A stainless steel on-line solution annealing and acid-free descaling method with adjustable roughness

Abstract

The application discloses a stainless steel on-line solid solution and acid-free descaling method with adjustable roughness, which comprises the following steps: preparing raw materials, smelting, continuous casting, hot rolling and solid solution process, and then entering the acid-free descaling process after the solid solution process; and the specific process comprises the following steps: treating the stainless steel strip after the solid solution process through S roller treatment and scale breaking treatment, and the surface temperature of the steel coil is not higher than 50 DEG C; treating the stainless steel strip after the scale breaking treatment through EPS treatment for surface descaling, wherein the EPS treatment is variable pass treatment, and the variable pass is one of one pass, two passes and three passes or more; brushing the stainless steel strip after the EPS treatment through a roller brush containing silicon carbide abrasive, and the brushing adopts three gears of light brushing mode, medium brushing mode and heavy brushing mode; rinsing the stainless steel strip after the brushing treatment; drying the stainless steel strip after the rinsing treatment, and then winding the stainless steel strip into a finished steel coil through a coiler.

Description

Technical Field

[0001] This invention belongs to the field of stainless steel acid-free descaling production process, specifically relating to an online solution-based acid-free descaling method for stainless steel with adjustable roughness. Background Technology

[0002] The main process for descaling traditional stainless steel is as follows: uncoiling → welding → straightening and descaling → shot blasting → sulfuric acid pre-pickling → brushing → nitric acid + hydrofluoric acid mixed acid pickling → multi-stage water spray rinsing → hot water rinsing → drying → oiling → coiling.

[0003] In the shot blasting process, traditional dry shot blasting is used, with shot diameters typically ranging from 1 to 3 mm. Different shapes, such as shot pellets and wire cuts, are employed to improve descaling efficiency. The shot blasting motors used are 7.5, 15, 22, and 30 kW, selected based on different working conditions and requirements, with the 15-30 kW range being commonly used (motor speed 2000-3000 RPM). Higher blasting speeds result in greater impact force and better descaling, but also significantly affect surface roughness. The blasting speed is generally 60-80 m / s. The optimal surface descaling effect is Sa2.5, but to improve descaling speed, Sa2.0 is typically achieved. The remaining oxide scale is then treated by acid pickling.

[0004] Dry shot blasting is essentially a surface bombardment process that uses high-speed shot to impact a surface. The size, material, shape, velocity, and quantity of the shot directly determine the surface roughness. Larger shot, higher velocity, and higher hardness result in a greater surface roughness value (Ra, Rz), making the surface more rough. Conversely, using smaller shot yields a relatively smooth but matte surface. The surface after shot blasting forms a uniform, non-directional roughness / textured surface. This surface is beneficial for the adhesion of subsequent coatings. However, stainless steel surfaces do not require coatings. Therefore, dry shot blasting is not conducive to controlling the surface roughness of stainless steel, often resulting in a relatively high roughness that requires pickling in conjunction with dry shot blasting.

[0005] Currently, stainless steel surface descaling uses sulfuric acid pre-pickling, mainly for preheating and preliminary pickling of the steel strip to remove most of the oxide scale, especially FeO and Fe3O4. Stainless steel surface descaling uses a mixed acid pickling process with nitric acid and hydrofluoric acid, which is the core step in stainless steel pickling. 304 stainless steel oxide scale contains difficult-to-remove chromium oxides (such as Cr2O3), necessitating the use of a mixed acid with strong oxidizing and complexing abilities. Nitric acid (HNO3) is used in stainless steel surface descaling to oxidize and promote passivation, forming a dense passivation film on the stainless steel surface, ensuring gloss and preventing excessive corrosion.

[0006] However, in existing technologies, the use of strong acids to descale stainless steel surfaces has the following impact on surface roughness: strong acids typically act as a "smoothing" or "modifying" agent on stainless steel surfaces. Strong acid pickling is a chemical corrosion process that preferentially dissolves protrusions, microcracks, and areas damaged or activated by machining on the stainless steel surface. Therefore, it can reduce the sharp peaks and valleys caused by shot blasting, making the stainless steel surface contour relatively smoother and reducing surface sharpness, ultimately resulting in a silvery-white matte surface. However, the acid fumes generated during pickling and descaling severely affect the working environment for workers, waste acid treatment is costly, and improper handling can easily pollute the environment. Furthermore, stainless steel absorbs hydrogen atoms during pickling, especially high-strength or sensitized steel, making it prone to hydrogen embrittlement, leading to cracks or stress corrosion cracking. While existing acid-free descaling processes (such as EPS) solve environmental problems, they generally suffer from insufficient control over the surface roughness of steel plates and difficulty in flexibly adjusting the surface condition according to the final product requirements. Summary of the Invention

[0007] This invention provides an online solution treatment method for acid-free descaling of stainless steel with adjustable roughness, which employs an online solution treatment process and acid-free descaling of the upper and lower surfaces of the steel strip.

[0008] To achieve the above objectives, in a first aspect, the present invention provides a method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness, comprising raw material preparation, steelmaking, continuous casting, hot rolling, and solution treatment processes. The solution treatment process utilizes the residual heat on the surface of the steel coil for online solution treatment. After the solution treatment process, the stainless steel enters the acid-free descaling process. The specific process includes the following steps:

[0009] (1) The stainless steel strip after the solution treatment process is processed by S roller and scale breaking process, and the surface temperature of the steel coil is not higher than 50℃.

[0010] (2) The stainless steel strip after the descaling treatment is descaled by EPS treatment. EPS treatment is a variable pass treatment, which can be one of one pass, two passes, three passes or more.

[0011] (3) The stainless steel strip after EPS treatment is brushed with a roller brush. The brushing is adjusted in three modes: light brush mode, medium brush mode, and heavy brush mode.

[0012] (4) Rinse the stainless steel strip after brushing.

[0013] (5) The stainless steel strip after rinsing is dried and then wound into finished steel coils by a coiler.

[0014] Preferably, after the hot rolling process, the residual heat on the surface of the steel coil is 800~900℃, and it is connected to a heating furnace. The heating furnace is set with different target heating temperatures and holding times according to different materials. After heating and holding in the heating furnace, it is rapidly cooled with a cooling rate of >30℃ / S to achieve online solution treatment.

[0015] Preferably, in step (2), when EPS is processed once, the light brush mode is selected, and the surface roughness of the stainless steel strip decreases by 0.1~0.5μm;

[0016] When performing two passes of EPS treatment, selecting the medium brush mode will reduce the surface roughness of the stainless steel strip by 0.5~1.0μm.

[0017] When EPS treatment is performed in three passes, the re-brush mode is selected, and the surface roughness of the stainless steel strip decreases by more than 1.0 μm.

[0018] Preferably, in step (3), a roller brush containing silicon carbide abrasive is used, the speed of the stainless steel strip is 20m / min to 150m / min, and the proportion of silicon carbide in the brush bristles is 15% to 35%.

[0019] Preferably, the silicon carbide abrasive using the light brush mode has a particle size of 500 mesh to 1500 mesh and a bristle diameter of 0.3 to 0.5 mm, or uses ultrafine bristles with a diameter of 0.02 to 0.2 mm.

[0020] The silicon carbide abrasive in the medium brush mode has a particle size of 180 mesh to 320 mesh and a bristle diameter of 0.5 to 0.7 mm.

[0021] The silicon carbide abrasive in the re-brushing mode has a particle size of 60-150 mesh and a bristle diameter of 0.8-1.0 mm.

[0022] Preferably, in the light brush mode, the motor speed is 500~800RPM, the brush roller pressure is 0~2 mm, the single brush bristle load power is 20~50kW, and the single brush bristle water spray volume is 80~120L / min with a water pressure of 2~4bar.

[0023] The motor speed in the medium brush mode is 800~1100RPM, the brush roller pressing amount is 2~3 mm, the single brush bristle load power is 50~90kW, and the water spray volume of a single brush bristle with a water pressure of 2~4ar is 120~250L / min.

[0024] In the re-brushing mode, the motor speed is 1100~1300RPM, the brush roller pressing amount is >3mm, the single brush bristle load power is 90~160kW, the water pressure is 2~4bar, and the single brush bristle spray volume is 250~400L / min.

[0025] Preferably, the material of the roller brush bristles containing silicon carbide abrasive is ultra-high molecular weight nylon, the S roller and EPS roller are rubber rollers, and the EPS-treated slurry includes solid particles and working fluid, the working fluid containing water and rust inhibitor.

[0026] Preferably, the steel grit particle size for EPS treatment is 0.1~1.0mm, and the slinging speed is 25~110m / s.

[0027] Preferably, when EPS is processed in one pass, the steel grit particle size is 0.5~1.0mm and the slinging speed is 50~110m / s;

[0028] When EPS is processed in two passes, the steel shot particle size is 0.3~0.5mm and the slinging speed is 35~60m / s;

[0029] When EPS is processed in three passes, the steel shot particle size is 0.1~0.4mm and the slinging speed is 25~40m / s.

[0030] Preferably, the roller roughness in the solution treatment and descaling process is 0.6~0.8μm; the S roller and EPS roller are rubber rollers with a roughness of 1~7μm.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention utilizes a variable-pass EPS (Expanded Polystyrene) treatment process, followed by brushing. The brushing process offers three adjustable modes: light, medium, and heavy. The brushing mode is selected based on the EPS treatment pass, allowing for consistent and stable target roughness of the treated stainless steel strip on a single production line. The EPS treatment employs abrasive slurry spraying technology, removing iron oxide scale from the hot-rolled strip surface without the use of acid, thus avoiding waste acid and slag generated during pickling. Completing both EPS treatment and brushing on the same production line shortens process changeover time, improves overall capacity utilization, and avoids downtime and increased costs associated with changing production lines or resetting processes. Detailed Implementation

[0033] In this invention, unless otherwise stated, directional terms such as "up," "down," "left," and "right" are generally understood in conjunction with the accompanying drawings and the directions shown in actual applications.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0035] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0036] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The terms "optional" and "discretionary" mean that they may or may not be included (or may or may not be present).

[0037] The applicant of this invention discovered that existing stainless steel surface descaling methods use sulfuric acid pre-pickling, mainly involving preheating and preliminary pickling of the steel strip to remove most of the oxide scale, especially FeO and Fe3O4. Stainless steel surface descaling now utilizes a mixed acid pickling process of nitric acid and hydrofluoric acid, which is the core step in stainless steel pickling. 304 stainless steel oxide scale contains difficult-to-remove chromium oxides (such as Cr2O3), necessitating the use of a mixed acid with strong oxidizing and complexing abilities. Nitric acid (HNO3) is used in stainless steel surface descaling to oxidize and promote stainless steel passivation, forming a dense passivation film on the stainless steel surface, ensuring gloss and preventing excessive corrosion.

[0038] The use of strong acid pickling for descaling stainless steel surfaces presents the following problems: uneven oxide scale thickness, residual black or red oxide scale, dotted defects, wavy / bent defects, and uneven color due to areas not immersed in acid; excessively long pickling time or high acid concentration leads to significantly increased surface roughness, decreased elongation, easy breakage, and the appearance of pits or micropores; the reaction of acid with metal produces hydrogen gas, and hydrogen atoms penetrate the crystal lattice, causing hydrogen embrittlement; excessively high pickling temperature and concentration exacerbate hydrogen permeation, leading to bubbles and microcracks on the stainless steel surface; decreased material elongation makes it prone to cracking or breakage; uneven descaling by mechanical means and excessive speed result in incomplete dissolution of oxide scale fragments; the use of fluorinated acid (HF) or nitric acid-fluorinated acid mixtures to pickle sensitized stainless steel promotes intergranular corrosion; the treated waste acid contains high concentrations of acidic substances and heavy metal ions, which, if leaked, can cause serious pollution to water bodies and soil.

[0039] The effect of using strong acids to descale stainless steel surfaces on surface roughness is as follows: Strong acids typically act as a "smoothing" or "modifying" agent on stainless steel surfaces. Acid pickling is a chemical corrosion process that preferentially dissolves protrusions, microcracks, and areas damaged or activated by machining on the stainless steel surface. Therefore, it can reduce the sharp peaks and valleys caused by shot blasting, making the stainless steel surface contour relatively smoother and reducing surface sharpness, ultimately resulting in a silvery-white matte surface. However, the acid fumes generated during acid pickling and descaling severely affect the working environment for workers. Waste acid treatment is costly, and improper handling can easily pollute the environment. Furthermore, stainless steel absorbs hydrogen atoms during pickling, especially high-strength or sensitized steels, making them prone to hydrogen embrittlement, leading to cracks or stress corrosion cracking.

[0040] To address the aforementioned problems, this invention provides a method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness. The method includes raw material preparation, steelmaking, continuous casting, hot rolling, and solution treatment. The solution treatment process utilizes the residual heat on the surface of the steel coil for online solution treatment. Following the solution treatment, the stainless steel undergoes an acid-free descaling process. The specific process includes the following steps:

[0041] (1) The stainless steel strip after the solution treatment process is processed by S roller and scale breaking process, and the surface temperature of the steel coil is not higher than 50℃.

[0042] (2) The stainless steel strip after the descaling treatment is descaled by EPS treatment. EPS treatment is a variable pass treatment, which can be one of one pass, two passes, three passes or more.

[0043] (3) The stainless steel strip after EPS treatment is brushed with a roller brush containing silicon carbide abrasive. The brushing is adjusted in three modes: light brush mode, medium brush mode, and heavy brush mode.

[0044] (4) Rinse the stainless steel strip after brushing.

[0045] (5) The stainless steel strip after rinsing is dried and then wound into finished steel coils by a coiler.

[0046] In this embodiment of the invention, EPS treatment is a variable-pass process, followed by brushing. The brushing process employs three adjustable modes: light brushing, medium brushing, and heavy brushing. The brushing mode is selected and controlled according to the number of passes used in the EPS treatment. By operating on the same production line, the surface roughness of the treated stainless steel strip can be adjusted to achieve a stable target roughness. The EPS treatment utilizes abrasive slurry spraying technology, which removes iron oxide scale from the surface of hot-rolled strip steel without the use of acid, avoiding waste acid and slag generated during pickling. Completing both EPS treatment and brushing processes on the same production line shortens process changeover time, improves overall capacity utilization, and avoids downtime and increased costs caused by changing production lines or resetting processes.

[0047] In step (1), the stainless steel strip after the solution treatment process is processed by S roller and descaling treatment, and the surface temperature of the steel coil is not higher than 50°C.

[0048] In one embodiment of the invention, after solution treatment, the surface temperature of the stainless steel does not exceed 50°C. The steel coil does not enter the winding machine but remains in a leveled state, immediately entering the acid-free descaling process section. Acid-free descaling is performed on the upper and lower surfaces of the steel strip. The S-roll device can precisely adjust the tension before the strip enters the descaling section, ensuring uniform tension throughout the process. This significantly reduces defects such as curling, ripples, and edge burrs. Stable tension contributes to the uniform action of subsequent descaling and pickling processes, improving surface smoothness and dimensional stability. Controlling the temperature below 50°C further reduces the heat load, thermal stress, and thermal deformation. Low-temperature operation also inhibits the regeneration of oxide scale, maintaining a weak oxide layer that facilitates thorough removal by mechanical or electrolytic descaling. Under low-temperature conditions, the bonding strength of the oxide layer decreases, making mechanical descaling (such as wet descaling machines) easier to peel off, increasing the descaling speed, and significantly reducing residual oxide scale.

[0049] In step (2), the stainless steel strip after the descaling treatment is descaled by EPS treatment. EPS treatment is a variable pass treatment, which can be one of one pass, two passes, three passes or more.

[0050] Understandably, in one embodiment, the stainless steel strip after descaling can be re-brushed or otherwise treated as needed before surface descaling by EPS treatment. That is, the stainless steel strip after descaling can be a stainless steel strip after descaling treatment, or a stainless steel strip after descaling and re-brushing treatment.

[0051] In one embodiment of the present invention, the three passes of EPS treatment are specifically selected based on the stainless steel grade (such as its susceptibility to oxidation) and the surface roughness of the stainless steel after rolling. For stainless steel grades with rough surfaces after rolling, one pass of EPS treatment is selected to avoid further roughness caused by EPS treatment. For easily oxidized steel grades with thicker surface oxide layers, two or three passes of treatment are used to enhance the descaling effect. The selection of the passes for stainless steel strip is determined in combination with the actual steel grade and production data. The specific surface roughness of the stainless steel and the corresponding passes for the stainless steel grade are not limited here. When EPS treatment is performed in a single pass, fewer passes result in a smaller increase in surface roughness of the stainless steel strip, thus requiring a light brush mode. The light brush mode only cleans away fine particles remaining on the surface, having minimal impact on the substrate roughness, reducing it by only 0.1~0.5μm (iron loss less than 1‰). When EPS treatment is performed in two passes, the increased number of passes leads to a greater increase in surface roughness, requiring a medium brush mode. This mode cleans away residual particles and the outermost layer, reducing roughness by 0.5~1μm (with an increase in iron loss of 1~2‰). When EPS treatment is performed in three or more passes, the increased number of passes significantly increases the surface roughness of the stainless steel strip, requiring a heavy brush mode. This mode provides the most thorough grinding and cleaning of the steel surface, reducing roughness by more than 1μm and reducing iron loss by >2‰. Three passes of EPS treatment can be achieved by setting up multiple EPS devices.

[0052] In step (3), the stainless steel strip after EPS treatment is brushed with a roller brush containing silicon carbide abrasive. The brushing is adjusted in three modes: light brush mode, medium brush mode, and heavy brush mode.

[0053] In one embodiment of the invention, the main purpose of brushing is to remove any loose oxide scale that may remain on the surface, and to clean any fine particles adhering to the surface after washing with the working fluid. Simultaneously, it allows for rapid and significant adjustment of the surface roughness of the steel after EPS treatment; for example, reducing it. A roller brush device made of a harder material, such as silicon carbide, can also be used. If a roller brush device made of ordinary nylon is used, it generally only has a cleaning function, reducing any particles that may remain on the surface. If a roller brush device containing wear-resistant materials such as silicon carbide is used, it not only cleans but also grinds the outermost layer of the steel; the specific amount of thinning can be set according to requirements. When set to light brush mode, it only cleans the fine particles remaining on the surface, with minimal impact on the roughness of the substrate, resulting in a roughness decrease of only 0.1~0.5μm (iron loss less than 1‰). If set to medium brush mode, it can clean the particles remaining on the surface and the outermost layer, resulting in a roughness decrease of 0.5~1μm (with iron loss increasing by 1~2‰). If set to heavy brush mode, it provides the most thorough grinding and cleaning of the steel surface, resulting in a roughness decrease of more than 1μm and an iron loss greater than 2‰.

[0054] In one embodiment of the present invention, the purpose of the silicon carbide (SiC) abrasive roller brush cleaning process for stainless steel strips after EPS treatment is to remove the residual oxide layer, fine particles, and lightly adhered impurities after EPS treatment. This improves surface finish without damaging the substrate, providing a clean and uniform base surface for subsequent coating or assembly. The roller brush uses silicon carbide abrasive filaments, with the filament material being SiC abrasive, suitable for deburring, polishing, and cleaning metals and alloys.

[0055] In step (4), the stainless steel strip after brushing is rinsed.

[0056] In one embodiment of the invention, if the preceding stage is a nylon roller brush wash, this rinsing step can be omitted. If the preceding stage uses a roller brush device with significant abrasion, this stage is generally necessary, primarily to remove any uncleaned fine particles and any remaining residues on the surface to achieve the user's desired surface cleanliness. The rinsing water is deionized water or demineralized water, and the temperature is generally controlled between 65°C and 80°C.

[0057] In step (5), the rinsed stainless steel strip is dried and then wound into finished steel coils by a coiler. After drying, the rinsed stainless steel strip may or may not be oiled.

[0058] In one embodiment of the invention, drying the rinsed stainless steel strip aims to thoroughly remove residual moisture from the rinse process and prevent oil spots or rust during subsequent oiling. Before drying, the strip passes through an edge blowing or squeezing device to further reduce moisture content. After drying, the strip typically enters the exit looper to maintain tension and prevent curling. The purpose of oiling is to form a rust-preventive oil film on the metal surface, preventing oxidation caused by moisture in the air and providing lubrication for subsequent winding. Tension adjustment is performed before oiling to ensure uniform strip tension. After oiling, the strip typically undergoes another drying process to solidify the oil film. Between drying and oiling, the strip often passes through online leveling or tension rollers to adjust its straightness and tension, preventing curling or slack during subsequent winding.

[0059] Optionally, in some embodiments, the temperature of the residual heat on the surface of the steel coil after the hot rolling process is 800~900°C, for example, it can be one of 800°C, 820°C, 840°C, 860°C, 880°C, 900°C or any range between two of them. By recovering residual heat, the fuel demand of the heating furnace is reduced, carbon emissions are reduced, the rate of temperature drop of the steel coil is reduced, and the temperature is kept uniform. The uniform temperature distribution reduces rolling resistance, reduces the power demand of the finishing mill, and improves the stability of the mill. After being heated by residual heat, the steel strip is already in a suitable temperature range before entering the finishing mill, which can achieve higher plastic deformation, reduce cracks and surface oxide scale, and improve surface finish and thickness accuracy. In the heating furnace, different target heating temperatures and holding times are set according to different materials. For example, for 304 stainless steel, the target temperature is 1050~1150℃, and the holding time is 1~5min / mm. For a 3mm thickness, the holding time is 3~15min. After heating and holding in the furnace, rapid cooling is performed at a rate >30℃ / s to achieve online solution treatment. No separate solution treatment is required, saving the unwinding and rewinding equipment needed for solution treatment, as well as the significant time and energy consumed in heating from room temperature to 1050~1150℃. After solution treatment, the surface temperature of the steel coil does not exceed 50℃. The steel coil does not enter the rewinding machine but remains in a leveled state, immediately proceeding to the acid-free descaling process.

[0060] Optionally, in some embodiments, in step (2), during one pass of EPS treatment, a light brushing mode is selected, which reduces the surface roughness of the stainless steel strip by 0.1~0.5μm. This can be a value within the range of 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, or any two of these values. Using the light brushing mode in a single pass of EPS treatment reduces the surface roughness of the stainless steel strip by 0.1~0.5µm, significantly improving corrosion resistance and surface stability. The roughness is primarily determined by the EPS process, and then gradually smoothed and finished by the roller brush.

[0061] When performing a two-pass EPS treatment, selecting the medium brush mode reduces the surface roughness of the stainless steel strip by 0.5~1.0μm, which can be any value within the range of 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 1.0μm, or any combination thereof. The reduction in surface defects and micro-pits makes the stainless steel strip less prone to corrosion pitting during subsequent use, improving overall corrosion resistance. The smoother surface of the stainless steel strip lowers the coefficient of friction, extending the product's service life.

[0062] When EPS treatment is performed in three passes, the re-brushing mode is selected. The surface roughness of the stainless steel strip decreases by more than 1.0 μm. The value can be one of 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm or any value between two of these ranges. Multiple re-brushing passes can gradually eliminate defects such as micro-pits and scratches. The roughness reduction is most significant between the first and third passes. The reduction of defects gives the stainless steel strip higher gloss and better mechanical contact properties.

[0063] Optionally, in some embodiments, in step (3), the strip speed of the stainless steel is 20m / min to 150m / min, which can be one or any two of the following values: 20m / min, 30m / min, 40m / min, 50m / min, 60m / min, 70m / min, 80m / min, 90m / min, 100m / min, 110m / min, 120m / min, 130m / min, 140m / min, and 150m / min. The proportion of silicon carbide in the bristles is 15% to 35%, preferably 16-29%, 17-26%, or 21-25%, which can be one or any two of the following values: 15%, 20%, 25%, 30%, and 35%. This proportion may vary depending on the size of the silicon carbide particles and the operating conditions.

[0064] Optionally, in some embodiments, the silicon carbide used in the light brush mode has a particle size of 500-1500 mesh, which can be one or any two of 500 mesh, 600 mesh, 700 mesh, 800 mesh, 900 mesh, 1000 mesh, 1100 mesh, 1200 mesh, 1300 mesh, 1400 mesh, and 1500 mesh. The bristle diameter is 0.3-0.5 mm, which can be one or any two of 0.3 mm, 0.4 mm, and 0.5 mm. Alternatively, ultrafine bristles can be used, with an ultrafine bristle diameter of 0.02-0.2 mm, which can be one or any two of 0.02 mm, 0.05 mm, 0.1 mm, 0.15 mm, and 0.2 mm. By weaving together multi-dimensional filaments, a bristle with a relatively large diameter is formed, thereby taking into account durability and polishing effect. Using large-grained abrasive and coarse-diameter bristles improves the brushing effect during the rebrushing stage and significantly improves the surface roughness of the strip steel; using fine-grained and fine-filament bristles allows for smaller adjustments and improvements to the surface roughness of the strip steel, thereby enhancing the improvement effect.

[0065] The silicon carbide particle size of the medium brush mode is 180 mesh to 320 mesh, which can be one or any two of 180 mesh, 200 mesh, 220 mesh, 240 mesh, 260 mesh, 280 mesh, 300 mesh, and 320 mesh. The bristle diameter is 0.5 to 0.7 mm, which can be one or any two of 0.5 mm, 0.55 mm, 0.6 mm, 0.65 mm, and 0.7 mm. The nylon material of the bristles is also very important. Ultra-high molecular weight nylon is used as the raw material (such as UHMW-PA6, which greatly enhances its wear resistance, toughness and mechanical strength). At the same time, during the processing and manufacturing process, the voids and impurities in the nylon bristles are minimized, which can significantly increase the durability and mechanical properties of the bristles.

[0066] The silicon carbide particle size in the heavy brushing mode is 60-150 mesh, which can be any one or any two of 60, 70, 80, 90, 100, 110, 120, 130, 140, and 150 mesh. The bristle diameter is 0.8-1.0 mm, which can be any one or any two of 0.8 mm, 0.85 mm, 0.9 mm, 0.95 mm, and 1.0 mm. Using a roller brush with low abrasive content is beneficial for achieving light brushing, medium brushing, and heavy brushing modes; if the abrasive content is too high, it will have a significant impact on the surface of the stainless steel strip, affecting the surface roughness.

[0067] Optionally, in some embodiments, the motor speed in the light brush mode is 500~800 RPM, which can be one or any value between 500 RPM, 550 RPM, 600 RPM, 650 RPM, 700 RPM, 750 RPM, and 800 RPM. By using a lower brush roller speed, it is beneficial to reduce the impact of abrasive on the surface of the stainless steel strip. Excessive brush roller speed will introduce too much cutting amount, further increasing the impact on the surface roughness of the stainless steel strip, which is not conducive to roughness control. The brush roller reduction is 0~2. The thickness can be 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, or any combination thereof. The single brush bristle load power is 20~50kW, or 20kW, 25kW, 30kW, 35kW, 40kW, 45kW, 50kW, or any combination thereof. The water pressure is 2~4bar, and the water spray rate per brush bristle is 80~120L / min, or 80L / min, 90L / min, 100L / min, 110L / min, 120L / min, or any combination thereof. By reducing the single brush bristle load power and the single brush bristle water spray rate, water consumption is saved, and the excessive impact on the roughness of the stainless steel strip is reduced. For light brushing, two sets of brush rollers (four brushes) are used in conjunction to achieve both surface cleaning and roughness adjustment functions.

[0068] The motor speed in the medium brush mode is 800~1100 RPM, which can be one or any two of 800 RPM, 850 RPM, 900 RPM, 950 RPM, 1000 RPM, 1050 RPM, and 1100 RPM. By using a higher brush roller speed, it is more conducive to improving the cutting effect of the abrasive on the stainless steel surface and to improving the adjustment and precise control of the rough surface of EPS. The brush roller deflection is 2~3 mm, which can be one or any two of 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, and 3 mm. By significantly bending the bristles, stable pressure is applied to the strip surface, thereby improving the cutting ability of the strip surface. The load power of a single brush bristle is 50~90kW, which can be one or any two of the following values: 50kW, 55kW, 60kW, 65kW, 70kW, 75kW, 80kW, 85kW, 90kW. The water spray volume of a single brush bristle is 120~250L / min, which can be one or any two of the following values: 120L / min, 130L / min, 140L / min, 150L / min, 160L / min, 170L / min, 180L / min, 190L / min, 200L / min, 210L / min, 220L / min, 230L / min, 240L / min, 250L / min. By increasing the load power and water spray volume of a single brush bristle, the kinetic energy of the abrasive acting on the surface of the stainless steel strip is increased, the influence of heat generation during brushing is suppressed, and the roughness of the stainless steel strip is further improved.

[0069] The motor speed in the re-brushing mode is 1100~1300RPM, which can be one of 1100RPM, 1150RPM, 1200RPM, 1250RPM, 1300RPM or any two of these values. By using a higher brush roller speed, it is beneficial to improve the cutting effect of the abrasive on the stainless steel surface and to improve the adjustment and precise control of the EPS on the increased roughness surface. The brush roller pressure is >3mm, which can be one of 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm or any two of these values. Through the obvious large bending of the brush bristles, stable pressure is applied to the strip steel surface to improve the cutting ability of the strip steel surface. The load power of a single brush bristle is 90~160kW, which can be one or any two of the following values: 90kW, 95kW, 100kW, 105kW, 110kW, 115kW, 120kW, 125kW, 130kW, 135kW, 140kW, 145kW, and 150kW. The water spray volume of a single brush bristle is 250~400L / min, which can be one or any two of the following values: 250L / min, 260L / min, 270L / min, 280L / min, 290L / min, 300L / min, 310L / min, 320L / min, 330L / min, 340L / min, 350L / min, 360L / min, 370L / min, 380L / min, 390L / min, and 400L / min. By increasing the load power and water spray volume of a single brush bristle, the kinetic energy of the abrasive acting on the surface of the stainless steel strip is increased, suppressing the heat generated during brushing and improving the surface roughness of the stainless steel strip. The heavy brushing mode can grind the surface of the stainless steel strip at high speed, which generates heat and a lot of abrasive debris, causing heat damage to the brush bristles, affecting the life of the equipment and also hindering the control of surface roughness. By increasing the pressure and flow rate of cooling water, it is ensured that the coolant can strongly penetrate the brush bristle barrier at high brush roller linear speed. At the same time, the large flow rate of cooling water reduces the surface temperature of the steel strip, thereby facilitating precise control of surface roughness.

[0070] Optionally, in some embodiments, the material of the roller brush bristles containing silicon carbide abrasive is ultra-high molecular weight nylon, the S roller and EPS roller are rubber rollers, and the EPS-treated slurry includes solid particles and working fluid, the working fluid containing water and rust inhibitor.

[0071] Optionally, in some embodiments, the steel grit particle size of the EPS treatment is 0.1~1.0mm, which can be one or any two of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm. Preferably, the steel grit particle size is 0.2~0.8mm or 0.3~0.4mm, which can be one or any two of 0.3mm, 0.35mm, and 0.4mm. The projectile velocity is 25~110m / s, which can be one or any two of 25m / s, 35m / s, 45m / s, 55m / s, 65m / s, 75m / s, 85m / s, 95m / s, 105m / s, and 110m / s.

[0072] Optionally, in some embodiments, during one pass of EPS treatment, the steel grit particle size is 0.5~1.0mm, which can be one or any two of 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, and 1.0mm, and the blasting velocity is 50~110m / s, which can be one or any two of 50m / s, 60m / s, 70m / s, 80m / s, 90m / s, 100m / s, and 110m / s. Smaller steel grit sizes result in lower blasting velocities and lower surface roughness after treatment; larger steel grit sizes result in higher blasting velocities and higher surface roughness after treatment. Using large-size, high-velocity steel grit with high mass and high kinetic energy per particle, resulting in strong impact force, effectively breaks down and peels off hard oxide scale and etches deep pits. The high velocity imparts extremely high kinetic energy to the steel grit, achieving efficient oxide scale removal and improving descaling efficiency.

[0073] When EPS is applied in two passes, the steel grit particle size is 0.3~0.49mm, which can be any one of 0.33mm, 0.36mm, 0.39mm, 0.42mm, 0.45mm, or 0.49mm, or any value between two of these. The blasting speed is 35~60m / s, which can be any one of 35m / s, 40m / s, 45m / s, 50m / s, 55m / s, or 60m / s, or any value between two of these. Preferably, it is 35~48m / s. This further descaling improves the descaling effect. At the same time, by using smaller steel grit and reducing the blasting speed, it is possible to smooth out any overly sharp protrusions that may have been generated on the surface of the stainless steel strip due to the first pass. This makes the rough protrusions and pits on the surface of the stainless steel strip relatively smoother. The reduced speed and impact energy avoid excessive roughening of the stainless steel surface by multiple passes of EPS, and reduce the risk of excessively increasing roughness while further descaling.

[0074] When EPS treatment is performed in three passes, the steel grit particle size is 0.1~0.4mm, which can be any one of 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm or any two of these values. The projectile velocity is 25~40m / s, which can be any one of 25m / s, 30m / s, 55m / s, 40m / s or any two of these values; preferably 25~34m / s, which further achieves descaling and improves the descaling effect. Simultaneously, by using... Using steel grit with the smallest particle size and a reduced blasting speed allows for further trimming of any overly sharp protrusions on the stainless steel strip surface. This results in smoother surfaces with rounded bumps and pits. The reduced speed and impact energy prevent excessive roughening of the stainless steel surface by multiple EPS passes, minimizing the risk of excessive roughness increase while further descaling. The fine steel grit generates dense, shallow impacts, effectively removing any tiny burrs that may remain from the first two passes, further improving surface uniformity.

[0075] Optionally, in some embodiments, the roller roughness in the solution treatment and descaling stages is 0.6~0.8μm (which can be one of 0.6μm, 0.65μm, 0.7μm, 0.75μm, 0.8μm or any value between two of them); the S-roller and EPS roller are rubber rollers, and the roughness of the rubber roller is 1~7μm, preferably 3.1~3.3μm (which can be 3.1μm, 3.2μm, 3.3μm). The relatively high roughness of the rollers in the solution treatment and descaling stages is beneficial for removing the rough protrusions on the surface of the stainless steel strip. In particular, the protrusions on the higher surfaces are micro-shaped, especially during the high-temperature solution treatment stage. This utilizes the residual heat from the hot rolling of stainless steel, which helps reduce the roughness of the rollers. Higher roughness facilitates the removal of the oxide layer on the stainless steel surface, especially during the descaling stage of the descaling machine, where increased friction enables efficient removal of the oxide layer. The S-rolls and EPS rollers are rubber rollers with a roughness controlled at 3.2 micrometers. Due to machining, rubber rollers have relatively high roughness. By controlling the roughness to be relatively low, frictional heat generation and frictional deterioration of the stainless steel surface during this process stage are avoided. Too low a roughness can cause slippage, hindering proper sheet formation.

[0076] The descaling method used in this invention has the following advantages: The descaling process involves repeatedly bending the steel strip in an "S" shape using descaling rollers and straightening rollers. This stretches the external structure of the strip. Since the iron oxide scale on the surface of the hot-rolled strip is brittle and lacks plasticity, it cannot deform along with the base metal. Therefore, repeated bending and stretching causes the iron oxide scale to break, resulting in cracks and spalling. During the descaling process, the two surfaces of the stainless steel are often under different stress states. One surface is subjected to tensile tension, leading to cracks at the interface between the iron oxide scale and the iron matrix; while the other surface, in contact with the descaling rollers, is subjected to pressure, causing the iron oxide scale to be crushed into a mesh-like structure and gradually detach. This method does not damage the surface of the hot-rolled coil.

[0077] The descaling process improves the effectiveness and efficiency of EPS descaling. After descaling and EPS processing, there is virtually no oxide scale residue on the stainless steel surface. When the strip is bent on the rollers, tension is applied simultaneously. Due to the simultaneous bending and deformation, the core layer of the strip undergoes plastic elongation under tension far below the material's yield strength. The strip fiber layer experiences repeated stretching, compression, and re-stretching in both directions, causing permanent plastic deformation in each fiber of the strip cross-section, resulting in uniform elongation. Under the combined action of stretching and bending, and after multiple stretching and bending cycles, the length of all internal fibers tends to be the same after plastic deformation, giving the strip better straightness and effectively eliminating shape defects such as edge waviness, center waviness, and camber. This prevents damage to the downstream rubber-lined rollers, extends their service life, and creates conditions for subsequent correction control and precision rolling to achieve the best strip shape and surface quality. The surface descaling quality of steel treated with EPS can reach the highest grade Sa3.0 (GB / T 8923.1-2011), while traditional dry shot blasting can generally only reach Sa2.0, and at most not exceeding Sa2.5.

[0078] Example 1

[0079] An online solution treatment and acid-free descaling method for stainless steel with adjustable roughness includes raw material preparation, steelmaking, continuous casting, hot rolling, and solution treatment. The solution treatment process utilizes residual heat from the surface of the steel coil (800°C) for online solution treatment. The coil is connected to a heating furnace, which is set with different target heating temperatures and holding times according to different materials. After heating and holding in the furnace, rapid cooling is performed at a rate of 30°C / s to achieve online solution treatment. Following the solution treatment, an acid-free descaling process is initiated, specifically including the following steps: The stainless steel grade is 304.

[0080] (1) The stainless steel strip after the solution treatment process is treated by S roller and descaling process, and the surface temperature of the steel coil is 50℃; the roughness of the roller for descaling process is 0.6μm, and the roughness of the roller for S roller treatment and EPS treatment is 3.2μm.

[0081] (2) The stainless steel strip after the descaling treatment is descaled by EPS treatment. EPS treatment is a variable pass treatment, with one pass being the variable pass. When EPS treatment is performed in one pass, the light brush mode is selected, and the surface roughness of the stainless steel strip decreases by 0.1 μm. The steel grit particle size of EPS treatment is 0.1 mm, the steel grit particle size is 0.3 mm, and the shot speed is 25 m / s. When EPS treatment is performed in one pass, the steel grit particle size is 0.5 mm and the shot speed is 50 m / s.

[0082] (3) The EPS-treated stainless steel strip is brushed with a roller brush containing silicon carbide abrasive in a light brush mode. The strip speed is 20 m / min, and the proportion of silicon carbide in the brush bristles is 15%. The silicon carbide particle size in the light brush mode is 500 mesh, and the bristle diameter is 0.3 mm, or ultrafine bristles with a diameter of 0.02 mm are used. The rotation speed in the light brush mode is 500 RPM, the roller pressure is 0.5 mm, the single bristle load power is 20 kW, and the water spray volume of a single bristle is 80 L / min at a water pressure of 3 bar. The material of the roller brush containing silicon carbide abrasive is ultra-high molecular weight nylon, and the S roller and EPS roller are rubber rollers. The EPS-treated slurry includes solid particles and working fluid, and the working fluid contains water and rust inhibitor.

[0083] (4) Rinse the stainless steel strip after brushing.

[0084] (5) The stainless steel strip after rinsing is dried and then wound into finished steel coils by a coiler. The surface quality of the steel reaches the highest grade Sa3.0 (GB / T 8923.1-2011).

[0085] Example 2

[0086] A method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness includes raw material preparation, steelmaking, continuous casting, hot rolling, and solution treatment. The solution treatment process utilizes residual heat from the surface of the steel coil (800°C) for online solution treatment. The coil is connected to a heating furnace, which is set with different target heating temperatures and holding times according to different materials. After heating and holding in the furnace, rapid cooling is performed at a rate of 40°C / s to achieve online solution treatment. The stainless steel grade used is 316. Following the solution treatment process, an acid-free descaling process is performed, which includes the following steps:

[0087] (1) The stainless steel strip after the solution treatment process is treated by S roller and descaling process, and the surface temperature of the steel coil is 40℃; the roughness of the roller for descaling process is 0.6μm, and the roughness of the roller for S roller treatment and EPS treatment is 3.2μm.

[0088] (2) The stainless steel strip after the descaling treatment is subjected to EPS treatment for surface descaling. The EPS treatment is a variable pass treatment, with two passes. When the EPS treatment is performed in two passes, the medium brush mode is selected, and the surface roughness of the stainless steel strip decreases by 0.5 μm. The steel grit particle size of the EPS treatment is 0.5 mm, the steel grit particle size is 0.35 mm, and the shot speed is 50 m / s. When the EPS treatment is performed in two passes, the steel grit particle size is 0.4 mm and the shot speed is 45 m / s.

[0089] (3) The EPS-treated stainless steel strip is brushed with a roller brush containing silicon carbide abrasive in a medium brush mode. The strip speed is 80 m / min, and the proportion of silicon carbide in the bristles is 25%. The silicon carbide particle size in the medium brush mode is 210 mesh, and the bristle diameter is 0.6 mm. The rotation speed in the medium brush mode is 800 RPM, the roller pressure is 2 mm, the single bristle load power is 50 kW, and the water spray volume of a single bristle is 120 L / min at a water pressure of 3 bar. The material of the roller brush containing silicon carbide abrasive is ultra-high molecular weight nylon, and the S roller and EPS roller are rubber rollers. The EPS-treated slurry includes solid particles and working fluid, and the working fluid contains water and rust inhibitor.

[0090] (4) Rinse the stainless steel strip after brushing.

[0091] (5) The stainless steel strip after rinsing is dried and then wound into finished steel coils by a coiler. The surface quality of the steel reaches the highest grade Sa3.0 (GB / T 8923.1-2011).

[0092] Example 3

[0093] A method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness includes raw material preparation, steelmaking, continuous casting, hot rolling, and solution treatment. The solution treatment process utilizes residual heat from the surface of the steel coil (900°C) for online solution treatment. The coil is connected to a heating furnace, which is set with different target heating temperatures and holding times according to different materials. After heating and holding in the furnace, rapid cooling is performed at a rate of 50°C / s to achieve online solution treatment. The stainless steel grade used is 316L. Following the solution treatment process, an acid-free descaling process is performed, which includes the following steps:

[0094] (1) The stainless steel strip after the solution treatment process is treated by S roller and descaling process, and the surface temperature of the steel coil is 30℃; the roughness of the roller for descaling process is 0.8μm, and the roughness of the roller for S roller treatment and EPS treatment is 3.2μm.

[0095] (2) The stainless steel strip after the descaling treatment is descaled by EPS treatment. The EPS treatment is a variable pass treatment, and the variable pass is three passes. When the EPS treatment is three passes, the re-brushing mode is selected, and the surface roughness of the stainless steel strip decreases by 1.2μm. The steel grit particle size of the EPS treatment is 1.0mm, the steel grit particle size is 0.4mm, and the blasting speed is 110m / s.

[0096] When EPS is processed in three passes, the steel shot particle size is 0.4mm and the slinging speed is 40m / s.

[0097] (3) The EPS-treated stainless steel strip is brushed with a roller brush containing silicon carbide abrasive in a heavy brushing mode. The strip speed is 150 m / min, and the proportion of silicon carbide in the brush bristles is 35%. The silicon carbide particle size in the heavy brushing mode is 150 mesh, and the bristle diameter is 1.0 mm. The rotation speed RPM in the heavy brushing mode is 1100, the roller pressure is 4 mm, the single brush bristle load power is 90 kW, and the water pressure is 2~4 bar with a single brush bristle spray volume of 250 L / min. The roller brush bristles containing silicon carbide abrasive are made of ultra-high molecular weight nylon, and the S roller and EPS roller are rubber rollers. The EPS-treated slurry includes solid particles and working fluid, and the working fluid contains water and rust inhibitor.

[0098] (4) Rinse the stainless steel strip after brushing.

[0099] (5) The stainless steel strip after rinsing is dried and then wound into finished steel coils by a coiler. The surface quality of the steel reaches the highest grade Sa3.0 (GB / T 8923.1-2011).

[0100] Table 1 Process parameters of the example

[0101]

[0102] Note: It is recommended that the cooling water temperature not exceed 40℃.

[0103] Comparative Example 1

[0104] The only difference from Example 1 is that the EPS treatment is done in one pass and no brushing process is performed. The surface quality of the steel reaches the highest grade Sa3.0 (GB / T 8923.1-2011), but the surface roughness is relatively high (generally, the average roughness is ≥ Ra 2.5), and the roughness cannot be flexibly adjusted (if roller brushes are included, the roller brush settings can be changed to further adjust the existing roughness). Moreover, the descaling speed is slow, less than 70% of that of the EPS + roller brush combination, resulting in problems such as low production capacity, high cost, and inflexible roughness adjustment.

[0105] Comparative Example 2

[0106] The only difference from Example 1 is that the surface of the stainless steel strip is descaled by pickling with sulfuric acid, nitric acid or hydrofluoric acid, which poses risks of hydrogen embrittlement and cracking, excessive surface corrosion, color difference, spots, and residual stains, and also brings problems such as environmental pollution and health hazards to employees.

[0107] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness, comprising raw material preparation, steelmaking, continuous casting, hot rolling, and solution treatment processes, characterized in that, The solution treatment process utilizes the residual heat on the surface of the steel coil for online solution treatment. After the solution treatment process, an acid-free descaling process is performed. The specific process includes the following steps: (1) The stainless steel strip after the solution treatment process is processed by S roller and descaling. (2) The stainless steel strip after the descaling treatment is descaled by EPS treatment. The EPS treatment adopts abrasive slurry spraying technology. The EPS treatment is a variable pass treatment, which can be one of one pass, two passes, or three passes. (3) The stainless steel strip after EPS treatment is brushed with a roller brush. The brushing is adjusted in three modes: light brush mode, medium brush mode, and heavy brush mode. (4) Rinse the stainless steel strip after brushing. (5) Dry the rinsed stainless steel strip and then roll it into a coiler to form a finished steel coil. In step (2), when EPS is processed once, the light brush mode is selected, and the surface roughness of the stainless steel strip decreases by 0.1~0.5μm; When performing two passes of EPS treatment, selecting the medium brush mode will reduce the surface roughness of the stainless steel strip by 0.5~1.0μm. When EPS treatment is performed in three passes, the re-brush mode is selected, and the surface roughness of the stainless steel strip decreases by more than 1.0 μm.

2. The method for online solution-based acid-free descaling of stainless steel with adjustable roughness according to claim 1, characterized in that, After the hot rolling process, the residual heat on the surface of the steel coil is 800~900℃. It is then connected to a heating furnace. The heating furnace is set with different target heating temperatures and holding times according to different materials. After heating and holding in the heating furnace, it is rapidly cooled with a cooling rate of >30℃ / S to achieve online solution treatment.

3. The method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness according to claim 1, characterized in that, In step (3), a roller brush containing silicon carbide abrasive is used, the speed of the stainless steel strip is 20m / min~150m / min, and the proportion of silicon carbide abrasive in the brush bristles is 15~35%.

4. The method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness according to claim 1, characterized in that, The silicon carbide abrasive using the light brush mode has a particle size of 500-1500 mesh and a bristle diameter of 0.3-0.5 mm, or uses ultrafine bristles with a diameter of 0.02-0.2 mm. The silicon carbide abrasive in the medium brush mode has a particle size of 180 mesh to 320 mesh and a bristle diameter of 0.5 to 0.7 mm. The silicon carbide abrasive in the re-brushing mode has a particle size of 60-150 mesh and a bristle diameter of 0.8-1.0 mm.

5. The method for online solution-based acid-free descaling of stainless steel with adjustable roughness according to claim 1, characterized in that, In the light brush mode, the motor speed is 500~800RPM, the brush roller pressure is 0~2 mm, the single brush bristle load power is 20~50kW, and the single brush bristle water spray volume is 80~120L / min with a water pressure of 2~4bar. The motor speed in the medium brush mode is 800~1100RPM, the brush roller pressing amount is 2~3 mm, the single brush bristle load power is 50~90kW, and the single brush bristle water spray volume is 120~250L / min with a water pressure of 2~4bar. In the re-brushing mode, the motor speed is 1100~1300RPM, the brush roller pressing amount is >3mm, the single brush bristle load power is 90~160kW, the water pressure is 2~4bar, and the single brush bristle spray volume is 250~400L / min.

6. The method for online solution-based acid-free descaling of stainless steel with adjustable roughness according to claim 3, characterized in that, The roller brush bristles made of silicon carbide abrasive are made of nylon, and the S roller and EPS roller are made of rubber. The slurry for EPS treatment includes solid particles and working fluid, and the working fluid contains water and rust inhibitor.

7. The method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness according to claim 1, characterized in that, The EPS-treated steel shot has a particle size of 0.1~1.0mm and a slinging speed of 25~110m / s.

8. The method for online solution treatment and acid-free descaling of stainless steel with adjustable roughness according to claim 7, characterized in that, During the first pass of EPS treatment, the steel shot particle size is 0.5~1.0mm, and the slinging speed is 50~110m / s; During the second pass of EPS treatment, the steel shot particle size is 0.3~0.5mm, and the slinging speed is 35~60m / s; During the third pass of EPS treatment, the steel shot particle size is 0.1~0.4mm, and the slinging speed is 25~40m / s.

9. The method for online solution-based acid-free descaling of stainless steel with adjustable roughness according to claim 1, characterized in that, The roller roughness in the solution treatment and descaling process is 0.6~0.8μm; The S-roller and EPS roller are rubber rollers with a surface roughness of 1~7μm.

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