A hot-dip galvanizing process for steel components

Abstract

The invention discloses a hot-dip galvanizing process for steel components, relates to the technical field of hot-dip galvanizing, and comprises the following steps: S1: degreasing treatment before plating: adopting a chemical degreasing method, using a degreasing liquid with a specific ratio to treat at 83°C for 25 minutes, and the degreasing equipment is connected with a closed exhaust gas treatment device; S2: pickling treatment before plating: using hydrochloric acid for pickling; S3: water washing treatment before plating; S4: auxiliary plating treatment before plating: using a solvent method to assist plating, reacting at 70°C for 11 seconds, and the auxiliary plating tank is connected with a closed exhaust gas recovery system; S5: hot-dip plating treatment: high-precision control of zinc liquid temperature, and an automatic zinc slag separation device in a zinc pot; S6: cooling treatment after plating; S7: passivation treatment after plating: passivating with a chromium-free passivating liquid at 40°C for 45 seconds, equipped with an automatic circulation filtering system; S8: inspection treatment after plating; in the invention, each link such as degreasing, pickling, auxiliary plating, etc. is equipped with high-efficiency equipment and precise control parameters to achieve high quality, environmental protection, and resource utilization optimization.

Description

Technical Field

[0001] The invention relates to the technical field of hot-dip galvanizing, in particular to a hot-dip galvanizing process for steel components. Background Art

[0002] In the field of protective treatment of steel components, hot-dip galvanizing has long been widely used to improve the corrosion resistance and service life of steel components. Although the traditional hot-dip galvanizing process meets the basic galvanizing needs to a certain extent, it has exposed many shortcomings with the development of industrial technology and the increasing environmental protection and quality standards. For example, the degreasing process often causes environmental pollution due to improper waste gas treatment, the acid mist diffuses during the pickling process affects the working environment and the surface quality control of steel components is unstable, the waste gas recovery efficiency of the plating process is low, resulting in resource waste and environmental pollution, the temperature and immersion time of the zinc liquid in the hot-dip plating process are limited in control accuracy, resulting in uneven quality of the galvanized layer, and the lack of refined operation of cooling and passivation treatment leads to insufficient corrosion resistance of the product. These problems urgently need a more advanced and complete hot-dip galvanizing process to solve.

[0003] In view of this, this application is hereby filed. Summary of the invention

[0004] The object of the present invention is to provide a hot-dip galvanizing process for steel components to solve the problems mentioned in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides a hot-dip galvanizing process for steel components, comprising the following steps: S1: degreasing treatment before plating: chemical degreasing method is adopted, and a degreasing liquid with a specific ratio is used for treatment at 83°C for 25 minutes, and the degreasing equipment is connected with a closed exhaust gas treatment device; S2: pickling treatment before plating: hydrochloric acid is used for pickling, and the concentration, acid mist and pickling time are controlled; S3: water washing treatment before plating: a multi-stage countercurrent cleaning system is adopted, and a water quality detection device is arranged at the last stage; S4: auxiliary plating treatment before plating: solvent method is adopted for auxiliary plating, and the reaction is carried out at 70°C for 11 seconds, and the auxiliary plating tank is connected with a closed exhaust gas recovery system; S5: hot-dip plating treatment: high-precision control of zinc liquid temperature, automatic control of immersion plating time, and an automatic separation device for zinc slag in the zinc pot; S6: cooling treatment after plating: air cooling first, water cooling and then drying; S7: passivation treatment after plating: passivation at 40°C for 45 seconds with a chromium-free passivation liquid, and an automatic circulation filtration system; S8: inspection treatment after plating: including appearance inspection, zinc layer thickness measurement and adhesion test.

[0006] Furthermore, in S1, the degreasing liquid is prepared by mixing 15 parts of sodium carbonate, 3.5 parts of surfactant, 5 parts of trisodium phosphate and water in a ratio of 1:20, and the degreasing liquid is stirred in a stirring tank for 30 minutes to be evenly mixed. The closed exhaust gas treatment device includes an exhaust gas collection pipe, a spray absorption tower filled with a 10% sodium hydroxide solution, and an activated carbon adsorber connected in sequence.

[0007] Furthermore, in S2, the concentration of the hydrochloric acid solution is 19%, and a high-efficiency acid mist absorption device is installed above the pickling tank, and a sodium hydroxide solution with a concentration of 10% is used to neutralize and absorb the hydrochloric acid mist. The automated pickling time control system uses a timer with a timing accuracy of ±0.1 second. The concentration and temperature of the hydrochloric acid solution are regularly checked during the pickling process. When the hydrochloric acid concentration drops below 15% or the temperature rises above 45°C, the pickling is stopped and the hydrochloric acid solution is replaced.

[0008] Furthermore, in S3, the multi-stage countercurrent cleaning system is provided with 3-stage water washing tanks in total, and the water of the last stage of water washing is used to supplement the water of the previous stage of water washing. The water quality detection device adopts an advanced ion chromatograph to ensure that the residual acid and impurity content are lower than the preset standards, that is, the hydrogen ion concentration is lower than 0.01 mol / L, the chloride ion concentration is lower than 20 mg / L, and the sulfate ion concentration is lower than 50 mg / L, and the water washing system is cleaned and maintained after each batch of steel components is processed.

[0009] Furthermore, in S4, the plating solution is prepared by 1.5 parts of zinc chloride solution, 4 parts of ammonium chloride solution and 15 parts of water. The closed waste gas recovery system recovers the irritating gas generated by the volatilization of ammonium chloride through condensation, absorption and other processes and converts it into ammonium chloride crystals for recycling.

[0010] Furthermore, in S5, the temperature of the zinc liquid is stabilized at 450°C by a high-precision temperature control system. The system uses a thermocouple thermometer for real-time temperature monitoring and is linked to an electromagnetic induction heating device. When the temperature deviates from the set range, the heating power is automatically adjusted with an adjustment accuracy of ±1°C. During the melting process of the zinc liquid, 0.05% aluminum and 0.02% nickel are added by mass; the immersion plating time is set at 45 seconds, and the immersion plating speed is 5 mm / s. The automatic zinc slag separation device includes a superconducting material electromagnetic coil installed at the bottom of the zinc pot and a high-temperature resistant ceramic zinc slag collection bucket located above the zinc pot to remove impurities and excess metal elements in the zinc liquid. The purity of zinc in the zinc liquid is maintained at above 99.5%.

[0011] Furthermore, in S6, the air cooling wind speed is controlled at 4m / s, the air cooling time is 45s, the length is 10 meters and the temperature in the channel is room temperature; the water cooling time is controlled at 15s, and the water temperature is controlled to be stable through the water circulation system during the water cooling process; the steel components after water cooling immediately enter the drying room and are dried at 70°C using hot air for 10 minutes, and the humidity in the drying room is less than 30%.

[0012] Furthermore, in the S7, the chromium-free passivation liquid contains 5% silane coupling agent, 3% titanate, and 2% organic corrosion inhibitor. The automatic circulation filtration system of the passivation liquid includes a filter, a circulation pump, and a liquid storage tank. The filter uses a microporous filtration membrane to filter out impurity particles with a particle size greater than 100 nanometers. The circulation pump flow rate is 2 cubic meters per hour.

[0013] Furthermore, in the S8, the appearance inspection uses a high-definition industrial camera combined with image recognition technology. The industrial camera has a resolution of 5 million pixels, a shooting distance of 30 cm, and a shooting angle that covers more than 90% of the surface of the steel component. The zinc layer thickness is measured using an X-ray fluorescence thickness gauge, which has an automatic calibration function. Through the built-in 3 sets of standard thickness samples and an intelligent calibration algorithm, it can be automatically calibrated regularly. The calibration time is 10 minutes. During measurement, the probe of the thickness gauge is gently placed on the surface of the steel component, maintaining a pressure of 1 Newton. The adhesion test uses an electronic universal testing machine for tensile testing.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. By precisely controlling the parameters of each link, such as the stable temperature of the zinc solution during hot-dip plating and the precise dipping time, the uniformity of the zinc coating thickness is ensured, with a deviation within ±5μm, effectively avoiding the occurrence of zinc nodules, zinc slag and other defects; at the same time, the use of advanced post-plating passivation treatment, the thickness of the passivation film formed by the chromium-free passivation solution is stable, and the corrosion resistance can reach more than 720 hours in the salt spray test, which greatly enhances the corrosion resistance of steel components and significantly improves the overall quality of the product, enabling it to be used for a long time in harsh environments, reducing structural damage and maintenance costs caused by corrosion; 2. Equipped with efficient waste gas treatment and recovery systems in degreasing, pickling and auxiliary plating, for example, the closed waste gas treatment device effectively purifies harmful gases during degreasing, the acid mist absorption device during pickling ensures a safe working environment, and the closed waste gas recovery system during auxiliary plating makes the ammonium chloride recovery efficiency reach more than 90%; this not only reduces the pollution of waste gas emissions to the environment and meets environmental protection requirements, but also realizes the recycling and reuse of resources, reduces the consumption of raw materials, and reduces production costs. At the same time, it also provides a healthier and safer working environment for operators, which is conducive to improving production efficiency and employee work enthusiasm; 3. By adopting the appearance inspection system with high-definition industrial cameras combined with image recognition technology, the appearance of the galvanized layer of steel components is fully inspected, with a recognition rate of over 95%. It can quickly and accurately detect defects such as missing plating, zinc nodules, and zinc slag; the X-ray fluorescence thickness gauge accurately measures the thickness of the zinc layer with an accuracy of ±1μm and has an automatic calibration function; the electronic universal testing machine accurately evaluates the adhesion between the zinc layer and the steel substrate; these detection methods realize precise control of product quality, facilitate timely discovery of problems in the production process and make adjustments and optimizations, effectively reduce the defective rate, improve the product qualification rate and stability, ensure that each batch of products can meet the high quality standards, and enhance the competitiveness of the products in the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1The figure is a principle block diagram of the hot-dip galvanizing process for steel components. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 The present invention provides a technical solution: a hot-dip galvanizing process for steel components, comprising the following steps: Equipment and material preparation: Degreasing equipment: Chemical degreasing tank: with a volume of 5 cubic meters, it is made of stainless steel and equipped with a stirring device inside to ensure uniform distribution of the degreasing liquid. In the closed exhaust gas treatment device, the exhaust gas collection pipe is made of acid and alkali resistant materials, and the spray absorption tower is filled with a 10% sodium hydroxide solution to neutralize the acidic exhaust gas. The activated carbon adsorber is filled with activated carbon with a specific surface area of ​​1,000 square meters / gram, which effectively absorbs residual odors and harmful gases.

[0018] Pickling equipment: Hydrochloric acid pickling tank: The volume is 3 cubic meters, made of plastic. There is a heating device in the tank to heat the hydrochloric acid solution to the required temperature. The efficient acid mist absorption device has an absorption efficiency of more than 95%. The automatic pickling time control system uses a high-precision timer with a timing accuracy of up to ±0.1 seconds.

[0019] Washing equipment: The multi-stage countercurrent cleaning system has 3 levels of water washing tanks, each of which is connected by pipes and water pumps to form a countercurrent cycle. The water quality detection device installed after the last stage of water washing uses an advanced ion chromatograph to ensure that the residual acid and impurity content are lower than the preset standards, such as hydrogen ion concentration below 0.01mol / L, chloride ion concentration below 20mg / L, and sulfate ion concentration below 50mg / L.

[0020] Plating equipment: Solvent-assisted plating tank: Made of carbon steel, with an anti-corrosion coating on the inside, the closed waste gas recovery system recycles the irritating gas generated by the volatilization of ammonium chloride through condensation, absorption and other processes, with a recovery efficiency of more than 90%.

[0021] Hot dip galvanizing equipment: Zinc pot: It is made of graphite crucible with a volume of 10 cubic meters. The thermocouple thermometer of the high-precision temperature control system has a measurement accuracy of ±1°C. The heating device adopts electromagnetic induction heating. The automatic immersion time control device is linked to the conveying equipment on the production line with an accuracy of ±0.1 seconds. The electromagnetic coil of the zinc slag automatic separation device is made of superconducting material, and the zinc slag collection bucket is made of high-temperature resistant ceramic material. The zinc slag collection bucket is cleaned after processing 50 batches of steel components.

[0022] Cooling equipment: Air cooling device: It uses a high-power fan to provide a stable wind speed of 3-5m / s. The wind temperature can be adjusted from room temperature to 50°C. The air cooling channel is made of stainless steel and is 10 meters long.

[0023] Water cooling device: The water cooling tank is made of stainless steel and has a water circulation system inside. The water cooling time can be accurately controlled within ±0.1 seconds. The hot air drying chamber uses electric heating to generate hot air. The temperature can be accurately adjusted between 60-80℃. The drying chamber is equipped with an air circulation device.

[0024] Passivation equipment: Passivation tank: Made of plastic material, with a capacity of 2 cubic meters. The filter of the automatic circulation filtration system of the passivation liquid adopts a microporous filter membrane, which can filter out impurity particles with a particle size greater than 100 nanometers. The circulation pump flow rate is 2 cubic meters / hour. The liquid storage tank is made of stainless steel with a capacity of 5 cubic meters. The content of silane coupling agent in the chromium-free passivation liquid is 5%, the content of titanate is 3%, and the content of organic corrosion inhibitor is 2%.

[0025] Inspection equipment: Appearance inspection system that combines high-definition industrial cameras with image recognition technology: The industrial camera has a resolution of 5 million pixels, the image processing server uses a high-performance GPU to accelerate computing, and the image recognition model has been trained with a large number of samples, with an accuracy rate of over 95% for defects such as missing plating, zinc nodules, and zinc slag; the display screen uses a high-definition LCD screen.

[0026] X-ray fluorescence thickness gauge: It uses an advanced X-ray tube, the emitted X-ray energy is stable, the measuring range is 10-100μm, and the automatic calibration function can automatically calibrate regularly through the built-in 3 sets of standard thickness samples and intelligent calibration algorithm to ensure the measurement accuracy reaches ±1μm.

[0027] Electronic universal testing machine: The maximum tensile force is 50,000 Newtons, the stretching speed can be precisely adjusted between 1-50 mm / min, the special stretching fixture is customized according to the different shapes and sizes of steel components, and uses rubber cushions and precision mechanical structures. The test data acquisition system uses high-precision sensors, and the data acquisition frequency is 10 Hz.

[0028] Steel component materials: A batch of Q345 steel components to be galvanized are selected, in the shape of angle steel and channel steel of different specifications, with oil, rust and oxide scale on the surface. The size range of steel components is: angle steel side length 30-100 mm, thickness 3-10 mm; channel steel width 40-120 mm, height 50-150 mm, thickness 4-12 mm.

[0029] Chemical reagents: sodium carbonate, surfactant, trisodium phosphate, hydrochloric acid, sulfuric acid, zinc chloride, ammonium chloride, rare earth element additives, etc., are all reagents that meet industrial standards. The purity of sodium carbonate is 99%, the content of surfactant active matter is 95%, the purity of trisodium phosphate is 98%, the concentration of hydrochloric acid is 36% (analytical pure), the concentration of sulfuric acid is 98% (analytical pure), the purity of zinc chloride is 99%, the purity of ammonium chloride is 99%, and the purity of rare earth element additives is 99%.

[0030] S1: Degreasing treatment before plating: Chemical degreasing method: In a stirring kettle, 15 parts of sodium carbonate, 3.5 parts of surfactant, 5 parts of trisodium phosphate and water are mixed in a ratio of 1:20, and the stirring device is turned on for 30 minutes to prepare a degreasing liquid.

[0031] Carefully place the steel components to be treated in the chemical degreasing tank, turn on the heating device to raise the temperature in the tank to 83°C, and soak for 25 minutes. During this period, the waste gas generated by degreasing enters the closed waste gas treatment device through the waste gas collection pipe made of acid and alkali resistant materials. The acid components are first neutralized by 10% sodium hydroxide solution in the spray absorption tower, and then the residual odor and harmful gases are adsorbed by the activated carbon adsorber. The treated gas is tested and discharged after meeting the environmental emission standards. After each batch of degreasing is completed, the components of the degreasing liquid are analyzed and tested using professional testing instruments, and the corresponding degreasing agent components are supplemented based on the results to ensure the stability of the degreasing effect. The test shows that the residual grease on the surface of the steel components after degreasing is less than 5mg / m².

[0032] S2: Pickling treatment before plating: Hydrochloric acid pickling: Accurately measure an appropriate amount of hydrochloric acid and prepare a 19% hydrochloric acid solution in a plastic hydrochloric acid pickling tank. The heating device in the tank preheats the solution to an appropriate temperature.

[0033] Put the chemically degreased steel components steadily into the pickling tank, and turn on the high-efficiency acid mist absorption device (with 10% sodium hydroxide solution inside) and the automatic pickling time control system (high-precision timer, accuracy ±0.1 second) at the same time. During the pickling process, use professional testing instruments to detect the concentration and temperature of the hydrochloric acid solution at regular intervals. When the hydrochloric acid concentration drops below 15% or the temperature exceeds 45°C, stop pickling immediately and replace the solution. After pickling, the surface of the steel component presents a metallic luster and there is no obvious rust and oxide scale residue. The surface iron ion content is 30mg / m², which is lower than the qualified standard of 50mg / m².

[0034] S3: Water washing before plating: After pickling, the steel components are sequentially placed in the three-stage water washing tank of the multi-stage countercurrent cleaning system. The water in the last-stage water washing tank is replenished to the previous stage through a water pump and pipeline, fully recycling water resources.

[0035] After the last level of water washing, the advanced ion chromatograph detects the residual acid and impurities on the surface of the steel components, focusing on the concentrations of hydrogen ions, chloride ions, and sulfate ions. If the hydrogen ion concentration is higher than 0.01mol / L, the chloride ion concentration is higher than 20mg / L, and the sulfate ion concentration is higher than 50mg / L, the steel components will be returned to the previous level of water washing tank for re-washing until they are qualified. After each batch of steel components is processed, the water washing system is fully cleaned and maintained, impurities and dirt in the tank are cleaned, and the operation of the pipeline and water pump is checked to ensure the normal and stable operation of the system. According to the test, the hydrogen ion concentration on the surface of the steel components after water washing is 0.005mol / L, the chloride ion concentration is 10mg / L, and the sulfate ion concentration is 20mg / L.

[0036] S4: Pre-plating auxiliary treatment: Solvent-assisted plating: In a clean container, mix 1.5 parts of zinc chloride solution, 4 parts of ammonium chloride solution and 15 parts of water, and stir for 15 minutes to prepare a plating solution.

[0037] The washed steel components are gently placed in a plating tank made of carbon steel with an anti-corrosion coating inside. The temperature in the tank is maintained at 70°C and the reaction lasts for 11 seconds. During the plating process, the closed exhaust gas recovery system operates continuously, and the irritating gas volatilized by ammonium chloride is converted into ammonium chloride crystals for recovery through condensation, absorption and other processes, with a recovery efficiency of more than 90%. After each batch of plating is completed, the plating solution is tested and analyzed for its components, and the missing components are supplemented or the proportions are adjusted based on the results to ensure that the plating effect is stable and reliable. The test shows that the plating agent on the surface of the steel components after plating is uniform and has no obvious defects.

[0038] S5: Hot dip treatment: Carefully place sufficient zinc ingots into a zinc pot made of graphite crucible material, and turn on the electromagnetic induction heating device to melt it into zinc liquid. The temperature of the zinc liquid is precisely controlled to be stable at 450℃ through a high-precision temperature control system (thermocouple thermometer accuracy ±1℃), and 0.05% aluminum and 0.02% nickel are added during the melting process to improve the performance of the zinc layer.

[0039] According to the Q345 material, size and shape data of the steel components, the automatic immersion time control device sets the immersion time to 45 seconds and the immersion speed to 5 mm / s. The steel components are slowly and steadily immersed in the zinc liquid through the automatic conveying device. During immersion plating, the superconducting material electromagnetic coil of the zinc slag automatic separation device is energized to generate appropriate electromagnetic force, so that the zinc slag moves to and collects the zinc slag collection bucket made of high-temperature ceramic material. The zinc slag collection bucket is cleaned once after processing 50 batches of steel components. Zinc liquid samples are regularly drawn, and professional instruments and equipment are used for component detection and purification to remove impurities and excess metal elements, ensure the stability of the zinc liquid quality, and keep the zinc purity in the zinc liquid above 99.5%. After testing, the galvanized layer has a uniform thickness, an average thickness of 60μm, a smooth surface, and no obvious zinc nodules, zinc slag and other defects.

[0040] S6: Cooling treatment after plating: After immersion plating, the steel components are quickly transferred to the air cooling device by the automated conveying device. The high-power fan generates a stable wind speed of 4m / s. The temperature in the air cooling channel (stainless steel material, 10 meters long) is at room temperature, and the air cooling lasts for 45 seconds. The wind speed sensor and temperature sensor monitor the wind speed and the surface temperature of the steel components in real time to ensure the stable air cooling effect. After air cooling, the surface temperature of the steel components drops to about 150°C.

[0041] After air cooling, the steel components immediately enter the water cooling device. The water temperature in the water cooling tank (made of stainless steel) is at room temperature. The water cooling time is precisely controlled at 15 seconds. The water temperature is maintained stable through the water circulation system to prevent water temperature fluctuations from affecting the cooling effect. After water cooling, the surface temperature of the steel components drops to about 50°C.

[0042] After water cooling, the steel components are immediately sent to the hot air drying room. The electric heating device generates 70℃ hot air. The drying time is 10 minutes. The humidity sensor in the drying room monitors the humidity in real time to ensure that the humidity is less than 30%, effectively preventing the steel components from rusting. After testing, there is no moisture residue on the surface of the steel components after cooling and drying, and there are no cracks in the zinc layer.

[0043] S7: Post-plating passivation treatment: The cooled and dried steel structure is gently placed into a plastic passivation tank filled with chromium-free passivation liquid (5% silane coupling agent, 3% titanate, 2% organic corrosion inhibitor).

[0044] The automatic circulation and filtration system of the passivation liquid is turned on. The filter (microporous filter membrane, which can filter impurity particles with a particle size greater than 100 nanometers) removes impurities in the passivation liquid. The circulation pump (flow rate 2 cubic meters / hour) circulates the passivation liquid between the passivation tank and the liquid storage tank (stainless steel material, capacity 5 cubic meters). The circulation cycle is once after every 100 batches of steel components are processed. The passivation treatment is carried out at 40°C for 45 seconds. After each batch of passivation is completed, the composition of the passivation liquid is tested and adjusted to ensure the stability of the passivation effect. After treatment, a uniform passivation film is formed on the surface of the steel component with a thickness of 50-100 nanometers. After the salt spray test, the corrosion resistance reaches more than 720 hours.

[0045] S8: Post-plating inspection and processing: Visual inspection: The steel component is placed steadily on the appearance inspection platform, and the appearance inspection system combining high-definition industrial cameras with image recognition technology is started. Multiple 5-megapixel industrial cameras shoot the appearance of the galvanized layer of the steel component from different angles, with a shooting distance of 30 cm and an angle covering more than 90% of the surface area. The image is transmitted to the image processing server in real time, and is analyzed and processed by high-performance GPU accelerated computing and pre-trained image recognition models (recognition accuracy of more than 95%) to quickly and accurately determine whether there are defects such as missing plating, zinc nodules, zinc slag, etc., and the results are displayed on the high-definition LCD screen. After each batch of inspection, new sample data is collected to optimize and update the image recognition model to improve the recognition accuracy. After appearance inspection, the appearance defect rate of the steel component in the embodiment is less than 3%.

[0046] Zinc layer thickness measurement: Before using the X-ray fluorescence thickness gauge, first perform automatic calibration for 10 minutes using the built-in 3 sets of standard thickness samples and intelligent calibration algorithms. During measurement, place the thickness gauge probe gently on the surface of the steel component, maintain a pressure of 1 Newton, the instrument emits X-rays and receives reflected signals, and calculates the zinc layer thickness based on the signal strength, with a measurement accuracy of ±1μm. After each batch of measurements, the thickness gauge is precision-calibrated to ensure that the measurement data is accurate and reliable. In the embodiment, the measured value of the zinc layer thickness of the steel component is between 55-65μm, the thickness uniformity is good, and the thickness deviation is within ±5μm.

[0047] Adhesion test: An electronic universal testing machine is used to test the adhesion. The steel component samples are firmly clamped with a special tensile fixture (clamping force 1000 Newtons). The fixture is customized according to the shape and size of the steel component, and uses a rubber cushion and a precision mechanical structure to avoid damaging the zinc layer. Start the test machine and perform a tensile test at a tensile speed of 5 mm / min. The high-precision sensor collects data in real time (acquisition frequency 10 Hz), which is automatically recorded and analyzed by the test machine. The adhesion is determined by measuring the bonding force between the zinc layer and the steel substrate. After each batch of tests, the tensile fixture is fully inspected and maintained to ensure its stable performance. In the embodiment, the average adhesion between the zinc layer of the steel component and the substrate reaches 35MPa, which meets the requirements of relevant standards.

[0048] In summary, in the hot-dip galvanizing process for steel components, the present embodiment adopts a chemical degreasing method in the degreasing process and is equipped with a closed device that can effectively treat waste gas, so as to ensure the degreasing effect and meet environmental protection standards; during pickling, not only the hydrochloric acid concentration and pickling time are accurately controlled, but also an efficient acid mist absorption device is provided, and a specific crystallization cleaning device is provided for sulfuric acid pickling; water washing adopts a multi-stage countercurrent cleaning system combined with an advanced water quality detection device to ensure the cleaning quality; the solvent-assisted plating tank for plating has a closed waste gas recovery system to achieve resource recycling; the hot-dip plating process ensures the quality of zinc liquid and the effect of the zinc plating layer through a high-precision temperature and time control system, and has an automatic zinc slag separation device; the cooling treatment combines air cooling, water cooling and drying and accurately controls the parameters of each link; the passivation treatment adopts a chromium-free passivation solution and an automatic circulation filtration system; the inspection treatment uses a high-definition industrial camera combined with image recognition technology, a high-precision thickness gauge and an electronic universal testing machine and other advanced equipment to achieve all-round, high-precision detection and control of product quality. These combined make this process have significant advantages over traditional processes in terms of quality, environmental protection, and resource utilization.

Claims

1. A hot dip galvanizing process for steel components, characterized in that: The following steps are involved: S1: Degreasing treatment before plating: chemical degreasing method is adopted, using a specific proportion of degreasing liquid to treat at 83℃ for 25min, and the degreasing equipment is connected with a closed exhaust gas treatment device; S2: Pickling treatment before plating: Use hydrochloric acid for pickling, control the concentration, acid mist and pickling time; S3: Pre-plating water washing treatment: a multi-stage countercurrent cleaning system is used, and a water quality detection device is installed at the last stage; S4: Pre-plating auxiliary treatment: Solvent-assisted plating is used, the reaction is at 70℃ for 11s, and the auxiliary plating tank is connected with a closed exhaust gas recovery system; S5: Hot dip treatment: high-precision control of zinc liquid temperature, automatic control of dipping time, automatic separation device for zinc pot and zinc slag; S6: Cooling after plating: first air cooling, then water cooling and then drying; S7: Post-plating passivation treatment: Use chromium-free passivation solution at 40℃ for 45s, equipped with automatic circulation filtration system; S8: Post-plating inspection: including appearance inspection, zinc layer thickness measurement and adhesion test.

2. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In S1, the degreasing liquid is prepared by mixing 15 parts of sodium carbonate, 3.5 parts of surfactant, 5 parts of trisodium phosphate and water in a ratio of 1:20, and the degreasing liquid is stirred in a stirring tank for 30 minutes to be evenly mixed. The closed exhaust gas treatment device includes an exhaust gas collection pipeline, a spray absorption tower filled with a 10% sodium hydroxide solution, and an activated carbon adsorber connected in sequence.

3. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In S2, the concentration of the hydrochloric acid solution is 19%. A high-efficiency acid mist absorption device is installed above the pickling tank, and a sodium hydroxide solution with a concentration of 10% is used to neutralize and absorb the hydrochloric acid mist. The automatic pickling time control system adopts a timer with a timing accuracy of up to ±0.1 second. The concentration and temperature of the hydrochloric acid solution are regularly checked during the pickling process. When the hydrochloric acid concentration drops below 15% or the temperature rises above 45°C, the pickling is stopped and the hydrochloric acid solution is replaced.

4. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In S3, the multi-stage countercurrent cleaning system is equipped with 3 levels of water washing tanks. The water from the last level of water washing is used to supplement the water from the previous level of water washing. The water quality detection device adopts an advanced ion chromatograph to ensure that the residual acid and impurity content are lower than the preset standards, that is, the hydrogen ion concentration is lower than 0.01 mol / L, the chloride ion concentration is lower than 20 mg / L, and the sulfate ion concentration is lower than 50 mg / L. The water washing system is cleaned and maintained after each batch of steel components is processed.

5. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In S4, the plating solution is prepared by 1.5 parts of zinc chloride solution, 4 parts of ammonium chloride solution and 15 parts of water. The closed waste gas recovery system recovers the irritating gas generated by the volatilization of ammonium chloride through condensation, absorption and other processes and converts it into ammonium chloride crystals for recycling.

6. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In S5, the temperature of the zinc liquid is stabilized at 450°C by a high-precision temperature control system. The system uses a thermocouple thermometer for real-time temperature monitoring and is linked to an electromagnetic induction heating device. When the temperature deviates from the set range, the heating power is automatically adjusted with an adjustment accuracy of ±1°C. During the melting process of the zinc liquid, 0.05% aluminum and 0.02% nickel are added by mass; the immersion plating time is set at 45 seconds, and the immersion plating speed is set at 5 mm / s. The automatic zinc slag separation device includes a superconducting material electromagnetic coil installed at the bottom of the zinc pot and a high-temperature resistant ceramic zinc slag collection bucket located above the zinc pot to remove impurities and excess metal elements in the zinc liquid. The purity of zinc in the zinc liquid is maintained at above 99.5%.

7. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In S6, the air cooling wind speed is controlled at 4m / s, the air cooling time is 45s, the length is 10 meters and the temperature in the channel is room temperature; the water cooling time is controlled at 15s, and the water temperature is controlled to be stable through the water circulation system during the water cooling process; the steel components after water cooling immediately enter the drying room and are dried at 70°C using hot air for 10 minutes, and the humidity in the drying room is less than 30%.

8. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In the S7, the chromium-free passivation liquid contains 5% silane coupling agent, 3% titanate, and 2% organic corrosion inhibitor. The automatic circulation filtration system of the passivation liquid includes a filter, a circulation pump, and a liquid storage tank. The filter uses a microporous filtration membrane to filter out impurity particles with a particle size greater than 100 nanometers. The circulation pump flow rate is 2 cubic meters per hour.

9. A hot-dip galvanizing process for steel components as claimed in claim 1, characterized in that: In the S8, the appearance inspection uses a high-definition industrial camera combined with image recognition technology. The industrial camera has a resolution of 5 million pixels, a shooting distance of 30 cm, and a shooting angle that covers more than 90% of the surface of the steel component. The zinc layer thickness is measured using an X-ray fluorescence thickness gauge. Through the built-in 3 sets of standard thickness samples and an intelligent calibration algorithm, it can be automatically calibrated regularly. The calibration time is 10 minutes. During measurement, the probe of the thickness gauge is gently placed on the surface of the steel component, maintaining a pressure of 1 Newton. The adhesion test uses an electronic universal testing machine for tensile testing.

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