Low-alloy hot-rolled coil sheet with high processability and preparation process thereof

Abstract

This invention relates to the field of steel materials technology, specifically to a low-alloy hot-rolled coil with high processing performance and its preparation process. The invention involves sequentially heating, rough rolling, finish rolling, cooling, and coiling the hot-rolled coil raw material to obtain the hot-rolled coil. A cladding powder is then coated onto the surface of the hot-rolled coil using a laser cladding process to obtain a high-hardness coating. A high-temperature and wear-resistant resin is obtained by adding butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, modified high-temperature resistant coating filler, and silicone-modified polyurethane emulsion. This high-temperature and wear-resistant resin is then coated onto the treated hot-rolled coil and dried and cured to obtain the finished product. The finished product prepared by this invention exhibits excellent hardness, wear resistance, and high-temperature resistance, thus possessing broad application prospects in the field of steel materials technology.

Description

Technical Field

[0001] This invention relates to the field of steel materials technology, specifically to a low-alloy hot-rolled coil with high processing performance and its preparation process. Background Technology

[0002] Hot-rolled coils, as an important steel product, have irreplaceable value in modern industry. They can meet the needs of various building structures, providing reliable material support for everything from high-rise steel structures to infrastructure construction such as bridges and tunnels. In the automotive manufacturing sector, hot-rolled coils also play a crucial role. As a key material for automobile body structures, hot-rolled coils possess excellent formability and weldability, meeting the stringent performance requirements of automakers. Especially with the rapid development of new energy vehicles, hot-rolled coils are not only used in body structures but also widely applied in the manufacture of components such as motor housings and battery packs. These components need to withstand high mechanical stress and temperature changes, and the performance of hot-rolled coils perfectly meets these requirements. Furthermore, the application of hot-rolled coils in the packaging materials industry is noteworthy. Particularly in the manufacture of metal packaging containers, such as food cans and beverage cans, the surface quality and formability of hot-rolled coils can significantly improve the performance of packaging materials. These packaging materials not only need good sealing and pressure resistance but also need to meet food safety standards, and the performance of hot-rolled coils perfectly meets these requirements.

[0003] However, the mechanical strength and stability of hot-rolled coil materials decrease significantly under high-temperature conditions. Insufficient high-temperature resistance of hot-rolled coils accelerates oxidation, corrosion, and mechanical property degradation, potentially leading to equipment structural failure and safety accidents. Therefore, improving high-temperature resistance ensures that equipment maintains good mechanical properties even under extreme temperatures, thereby enhancing the overall system safety. Hardness is a crucial indicator of a material's resistance to deformation and scratches. In automotive manufacturing, construction, and machinery, hot-rolled coils need to withstand high mechanical stresses. Therefore, increasing hardness enhances the material's compressive and tensile strength, ensuring it is less prone to deformation or breakage under high loads. For example, in automotive body and chassis structures, high-hardness hot-rolled coils improve vehicle collision safety and overall rigidity. Wear resistance is a material's ability to maintain its integrity and function under friction and impact. In many industrial sectors, such as mining, machinery manufacturing, and transportation, the wear resistance of materials directly affects equipment lifespan and efficiency. Wear of equipment parts is one of the main causes of equipment failure and downtime, especially in mining and machinery manufacturing. Therefore, improving the wear resistance of hot-rolled coils can significantly reduce wear, lower the frequency and cost of equipment maintenance, extend the service life of equipment parts, and reduce the frequency of replacement.

[0004] To overcome the shortcomings of the prior art, the present invention provides a low-alloy hot-rolled coil with high processing performance and its preparation process. Summary of the Invention

[0005] The purpose of this invention is to provide a low-alloy hot-rolled coil with high processing performance and its preparation process, so as to solve the problems in the prior art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A process for preparing low-alloy hot-rolled coils with high machinability includes the following steps:

[0008] Step 1: The hot-rolled coil raw material is sequentially heated, rough rolled, fine rolled, cooled, and coiled to obtain a hot-rolled coil; the cladding powder is coated onto the surface of the hot-rolled coil through a laser cladding process to obtain a high-hardness coating.

[0009] Step 2: Dissolve zirconium oxide powder and polyacrylamide in deionized water, ultrasonically disperse until uniform, then add anhydrous aluminum chloride, stir until uniform, and then add ammonia water dropwise to adjust the pH to 5.3-5.7. Stir and react at 25-30℃ for 2-3 hours. After the reaction, allow to stand, filter, wash, and dry to obtain high-temperature resistant coated filler. Mix the high-temperature resistant coated filler with anhydrous ethanol until uniform, then add γ-methacryloyloxypropyltrimethoxysilane, and reflux at 110-120℃ for 10-12 hours. After the reaction, filter, wash, and freeze-dry to obtain modified high-temperature resistant coated filler.

[0010] Step 3: Add trimethylolpropane to the polyurethane prepolymer and allow it to react fully. Then add high-temperature resistant silicone resin, tetraethyl orthosilicate, and dibutyltin dilaurate. React at 120-130℃ for 3-5 hours. After the reaction, a silicone-modified polyurethane emulsion is obtained. Then add butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, and modified high-temperature resistant coating filler to the silicone-modified polyurethane emulsion. Heat the mixture to 40-50℃ and add 10-12% potassium persulfate solution. Stir and react for 4-5 hours to obtain a high-temperature resistant and wear-resistant resin. Coat the hot-rolled coil obtained in Step 1 with the high-temperature resistant and wear-resistant resin and dry and cure at 60-70℃ for 15-20 hours to obtain the finished product.

[0011] In a more optimized manner, in step one, diamond micro powder and chromium powder are mixed and heated at 830-850℃ for 120-150 min. After heating, the mixture is washed and dried to obtain metallized diamond. Then, the metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder are mixed and ball-milled at 250-300 r / min for 45-50 h to obtain reinforcing powder. The reinforcing powder is then mixed with Fe-Cr-B-Si alloy powder and ball-milled at 250-300 r / min for 30-40 min to obtain cladding powder.

[0012] In a more optimized manner, when preparing metallized diamond, the mass ratio of diamond micro powder to chromium powder is 1:(0.3-0.4); when preparing reinforcing powder, the mass ratio of metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder is (5-6):3:2:1; and when preparing cladding powder, the mass ratio of reinforcing powder to gas-atomized Fe-Cr-B-Si alloy powder is (2-3):7.

[0013] In a more optimized manner, in step one, the slab heating temperature is 1200-1300℃, the roughing mill exit temperature is 950-1100℃, the finishing mill temperature is 800-900℃, the slab temperature after cooling is 500-550℃, and the coiling temperature is 380-400℃; the laser cladding process has a laser power of 1800-2000W, a powder feeding rate of 25-30g / min, and a scanning speed of 450-550mm / min.

[0014] In a more optimized manner, in step two, the polyacrylamide is 1-2 wt% of the zirconium oxide powder; the aluminum chloride concentration is 0.3-0.4 mol / L; and the reaction mass ratio of the high-temperature resistant coating filler and γ-methacryloyloxypropyltrimethoxysilane is (0.5-0.7):3.

[0015] In a more optimized manner, in step three, the preparation process of the polyurethane prepolymer is as follows: polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate are dissolved in acetone, then toluene diisocyanate is added, and after the reaction is fully completed, triethylamine is added for neutralization. After the reaction is completed, the mixture is emulsified with deionized water and acetone is removed by rotary evaporation to obtain the polyurethane prepolymer. The preparation process of the high-temperature resistant silicone resin is as follows: under a nitrogen atmosphere, dimethylcyclosiloxane, trifluoropropyltrimethylcyclotrisiloxane, and tetramethyltetraenylcyclotetrasiloxane are mixed, heated to 95-105℃ and stirred for 35-45 min, then heated to 110-120℃ and 25-30% tetramethylammonium hydroxide aqueous solution and deionized water are added, and the reaction is continued for 3-4 h. After the reaction is completed, the temperature is raised to 150-160℃ and kept at that temperature for 2-3 h, and then impurities are removed by vacuum to obtain the high-temperature resistant silicone resin.

[0016] In a more optimized manner, when preparing the polyurethane prepolymer, the reaction molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate to the isocyanate groups in toluene diisocyanate is 1:(1.3-1.4); the reaction molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate is (1.8-2.0):1:1; and the content of each component of the high-temperature resistant silicone resin is as follows (by mass): 30-40 parts dimethylcyclosiloxane, 35-45 parts trifluoropropyltrimethylcyclotrisiloxane, 25-30 parts tetramethyltetraenylcyclotetrasiloxane, 0.015-0.017 parts tetramethylammonium hydroxide aqueous solution, and 0.08-0.09 parts deionized water.

[0017] In a more optimized manner, in step three, the content of each component of the silicone-modified polyurethane emulsion is as follows (by mass): 3-4 parts trimethylolpropane, 12-15 parts polyurethane prepolymer, 10-12 parts high-temperature resistant silicone resin, 2-3 parts tetraethyl orthosilicate, and 0.1-0.2 parts dibutyltin dilaurate; the content of each component of the high-temperature resistant and wear-resistant resin is as follows (by mass): 50-60 parts silicone-modified polyurethane emulsion, 10-12 parts butyl acrylate, 10-12 parts styrene, 5-8 parts glycidyl methacrylate, 5-8 parts dodecafluoroheptyl methacrylate, 5-8 parts modified high-temperature resistant coating filler, and 1.0-1.2 parts potassium persulfate solution.

[0018] The beneficial effects of this invention are:

[0019] The invention is characterized in that, in step one, diamond, the hardest naturally occurring material, is metallized, thereby improving the wettability of diamond as a coating. Furthermore, the metallized diamond, chromium carbide powder, and other hard phases are blended and ball-milled with metal powder to obtain a cladding powder. This cladding powder is then coated onto the surface of a hot-rolled coil using a laser cladding process to obtain a high-hardness, wear-resistant coating.

[0020] The key feature of this invention is that, in step two, a high-temperature resistant filler with alumina-coated zirconia is obtained by adding zirconia powder, polyacrylamide, anhydrous aluminum chloride, and ammonia. Then, the high-temperature resistant filler is modified using the silane coupling agent γ-methacryloyloxypropyltrimethoxysilane, which improves the dispersibility of the filler and introduces C=C on the surface of the filler, resulting in a modified high-temperature resistant filler.

[0021] The invention is characterized in that, in step three, trimethylolpropane, high-temperature resistant silicone resin, tetraethyl orthosilicate, and dibutyltin dilaurate are added to the polyurethane prepolymer to obtain a silicone-modified polyurethane emulsion with a uniform and stable crosslinked network. Reaction mechanism: The polyurethane prepolymer prepared in this step introduces C=C groups and retains a certain amount of isocyanate groups, while the high-temperature resistant silicone resin prepared in this step is hydroxyl-terminated. Therefore, on the one hand, trimethylolpropane can fully crosslink with the isocyanate groups in the polyurethane prepolymer to form a crosslinked network structure; on the other hand, the high-temperature resistant silicone resin can react with the isocyanate groups in the polyurethane prepolymer through its hydroxyl groups to form a polyurethane-silicone copolymer; tetraethyl orthosilicate hydrolyzes under the action of the catalyst dibutyltin dilaurate to generate silanol, which further condenses with the siloxane groups in the silicone resin to form a crosslinked network structure.

[0022] Furthermore, butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, and modified high-temperature resistant coating fillers were added to an organosilicon-modified polyurethane emulsion. Potassium persulfate solution was then added and the mixture was stirred to obtain a high-temperature resistant and wear-resistant resin. Reaction mechanism: Using an organosilicon-modified polyurethane emulsion containing C=C as the main resin, various acrylic monomers and modified high-temperature resistant coating fillers were added. Under the action of potassium persulfate initiator, a free radical copolymerization reaction occurred, introducing hydrophobic fluorinated materials and fully dispersing the modified high-temperature resistant coating filler in the main resin, thus obtaining a high-temperature resistant and wear-resistant resin. In summary, the synergistic effect of the organosilicon resin and polyurethane resin in step three significantly improved the wear resistance of the finished resin. In addition, step three, by adding modified high-temperature resistant coating fillers and introducing organosilicon resin during the reaction process, can significantly improve the high-temperature resistance of the finished resin. These multifaceted optimizations result in a resin with excellent comprehensive performance in demanding application environments, showing broad application prospects. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Raw material source:

[0025] Diamond micron powder, with an average particle size of 100 μm; chromium powder, with an average particle size of 50 μm; chromium carbide powder, with an average particle size of 50 μm; titanium carbide powder, with an average particle size of 0.5 μm; titanium powder, with an average particle size of 0.5 μm; Fe-Cr-B-Si alloy powder, with an average particle size of 100 μm; zirconia powder, with an average particle size of 10 μm; polyacrylamide, provided by Guangdong Zhongke Hongtai New Materials Co., Ltd., model K-137; polycaprolactone polyol, provided by Iwase (Tianjin) International Trade Co., Ltd., model CELLOXIDE2000.

[0026] Example 1: Step 1: Diamond micro powder and chromium powder are mixed and heated at 850℃ for 150 min. After heating, the mixture is washed and dried to obtain metallized diamond. Then, metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder are mixed and ball-milled at 300 r / min for 50 h to obtain reinforcing powder. The reinforcing powder is mixed with Fe-Cr-B-Si alloy powder and ball-milled at 300 r / min for 40 min to obtain cladding powder. When preparing metallized diamond, the mass ratio of diamond micro powder to chromium powder is 1:0.35. When preparing reinforcing powder, the mass ratio of metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder is 5.5:3:2:1. When preparing cladding powder, the mass ratio of reinforcing powder to atomized Fe-Cr-B-Si alloy powder is 2.5:7.

[0027] Hot-rolled coil raw material is sequentially heated, rough rolled, finish rolled, cooled, and coiled to obtain hot-rolled coil. A high-hardness coating is obtained by applying cladding powder to the surface of the hot-rolled coil using a laser cladding process. The slab heating temperature is 1300℃, the rough rolling exit temperature is 1100℃, the finish rolling temperature is 900℃, the slab temperature after cooling is 550℃, and the coiling temperature is 400℃. The laser cladding process uses a laser power of 2000W, a powder feeding rate of 30g / min, and a scanning speed of 550mm / min.

[0028] Step 2: Dissolve zirconia powder and polyacrylamide in deionized water, ultrasonically disperse until uniform, then add anhydrous aluminum chloride, stir until uniform, and then add ammonia water dropwise to adjust the pH to 5.7. React at 30℃ for 3 hours. After the reaction, allow to stand, filter, wash, and dry to obtain the high-temperature resistant coated filler. Mix the high-temperature resistant coated filler with anhydrous ethanol until uniform, then add γ-methacryloyloxypropyltrimethoxysilane. Reflux at 120℃ for 12 hours. After the reaction, filter, wash, and freeze-dry to obtain the modified high-temperature resistant coated filler. The polyacrylamide content is 1.5 wt% of the zirconia powder; the aluminum chloride concentration is 0.35 mol / L; the mass ratio of the high-temperature resistant coated filler to γ-methacryloyloxypropyltrimethoxysilane is 0.6:3.

[0029] Step 3: Dissolve polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate in acetone, then add toluene diisocyanate. After the reaction is complete, add triethylamine for neutralization. After the reaction is complete, emulsify with deionized water and remove acetone by rotary evaporation to obtain the polyurethane prepolymer. The molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate to the isocyanate groups in toluene diisocyanate is 1:1.35; the molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate is 1.9:1:1.

[0030] Under nitrogen atmosphere, dimethylcyclosiloxane, trifluoropropyltrimethylcyclotrisiloxane, and tetramethyltetraenylcyclotetrasiloxane were mixed, heated to 105°C and stirred for 45 min, then heated to 120°C and 30% tetramethylammonium hydroxide aqueous solution and deionized water were added. The reaction was continued for 4 h. After the reaction was completed, the temperature was raised to 160°C and held for 3 h. The mixture was then purified by vacuum to obtain a high-temperature resistant organosilicon resin. The composition of the high-temperature resistant organosilicon resin was as follows (by mass): 35 parts dimethylcyclosiloxane, 40 parts trifluoropropyltrimethylcyclotrisiloxane, 27 parts tetramethyltetraenylcyclotetrasiloxane, 0.016 parts tetramethylammonium hydroxide aqueous solution, and 0.09 parts deionized water.

[0031] Trimethylolpropane was added to a polyurethane prepolymer, and after the reaction was complete, high-temperature resistant silicone resin, tetraethyl orthosilicate, and dibutyltin dilaurate were added. The mixture was reacted at 130°C for 5 hours, and a silicone-modified polyurethane emulsion was obtained after the reaction was completed. Then, butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, and modified high-temperature resistant coating filler were added to the silicone-modified polyurethane emulsion. The mixture was heated to 50°C and then 12% potassium persulfate solution was added. The mixture was stirred and reacted for 5 hours to obtain a high-temperature resistant and wear-resistant resin. The components of the silicone-modified polyurethane emulsion are as follows (by weight): 3 parts trimethylolpropane, 12 parts polyurethane prepolymer, 10 parts high-temperature resistant silicone resin, 2 parts tetraethyl orthosilicate, and 0.1 parts dibutyltin dilaurate; the components of the high-temperature resistant and wear-resistant resin are as follows (by weight): 50 parts silicone-modified polyurethane emulsion, 10 parts butyl acrylate, 10 parts styrene, 5 parts glycidyl methacrylate, 5 parts dodecafluoroheptyl methacrylate, 5 parts modified high-temperature resistant coating filler, and 1 part potassium persulfate solution.

[0032] The high-temperature and wear-resistant resin is coated onto the hot-rolled coil obtained after step one, and then dried and cured at 70°C for 20 hours to obtain the finished product.

[0033] Example 2: Step 1: Diamond micro powder and chromium powder are mixed and heated at 840℃ for 130 min. After heating, the mixture is washed and dried to obtain metallized diamond. Then, metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder are mixed and ball-milled at 270 r / min for 47 h to obtain reinforcing powder. The reinforcing powder is mixed with Fe-Cr-B-Si alloy powder and ball-milled at 270 r / min for 35 min to obtain cladding powder. When preparing metallized diamond, the mass ratio of diamond micro powder to chromium powder is 1:0.35. When preparing reinforcing powder, the mass ratio of metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder is 5.5:3:2:1. When preparing cladding powder, the mass ratio of reinforcing powder to atomized Fe-Cr-B-Si alloy powder is 2.5:7.

[0034] Hot-rolled coil raw material is sequentially heated, rough rolled, finish rolled, cooled, and coiled to obtain hot-rolled coil. A high-hardness coating is obtained by applying cladding powder to the surface of the hot-rolled coil using a laser cladding process. The slab heating temperature is 1250℃, the rough rolling exit temperature is 1000℃, the finish rolling temperature is 850℃, the slab temperature after cooling is 525℃, and the coiling temperature is 390℃. The laser cladding process uses a laser power of 1900W, a powder feeding rate of 27g / min, and a scanning speed of 500mm / min.

[0035] Step 2: Dissolve zirconia powder and polyacrylamide in deionized water, ultrasonically disperse until uniform, then add anhydrous aluminum chloride, stir until uniform, and then add ammonia water dropwise to adjust the pH to 5.34. React at 27℃ for 2.5 hours. After the reaction, allow to stand, filter, wash, and dry to obtain the high-temperature resistant coated filler. Mix the high-temperature resistant coated filler with anhydrous ethanol until uniform, then add γ-methacryloyloxypropyltrimethoxysilane. Reflux at 115℃ for 11 hours. After the reaction, filter, wash, and freeze-dry to obtain the modified high-temperature resistant coated filler. The polyacrylamide content is 1.5 wt% of the zirconia powder; the aluminum chloride concentration is 0.35 mol / L; the mass ratio of the high-temperature resistant coated filler to γ-methacryloyloxypropyltrimethoxysilane is 0.6:3.

[0036] Step 3: Dissolve polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate in acetone, then add toluene diisocyanate. After the reaction is complete, add triethylamine for neutralization. After the reaction is complete, emulsify with deionized water and remove acetone by rotary evaporation to obtain the polyurethane prepolymer. The molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate to the isocyanate groups in toluene diisocyanate is 1:1.35; the molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate is 1.9:1:1.

[0037] Under nitrogen atmosphere, dimethylcyclosiloxane, trifluoropropyltrimethylcyclotrisiloxane, and tetramethyltetraenylcyclotetrasiloxane were mixed, heated to 100°C and stirred for 40 min, then heated to 115°C and 27% tetramethylammonium hydroxide aqueous solution and deionized water were added. The reaction was continued for 3.5 h. After the reaction was completed, the temperature was raised to 155°C and held for 2.5 h. The mixture was then purified by vacuum to obtain a high-temperature resistant organosilicon resin. The composition of the high-temperature resistant organosilicon resin was as follows (by mass): 35 parts dimethylcyclosiloxane, 40 parts trifluoropropyltrimethylcyclotrisiloxane, 27 parts tetramethyltetraenylcyclotetrasiloxane, 0.016 parts tetramethylammonium hydroxide aqueous solution, and 0.09 parts deionized water.

[0038] Trimethylolpropane was added to a polyurethane prepolymer, and after sufficient reaction, high-temperature resistant silicone resin, tetraethyl orthosilicate, and dibutyltin dilaurate were added. The mixture was reacted at 125°C for 3.5 hours, resulting in a silicone-modified polyurethane emulsion. Butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, and a modified high-temperature resistant coating filler were then added to the silicone-modified polyurethane emulsion. The mixture was heated to 45°C, and then 11% potassium persulfate solution was added. The mixture was stirred and reacted for 4.5 hours to obtain a high-temperature resistant and wear-resistant resin. The components of the silicone-modified polyurethane emulsion are as follows (by weight): 3 parts trimethylolpropane, 12 parts polyurethane prepolymer, 10 parts high-temperature resistant silicone resin, 2 parts tetraethyl orthosilicate, and 0.1 parts dibutyltin dilaurate; the components of the high-temperature resistant and wear-resistant resin are as follows (by weight): 50 parts silicone-modified polyurethane emulsion, 10 parts butyl acrylate, 10 parts styrene, 5 parts glycidyl methacrylate, 5 parts dodecafluoroheptyl methacrylate, 5 parts modified high-temperature resistant coating filler, and 1 part potassium persulfate solution.

[0039] The high-temperature and wear-resistant resin is coated onto the hot-rolled coil obtained after step one, and then dried and cured at 65°C for 17 hours to obtain the finished product.

[0040] Example 3: Step 1: Diamond micro powder and chromium powder are mixed and heated at 830℃ for 120 min. After heating, the mixture is washed and dried to obtain metallized diamond. Then, metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder are mixed and ball-milled at 250 r / min for 45 h to obtain reinforcing powder. The reinforcing powder is mixed with Fe-Cr-B-Si alloy powder and ball-milled at 250 r / min for 30 min to obtain cladding powder. When preparing metallized diamond, the mass ratio of diamond micro powder to chromium powder is 1:0.35. When preparing reinforcing powder, the mass ratio of metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder is 5.5:3:2:1. When preparing cladding powder, the mass ratio of reinforcing powder to atomized Fe-Cr-B-Si alloy powder is 2.5:7.

[0041] Hot-rolled coil raw material is sequentially heated, rough rolled, finish rolled, cooled, and coiled to obtain hot-rolled coil. A high-hardness coating is obtained by applying cladding powder to the surface of the hot-rolled coil using a laser cladding process. The slab heating temperature is 1200℃, the rough rolling exit temperature is 950℃, the finish rolling temperature is 800℃, the slab temperature after cooling is 500℃, and the coiling temperature is 380℃. The laser cladding process uses a laser power of 1800W, a powder feeding rate of 25g / min, and a scanning speed of 450mm / min.

[0042] Step 2: Dissolve zirconia powder and polyacrylamide in deionized water, ultrasonically disperse until uniform, then add anhydrous aluminum chloride, stir until uniform, and then add ammonia water dropwise to adjust the pH to 5.3. React at 25℃ for 2 hours. After the reaction, allow to stand, filter, wash, and dry to obtain the high-temperature resistant coated filler. Mix the high-temperature resistant coated filler with anhydrous ethanol until uniform, then add γ-methacryloyloxypropyltrimethoxysilane, and reflux at 110℃ for 10 hours. After the reaction, filter, wash, and freeze-dry to obtain the modified high-temperature resistant coated filler. The polyacrylamide content is 1.5 wt% of the zirconia powder; the aluminum chloride concentration is 0.35 mol / L; the mass ratio of the high-temperature resistant coated filler to γ-methacryloyloxypropyltrimethoxysilane is 0.6:3.

[0043] Step 3: Dissolve polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate in acetone, then add toluene diisocyanate. After the reaction is complete, add triethylamine for neutralization. After the reaction is complete, emulsify with deionized water and remove acetone by rotary evaporation to obtain the polyurethane prepolymer. The molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate to the isocyanate groups in toluene diisocyanate is 1:1.35; the molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate is 1.9:1:1.

[0044] Under nitrogen atmosphere, dimethylcyclosiloxane, trifluoropropyltrimethylcyclotrisiloxane, and tetramethyltetraenylcyclotetrasiloxane were mixed, heated to 95°C and stirred for 35 min, then heated to 110°C and 25% tetramethylammonium hydroxide aqueous solution and deionized water were added. The reaction was continued for 3 h. After the reaction was completed, the temperature was raised to 150°C and held for 2 h. The mixture was then purified by vacuum to obtain a high-temperature resistant organosilicon resin. The composition of the high-temperature resistant organosilicon resin was as follows (by mass): 35 parts dimethylcyclosiloxane, 40 parts trifluoropropyltrimethylcyclotrisiloxane, 27 parts tetramethyltetraenylcyclotetrasiloxane, 0.016 parts tetramethylammonium hydroxide aqueous solution, and 0.09 parts deionized water.

[0045] Trimethylolpropane was added to a polyurethane prepolymer, and after the reaction was complete, high-temperature resistant silicone resin, tetraethyl orthosilicate, and dibutyltin dilaurate were added. The mixture was reacted at 120°C for 3 hours, and a silicone-modified polyurethane emulsion was obtained after the reaction was completed. Then, butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, and modified high-temperature resistant coating filler were added to the silicone-modified polyurethane emulsion. The mixture was heated to 40°C and then 10% potassium persulfate solution was added. The mixture was stirred and reacted for 4 hours to obtain a high-temperature resistant and wear-resistant resin. The components of the silicone-modified polyurethane emulsion are as follows (by weight): 3 parts trimethylolpropane, 12 parts polyurethane prepolymer, 10 parts high-temperature resistant silicone resin, 2 parts tetraethyl orthosilicate, and 0.1 parts dibutyltin dilaurate; the components of the high-temperature resistant and wear-resistant resin are as follows (by weight): 50 parts silicone-modified polyurethane emulsion, 10 parts butyl acrylate, 10 parts styrene, 5 parts glycidyl methacrylate, 5 parts dodecafluoroheptyl methacrylate, 5 parts modified high-temperature resistant coating filler, and 1 part potassium persulfate solution.

[0046] The high-temperature and wear-resistant resin is coated onto the hot-rolled coil obtained after step one, and then dried and cured at 60°C for 15 hours to obtain the finished product.

[0047] Comparative Example 1: The laser cladding process on the surface of the hot-rolled coil was removed, and the rest was the same as in Example 1. The specific steps are as follows: Step 1: The hot-rolled coil raw material was sequentially heated, rough rolled, finished rolled, cooled, and coiled to obtain the hot-rolled coil; the slab heating temperature was 1300℃, the rough rolling exit temperature was 1100℃, the finishing rolling temperature was 900℃, the slab temperature after cooling was 550℃, and the coiling temperature was 400℃;

[0048] Step 2: Dissolve zirconia powder and polyacrylamide in deionized water, ultrasonically disperse until uniform, then add anhydrous aluminum chloride, stir until uniform, and then add ammonia water dropwise to adjust the pH to 5.7. React at 30℃ for 3 hours. After the reaction, allow to stand, filter, wash, and dry to obtain the high-temperature resistant coated filler. Mix the high-temperature resistant coated filler with anhydrous ethanol until uniform, then add γ-methacryloyloxypropyltrimethoxysilane. Reflux at 120℃ for 12 hours. After the reaction, filter, wash, and freeze-dry to obtain the modified high-temperature resistant coated filler. The polyacrylamide content is 1.5 wt% of the zirconia powder; the aluminum chloride concentration is 0.35 mol / L; the mass ratio of the high-temperature resistant coated filler to γ-methacryloyloxypropyltrimethoxysilane is 0.6:3.

[0049] Step 3: Dissolve polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate in acetone, then add toluene diisocyanate. After the reaction is complete, add triethylamine for neutralization. After the reaction is complete, emulsify with deionized water and remove acetone by rotary evaporation to obtain the polyurethane prepolymer. The molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate to the isocyanate groups in toluene diisocyanate is 1:1.35; the molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate is 1.9:1:1.

[0050] Under nitrogen atmosphere, dimethylcyclosiloxane, trifluoropropyltrimethylcyclotrisiloxane, and tetramethyltetraenylcyclotetrasiloxane were mixed, heated to 105°C and stirred for 45 min, then heated to 120°C and 30% tetramethylammonium hydroxide aqueous solution and deionized water were added. The reaction was continued for 4 h. After the reaction was completed, the temperature was raised to 160°C and held for 3 h. The mixture was then purified by vacuum to obtain a high-temperature resistant organosilicon resin. The composition of the high-temperature resistant organosilicon resin was as follows (by mass): 35 parts dimethylcyclosiloxane, 40 parts trifluoropropyltrimethylcyclotrisiloxane, 27 parts tetramethyltetraenylcyclotetrasiloxane, 0.016 parts tetramethylammonium hydroxide aqueous solution, and 0.09 parts deionized water.

[0051] Trimethylolpropane was added to a polyurethane prepolymer, and after the reaction was complete, high-temperature resistant silicone resin, tetraethyl orthosilicate, and dibutyltin dilaurate were added. The mixture was reacted at 130°C for 5 hours, and a silicone-modified polyurethane emulsion was obtained after the reaction was completed. Then, butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, and modified high-temperature resistant coating filler were added to the silicone-modified polyurethane emulsion. The mixture was heated to 50°C and then 12% potassium persulfate solution was added. The mixture was stirred and reacted for 5 hours to obtain a high-temperature resistant and wear-resistant resin. The components of the silicone-modified polyurethane emulsion are as follows (by weight): 3 parts trimethylolpropane, 12 parts polyurethane prepolymer, 10 parts high-temperature resistant silicone resin, 2 parts tetraethyl orthosilicate, and 0.1 parts dibutyltin dilaurate; the components of the high-temperature resistant and wear-resistant resin are as follows (by weight): 50 parts silicone-modified polyurethane emulsion, 10 parts butyl acrylate, 10 parts styrene, 5 parts glycidyl methacrylate, 5 parts dodecafluoroheptyl methacrylate, 5 parts modified high-temperature resistant coating filler, and 1 part potassium persulfate solution.

[0052] High-temperature and wear-resistant resin is coated onto the surface of hot-rolled coil and dried and cured at 70°C for 20 hours to obtain the finished product.

[0053] Comparative Example 2: The preparation steps of the high-temperature wear-resistant resin were removed, and the rest were the same as in Example 1. The specific steps are as follows: Step 1: Diamond micro powder and chromium powder were mixed and heated at 850℃ for 150 min. After heating, the mixture was washed and dried to obtain metallized diamond. Then, metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder were mixed and ball-milled at 300 r / min for 50 h to obtain reinforcing powder. The reinforcing powder and Fe-Cr-B-Si alloy powder were mixed and ball-milled at 300 r / min for 40 min to obtain cladding powder. When preparing metallized diamond, the mass ratio of diamond micro powder to chromium powder was 1:0.35. When preparing reinforcing powder, the mass ratio of metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder was 5.5:3:2:1. When preparing cladding powder, the mass ratio of reinforcing powder to atomized Fe-Cr-B-Si alloy powder was 2.5:7.

[0054] Hot-rolled coil raw material is sequentially heated, rough rolled, finish rolled, cooled, and coiled to obtain hot-rolled coil. Cladding powder is coated onto the surface of the hot-rolled coil using a laser cladding process to obtain a high-hardness coating, i.e., the finished product. The slab heating temperature is 1300℃, the rough rolling exit temperature is 1100℃, the finish rolling temperature is 900℃, the slab temperature after cooling is 550℃, and the coiling temperature is 400℃. The laser cladding process has the following parameters: laser power of 2000W, powder feeding rate of 30g / min, and scanning speed of 550mm / min.

[0055] Hardness test: The finished product prepared by this invention is used as a sample. The microstructure of the coating interface is observed using a Zeiss metallographic microscope. Vickers hardness is tested according to GB / T4340.1—2009 standard. At least 6 different areas are measured for each sample to reduce error. The average value is taken as the final result.

[0056] Abrasion resistance test: The finished product prepared by this invention is used as a sample. According to the ASTM G65-16 standard, a load of 140N is applied to the sample. The rubber rotates at a speed of 250r / min and the gravel contacts the interface at a speed of 300g / min. The mass loss of the sample after linear wear is used as the abrasion resistance test.

[0057] High-temperature resistance test: The finished product prepared according to this invention was used as a sample. The high-temperature oxidation resistance of the sample was tested according to GB / T 13303-1991 standard. The sample was subjected to high-temperature oxidation at 600℃ for 800 hours, and the degree of surface oxidation and peeling were recorded. The results are shown in the table below:

[0058]

[0059] Conclusion: The dosages in Examples 1-3 remained unchanged, with only some reaction parameters modified. Experimental data show that the various properties of the samples did not exhibit significant fluctuations.

[0060] Comparative Example 1: The laser cladding process on the surface of the hot-rolled coil was removed, and the rest was the same as in Example 1. The experimental data showed that compared with Example 1, the Vickers hardness decreased to 272 HV, the mass loss increased to 8.7 mg, and the surface morphology was characterized by large-area peeling of the surface coating, with the peeling morphology being blocky or flaky. The reason for this is that in this invention, hard phases such as metallized diamond and chromium carbide powder are mixed and ball-milled with metal powder to obtain cladding powder. The cladding powder is then coated onto the surface of the hot-rolled coil through a laser cladding process to obtain a high-hardness wear-resistant coating. This coating can play a good protective role for the substrate. Therefore, after removing the high-hardness wear-resistant coating prepared by the laser cladding process, the Vickers hardness decreased, the mass loss increased, and the surface peeling was obvious. The hardness, wear resistance, and high-temperature resistance of the finished product were all reduced.

[0061] Comparative Example 2: The preparation steps of the high-temperature wear-resistant resin were removed, while the rest remained the same as in Example 1. Experimental data showed that, compared to Example 1, the Vickers hardness decreased to 835 HV, the mass loss increased to 3.8 mg, and the surface morphology showed localized peeling of the surface coating, with the peeling morphology being granular or blocky. The reason for this is that the high-temperature wear-resistant resin prepared in this invention, by adding modified high-temperature coating fillers and introducing organosilicon resin during the reaction process, can significantly improve the high-temperature resistance of the finished product. Furthermore, the synergistic effect of organosilicon resin and polyurethane resin significantly improves the wear resistance of the finished product. Therefore, removing the preparation steps of the high-temperature wear-resistant resin resulted in increased mass loss, localized peeling of the surface coating, and a decrease in both the wear resistance and high-temperature resistance of the finished product.

[0062] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process method article or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process method article or apparatus. Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A manufacturing process for low-alloy hot-rolled coils with high machinability, characterized in that: Includes the following steps: Step 1: The hot-rolled coil raw material is sequentially heated, rough rolled, fine rolled, cooled, and coiled to obtain a hot-rolled coil; the cladding powder is coated onto the surface of the hot-rolled coil through a laser cladding process to obtain a high-hardness coating. Step 2: Dissolve zirconium oxide powder and polyacrylamide in deionized water, ultrasonically disperse until uniform, then add anhydrous aluminum chloride, stir until uniform, and then add ammonia water dropwise to adjust the pH to 5.3-5.

7. Stir and react at 25-30℃ for 2-3 hours. After the reaction, allow to stand, filter, wash, and dry to obtain high-temperature resistant coated filler. Mix the high-temperature resistant coated filler with anhydrous ethanol until uniform, then add γ-methacryloyloxypropyltrimethoxysilane, and reflux at 110-120℃ for 10-12 hours. After the reaction, filter, wash, and freeze-dry to obtain modified high-temperature resistant coated filler. Step 3: Add trimethylolpropane to the polyurethane prepolymer and allow it to react fully. Then add high-temperature resistant silicone resin, tetraethyl orthosilicate, and dibutyltin dilaurate. React at 120-130℃ for 3-5 hours. After the reaction, a silicone-modified polyurethane emulsion is obtained. Then add butyl acrylate, styrene, glycidyl methacrylate, dodecafluoroheptyl methacrylate, and modified high-temperature resistant coating filler to the silicone-modified polyurethane emulsion. Heat the mixture to 40-50℃ and add 10-12% potassium persulfate solution. Stir and react for 4-5 hours to obtain a high-temperature resistant and wear-resistant resin. Coat the hot-rolled coil obtained in Step 1 with the high-temperature resistant and wear-resistant resin and dry and cure at 60-70℃ for 15-20 hours to obtain the finished product.

2. The preparation process of a low-alloy hot-rolled coil with high processing performance according to claim 1, characterized in that: In step one, diamond micro powder and chromium powder are mixed and heated at 830-850℃ for 120-150 min. After heating, the mixture is washed and dried to obtain metallized diamond. Then, the metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder are mixed and ball-milled at 250-300 r / min for 45-50 h to obtain reinforcing powder. The reinforcing powder is mixed with Fe-Cr-B-Si alloy powder and ball-milled at 250-300 r / min for 30-40 min to obtain cladding powder.

3. The preparation process of a low-alloy hot-rolled coil with high processing performance according to claim 2, characterized in that: When preparing metallized diamond, the mass ratio of diamond micro powder to chromium powder is 1:(0.3-0.4); when preparing reinforcing powder, the mass ratio of metallized diamond, chromium carbide powder, titanium carbide powder, and titanium powder is (5-6):3:2:1; when preparing cladding powder, the mass ratio of reinforcing powder to gas-atomized Fe-Cr-B-Si alloy powder is (2-3):

7.

4. The preparation process of a low-alloy hot-rolled coil with high processing performance according to claim 1, characterized in that: In step one, the slab heating temperature is 1200-1300℃, the roughing mill exit temperature is 950-1100℃, the finishing mill temperature is 800-900℃, the slab temperature after cooling is 500-550℃, and the coiling temperature is 380-400℃; the laser cladding process: the laser power is 1800-2000W, the powder feeding rate is 25-30g / min, and the scanning speed is 450-550mm / min.

5. The preparation process of a low-alloy hot-rolled coil with high processing performance according to claim 1, characterized in that: In step two, the polyacrylamide is 1-2 wt% of the zirconium oxide powder; the aluminum chloride concentration is 0.3-0.4 mol / L; and the reaction mass ratio of the high-temperature resistant coating filler and γ-methacryloyloxypropyltrimethoxysilane is (0.5-0.7):

3.

6. The preparation process of a low-alloy hot-rolled coil with high processing performance according to claim 1, characterized in that: In step three, the preparation process of the polyurethane prepolymer is as follows: polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate are dissolved in acetone, toluene diisocyanate is added, and after the reaction is complete, triethylamine is added for neutralization. After the reaction is completed, the mixture is emulsified with deionized water and acetone is removed by rotary evaporation to obtain the polyurethane prepolymer. The preparation process of the high-temperature resistant silicone resin is as follows: under a nitrogen atmosphere, dimethylcyclosiloxane, trifluoropropyltrimethylcyclotrisiloxane, and tetramethyltetraenylcyclotetrasiloxane are mixed, heated to 95-105℃ and stirred for 35-45 min, then heated to 110-120℃ and 25-30% tetramethylammonium hydroxide aqueous solution and deionized water are added. The reaction is continued for 3-4 h. After the reaction is completed, the temperature is raised to 150-160℃ and kept at that temperature for 2-3 h. The resin is then removed by vacuum to obtain the high-temperature resistant silicone resin.

7. The preparation process of a low-alloy hot-rolled coil with high processing performance according to claim 6, characterized in that: When preparing polyurethane prepolymer, the reaction molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate to the isocyanate groups in toluene diisocyanate is 1:(1.3-1.4); the reaction molar ratio of the hydroxyl groups in polycaprolactone polyol, dimethylolpropionic acid, and hydroxyethyl methacrylate is (1.8-2.0):1:1; the content of each component of the high-temperature resistant silicone resin is as follows (by mass): 30-40 parts dimethylcyclosiloxane, 35-45 parts trifluoropropyltrimethylcyclotrisiloxane, 25-30 parts tetramethyltetraenylcyclotetrasiloxane, 0.015-0.017 parts tetramethylammonium hydroxide aqueous solution, and 0.08-0.09 parts deionized water.

8. The preparation process of a low-alloy hot-rolled coil with high processing performance according to claim 1, characterized in that: In step three, the components of the silicone-modified polyurethane emulsion are as follows (by mass): 3-4 parts trimethylolpropane, 12-15 parts polyurethane prepolymer, 10-12 parts high-temperature resistant silicone resin, 2-3 parts tetraethyl orthosilicate, and 0.1-0.2 parts dibutyltin dilaurate; the components of the high-temperature resistant and wear-resistant resin are as follows (by mass): 50-60 parts silicone-modified polyurethane emulsion, 10-12 parts butyl acrylate, 10-12 parts styrene, 5-8 parts glycidyl methacrylate, 5-8 parts dodecafluoroheptyl methacrylate, 5-8 parts modified high-temperature resistant coating filler, and 1.0-1.2 parts potassium persulfate solution.

9. A low-alloy hot-rolled coil with high machinability, characterized in that, It is prepared according to any one of the preparation processes described in claims 1-8.

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