A method for manufacturing ultrafine grain high-strength structural steel

Abstract

The invention relates to the field of metal rolling and discloses a method for manufacturing ultrafine grain high-strength structural steel. The method comprises the following specific steps: step 1: selecting high-purity iron (Fe) remainder, carbon (C) 0.05%-0.15%, vanadium (V) 0.01%-0.1%, titanium (Ti) 0.01%-0.05%, tungsten (W) 0.05%-0.2%, and niobium (Nb) 0.01%-0.1% alloy elements according to a set chemical composition ratio, wherein iron is used as a basic element to provide the main structure of the steel, and carbon improves the hardness and strength of the steel; the optimized rolling mill design effectively solves the problem of debris, oxide scale or other tiny impurity residues on the surface of the workpiece in the prior art, improves the manufacturing quality of the ultrafine grain high-strength structural steel, and meets the strict requirements of the modern steel industry for high-performance steel.

Description

Technical Field

[0001] The invention relates to the technical field of metal rolling, and in particular to a method for manufacturing ultrafine grain high-strength structural steel. Background Art

[0002] In the current steel industry, high-strength structural steel is widely used in bridges, construction, automobile manufacturing, shipbuilding and other fields due to its excellent mechanical properties, such as high strength, high toughness and good wear resistance. However, with the continuous improvement of the performance requirements of structural steel, the traditional steel manufacturing process has been difficult to meet the high performance requirements. Therefore, the manufacturing technology of ultrafine grain high-strength structural steel has gradually attracted attention.

[0003] Ultrafine grain high-strength structural steel is a high-performance steel that controls the grain size of the steel to refine the grain structure and significantly improve the material strength. The grain refinement is achieved by adopting advanced process technologies such as controlled rolling and controlled cooling, so that the steel has good toughness and ductility while maintaining high strength.

[0004] Among them, during the rolling process, the workpiece needs to move back and forth between the rollers. This method gradually reduces the thickness of the workpiece through multiple reverse rolling and accurately controls its size and shape. Reverse rolling equipment is usually flexible and suitable for multi-variety and small-batch production. However, due to the high-pressure contact between the rollers and the workpiece, some debris, oxide scale or other tiny impurities may be generated on the surface of the workpiece. These debris may remain on the surface of the rollers. If these residual debris are not cleaned in time, they may be pressed into the surface during the subsequent rolling process of the workpiece, resulting in surface defects such as scratches, pits or uneven surface quality. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method for manufacturing ultrafine grain high-strength structural steel, aiming to alleviate the above problems at least to a certain extent.

[0006] The above technical objectives of the present invention are achieved through the following technical solutions:

[0007] A method for manufacturing ultrafine grain high-strength structural steel, the specific steps of the method are as follows:

[0008] Step 1: According to the set chemical composition ratio, select high-purity iron (Fe) remainder, carbon (C) 0.05% -0.15%, vanadium (V) 0.01% - 0.1%, titanium (Ti) 0.01% - 0.05%, tungsten (W) 0.05% - 0.2%, niobium (Nb) 0.01% -0.1% alloying elements. Iron is the basic element, providing the main structure of the steel; carbon improves the hardness and strength of the steel; vanadium enhances the strength and wear resistance of the steel and refines the grains; titanium eliminates oxides and nitrides and further refines the grains; tungsten improves the heat resistance and hardness of the steel; niobium enhances the strength and toughness of the steel and refines the grains. These raw materials need to be accurately weighed and fully mixed to ensure that the chemical composition of the final steel meets the requirements;

[0009] Step 2: Put the mixed raw materials into an electric arc furnace for smelting. The smelting temperature is controlled at 1600°C for 2 hours. During the smelting process, slag removal is performed to remove impurities in the molten steel. After the smelting is completed, argon gas is purged for refining to further remove harmful elements such as oxygen, nitrogen, and sulfur.

[0010] Step 3: The refined molten steel is cast into a round billet with a diameter of 200 mm through a continuous casting process. During the casting process, the cooling rate is controlled at 20°C / second to ensure the grain refinement of the billet and avoid the formation of coarse grains. After the casting is completed, the internal structure of the billet is inspected by ultrasonic flaw detection to ensure that there are no defects such as segregation and shrinkage holes;

[0011] Step 4: The heated billet is rolled on a rolling mill for multiple passes. During the rolling process, the workpiece moves back and forth between the rolls. There is high pressure contact between the rolls and the workpiece to ensure the dimensional accuracy of the final product.

[0012] Step 5: After rolling, the steel is immediately water-cooled at a cooling rate of 10°C / second. By precisely controlling the cooling rate, the steel grains are refined so that the final grain size is controlled below 10 microns. The cooled steel is quenched at a temperature of 850°C for 30 minutes. After quenching, it is immediately tempered at a temperature of 600°C for 2 hours to improve the strength and toughness of the steel. After the treatment, the steel is pickled and fully inspected to ensure that the dimensional accuracy and surface quality meet the design standards.

[0013] Among them, the rolling mill includes a rolling stand, two box bodies are provided on the rolling stand, rolling rollers are provided in the box bodies, two platforms are provided on the rolling mill, the two platforms are located on both sides of the rolling rollers, a plurality of conveying rollers are provided on the platforms, a collecting box is provided in the box body, an industrial vacuum cleaner is provided on the rolling stand, the suction end of the industrial vacuum cleaner is connected with the collecting box, a driving component for rotating the conveying roller is provided between the rolling stand and the conveying roller, a moving component for moving the rolling roller is provided between the two box bodies, the moving component can move the position of the rolling roller when the conveying roller rotates counterclockwise and the two rolling rollers move away from each other, and the driving component can also rotate the two rolling rollers when rotating the conveying roller.

[0014] Preferably, the movable component includes a bracket slidably connected to the rolling stand, the roller is rotatably connected to the bracket, an escape opening is opened on the box body, the roller is slidably connected in the escape opening, the rolling stand is connected to a support frame, the support frame is rotatably connected to a first screw rod, and the bracket is connected to a threaded tube threadedly connected to the first screw rod.

[0015] Preferably, the driving component includes a first gear connected to the conveying roller, a sliding frame on the rolling frame, a first rack connected to the sliding frame and meshing with the first gear, a second rack connected to the sliding frame, and a second gear connected to the first screw rod and meshing with the second rack.

[0016] Preferably, a connecting ring is connected to the first screw rod, a connecting groove is provided on the inner side wall of the second gear, a push rod is slidably connected in the connecting groove, one end of the push rod is semi-spherical, and a top groove adapted to the semi-spherical end of the push rod is provided on the outer wall of the connecting ring, and a first spring is connected between the push rod and the connecting groove.

[0017] Preferably, the moving component further comprises a connecting rod connected to the sliding frame, the second rack is connected to the connecting rod, a third rack is further provided on the connecting rod, and a third gear meshing with the third rack is connected to the roller.

[0018] Preferably, the third rack is slidably connected to the connecting rod, and a second spring is provided between the third rack and the connecting rod.

[0019] Preferably, the collection box is connected to the right side of the box body, one end of the collection box is inclined, a suction pipe is connected to the box body, a side opening connected to the collection box is opened on the suction pipe, and the suction pipe is connected to the industrial vacuum cleaner.

[0020] Preferably, the roller frame is rotatably connected to a second screw rod, the second screw rod is a reciprocating screw rod, the sliding frame is slidably connected to the second screw rod, the roller frame is connected to a motor, and a first chain transmission mechanism is connected between the driving shaft of the motor and the second screw rod.

[0021] Preferably, a second transmission mechanism is connected between every two of the conveying rollers.

[0022] Preferably, a connecting frame is connected to the platform, and a plurality of limiting shafts are rotatably connected to the connecting frame, and the limiting shafts correspond to the positions of the conveying rollers.

[0023] In summary, the present invention mainly has the following beneficial effects:

[0024] 1. Accurate workpiece support and positioning:

[0025] The operator can place the workpiece to be rolled on the platform, and the conveyor rollers on the platform effectively support and limit the workpiece, ensuring that the workpiece can accurately enter the rolling channel of the roller. This support and positioning mechanism ensures that the workpiece is stable and reliable during the rolling process, and improves the rolling accuracy and consistency.

[0026] 2. Automatic cleaning function:

[0027] The collection box and industrial vacuum cleaner can remove the debris and scale on the roll surface in real time. The collection box scrapes away the impurities on the roll, and the industrial vacuum cleaner sucks away these impurities, preventing the impurities from being pressed into the workpiece surface during the subsequent rolling process, avoiding the occurrence of surface defects.

[0028] 3. Flexible rolling operation:

[0029] The drive unit controls the rotation of the conveyor rollers, supporting the movement of the workpiece in and out between the rollers. By rotating the conveyor rollers in the opposite direction, the moving unit can adjust the position of the rollers, realize the reset of the rollers, and optimize the rolling efficiency and quality.

[0030] 4. Efficient cleaning and defect reduction:

[0031] In each rolling cycle, the cleaning function of the collection box and industrial vacuum cleaner ensures that the surface of the rolls and workpieces are always clean. This further reduces surface defects such as scratches, pits or uneven surface quality caused by residual impurities, thereby improving the quality of the final steel.

[0032] 5. Improve production efficiency:

[0033] Through the automated cleaning and rolling adjustment mechanism, the need for manual intervention is reduced, improving the overall efficiency of the production line. The automated operation of the entire rolling process and the effective removal of impurities enable the steel to achieve the predetermined final size and surface quality requirements during the production process, improving production efficiency and product consistency.

[0034] This optimized rolling mill design effectively solves the problem of debris, oxide scale or other tiny impurities remaining on the workpiece surface in the prior art, improves the manufacturing quality of ultra-fine grain high-strength structural steel, and meets the strict requirements of the modern steel industry for high-performance steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic flow chart of the method of the present invention;

[0036] Figure 2 It is a schematic structural diagram of a rolling mill of the present invention;

[0037] Figure 3 It is a schematic diagram of the support frame structure of the present invention;

[0038] Figure 4 is a cross-sectional schematic diagram of the box structure of the present invention;

[0039] Figure 5 It is a schematic diagram of the platform structure of the present invention;

[0040] Figure 6 It is a schematic diagram of the structure of the sliding frame of the present invention;

[0041] Figure 7 It is a schematic diagram of the support structure of the present invention;

[0042] Figure 8 It is a schematic diagram of the roller structure of the present invention;

[0043] Fig. 9 It is a schematic diagram of the structure of the collection box of the present invention;

[0044] Fig.10 It is a schematic diagram of the connecting rod structure of the present invention;

[0045] Fig.11 is a schematic diagram of the second rack structure of the present invention;

[0046] Fig.12 It is a schematic diagram of the second gear structure of the present invention.

[0047] Reference numerals:

[0048] 100, rolling stand; 101, box body; 102, rolling roller; 103, platform; 104, conveying roller; 105, collecting box; 106, industrial vacuum cleaner;

[0049] 200, bracket; 201, avoidance; 202, support frame; 203, first screw rod; 204, threaded tube;

[0050] 300, first gear; 301, sliding frame; 302, first rack; 303, second rack; 304, second gear; 305, connecting ring; 306, connecting groove; 307, top rod; 308, top groove; 309, first spring;

[0051] 400, connecting rod; 401, third rack; 402, third gear; 403, second spring;

[0052] 500, suction tube; 501, side opening;

[0053] 600, second screw rod; 601, motor; 602, first chain transmission mechanism; 603, second transmission mechanism; 604, connecting frame; 605, limiting shaft. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] refer to Figure 1-Figure 12 , a method for manufacturing ultrafine grain high strength structural steel, the specific steps of the method are as follows:

[0056] Step 1: According to the set chemical composition ratio, select high-purity iron (Fe) remainder, carbon (C) 0.05% -0.15%, vanadium (V) 0.01% - 0.1%, titanium (Ti) 0.01% - 0.05%, tungsten (W) 0.05% - 0.2%, niobium (Nb) 0.01% -0.1% alloying elements. Iron is the basic element, providing the main structure of the steel; carbon improves the hardness and strength of the steel; vanadium enhances the strength and wear resistance of the steel and refines the grains; titanium eliminates oxides and nitrides and further refines the grains; tungsten improves the heat resistance and hardness of the steel; niobium enhances the strength and toughness of the steel and refines the grains. These raw materials need to be accurately weighed and fully mixed to ensure that the chemical composition of the final steel meets the requirements;

[0057] Step 2: Put the mixed raw materials into an electric arc furnace for smelting. The smelting temperature is controlled at 1600°C for 2 hours. During the smelting process, slag removal is performed to remove impurities in the molten steel. After the smelting is completed, argon gas is purged for refining to further remove harmful elements such as oxygen, nitrogen, and sulfur.

[0058] Step 3: The refined molten steel is cast into a round billet with a diameter of 200 mm through a continuous casting process. During the casting process, the cooling rate is controlled at 20°C / second to ensure the grain refinement of the billet and avoid the formation of coarse grains. After the casting is completed, the internal structure of the billet is inspected by ultrasonic flaw detection to ensure that there are no defects such as segregation and shrinkage holes;

[0059] Step 4: The heated billet is rolled on a rolling mill for multiple passes. During the rolling process, the workpiece moves back and forth between the rolls. There is high pressure contact between the rolls and the workpiece to ensure the dimensional accuracy of the final product.

[0060] Step 5: After rolling, the steel is immediately water-cooled at a cooling rate of 10°C / second. By precisely controlling the cooling rate, the steel grains are refined so that the final grain size is controlled below 10 microns. The cooled steel is quenched at a temperature of 850°C for 30 minutes. After quenching, it is immediately tempered at a temperature of 600°C for 2 hours to improve the strength and toughness of the steel. After the treatment, the steel is pickled and fully inspected to ensure that the dimensional accuracy and surface quality meet the design standards.

[0061] The rolling mill comprises a rolling stand 100, two boxes 101 are arranged on the rolling stand 100, a rolling roll 102 is arranged in the box 101, two platforms 103 are arranged on the rolling mill, the two platforms 103 are located on both sides of the rolling roll 102, a plurality of conveying rollers 104 are arranged on the platform 103, a collecting box 105 is arranged in the box 101, an industrial vacuum cleaner 106 is arranged on the rolling stand 100, the suction end of the industrial vacuum cleaner 106 is connected with the collecting box 105, a driving component for rotating the conveying roller 104 is arranged between the rolling stand 100 and the conveying roller 104, a moving component for moving the rolling roll 102 is arranged between the two boxes 101, the moving component can move the position of the rolling roll 102 when the conveying roller 104 rotates counterclockwise and the two rolling rolls 102 move away from each other, and the driving component can also rotate the two rolling rolls 102 when the conveying roller 104 is rotated;

[0062] By setting the platform 103, when in use, the operator can place the workpiece that needs to be rolled on the platform 103, and the conveying roller 104 provided can support and limit the workpiece, ensuring that the workpiece can reach the rolling channel on the roller 102 when the workpiece is subsequently rolled. The operator can start the driving component, and the driving component can rotate the conveying roller 104. When the conveying roller 104 is rotated, the workpiece can be conveyed between the two rollers 102. After the workpiece passes through the roller 102 for the first rolling work, the driving component can be used to reversely rotate the conveying roller 104. The conveying roller 10 When rotating counterclockwise, the moving component can move the positions of the two rollers 102, and the two rollers 102 move away from each other. The workpiece can reach the initial position due to the counterclockwise rotation of the conveying roller 104. In this process, when the two rollers 102 move away from each other to the preset position, the rollers 102 can contact the box body 101, the roller 102 located at the upper part can contact the bottom of the collecting box 105, and the roller 102 located at the lower part can contact the top of the collecting box 105. Under this setting, the driving component can rotate the two rollers 102 while rotating the conveying roller 104. In conjunction with the rotation of the roller 102, the collecting box 105 can scrape off the debris and oxide scale on the surface of the roller 102. The industrial vacuum cleaner 106 is connected to the collecting box 105 through its suction end to absorb the impurities scraped from the surface of the roller 102 in real time, ensuring the surface cleanliness during the rolling process. This arrangement effectively prevents impurities from being pressed into the surface of the workpiece during the subsequent rolling process, avoiding the occurrence of surface defects. After the conveying roller 104 rotates to convey the workpiece to the original position, the driving component rotates clockwise again to allow the workpiece to reach the two positions again. Between the rollers 102, while the conveying roller 104 rotates clockwise, the two rollers 102 can be reset and moved, shortening the distance between the two rollers 102 to complete further rolling operations. In each rolling cycle, the thickness of the workpiece will be further reduced, and the size and shape will be precisely controlled. After each rolling, in the process of resetting the workpiece position, the collection box 105 and the industrial vacuum cleaner 106 can be used to promptly absorb the debris and oxide scale scraped from the surface of the roller 102, further cleaning the roller 102 and the workpiece surface.Through this mechanism, it is ensured that the surface of the workpiece always remains clean when passing through each rolling process, preventing surface defects caused by residual impurities. After the workpiece completes the required rolling process, the driving component will continue to rotate the conveyor roller 104 clockwise to convey the workpiece from between the rollers 102 to the removal position / placement position. The whole process is repeated until the workpiece reaches the predetermined final size and surface quality requirements. This optimized rolling mill design not only improves the manufacturing quality of ultra-fine grain high-strength structural steel, but also meets the strict requirements of the modern steel industry for high-performance steel. It solves the problem in the prior art that some debris, oxide scale or other tiny impurities will be generated on the surface of the workpiece. These debris remain on the surface of the roller 102 and are pressed into the surface during the subsequent rolling process of the workpiece, resulting in surface defects such as scratches, pits or uneven surface quality.

[0063] Through the above steps, the manufactured ultrafine grain high strength structural steel has the following technical effects:

[0064] 1. Excellent mechanical properties

[0065] By precisely controlling the chemical composition, especially by adding alloying elements such as vanadium, titanium, tungsten and niobium, the strength, toughness and wear resistance of the steel are effectively improved, allowing the steel to maintain excellent performance in a high stress environment.

[0066] 2. Refined grain structure

[0067] By strictly controlling the temperature and cooling rate during the smelting, casting and rolling processes, the grain structure of the steel was successfully refined so that the grain size could be controlled below 10 microns, thereby significantly improving the overall mechanical properties and uniformity of the steel.

[0068] 3. High surface quality

[0069] By setting up a cleaning mechanism during the rolling process to clean the debris on the roller surface in time, scratches, pits and other defects on the workpiece surface are avoided, ensuring the surface quality of the steel. This measure greatly reduces the incidence of surface defects and improves the appearance and quality consistency of the finished product.

[0070] 4. Precise and controllable size

[0071] Through multiple reverse rolling processes, not only the thickness of the steel is gradually reduced, but also the size and shape of the workpiece are precisely controlled, making this manufacturing method suitable for the production needs of multiple varieties and small batches, and enhancing the flexibility of production.

[0072] 5. Enhanced process stability

[0073] Through strict control of each step, especially the precise operation of smelting, refining and heat treatment, the stability and repeatability of the entire manufacturing process are effectively improved, ensuring the performance consistency of each batch of steel and meeting high-standard application requirements.

[0074] As a further solution of the present invention, the moving part includes a bracket 200 slidably connected to the rolling frame 100, the roller 102 is rotatably connected to the bracket 200, the box body 101 is provided with an escape opening 201, the roller 102 is slidably connected in the escape opening 201, the rolling frame 100 is connected to a support frame 202, the support frame 202 is rotatably connected to a first screw rod 203, and the bracket 200 is connected to a threaded tube 204 threadedly connected to the first screw rod 203;

[0075] By setting the threaded tube 204, when used, the position of the first screw rod 203 can be rotated. The rotation of the first screw rod 203 can use the force of the thread to move the position of the threaded tube 204, so that the two brackets 200 can move away from each other. The movement of the bracket 200 changes the relative position of the rollers 102 connected to the bracket 200, so that the spacing between the two rollers 102 is adjusted to a suitable distance. This setting allows the rollers 102 to effectively contact the collection box 105 during the rolling process. The contact of the collection box 105 can not only scrape off the debris and oxide scale on the surface of the roller 102, but also ensure that the surface of the roller 102 remains clean, preventing impurities from being pressed into the surface of the workpiece during the subsequent rolling process. In this way, surface defects such as scratches, pits or uneven surface quality can be avoided, ensuring that the workpiece meets the predetermined surface quality requirements after each rolling process.

[0076] As a further solution of the present invention, the driving component includes a first gear 300 connected to the conveying roller 104, a sliding frame 301 on the rolling frame 100, a first rack 302 meshing with the first gear 300 is connected to the sliding frame 301, a second rack 303 is connected to the sliding frame 301, and a second gear 304 meshing with the second rack 303 is connected to the first screw rod 203;

[0077] By setting the sliding frame 301, the position of the sliding frame 301 can be moved in application. When the sliding frame 301 moves to the right, the first rack 302 and the first gear 300 can be used to rotate the conveying roller 104 counterclockwise. When the sliding frame 301 moves to the right, the second rack 303 can also be driven to move. The movement of the second rack 303 can rotate the first screw rod 203 through the second gear 304, so that the two brackets 200 can be moved away from each other through the force of the thread, so as to move the position of the roller 102. The key advantage of this design is that complex mechanical actions and precise position control of the roller 102 can be achieved by adjusting the position of the sliding frame 301. In specific operation, the movement of the sliding frame 301 not only changes the rotation direction of the conveying roller 104, but also accurately adjusts the spacing of the roller 102 through the cooperation of a series of gears and screw rods. In this way, it is ensured that during the rolling process, the roller 102 can effectively contact the collecting box 105 to achieve the cleaning of the debris and oxide scale on the surface of the roller 102.

[0078] As a further solution of the present invention, a connecting ring 305 is connected to the first screw rod 203, a connecting groove 306 is provided on the inner side wall of the second gear 304, a push rod 307 is slidably connected in the connecting groove 306, one end of the push rod 307 is semi-spherical, a top groove 308 adapted to the semi-spherical end of the push rod 307 is provided on the outer wall of the connecting ring 305, and a first spring 309 is connected between the push rod 307 and the connecting groove 306;

[0079] By setting the first spring 309, the first spring 309 can limit the position of the push rod 307, so that the push rod 307 and the top groove 308 can be sleeved and form a certain friction force. When the sliding frame 301 moves to the right to rotate the second gear 304 through the second rack 303, the second gear 304 can use the friction between the push rod 307 and the top groove 308 to transmit the rotational motion, and the first screw rod 203 can rotate. When the bracket 200 drives the roller 102 thereon to move to the extreme position, the friction force increases, and the push rod 307 and the top groove 308 are separated and compressed. The first spring 309, that is, the second gear 304 is idle outside the first screw rod 203, avoiding the collision and damage in the mechanical movement, ensuring the stability and safety of the system. When the sliding frame 301 moves to the left to reset, the conveying roller 104 can rotate clockwise. At this time, the friction between the top rod 307 and the top groove 308 can be used again to make the first screw rod 203 rotate in the opposite direction to reset the position of the bracket 200, so that the two rollers 102 can be reset in time. Through this design, the two rollers 102 can be reset in time and prepare for the next working cycle. This design not only effectively avoids the damage of mechanical parts, but also ensures that the system can be quickly adjusted and reset during efficient operation, ensuring the precise positioning of the rollers 102 and the high-quality processing of the workpiece.

[0080] As a further solution of the present invention, the moving part further comprises a connecting rod 400 connected to the sliding frame 301, the second rack 303 is connected to the connecting rod 400, a third rack 401 is further provided on the connecting rod 400, and a third gear 402 meshing with the third rack 401 is connected to the roller 102;

[0081] By setting the third rack 401, when the sliding frame 301 moves to the right to allow the conveying roller 104 to rotate counterclockwise and the two brackets 200 move away from each other to allow the roller 102 to contact the collecting box 105, the third rack 401 can follow the movement of the sliding frame 301, and the third rack 401 can be used to rotate the roller 102, so as to achieve the purpose of rotating the roller 102 and scraping the roller 102 with the collecting box 105, so as to effectively scrape off the debris and oxide scale on the surface of the roller 102 with the collecting box 105. This process ensures the cleanliness of the surface of the roller 102 during the rolling process. When the slide frame 301 moves to the left to reset and allow the conveying roller 104 to rotate clockwise, the third rack 401 and the third gear 402 can be used to rotate the two rollers 102, and the roller 102 located at the top rotates counterclockwise and the roller 102 located at the bottom rotates clockwise to achieve the rolling of the workpiece. When the workpiece completes a cycle of the rolling process, the movement of the slide frame 301 can automatically trigger the cleaning operation of the roller 102 to ensure that the cleanliness of the surface of the roller 102 is always maintained in the best state. This structural design improves the automation level and work efficiency of the overall rolling system, while effectively reducing the generation of surface defects on the workpiece, providing a solid guarantee for the production of high-quality ultra-fine grain high-strength structural steel.

[0082] As a further solution of the present invention, the third rack 401 is slidably connected to the connecting rod 400, and a second spring 403 is provided between the third rack 401 and the connecting rod 400;

[0083] By setting the second spring 403, when the bracket 200, the roller 102 and the third gear 402 are displaced under the rotation of the first gear 300, the set second spring 403 can allow the third rack 401 to adapt to the position of the third gear 402, so that the third rack 401 always maintains a state of meshing with the third gear 402, and the third rack 401 will not lose contact with the third gear 402 due to position deviation, thereby ensuring that the roller 102 can rotate continuously and smoothly, and then the collection box 105 is used to effectively scrape off the debris and oxide scale on the surface of the roller 102.

[0084] As a further solution of the present invention, the collection box 105 is connected to the right side of the box body 101, one end of the collection box 105 is inclined, and a suction pipe 500 is connected to the box body 101, and a side opening 501 connected to the collection box 105 is opened on the suction pipe 500, and the suction pipe 500 is connected to the industrial vacuum cleaner 106;

[0085] By setting the suction pipe 500, when in use, in conjunction with the industrial vacuum cleaner 106, the scraped debris and oxide scale in the collection box 105 can be effectively and quickly exported. One end of the collection box 105 is designed to be inclined, which can make the scraped impurities automatically gather at the bottom of the collection box 105 and enter the suction pipe 500 through the side opening 501. The suction pipe 500 is connected to the industrial vacuum cleaner 106, and the vacuum cleaner quickly sucks away these impurities through its strong suction force to prevent them from re-attaching to the surface of the roller 102 or the workpiece during the rolling process. This design not only ensures that the impurities in the collection box 105 can be removed in time, but also reduces the frequency and difficulty of manual cleaning, further improving the automation level and production efficiency of the system. In addition, the close connection between the suction pipe 500 and the collection box 105 avoids secondary contamination of impurities, ensures a clean environment in the rolling process, and effectively improves the surface quality of the finished product.

[0086] As a further solution of the present invention, a second screw rod 600 is rotatably connected to the rolling frame 100, the second screw rod 600 is a reciprocating screw rod, the sliding frame 301 is slidably connected to the second screw rod 600, a motor 601 is connected to the rolling frame 100, and a first chain transmission mechanism 602 is connected between the driving shaft of the motor 601 and the second screw rod 600;

[0087] By setting the motor 601, when applied, the rotation of the second screw rod 600 can be controlled by the driving force of the motor 601, so that the sliding frame 301 can slide back and forth along the second screw rod 600. The driving shaft of the motor 601 is connected to the second screw rod 600 through the first chain transmission mechanism 602. When the motor 601 is started, the second screw rod 600 can be driven to perform precise reciprocating motion. Since the second screw rod 600 is a reciprocating screw rod, its rotation can make the sliding frame 301 move back and forth on the roller stand 100, thereby driving the conveying roller 104 to rotate and controlling the position and movement of the roller 102. This setting makes the operation of the entire system more automated and accurate. The operator can achieve accurate positioning of the workpiece and accurate adjustment of the roller 102 through the control of the motor 601, ensuring that the best process parameters can be maintained at different rolling stages. This not only improves work efficiency, but also reduces human errors and ensures product consistency and quality stability. During each rolling process of the workpiece, the motor 601 drives the second screw rod 600 to adjust the position of the sliding frame 301, so that the operation of the roller 102 is more flexible and diversified to meet the processing requirements of different workpieces.

[0088] As a further solution of the present invention, a second transmission mechanism 603 is connected between every two conveying rollers 104;

[0089] By setting up the second chain transmission mechanism, every two conveying rollers 104 can achieve synchronous rotation, thereby ensuring the stability and consistency of the workpiece during the conveying process. This synchronous transmission design can effectively reduce the problem of workpiece surface damage or inaccurate positioning caused by inconsistent speeds between the conveying rollers 104. At the same time, through the linkage of the second chain, the power transmission of the entire conveying system is more efficient, reducing energy loss and improving the overall operating efficiency of the equipment. This design optimizes the transmission path of the workpiece, ensuring that the workpiece can accurately enter between the rollers 102 for processing in the subsequent rolling process, thereby improving the final quality of the product.

[0090] As a further solution of the present invention, a connecting frame 604 is connected to the platform 103, and a plurality of limiting shafts 605 are rotatably connected to the connecting frame 604, and the limiting shafts 605 correspond to the positions of the conveying rollers 104;

[0091] By setting the limiting shaft 605, the workpiece can be effectively limited when it is placed on the platform 103, preventing the workpiece from being offset or tilted during the conveying process. The limiting shaft 605 corresponds to the position of the conveying roller 104, which means that the workpiece will be firmly fixed on the correct conveying path by the limiting shaft 605 during conveying, thereby ensuring that the workpiece can smoothly and accurately enter between the rollers 102 for rolling. This design not only enhances the stability during the conveying process, but also improves the accuracy of the workpiece positioning, avoiding the processing error caused by the workpiece position offset. At the same time, the setting of the limiting shaft 605 also helps to improve the safety of the entire system, reduces the possible sliding or jumping of the workpiece during the conveying process, and further ensures the smooth progress of the processing process. This limiting mechanism can maintain the uniform position of the workpiece in multiple rolling cycles, ensure the consistency of the size and shape of the rolled product, and thus improve the quality of the final product.

[0092] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing ultrafine grain high strength structural steel, characterized in that: The specific steps of this method are as follows: Step 1: According to the set chemical composition ratio, select 0.05% - 0.15% carbon, 0.01% - 0.1% vanadium, 0.01% - 0.05% titanium, 0.05% - 0.2% tungsten, 0.01% - 0.1% niobium alloy elements, and the balance is iron, and mix these raw materials thoroughly; Step 2: Put the mixed raw materials into an electric arc furnace for smelting. The smelting temperature is controlled at 1600°C for 2 hours. During the smelting process, slag removal is performed to remove impurities in the molten steel. After the smelting is completed, argon gas is purged for refining to further remove harmful elements such as oxygen, nitrogen and sulfur. Step 3: The refined molten steel is cast into a round billet with a diameter of 200 mm through a continuous casting process. During the casting process, the cooling rate is controlled at 20°C / second to ensure the grain refinement of the billet and avoid the formation of coarse grains. After the casting is completed, the internal structure of the billet is checked by ultrasonic flaw detection to ensure that there are no segregation and shrinkage defects; Step 4: The heated billet is rolled on a rolling mill for multiple passes. During the rolling process, the workpiece moves back and forth between the rolls. There is high pressure contact between the rolls and the workpiece to ensure the dimensional accuracy of the final product. Step 5: After rolling, the steel is immediately water-cooled at a cooling rate of 10°C / second. By precisely controlling the cooling rate, the steel grains are refined so that the final grain size is controlled below 10 microns. The cooled steel is quenched at a quenching temperature of 850°C for 30 minutes. After quenching, it is immediately tempered at a tempering temperature of 600°C for 2 hours. After the treatment, the steel is pickled and fully inspected to ensure that the dimensional accuracy and surface quality meet the design standards. The rolling mill comprises a rolling stand (100), the rolling stand (100) being provided with two boxes (101), a rolling roll (102) being provided in the boxes (101), the rolling mill being provided with two platforms (103), the two platforms (103) being located on both sides of the rolling roll (102), a plurality of conveying rollers (104) being provided on the platforms (103), a collecting box (105) being provided in the boxes (101), and an industrial vacuum cleaner (106) being provided on the rolling stand (100), the suction of the industrial vacuum cleaner (106) The end of the roller frame (100) is connected to the collecting box (105); a driving component for rotating the conveying roller (104) is provided between the roller frame (100) and the conveying roller (104); a moving component for moving the roller (102) is provided between the two box bodies (101); the moving component is capable of moving the position of the roller (102) and moving the two rollers (102) away from each other when the conveying roller (104) rotates counterclockwise; and the driving component is also capable of rotating the two rollers (102) when the conveying roller (104) is rotated; The moving component comprises a bracket (200) slidably connected to the rolling stand (100), the rolling roller (102) is rotatably connected to the bracket (200), the box body (101) is provided with an escape opening (201), the rolling roller (102) is slidably connected in the escape opening (201), the rolling stand (100) is connected to a support frame (202), a first screw rod (203) is rotatably connected to the support frame (202), and a threaded tube (204) threadedly connected to the first screw rod (203) is connected to the bracket (200); The driving component comprises a first gear (300) connected to the conveying roller (104), a sliding frame (301) on the rolling frame (100), a first rack (302) meshing with the first gear (300) connected to the sliding frame (301), a second rack (303) connected to the sliding frame (301), and a second gear (304) meshing with the second rack (303) connected to the first screw rod (203).

2. The method for manufacturing ultrafine grain high strength structural steel according to claim 1, characterized in that: A connecting ring (305) is connected to the first screw rod (203); a connecting groove (306) is provided on the inner side wall of the second gear (304); a push rod (307) is slidably connected in the connecting groove (306); one end of the push rod (307) is semi-spherical; an outer wall of the connecting ring (305) is provided with a top groove (308) adapted to the semi-spherical end of the push rod (307); and a first spring (309) is connected between the push rod (307) and the connecting groove (306).

3. The method for manufacturing ultrafine grain high strength structural steel according to claim 1, characterized in that: The moving component also includes a connecting rod (400) connected to the sliding frame (301), the second rack (303) is connected to the connecting rod (400), a third rack (401) is also provided on the connecting rod (400), and the roller (102) is connected to a third gear (402) meshing with the third rack (401).

4. The method for manufacturing ultrafine grain high strength structural steel according to claim 3, characterized in that: The third rack (401) is slidably connected to the connecting rod (400), and a second spring (403) is provided between the third rack (401) and the connecting rod (400).

5. The method for manufacturing ultrafine grain high strength structural steel according to claim 1, characterized in that: The collection box (105) is connected to the right side of the box body (101); one end of the collection box (105) is inclined; a suction pipe (500) is connected to the box body (101); a side opening (501) communicating with the collection box (105) is provided on the suction pipe (500); and the suction pipe (500) is connected to the industrial vacuum cleaner (106).

6. The method for manufacturing ultrafine grain high strength structural steel according to claim 1, characterized in that: A second screw rod (600) is rotatably connected to the rolling frame (100), the second screw rod (600) is a reciprocating screw rod, the sliding frame (301) is slidably connected to the second screw rod (600), a motor (601) is connected to the rolling frame (100), and a first chain transmission mechanism (602) is connected between the drive shaft of the motor (601) and the second screw rod (600).

7. The method for manufacturing ultrafine grain high strength structural steel according to claim 1, characterized in that: A second transmission mechanism (603) is connected between every two of the conveying rollers (104).

8. The method for manufacturing ultrafine grain high strength structural steel according to claim 1, characterized in that: The platform (103) is connected to a connecting frame (604), and a plurality of limiting shafts (605) are rotatably connected to the connecting frame (604), wherein the limiting shafts (605) correspond to the positions of the conveying rollers (104).

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