistant alloy plate; and / or

[0048] The water-absorbing barrier layer is made of porous water-absorbing insulating material; and / or

[0049] The locking mechanism adopts a telescopic structure and comprises a first locking member and a second locking member symmetrically arranged at two ends of the electrode plate, and an insulating roller is arranged at a position opposite to the first locking member and the second locking member.

[0050] Preferably, the electrode plate is made of stainless steel, aluminum and its alloys, or copper and its alloys; and / or

[0051] The material of the water-absorbing barrier is sponge or flannel.

[0052] Preferably, the conveying track is arranged in the shape of a circular track, and the conveying track is composed of two straight tracks and arc tracks symmetrically arranged at both ends of the straight tracks;

[0053] The material-incoming area and the material-outlet area are symmetrically arranged in the circular arc track; the processing area and the circulation area are arranged in two linear tracks, and the processing area is arranged above the circulation area.

[0054] Preferably, the treatment area is provided with an electrolytic oxidation area, a squeezing and wetting area, and a drying area in sequence;

[0055] The multiple groups of spraying mechanisms are separately arranged on the top of the squeezing and wetting area and the flattening area;

[0056] The multiple groups of purge mechanisms are separately arranged on the top of the squeeze and moistening area and the flattening area;

[0057] The drying mechanism is arranged on the top of the drying area.

[0058] Preferably, the circulation area includes a cleaning area arranged near the discharging area and a conductive liquid spraying area arranged near the feeding area;

[0059] The recycling tank includes a first recycling tank arranged below the feeding area and the conductive liquid spraying area, a second recycling tank arranged below the cleaning area and the discharging area, and a third recycling tank arranged above the circulation area and below the processing area;

[0060] The spray mechanism above the cleaning area is used to spray clean water onto the fixed bracket, and the spray mechanism above the conductive liquid spray area is used to spray conductive liquid onto the fixed bracket.

[0061] Preferably, the length L of the online rusting and stabilization treatment equipment for the steel plate surface is determined by the following formula:

[0062]

[0063] Among them, V0 is the traveling speed of the incoming steel plate 1 before side erection, in m / min; a is the length of the steel plate 1 along the traveling direction of the incoming material, in m; b is the width of the steel plate 1, in m; d is the spacing between the steel plates 1 after side erection, in m; t is the total time of the surface treatment process, in min.

[0064] The third aspect of the present invention provides a weathering steel plate prepared by the electrochemical-based online rusting and stabilization treatment method for the steel plate surface as described in the first aspect of the present invention, wherein the weathering steel plate comprises a steel plate base, a rust layer disposed on the surface of the steel plate base, and a protective coating disposed on the surface of the rust layer.

[0065] Preferably, the total thickness of the rust layer and the protective coating is 0.5-50 μm.

[0066] The electrochemical-based online rusting and stabilization treatment method and equipment for the steel plate surface provided by the present invention have the following beneficial effects:

[0067] 1. The electrochemical-based online rusting and stabilization treatment method and equipment of the steel plate surface of the present invention can realize the rapid rusting treatment of the weathering steel surface, and the assembly line of the equipment occupies a very small area. The specific process assembly line length is related to the ratio of the length and thickness of the steel plate. According to the 10-meter-long and 4-6-meter-thick weathering steel plate, the process assembly line site using the technology of the present invention is only 1% of the conventional processing line that does not use the patented technology. It can complete the synchronous rapid rusting treatment of weathering steel plates of various sizes with a running speed of 100m / min in a limited space of 10m×20m, which greatly improves the space utilization rate and reduces the floor space;

[0068] 2. The bare weathering steel produced by the electrochemical-based online rusting and stabilization treatment method for the steel plate surface of the present invention has a uniform rust layer, and the coating on the rust layer further seals the rust layer, thereby avoiding the problems of slow rust layer formation during use of the weathering steel in the prior art, and the rust layer being prone to uneven rust color, yellow rust, and rust residue falling off in the early stage of formation;

[0069] 3. The electrochemical-based online rusting and stabilization treatment method for the steel plate surface of the present invention can use the assembly line equipment to quickly rust the steel plate online, and its process and material costs are much lower than painting;

[0070] 4. When the electrochemical-based online rusting and stabilization treatment method for the steel plate surface of the present invention is used to rapidly rust the weather-resistant steel, only conventional salt and a small amount of clean water are needed for treatment. During the process, all substances participate in the reaction, there is no emission, and the manufacturing process is safe and environmentally friendly.

[0071] 5. The product prepared by the electrochemical-based online rusting and stabilization treatment method for the steel plate surface of the present invention has excellent welding and forming friendliness. When welding, only the groove needs to be polished to perform welding, and no treatment is required after welding to be in normal service. The weld will naturally form a protective rust layer during service, and after the final rust layer is stabilized, it will be integrated with other parts. If there are high requirements for the early appearance, the weld can also be simply and quickly rusted. The product can be bent 180 degrees without significantly affecting the service;

[0072] 6. The electrochemical-based online rusting and stabilization treatment method for the steel plate surface of the present invention realizes the recycling of waste liquid, which is more environmentally friendly and can also save material costs, taking into account both economic benefits;

[0073] 7. The electrochemical-based online rusting and stabilization treatment method for the steel plate surface of the present invention produces rust plates of standard rust plates of uniform size, which can facilitate subsequent packaging, transportation and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0075] Figure 1 It is a structural schematic diagram of the electrochemical-based on-line rusting and stabilization treatment equipment for the steel plate surface of the present invention;

[0076] Figure 2 It is a schematic cross-sectional view of a weathering steel plate having a rust layer and a protective coating obtained by the on-line rusting and stabilization treatment method of the steel plate surface based on electrochemistry of the present invention;

[0077] Figure 3 Schematic diagram of an outdoor exposure test device for evaluating the corrosion resistance of bare weathering steel prepared by the present invention by weight gain method. DETAILED DESCRIPTION

[0078] In order to better understand the above technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with embodiments.

[0079] The present invention provides an electrochemical-based online rusting and stabilization treatment method for the surface of a steel plate, which uses an electrochemical method to complete the rusting treatment of the steel plate online, so that a uniform rust layer is generated on the surface of the steel plate, and then a protective coating is sprayed on the surface of the steel plate online, and the protective coating is used to lock the rust layer, and finally the rusting and stabilization treatment of the steel plate is completed in a limited space. Specifically, the method applies a constant anode point on the surface of the treated steel plate by an electrochemical method to promote the oxidation of iron atoms on its surface, accelerate the rusting process, and reduce dependence on corrosive agents, thereby avoiding corrosion of metal equipment in contact with the steel plate, greatly extending the life of the equipment, and enhancing the safety of the equipment; the method of the present invention can complete the rusting process of the weather-resistant steel plate online, which takes 3 to 6 months to complete in the natural environment, so that a uniform rust layer is generated on the surface of the weather-resistant steel plate, and an environmentally friendly protective coating is sprayed on the surface of the rust layer of the steel plate through an assembly line, and quickly solidified, and the protective coating is used to further lock the rust layer. The rust layer is removed, and the human body does not get rusty when touched; the growth of rust layer on the surface of the steel plate is not hindered outdoors, and the corrosion products produced during the growth of the rust layer are locked by the protective coating and participate in the rust layer stabilization process in the form of precipitation, shortening the rust layer stabilization process that takes 4 to 8 years to complete in a natural environment to 3 to 6 months; in addition, a significant advantage of the present invention is that the transmission track designed for online rusting and stabilization treatment equipment on the surface of the steel plate is used to save space, and continuous online treatment of weather-resistant steel plates with a running speed of 100 meters / minute for 10 to 40 minutes can be completed within a production line range of 10 to 20 meters.

[0080] Combination Figure 1As shown, the method of the present invention, through the process of incoming materials → side standing → electrolytic oxidation → squeezing and wetting → drying → coating and curing → laying flat → feeding, completes the online rusting treatment of the steel plate 1 in batches automatically and continuously. In the process, the drying time is greatly shortened by means of vertical drainage and accelerated air circulation, and the whole process time is compressed to within 10 to 40 minutes. The method of the present invention uses the online rusting and stabilization treatment equipment for the steel plate surface to treat the steel plate 1, and the specific steps are as follows:

[0081] S1, incoming materials, firstly, the continuous strip steel is cross-cut into steel plates 1 of uniform length, and then the steel plates 1 are conveyed online by conveying rollers to the upper part of the fixed bracket 2 in the incoming material area A of the online rusting and stabilization treatment equipment for the steel plates surface, and after the steel plates 1 stop steadily, the fixed bracket 2 is lifted by the conveying mechanism until the water-absorbing barrier 9 of the fixed bracket 2 contacts the lower surface of the steel plates 1, and then the locking mechanism 8 on the fixed bracket 2 automatically extends and locks the steel plates 1, and the fixed bracket 2 under the steel plates 1 holds and fixes the steel plates 1;

[0082] S2, sideways, the fixed bracket 2 and the steel plate 1 are slowly lifted and rotated 90° along the conveying track 3 driven by the conveying mechanism until the upper surface of the steel plate 1 contacts the water-absorbing barrier 9 of the previous fixed bracket 2, so that the steel plate 1 is kept sideways while ensuring that the steel plate 1 is always under the control of the front and rear fixed brackets 2, and the sideways operation of the steel plate 1 is completed; the locking mechanism 8 on the fixed bracket 2 is retractable and can be automatically adjusted according to different plate thicknesses and plate widths;

[0083] S3, electrolytic oxidation. After the side-standing, the steel plate 1 enters the electrolytic oxidation zone C in the treatment area. The electrolytic oxidation device 4 is started. The electrode plate 10 of the fixed support 2 and the steel plate 1 thereon are respectively connected to the positive and negative electrodes of the electrolytic oxidation device 4. The iron atoms on the surface of the steel plate 1 lose electricity under the action of the external anode potential and become Fe 2+ ions, completing the electrolytic oxidation process; wherein the conductive liquid 11 used in the electrolytic oxidation process is a salt solution containing potassium ions or sodium ions, and the electrolysis current is 20 to 1000A / m 2 , the electrolysis time is 0.5~25min.

[0084] S4, squeeze and dry. The steel plate 1 treated in step S3 enters the squeeze and wet zone D of the treatment area. By reducing the distance between the front and rear fixed brackets 2 of the steel plate 1, the front fixed bracket 2 of the steel plate 1 moves forward at a low speed or stands still, and the rear fixed bracket 2 of the steel plate 1 continues to move forward. The reduced distance between the front and rear fixed brackets 2 of the steel plate 1 is used to squeeze out the excess conductive liquid 11 in the water-absorbing interlayer 9 of the front and rear fixed brackets 2 of the steel plate 1. The extruded conductive liquid 11 enters the recycling tank 7 for subsequent recycling. After squeezing and drying, the distance between the front and rear fixed brackets 2 of the steel plate 1 is restored, that is, the front fixed bracket 2 of the steel plate 1 resumes its original speed, and the rear fixed bracket 2 keeps moving forward at a low speed or stands still. In this way, the distance between the front and rear fixed brackets 2 of the steel plate 1 is opened until the distance between the front and rear fixed brackets 2 of the steel plate 1 is restored, and the rear fixed bracket 2 of the steel plate 1 resumes its original speed. At the same time, the purge mechanism 5 above the squeeze and wet zone D is started to pass compressed air 13 to accelerate the volatilization of the conductive liquid 11 on the surface of the steel plate 1.

[0085] S5, wetting. After no obvious droplets remain on the surface of the steel plate 1, the spray mechanism 6 above the squeezed and wetted area D is started, and the nozzle of the spray mechanism 6 starts to spray water onto the surface of the steel plate 1, so that the water-absorbing interlayer 9 is filled with water, and the surface of the steel plate 1 is wetted while cleaning the water-absorbing interlayer 9 on both sides of the steel plate 1;

[0086] S6, drying, repeating the squeezing and wetting actions several times in the squeezing and wetting area D until rust is generated on the surface of the steel plate 1 and turns into yellow or yellow-brown, and then the steel plate 1 enters the drying area E driven by the conveying mechanism, and the drying mechanism 16 above the drying area E is started to accelerate the volatilization of water in the steel plate 1 and the rust layer by radiation heating or hot air baking;

[0087] S7, coating and curing. After all the moisture in the steel plate 1 and the rust layer has evaporated, the steel plate 1 and the fixed bracket 2 are driven by the transmission mechanism to enter the flattening area F. At the same time, the spray mechanism 6 above the flattening area F is started, and the spray head begins to spray the water-based coating 14 onto the surface of the b side of the steel plate 1, and accelerates the curing of the coating by air drying to form a protective coating; wherein the protective coating has a water-based protective coating with good water permeability, and the water-based coating 14 adopts water-based acrylic, water-based alkyd resin, water-based polyester or styrene acrylic emulsion and its modified coating, etc.

[0088] S8, laying flat, after the protective coating on the side b of the steel plate 1 is cured, the steel plate 1 continues to be slowly laid flat with the fixed bracket 2 under the drive of the conveying mechanism until the steel plate is caught by the conveying rack 15;

[0089] S9, feeding, after the steel plate 1 is caught by the conveying rack 15, the locking mechanism 8 of the fixed bracket 2 is loosened and slightly lifted upward to make the steel plate 1 detach from the fixed bracket, and the steel plate 1 is conveyed to the conveying roller together with the conveying rack 15, and the steel plate is sent away, and the conveying rack returns. During the conveying process of the steel plate 1, the spray mechanism 6 above the flattening area F sprays the water-based paint 14 onto the a-side surface of the steel plate 1 and accelerates the curing through air drying.

[0090] After the steel plate 1 and the conveying rack 15 are sent away, the fixed bracket 2 rotates downward to the circulation area, and the fixed bracket 2 is conveyed to the incoming material area A through the conveying mechanism for the next processing; in the circulation area, multiple groups of spraying mechanisms 6 can be installed above the cleaning area of ​​the circulation area (the non-track area in the middle of the conveying track 3) to continuously spray water on the fixed bracket 2 to clean the rust on its surface, and then the fixed bracket enters the conductive liquid spraying area of ​​the circulation area from the cleaning area of ​​the circulation area, and the conductive liquid is sprayed on the fixed bracket through the spraying mechanism 6 in the conductive liquid spraying area above the fixed bracket. After the water absorption layer of the fixed bracket is filled with the conductive liquid, the fixed bracket rotates to the feeding area and waits for the next circulation. The waste liquid generated in the above-mentioned electrochemical-based online rusting and stabilization treatment method for the steel plate surface is collected by the recycling tank 7 of the online rusting and stabilization treatment equipment for the steel plate surface; wherein the conductive liquid 11 flowing down from the fixed bracket 2 is collected and recycled by the first recycling tank 7a below the feeding area and the conductive liquid spraying area, the conductive liquid flowing down from the fixed bracket 2 and the steel plate 1 is collected and recycled by the third recycling tank 7c below the treatment area, the solution containing the aqueous coating 14 flowing down from the fixed bracket 2 is collected and recycled by the second recycling tank 7b below the cleaning area of ​​the circulation area, and the flowing rust can be replaced by regularly adding reducing acid to the recycling tank 7 to Fe 3+ The ions are recycled and reused. The reducing acid can be dilute hydrochloric acid or other reducing acids. The reducing acid is used to replace the oxygen in the rust to make it Fe in the rust-forming agent. 3+ Cationic oxidants.

[0091] The weathering steel plate 1 after the above treatment includes a steel plate base 20, a rust layer 21 arranged on the surface of the steel plate base 20, and a protective coating 22 arranged on the surface of the rust layer 21, wherein the total thickness of the rust layer 21 and the protective coating 22 is 0.5-50 μm. In a further preferred embodiment, the total thickness of the rust layer 21 and the protective coating 22 is 5-50 μm; the above-mentioned weathering steel still retains excellent formability and weldability, can be conventionally bent 180 degrees, and can also be directly butt-welded to ensure that the conventional mechanical properties of the joint meet the requirements.

[0092] During the above treatment process, the average walking speed V of the steel plate 1 in the treatment area is:

[0093]

[0094] Among them, V0 is the traveling speed of the steel plate 1 before the side stand, the unit is m / min;

[0095] a is the length of the steel plate 1 along the direction of incoming material travel, in m;

[0096] d is the distance between the steel plates 1 after being erected sideways, and the unit is m.

[0097] Therefore, the processing method of the present invention uses matching equipment to flip the extension direction of the steel plate by 90 degrees, so that the steel plate is changed from being placed horizontally and moving along the length direction to being placed vertically and moving horizontally along the length direction to save production line space. The length L of the entire production line is determined by the following formula:

[0098]

[0099] Among them, V0 is the traveling speed of the incoming steel plate 1 before side erection, in m / min; a is the length of the steel plate 1 along the traveling direction of the incoming material, in m; b is the width of the steel plate 1, in m; d is the spacing between the steel plates 1 after side erection, in m; t is the total time of the surface treatment process, in min.

[0100] Through the above treatment, it is possible to achieve 10 to 40 minutes of continuous online treatment of the steel plate 1 at a speed of 100 m / min within a production line range of 10 to 20 m.

[0101] Combination Figure 1 As shown, the equipment used in the above-mentioned electrochemical-based online rusting and stabilization treatment method for steel plate surface includes an equipment body, a conveying device, multiple fixed brackets 2, an electrolytic oxidation device 4, multiple groups of spraying mechanisms 6, multiple groups of purge mechanisms 5, a drying mechanism 16 and a recycling tank 7.

[0102] Combination Figure 1As shown, the conveying device includes a conveying track 3 and a conveying mechanism arranged on the equipment body; the conveying track 3 is arranged upright and perpendicular to the bottom of the equipment body, and the conveying track 3 is sequentially provided with a material-incoming area A, a side-standing area B, an electrolytic oxidation area C, a squeeze-drying and moistening area D, a drying area E, a flattening area F, a material-outlet area G and a circulation area H. In a preferred embodiment, the conveying track 3 is arranged in a circular runway shape, and the conveying track 3 is composed of two straight tracks and arc tracks symmetrically arranged at both ends of the straight tracks; wherein the material-incoming area A and the material-outlet area G are symmetrically arranged in the arc track; the processing area and the circulation area are arranged in the two straight tracks, and the processing area is arranged above the circulation area. An electrolytic oxidation zone C, a squeezing and wetting zone D and a drying zone E are sequentially arranged in the treatment zone; wherein a plurality of spraying mechanisms 6 are arranged at the top of the squeezing and wetting zone D and the flattening zone F, the spraying mechanism 6 arranged at the top of the squeezing and wetting zone D is used to spray clean water 12 on the surface of the steel plate 1; the spraying mechanism 6 arranged at the top of the flattening zone F is used to spray water-based paint 14 on the steel plate 1; a plurality of purge mechanisms 5 are arranged at the top of the squeezing and wetting zone D and the flattening zone F, the purge mechanism 5 arranged at the top of the squeezing and wetting zone D is used to accelerate the volatilization of the solution on the surface of the steel plate 1 through air 13 after the steel plate 1 is wetted; a drying mechanism 16 is arranged at the top of the drying zone E, and the drying mechanism 16 can accelerate the volatilization of moisture in the steel plate 1 and the rust layer by radiation heating or hot air baking.

[0103] Combination Figure 1As shown, a plurality of fixed brackets 2 are used to support and lock the steel plate 1, and drive the steel plate 1 to move along the conveying track 3 under the action of the conveying mechanism; when the fixed bracket 2 moves to the electrolytic oxidation zone C of the treatment zone, the fixed bracket 2 is connected to the electrolytic oxidation device 4, so that the iron atoms on the surface of the steel plate 1 on the fixed bracket 2 lose electrons and become ferrous ions, completing the oxidation process; in a specific embodiment, the fixed bracket 2 includes an electrode plate 10, a locking mechanism 8 arranged at both ends of the electrode plate 10, and a water-absorbing barrier 9 symmetrically arranged on both sides of the electrode plate 10; wherein both sides of the electrode plate 10 are provided with a locking mechanism 8, and the locking mechanism 8 is used to fix the steel plate 1 on the electrode plate 10; taking the fixed bracket 2 of the incoming material zone A as an example, the upper and lower sides of the electrode plate 10 are provided with a retracting mechanism, and the locking mechanism 8 on or below the electrode plate 10 can lock the steel plate 1 on the fixed bracket 2. The electrode plate 10 is made of corrosion-resistant alloy plate, and the material can be stainless steel, aluminum and its alloys or copper and its alloys. The locking mechanism 8 is arranged at the top of the electrode plate 10 in the width direction, and adopts a retractable structure to adapt to steel plates 1 of different widths and thicknesses; the locking mechanism 8 includes a first locking member and a second locking member symmetrically arranged at both ends of the electrode plate 10. When the steel plate 1 is fixed on the fixed bracket 2, the first locking member and the second locking member are retracted and locked toward each other in the direction perpendicular to and parallel to the electrode plate 10, so as to limit the steel plate 1 on the fixed bracket 2; wherein an insulating roller is arranged at the position opposite to the first locking member and the second locking member, and the locking mechanism 8 limits the steel plate 1 through the insulating roller, prevents the steel plate 1 from falling off, and reduces the resistance and friction of the steel plate 1 entering or exiting in the direction parallel to the electrode plate 10. The water-absorbing barrier 9 adopts a porous water-absorbing insulating material, such as a sponge or flannel. The water-absorbing barrier 9 can conduct electricity after absorbing the conductive liquid 11, and can also quickly discharge the absorbed liquid after being squeezed.

[0104] Combination Figure 1 As shown, the electrolytic oxidation device 4 is arranged above the processing area of ​​the conveying track 3, that is, above the electrolytic oxidation area C, and is used to perform electrolytic oxidation treatment on the steel plate 1 after being sideways; after the electrolytic oxidation device 4 is started, it is connected to the electrode plate 10 of the fixed bracket 2 and the steel plate thereon, and the electrolytic oxidation device 4 includes a power supply 4a, an anode plate 4c connected to the positive electrode of the power supply 4a, and a cathode plate 4b connected to the negative electrode of the power supply 4a. When in use, the anode plate 4c is connected to the steel plate 1, and the cathode plate 4b is connected to the electrode plate 10 of the fixed bracket 2. By applying a constant current to the surface of the steel plate 1, the iron atoms on the surface of the steel plate 1 lose electrons and become ferrous ions, thereby completing the oxidation process.

[0105] Combination Figure 1 As shown, multiple groups of spraying mechanisms 6 are arranged above the processing area and the flattening area F of the conveying track 3, and are used to spray the steel plates 1 on the conveying track 3, such as spraying clean water 12 or water-based paint 14.

[0106] Combination Figure 1 As shown, multiple groups of purge mechanisms 5 are arranged above the processing area of ​​the conveying track 3, and are used to purge the steel plate 1 after the spraying treatment on the conveying track 3, so as to accelerate the volatilization of the solution on the surface of the steel plate 1;

[0107] Combination Figure 1 As shown, the drying mechanism 16 is arranged above the drying area E in the processing area of ​​the conveying track 3, and is used to dry the steel plate 1 to be discharged; the drying mechanism 16 can use radiation heating or hot air baking to volatilize the moisture in the steel plate 1 and the rust layer.

[0108] Combination Figure 1 As shown, the recycling trough 7 is used to collect the waste liquid flowing down from the steel plate 1 and the fixed bracket 2; wherein the recycling area includes a cleaning area arranged near the discharging area and a conductive liquid spraying area arranged near the feeding area; the recycling trough 7 includes a third recycling trough 7c arranged in the middle trackless area of ​​the conveying track 3, a first recycling trough 7a arranged below the feeding area and the conductive liquid spraying area, and a second recycling trough 7b arranged below the cleaning area and the discharging area G; the first recycling trough 7a is mainly used to collect the conductive liquid 11 flowing down from the fixed bracket in the feeding area and the electrolytic oxidation area; the second recycling trough 7b is mainly used to collect the solution and rust containing aqueous coating 14 flowing down from the steel plate 1 and the fixed bracket; the third recycling trough 7c is arranged below the treatment area, mainly used to collect the conductive liquid 11 and clean water 12 flowing down from the steel plate 1 and the fixed bracket 2. There are multiple spraying mechanisms 6 above the circulation area, and the multiple spraying mechanisms 6 are horizontally arranged above the circulation area along the trackless area in the middle of the conveying track 3. The spraying mechanism 6 in the cleaning area is mainly used to continuously spray water on the fixed bracket 2 in the circulation area to clean the rust on the surface of the fixed bracket 2; the spraying mechanism 6 in the conductive liquid spraying area is mainly used to spray the conductive liquid 11 on the fixed bracket 2 in the circulation area, so that the water absorption barrier on the fixed bracket 2 can be filled with conductive liquid and conduct electricity.

[0109] Combination Figure 1 As shown, the discharging area G is also provided with a conveying rack 15 for conveying the processed steel plate 1 to the conveying roller; the conveying rack 15 is provided with a small retractable protrusion to reduce the contact with the lower surface of the steel plate 1. During the conveying process, the steel plate 1 is driven to move by the overall movement of the conveying rack 15, so as to minimize the relative movement between the two and reduce scratches and friction.

[0110] The following is a further introduction to the electrochemical-based online rusting and stabilization treatment method and equipment for the steel plate surface of the present invention with reference to specific examples.

[0111] Example

[0112] In the embodiment, BC550 steel plate is taken as an example, and the method and equipment for online rusting and rust layer stabilization treatment of steel plate provided by the present invention are used to treat continuous strip steel, and the specific process is as follows:

[0113] S1, incoming materials. When the weathering steel plate cut into standard size is conveyed by the conveyor roller to the water-absorbing barrier on the fixed bracket and stops steadily, the locking mechanism of the fixed bracket located at the edge of the steel plate automatically locks and fixes the steel plate.

[0114] S2, sideways. Driven by the conveying mechanism, the fixed bracket and the steel plate are slowly lifted and rotated 90 degrees until the upper surface (side b) of the steel plate contacts the water-absorbing barrier on the back of the previous fixed bracket, so that the steel plate and the bracket remain in the sideways state while ensuring that the steel plate is always under the control of the front and rear fixed brackets.

[0115] S3, electrolytic oxidation. After the steel plate and the fixed bracket are placed sideways, the electrode plate and the steel plate are connected to the electrolytic oxidation device. The iron atoms on the surface of the steel plate lose electrons and become ferrous ions under the action of the external anode potential, completing the oxidation process.

[0116] S4, squeeze dry. The front fixed bracket of the steel plate moves forward at a low speed or remains stationary, and the rear fixed bracket of the steel plate continues to move forward. The excess conductive liquid in the water-absorbing interlayer is squeezed out by reducing the distance between the front and rear fixed brackets. The squeezed conductive liquid enters the recycling tank to complete the squeeze dry action. After that, the front fixed bracket of the steel plate resumes to move forward at the original speed, and the rear fixed bracket of the steel plate maintains a low speed or remains stationary. In this way, the distance between the front and rear brackets of the sample is widened. After that, the steel plate and the rear fixed bracket resume to move forward at the original speed, and at the same time, the purge mechanism starts to blow compressed air above the steel plate and the fixed bracket to help the solution on the surface of the steel plate evaporate.

[0117] S5, wetting. When there are no obvious droplets left on the surface of the steel plate, the nozzle of the spray mechanism above it starts to spray clean water, so that the water absorption barrier is filled with water, and the surface of the steel plate is wetted while cleaning the water absorption barrier.

[0118] S6, drying. Repeat the squeezing and wetting actions several times until the steel plate surface is rusted and turns yellow or yellow-brown. Then, driven by the conveying mechanism, the steel plate and the front and rear fixed brackets enter the next process, where the volatilization of water in the steel plate and the rust layer is accelerated by radiation heating or hot air baking.

[0119] S7, coating and curing. After all the water in the steel plate and the rust layer has evaporated, the steel plate enters the flattening area, and the nozzle of the spray mechanism above it starts to spray water-based paint on the b-side surface of the steel plate and accelerates curing through air blowing to form a protective coating.

[0120] S8, lay flat. After 5 to 20 seconds, when the protective coating on the surface of the steel plate is cured, the steel plate is slowly laid flat together with the previous fixed bracket under the drive of the conveying mechanism until the steel plate is caught by the conveying frame, the retracting mechanism at the edge of the steel plate is released and slightly lifted upward, and the steel plate is conveyed by the conveying frame to the conveying roller.

[0121] S9 feeding. After the steel plate is received by the conveying roller, the steel plate is sent away by the conveying roller. During the movement of the steel plate, the nozzle of the spray mechanism located above the steel plate sprays the water-based paint on the surface of the side a of the steel plate and accelerates the curing through air blowing.

[0122] S10 cycle: After the treatment is completed, the fixed bracket continues to rotate downward and is transported by the conveying mechanism to the steel plate entrance position (i.e., the incoming material area) for the next treatment. During the cycle, the fixed bracket can be continuously sprayed with water through the spraying mechanism to clean the rust on the surface of the fixed bracket. The waste liquid generated during the entire treatment process is collected separately, and the conductive liquid and the solution containing aqueous paint flowing down the steel plate are respectively recovered and recycled by the first recycling tank and the second recycling tank. The flowing rust water enters the recovery tank and is replaced by the reducing acid into Fe 3+ Recycle and reuse.

[0123] The specific process parameters involved in Examples 1-8 are shown in Table 1. The concentrations of the following conductive liquids are all percentages;

[0124] Table 1 Main process parameters in the examples

[0125]

[0126] The structure of the weathering steel with rust layer and transparent protective coating obtained in the above examples 1-8 is as follows: Figure 2 As shown, the weathering steel with rust layer and transparent protective coating includes a steel plate substrate, a rust layer arranged on the surface of the steel plate substrate, and a protective coating on the surface of the rust layer; wherein the rust layer is a uniform rust film that is densely bonded and prevents the corrosive medium from entering the internal corrosive material. The protective coating is an environmentally friendly water-based coating with certain water permeability and air permeability and good extensibility. The coating can lock the rust layer, minimize the flow of rust liquid and the shedding of rust powder, and achieve non-stick rust when touched by the human body. At the same time, it can allow water molecules and oxygen to enter outdoors to promote the growth of the rust layer, and at the same time lock the corrosion products so that they accumulate in the rust layer in the form of precipitation and participate in stabilization, thereby accelerating the stabilization of the rust layer. When the coating is continuously damaged and aged, the rust layer has been stabilized, so there is no need to repair or re-coat the coating, which not only solves the problems of early rust layer appearance and rust powder pollution of weathering steel, but also solves the weather resistance problem of the coating. The total thickness of the rust layer and the protective coating is 0.5 to 50 μm.

[0127] In order to verify the corrosion resistance, color difference stability and rust resistance of the weathering steel with rust layer and transparent protective coating prepared by the present invention, a series of experiments were conducted to evaluate various performances of the products obtained by using Examples 1-8, and the implementation effect of the technical solution claimed in the patent was verified, including:

[0128] 1. Rust fixing performance test

[0129] Take the sample treated by the present invention (fast rust treatment + coating) and the sample treated by fast rust only (sample without coating), cut into samples with a side length of 10 cm, wipe the sample surface with a clean eraser 20 times, and then observe the eraser morphology. The sample treated by the present invention (sample with coating) has no obvious change on the sample surface after being wiped by the eraser, and the eraser and eraser crumbs are not contaminated by rust powder; for the sample without coating, the rust layer color of the wiped part of the sample surface becomes lighter after being wiped by the eraser, and the eraser and eraser crumbs are obviously contaminated by rust powder and are yellow-brown. Experiments show that the product obtained by the method of the present invention has a coating that can effectively seal the rust layer, prevent rust powder from falling off, reduce rust powder pollution, and can achieve non-stick rust when touched by human hands.

[0130] 2. Weldability verification

[0131] In order to verify the influence of coating on welding process and weldability, a comparative verification was conducted using a BC550 sample treated by the method of the present invention and a sample only treated with quick rust. The total thickness of the rust layer and coating of the BC550 sample treated by the present invention was about 10 μm. The two samples were cut along the center line and the grooves were directly butt welded. The groove type is a 45-degree Y shape, with 1 mm left at the bottom and a gap of ≤0.5 mm. Argon-rich gas shielded welding was adopted, and the shielding gas was 80% Ar+20% CO2. The groove was cleaned before welding, and the additional rust layer and coating on the front sides of the groove were not polished, and no preheating was performed before welding. The welding wire was selected as CHW-60C. No abnormality was found in the sample of the present invention (sample with coating) during the welding process; while the welding spatter on the surface of the sample without coating was tightly combined with the sample and required mechanical polishing to be removed. The welding spatter on the surface of the sample of the present invention is easier to remove and can be removed by wiping with a rag. Visual inspection of the weld morphology also shows no obvious abnormality. The welds of the uncoated samples are relatively flat and smooth, without obvious pores and slag inclusions.

[0132] The joint was cut and polished, and the macro and micro structural morphologies of the cross section were observed after etching with 4% nitric acid alcohol. It was found that the structures of the two welds were normal, and no obvious defects such as pores, cracks, slag inclusions and undercuts were found.

[0133] The National Standard of the People's Republic of China GB / T 19869.1 "Welding Procedure Qualification Test for Steel, Nickel and Nickel Alloys" is adopted as the selection of inspection items and the basis for evaluation, and external tensile inspection and bending inspection are carried out on the joints.

[0134] According to the standard, tensile test pieces were prepared and the weld reinforcement height (reinforced height) was ground flat. The tensile results are shown in Table 2. From the results, it can be seen that the fracture positions of all joints are not in the weld area, and all tensile results meet the strength requirements. This shows that the surface coating has no significant effect on the tensile properties of the joints obtained by butt welding.

[0135] Table 2 Joint tensile test results

[0136]

[0137] The bending test pieces were prepared according to the standard. The bending core diameter of d = 5ts (20 mm) and the bending angle of 180° were used in this experiment. The bending test results are shown in Table 3. From the results, it can be seen that all joints have withstood the bending test. This shows that the surface coating has no significant effect on the bending performance of the joints obtained by butt welding.

[0138] Table 3 Joint bending test results

[0139]

[0140] Combined with what is shown in Table 3, according to the National Standard of the People's Republic of China GB / T 19869.1 "Welding Procedure Assessment Test for Steel, Nickel and Nickel Alloys", we can believe that the coating selected in the present invention has no obvious negative impact on the weldability of the material and the conventional mechanical properties of the joint, and can be applied to conventional butt welding of metal materials.

[0141] 3. Formability verification

[0142] In order to study the effect of coating on conventional bending deformation, experiments were conducted using BC550 hot-rolled plates. Take 50mm×100mm×2mm BC550 hot-rolled plates, clean the dust on the surface of the sample and blow dry it, then coat half of the sample with coating (two coats) and leave the other half bare. Use a 5mm diameter indenter to bend the sample at different angles up to 180 degrees, and observe whether the surface coating is damaged or delaminated.

[0143] After the experiment, it was found that after the coating was bent 180 degrees (2.5a) with the sample, no damage or cracking was found on the coating that was visible to the naked eye.

[0144] In order to further determine whether the bending process causes invisible damage to the coating, a neutral salt spray test was conducted on the sample after 180-degree bending. During the test, the cut was protected with tape, and then the bent part was placed in a neutral salt spray test chamber with the bent part facing up, and the salt spray test was conducted according to ASTM B117 standard. The surface corrosion was observed and recorded after different time periods.

[0145] It was observed that the coating still showed a certain degree of protection after being bent 180 degrees. The uncoated sample area began to rust after 15 minutes of salt spray test, while no corrosion was seen in the protected area at this time. It was not until after 1 hour of salt spray test that sporadic rust spots began to appear in local areas. It can be seen that the coating did not produce microscopic damage invisible to the naked eye after being bent 180 degrees.

[0146] 4. Outdoor exposure experiment

[0147] A sample with a side length of 10 cm treated by the method of the present invention is exposed outdoors, and the treatment device is as follows: Figure 3 As shown, the sample 23 is placed obliquely in the beaker 24, and the corrosion products are collected by the beaker after falling off and the falling conditions are recorded. The color difference of the sample of the present invention is measured regularly and compared with the bare weathering steel plate and the fast rusting sample (uncoated sample). Considering that the color difference and flow performance of the rust layer will be affected by the climate. It was selected to be exposed in Shanghai, China (the average salt spray content in the atmosphere is less than 0.05mg*NaCl / dm2 / day), and the color difference of the sample was measured regularly, as shown in Table 4; Table 5 is an investigation of the surface color difference of typical weathering steel after outdoor exposure for different periods of time in different regions.

[0148] Table 4 Evolution of color values ​​of bare weathering steel plates, fast-rusting plates and fast-rusting reinforced rust samples

[0149]

[0150] Table 5 Color difference of BC550 weathering steel after outdoor exposure for different time periods

[0151]

[0152] Combining the color difference results in Table 4 and Table 5, it is not difficult to find that the weathering steel plate treated by the method of the present invention has a color appearance similar to the rust layer exposed outdoors for 2 years when it leaves the factory. After half a year of exposure, the appearance of the rust layer is basically the same as the rust layer exposed outdoors for 8 years, and then remains stable, and the color basically no longer changes significantly.

[0153] After the two-year hanging, the residue in the beaker was observed and the shedding was analyzed. After comparison, it was found that the yellow-brown rust product in the beaker corresponding to the sample with protective coating obtained by the method of the present invention was significantly less than that of the fast rust sample (sample without coating) and the bare weathering steel plate. In addition, organic powder was found in the beaker, which should be caused by the shedding of the coating after breaking and aging.

[0154] From the above, it can be seen that the electrochemical-based online rusting and stabilization treatment method and equipment for steel plate surface of the present invention have the following effects: (1) The bare weathering steel obtained by the electrochemical-based online rusting and stabilization treatment method for steel plate surface of the present invention has a uniform rust layer with a protective coating, which avoids the slow formation of rust layer of the weathering steel in the prior art during use, and the instability in the initial stage of formation. The unstable rust layer is prone to problems such as uneven rust layer color, yellow rust, and rust residue falling. (2) The weathering steel with a rust layer and a transparent protective coating obtained by the electrochemical-based online rusting and stabilization treatment method for steel plate surface of the present invention can provide sufficient protection, so that the weathering steel with a rust layer and a transparent protective coating has excellent corrosion resistance at the initial stage of service, avoiding corrosion damage to the bare weathering steel at the initial stage of service. (3) The transparent protective coating on the surface of the weathering steel prepared by the present invention does not substantially hinder the entry of oxygen and water required for the growth of the rust layer, but can lock in the corrosion products to reduce their flow, so that most of the corrosion products participate in the stabilization of the rust layer in the form of precipitation, thereby greatly reducing the stabilization time of the rust layer, and can shorten the stabilization time of 4-8 years under natural conditions to 3-6 months. (4) The method of the present invention can use assembly line equipment to quickly rust the steel, and its process and material costs are much lower than those of coating. (5) When the method of the present invention is used to quickly rust the weathering steel, it is only necessary to use conventional salt, weak acid and a small amount of clean water for treatment. During the process, all substances participate in the reaction, there is no emission, and the manufacturing process is safe and environmentally friendly. (6) The weathering steel with a rust layer and a transparent protective coating obtained by the method of the present invention only needs to grind out the groove before welding, and can be used normally without any treatment after welding. The weld will naturally form a protective rust layer during service and will be integrated with other parts after the final rust layer is stabilized. If there are high requirements for the early appearance, the weld can also be simply and quickly rusted. (7) The method of the present invention can greatly shorten the rusting time. In some preferred embodiments, the rusting time can be shortened by 1-2 hours. Moreover, the optimized design advocated by the present invention can realize continuous batch processing of 100 m / min high-speed steel plates within a 10-20 m production line space, successfully solving the contradiction between processing time, production efficiency and production line space, which is very conducive to mass production. (8) The reagents applied by the method described in the present invention do not involve the use of precious metal salts, the components are simpler, the cost is lower, and it is more suitable for mass production.

[0155] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. An electrochemical-based online rusting and stabilization treatment method for steel plate surface, characterized in that: The rust treatment of steel plates is completed online by electrochemical method, so that a uniform rust layer is formed on the surface of the steel plates, and then a protective coating is sprayed online on the surface of the steel plates. The protective coating is used to lock the rust layer, so that the continuous rusting and stable treatment of steel plates at a speed of 10-100 meters / minute can be completed in a limited space of 10-20 meters. The treatment method uses an electrochemical steel plate surface online rusting and stabilization treatment device to treat the steel plate, and specifically includes the following steps: S1, incoming materials, after the continuous strip steel is cross-cut into steel plates of uniform length, the steel plates are conveyed online via conveyor rollers to the fixed brackets in the incoming material area of ​​the online rusting and stabilization treatment equipment for the steel plates, and the steel plates are fixed by the fixed brackets; S2, side-standing, the fixed support and the steel plate are lifted and rotated 90° along the conveying track driven by the conveying mechanism until the upper surface of the steel plate contacts the water-absorbing barrier of the previous fixed support, completing the side-standing operation of the steel plate; S3, electrolytic oxidation, the steel plate after side standing enters the electrolytic oxidation zone of the treatment area, the electrolytic oxidation device is started, and the iron atoms on the surface of the steel plate lose electricity under the action of the external anode potential and become Fe 2+ ions, completing the electrolytic oxidation process; S4, squeezing, the steel plate treated in step S3 enters the squeezing and wetting area of ​​the treatment area, and squeezes out the excess conductive liquid in the water-absorbing interlayer of the front and rear fixed brackets of the steel plate by reducing the distance between the front and rear fixed brackets of the steel plate. After squeezing, the distance between the front and rear fixed brackets of the steel plate is restored, and compressed air is passed to accelerate the volatilization of the conductive liquid on the surface of the steel plate; S5, wetting, after no obvious droplets remain on the surface of the steel plate, spray water on the surface of the steel plate to clean the water-absorbing interlayers on both sides of the steel plate and wet the surface of the steel plate; S6, drying, repeating the squeezing and wetting actions several times until rust is generated on the surface of the steel plate and turns yellow or yellow-brown, and then the steel plate enters the drying area, and the volatilization of water in the steel plate and the rust layer is accelerated by radiation heating or hot air baking; S7, coating and curing, after all the water in the steel plate and the rust layer has evaporated, the fixed bracket and the steel plate are driven by the transmission mechanism to enter the flattening area, and water-based paint is sprayed on the surface of the steel plate, and the paint is accelerated to cure by air drying to form a protective coating; S8, laying flat, after the protective coating on the surface of the steel plate is cured, the steel plate is slowly laid flat together with the fixed bracket under the drive of the conveying mechanism, and the steel plate is received by the conveying rack; S9, feeding, after the steel plate is received by the conveying rack, the fixed bracket releases the steel plate, and the steel plate and the conveying rack are conveyed to the conveying roller, and then the steel plate is sent away, and the conveying rack returns, and during the conveying process of the steel plate, the water-based paint is continuously sprayed on the surface of the steel plate and the curing is accelerated by air drying, In step S3, the conductive liquid used in the electrolytic oxidation process is a salt solution containing potassium ions or sodium ions, and the electrolysis current is 20 to 1000 A / m 2 , electrolysis time is 0.5~25min; In the step S4, the method of reducing the distance between the front and rear fixed brackets of the steel plate is that the front fixed bracket of the steel plate moves forward at a low speed or remains stationary, and the rear fixed bracket of the steel plate continues to move forward; In the step S7 and the step S9, the water-based paint is water-based acrylic acid, water-based alkyd resin, water-based polyester or styrene acrylic emulsion and modified paint thereof, The average walking speed V of the steel plate in the treatment area is: Among them, V0 is the traveling speed of the steel plate before the side stand, the unit is m / min; a is the length of the steel plate along the direction of incoming material travel, in meters; d is the distance between the steel plates after side erection, in m.

2. The electrochemical-based online rusting and stabilization treatment method for steel plate surface according to claim 1, characterized in that: The waste liquid generated in the electrochemical-based on-line rusting and stabilization treatment method for the steel plate surface is collected by the recycling tank of the on-line rusting and rust layer stabilization treatment of the steel plate; and / or After the step S9 is completed, the fixed bracket rotates downward and is transported to the incoming material area through the conveying mechanism for the next processing.

3. The electrochemical-based online rusting and stabilization treatment method for steel plate surface according to claim 1, characterized in that: In the electrochemical-based online rusting and stabilization treatment method for the steel plate surface, reducing acid is regularly added to the recycling tank to convert the waste liquid into Fe 3+ Oxidants.

4. An electrochemical-based online rusting and stabilization treatment device for steel plate surface, used to complete the electrochemical-based online rusting and stabilization treatment method for steel plate surface according to any one of claims 1 to 3, characterized in that: It includes an equipment body, a conveying device, a plurality of fixed brackets, an electrolytic oxidation device, a plurality of spraying mechanisms, a plurality of purge mechanisms, a drying mechanism, a recycling tank and a conveying rack; The conveying device comprises a conveying track and a conveying mechanism arranged on the equipment body; the conveying track is arranged vertically with the bottom of the equipment body, and the conveying track is sequentially provided with a material incoming area, a side standing area, a processing area, a flattening area, a material outgoing area and a circulation area; The fixed bracket is used to support and lock the steel plate, and drives the steel plate to move along the conveying track under the action of the conveying mechanism; the steel plate on the fixed bracket in the processing area is connected to the electrolytic oxidation device, so that the iron atoms on the surface of the steel plate on the fixed bracket lose electrons and become ferrous ions; The electrolytic oxidation device is arranged above the conveyor track processing area and is used to perform electrolytic oxidation treatment on the steel plate after being side-stacked; The multiple groups of spray mechanisms are arranged above the processing area and the flattening area of ​​the conveying track and above the circulation area of ​​the conveying track, and are used to spray the fixed brackets and / or steel plates on the processing area, the flattening area and the circulation area; The multiple groups of purge mechanisms are arranged above the processing area of ​​the conveying track, and are used to purge the steel plates on the conveying track after spraying treatment; The drying mechanism is arranged above the conveyor track processing area and is used to dry the steel plate to be sprayed; The recycling tank is arranged below the conveying track and is used to collect waste liquid flowing down from the steel plate and the fixed bracket; The conveyor frame is arranged in the discharging area and is used for conveying the processed steel plate to the conveyor roller.

5. The electrochemical-based online rusting and stabilization treatment equipment for steel plate surface according to claim 4 is characterized in that: The fixing bracket includes an electrode plate, locking mechanisms disposed at both ends of the electrode plate, and water-absorbing barriers symmetrically disposed on both sides of the electrode plate; The locking mechanism is used to fix the steel plate on the electrode plate.

6. The electrochemical-based online rusting and stabilization treatment equipment for steel plate surface according to claim 5, characterized in that: The electrode plate is made of corrosion-resistant alloy plate; and / or The water-absorbing barrier layer is made of porous water-absorbing insulating material; and / or The locking mechanism adopts a telescopic structure and comprises a first locking member and a second locking member symmetrically arranged at two ends of the electrode plate, and an insulating roller is arranged at a position opposite to the first locking member and the second locking member.

7. The electrochemical-based online rusting and stabilization treatment equipment for steel plate surface according to claim 6, characterized in that: The electrode plate is made of stainless steel, aluminum and its alloys, or copper and its alloys; and / or The material of the water-absorbing barrier is sponge or flannel.

8. The electrochemical-based online rusting and stabilization treatment equipment for steel plate surface according to claim 4, characterized in that: The conveying track is arranged in the shape of a circular track, and the conveying track is composed of two straight tracks and arc tracks symmetrically arranged at both ends of the straight tracks; The material-incoming area and the material-outlet area are symmetrically arranged in the circular arc track; the processing area and the circulation area are arranged in two linear tracks, and the processing area is arranged above the circulation area.

9. The electrochemical-based online rusting and stabilization treatment equipment for steel plate surface according to claim 8, characterized in that: The treatment area is provided with an electrolytic oxidation area, a squeezing and wetting area, and a drying area in sequence; The multiple groups of spraying mechanisms are separately arranged on the top of the squeezing and wetting area and the flattening area; The multiple groups of purge mechanisms are separately arranged on the top of the squeeze and moistening area and the flattening area; The drying mechanism is arranged on the top of the drying area.

10. The electrochemical-based online rusting and stabilization treatment equipment for steel plate surface according to claim 9, characterized in that: The circulation area includes a cleaning area arranged near the discharging area and a conductive liquid spraying area arranged near the feeding area; The recycling tank includes a first recycling tank arranged below the feeding area and the conductive liquid spraying area, a second recycling tank arranged below the cleaning area and the discharging area, and a third recycling tank arranged above the circulation area and below the processing area; The spray mechanism above the cleaning area is used to spray clean water onto the fixed bracket, and the spray mechanism above the conductive liquid spray area is used to spray conductive liquid onto the fixed bracket.

11. The electrochemical-based online rusting and stabilization treatment equipment for steel plate surface according to claim 5, characterized in that: The length L of the online rusting and stabilization treatment equipment for the steel plate surface is determined by the following formula: Among them, V0 is the traveling speed of the incoming steel plate 1 before side erection, in m / min; a is the length of the steel plate 1 along the traveling direction of the incoming material, in m; b is the width of the steel plate 1, in m; d is the spacing between the steel plates 1 after side erection, in m; t is the total time of the surface treatment process, in min.

12. A weathering steel plate prepared by the electrochemical-based online rusting and stabilization treatment method for the surface of a steel plate according to any one of claims 1 to 3, characterized in that: The weathering steel plate comprises a steel plate base, a rust layer arranged on the surface of the steel plate base, and a protective coating layer arranged on the surface of the rust layer.

13. The weathering steel plate according to claim 12, characterized in that: The total thickness of the rust layer and the protective coating is 0.5 to 50 μm.

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