A production system and a production method of a ribbed steel bar, and a ribbed steel bar

Abstract

The application discloses a ribbed steel bar production system and method and a ribbed steel bar, and belongs to the field of steel bar preparation.The ribbed steel bar is more cylindrical in shape, the transverse ribs are in the shape of willow leaves, and two willow-shaped inclined ribs are alternately arranged.The ribbed steel bar has the following unique advantages due to the different shape structure characteristics: 1. The ribbed steel bar is easy to straighten;2. In the use of the ribbed steel bar for welding a steel bar net, the ribbed steel bar is more cylindrical, and no matter the rotation angle of the ribbed steel bar is in any position, the ribbed steel bar can be well welded, the construction difficulty is reduced, construction problems are not prone to occur, and the reliability of a reinforced concrete product is improved; and 3. The ribbed steel bar is easy to bend, and in the process of welding a steel bar cylinder, a steel bar strip at any angle can be easily bent into a rectangular ring, thereby facilitating construction.

Description

Technical Field

[0001] This invention relates to a steel bar production system and production method, and particularly to a ribbed steel bar production system, production method, and ribbed steel bar, belonging to the field of steel bar preparation. Background Technology

[0002] The national ferrous metallurgical industry standard YB / T4657-2018 "Reinforced Concrete Four-Sided Ribbed Steel Bars" discloses a four-sided ribbed steel bar with four planes on its outer periphery, each plane having crescent-shaped transverse ribs. It has the ability to generate a strong interlocking force with concrete. The above-mentioned four-sided ribbed steel bar is widely used in various construction industries.

[0003] For example, in the construction of high-speed railways, a large number of the aforementioned four-ribbed steel bars are needed during the track laying process. During construction, after the coils of four-ribbed steel bars purchased from the manufacturer are straightened, the vertical steel bars need to be cut and assembled into a mesh structure for the horizontally laid steel reinforcement skeleton in the concrete. The assembled steel bars are then welded to form a steel mesh, which is laid underground on the high-speed railway tracks, and a concrete foundation is poured to form the foundation.

[0004] For example, in the construction industry, after straightening the coiled four-sided ribbed steel bars purchased from the manufacturer, for the steel reinforcement skeleton laid vertically in the concrete, the vertical steel bars need to be cut and assembled into a tube structure. The assembled steel bars are then welded to form a steel reinforcement tube, which is placed at the location where a cement column needs to be set up, and then concrete is poured to form the cement column.

[0005] While the aforementioned four-sided ribbed steel bars have the advantage of generating strong interlocking force with concrete, in actual use, the rectangular cross-section of the rolled four-sided ribbed steel bars is prone to problems during the straightening process when the outer perimeter has four planes. Furthermore, in the welding of steel mesh, when two steel bars are lapped, the corners of the four-sided ribbed steel bars often intersect, making it difficult to achieve a stable weld. Summary of the Invention

[0006] Addressing the technical problem of inconvenient use of four-sided ribbed steel bars in the construction of buildings, high-speed railway viaducts, and ballastless tracks, the inventors discovered that current straightening processes often result in noticeable damage to the appearance of the steel bars and a decrease in strength (particularly when straightening higher-strength steel bars, the following problems are prominent: 1. Obvious surface damage and unsightly appearance. 2. Poor straightness during straightening, affecting the production efficiency of welded wire mesh. 3. Reduced yield strength after straightening, leading to disputes during user inspection). This invention provides a production system, method, and ribbed steel bar, aiming to improve its convenience in practical use.

[0007] The technical solution of this invention is: a method for producing ribbed steel bars, comprising a wire laying process, a descaling process, a rolling and diameter reduction process, a looper process, a rolling and rib-pressing process, a heat treatment process, and a wire take-up process. In the method for producing ribbed steel bars, the rolling and rib-pressing process includes:

[0008] A rib-pressing mill is used to roll steel wire rods, simultaneously performing rib-pressing and / or scoring. The rib-pressing and / or scoring includes rolling operations in the left-right direction and rolling operations in the up-down direction. The rolling reducing mill includes both left-right and up-down rolling reducing mills, and the rib-pressing mill includes both left-right and up-down rolling rib-pressing mills. Both the reducing mill and the rib-pressing mill are equipped with paired rollers. The last pair of rollers in the rib-pressing mill is a pair of die rollers with rib-pressing and / or scoring. The outer circumference of the last pair of die rollers with rib-pressing and / or scoring has a V-shaped groove. The openings are set opposite each other. The two sides of the V-shaped groove are concave arcs. There are two willow leaf-shaped inclined ribs arranged alternately in the V-shaped groove. The apex of the chords intersecting is concave. The circumference formed by the apex of the chords in the V-shaped groove and the mold parting line of the upper and lower rollers are both provided with concave parts.

[0009] A ribbed steel bar, comprising:

[0010] The main body of the reinforcing bar is a tetrahedron, with each face being a convex arc. The four faces of the main body include a first face, a second face, a third face, and a fourth face. These four faces sequentially surround the centerline of the main body of the reinforcing bar, forming the tetrahedron.

[0011] The first and second surfaces are provided with two alternating willow leaf-shaped inclined ribs, and the third and fourth surfaces are provided with two alternating willow leaf-shaped inclined ribs.

[0012] A protruding diagonal portion is formed between each pair of adjacent faces. The diagonal portion between the first face and the second face intersects with the willow-leaf-shaped inclined ribs of the first face and the second face. The diagonal portion between the third face and the fourth face intersects with the willow-leaf-shaped inclined ribs of the third face and the fourth face.

[0013] Furthermore, the diagonal portion between the second surface and the third surface is separated from the willow-leaf-shaped inclined ribs of the first surface and the second surface, and the willow-leaf-shaped inclined ribs of the third surface and the fourth surface, respectively.

[0014] Furthermore, the height of the willow-leaf-shaped inclined ribs on the first and second surfaces, and the third and fourth surfaces, is less than 2 mm.

[0015] Furthermore, the height of the willow-leaf-shaped inclined ribs on the first and second surfaces, as well as the height of the willow-leaf-shaped inclined ribs on the third and fourth surfaces, is the same as the height of the diagonal portion.

[0016] Furthermore, the apex angle of the intersection of the two arcs of the willow-leaf-shaped inclined rib is 90°.

[0017] Furthermore, the angles between the midline of the two willow-leaf-shaped inclined rib grooves along their length and the axis of the main steel bar are 100-130° and 130-145°, respectively.

[0018] Furthermore, the inclination angles of the willow-leaf-shaped inclined ribs on the first and second surfaces and the willow-leaf-shaped inclined ribs on the third and fourth surfaces differ by 180°.

[0019] Furthermore, the spacing between the midlines of the alternating willow-leaf-shaped inclined rib grooves along their length direction is less than 10 mm.

[0020] A production system for ribbed steel bars includes: rolling equipment, which includes a rolling reducing mill and a rolling rib-pressing mill. The rolling reducing mill includes a left-right rolling reducing mill and a right-up rolling reducing mill. The rolling rib-pressing mill includes a left-right rolling rib-pressing mill and a right-up rolling rib-pressing mill. Both the rolling reducing mill and the rolling rib-pressing mill are equipped with paired rollers. The paired rollers of the last rolling rib-pressing mill are paired die rollers with rib pressing and / or markings. The outer periphery of the last pair of paired die rollers with rib pressing and / or markings is provided with a V-shaped groove. The V-shaped openings of the pair of rollers are arranged opposite each other. The two sides of the V-shaped groove are concave arc-shaped. Two alternating willow leaf-shaped inclined rib grooves are provided in the V-shaped groove. The apex of the intersection of the chords is concave. The circumference formed by the apex of the intersection of the chords in the V-shaped groove and the mold closing line of the upper and lower rollers are both provided with concave portions.

[0021] In this embodiment of the invention, the ribbed steel bars can be prepared using the aforementioned ribbed steel bar production system and method, but are not limited thereto. The ribbed steel bars prepared using the aforementioned ribbed steel bar production system and method have different shape characteristics from the steel bars in the national ferrous metallurgical industry standard YB / T4657-2018 "Reinforced Concrete Four-Sided Ribbed Steel Bars". Compared to the steel bars in the national ferrous metallurgical industry standard YB / T4657-2018 "Reinforced Concrete Four-Sided Ribbed Steel Bars", the ribbed steel bars of this application are more cylindrical in shape, with the transverse ribs forming willow leaf shapes, and two willow leaf-shaped inclined ribs arranged alternately. Due to the different shape characteristics, the ribbed steel bars of this application have the following unique advantages: 1. They are easy to straighten. 2. When using ribbed steel bars to weld steel mesh, the cylindrical ribbed steel bars can be welded well regardless of the rotation angle of the ribbed steel bars, reducing construction difficulty, minimizing construction problems, and improving the reliability of reinforced concrete products. 3. It has the characteristic of being easy to bend. During the process of welding ribbed steel bars into steel cylinders, steel bars at any angle can be easily bent into a rectangular ring, which facilitates construction. Attached Figure Description

[0022] Figure 1 A schematic diagram of the production system of this invention.

[0023] Figure 2 A schematic diagram of the structure of multiple arched holes in the steering device.

[0024] Figure 3 A schematic diagram of a single heat treatment unit.

[0025] Figure 4 A schematic diagram of the structure within the V-shaped groove on the outer periphery of one of the last pair of mold rollers in the pressure ribs and / or markings.

[0026] Figure 5 A schematic diagram of the structure within the V-shaped groove on the outer periphery of another roller in the last set of paired mold rollers for pressure ribs and / or markings.

[0027] Figure 6 A longitudinal cross-sectional view of the last set of paired mold rollers with pressure ribs and / or indentations.

[0028] Figure 7 Partial front view structural schematic diagram of ribbed steel bars.

[0029] Figure 8 A side view of the ribbed steel reinforcement structure.

[0030] Figure 9 Figure 7 A schematic diagram of a partial cross-sectional view of AA.

[0031] Figure 10 A schematic diagram of a ribbed steel bar structure.

[0032] Figure 11 A schematic diagram of the inner circle radius formed by the arc-shaped edge of the main body of a ribbed steel bar;

[0033] Figure 12 This is a statistical chart showing the performance of ribbed steel bars after straightening according to an embodiment of the present invention;

[0034] Figure 13 This is a statistical chart showing the performance of double-ribbed steel bars after straightening, based on existing technology. Detailed Implementation

[0035] The specific technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. In the following description, the front-back direction refers to the flow direction of the reinforcing bars, the left-right direction refers to the two sides of the reinforcing bar production line in the forward direction, and the up-down direction refers to the vertical direction.

[0036] The labels in the attached diagram represent: 10-Wire feeding machine, 11a-Directional sleeve one, 11-Descaling machine, 12a-Directional roller one, 12-Up-down rolling reducing mill, 13a-Directional sleeve two, 13-Left-right rolling reducing mill, 14a-Rebar directional stabilizing roller one, 14-Primary heat treatment device, 15-Temperature detector, 16-Steering device, 17a-Directional sleeve three, 17-Left-right rolling rib pressing mill, 18a-Directional roller two, 18-Up-down rolling rib pressing mill, 19a-Rebar directional stabilizing roller two, 20a-Wire rod, 20b-Ribped rebar, 21-Flying shear, 22-Conveyor track switcher, 23a-Take-up machine one, 23b-Take-up machine two, 24-Wear-resistant plate, 25-Arched hole, 26-High-frequency or medium-frequency generator. 27-Heating coil, 27a-Insulation cover, 28-Moving stabilizing roller, 29-Hollow shaft cooling water pipe, 30a-V-shaped groove side one, 30b-V-shaped groove side two, 31a-Willow leaf-shaped inclined rib groove one, 31b-Willow leaf-shaped inclined rib groove two, 32-Center line, 33-Top corner recess, 34-Mold closing recess.

[0037] With the continuous development of my country's high-speed rail, the demand for steel bars used in high-speed rail is also rising sharply. However, the steel bars used in high-speed rail have special requirements, requiring them to have both high ductility and a certain tensile strength. Traditional steel bar production includes hot rolling and cold rolling. Compared with hot rolling, cold rolling is more environmentally friendly and stable. In cold rolling, the raw materials are melted according to a certain proportion formula, and then formed into wire rods through rough rolling, intermediate rolling, fine rolling, wire drawing, and air cooling or water cooling. In the process of forming wire rods, in order to improve the tensile strength of the wire rods and increase the production speed, they must go through processes such as air cooling, water cooling or oil cooling. After cold treatment, the hot-formed steel bars have at least one stress formed on the surface of the steel bars. In addition, the tensile strength of the wire rods is 400-800MPa.

[0038] In order to further improve the elongation and tensile strength of the steel bars required for high-speed rail construction, the current production equipment was analyzed and studied, and the existing cold-rolled steel bar processes, including patented technologies, were analyzed. Based on this, experimental analysis was conducted.

[0039] Prior to the experiment, the following patent searches and analyses were conducted.

[0040] Patent application number 00122927.3 provides a method for manufacturing low-relaxation prestressed high-strength steel wire, the process steps of which are descaling, cold rolling, wire drawing spiral forming, and stabilization heat treatment.

[0041] Patent No. 200410013658.2 provides a high-strength, low-relaxation cold-rolled ribbed and scored steel bar, its production method, and a dedicated production line. The production process includes uncoiling, unwinding, descaling, cold rolling, scoring, heat treatment, and winding.

[0042] Patent application number 201510945123.7 provides a cold-rolled steel bar processing technology, which includes the following steps: 1) feeding hot-rolled wire rod into a rolling mill unit for diameter reduction and cold rolling to generate ribs; 2) heat-treating the hot-rolled wire rod that has been cold-rolled in step 1); 3) straightening the heat-treated hot-rolled wire rod in step 2), cutting it to length and collecting it.

[0043] Patent No. 201610669407.2 provides a method for processing high-ductility cold-rolled ribbed steel bars, the process of which includes steps such as descaling, diameter reduction, forming, heat treatment, and cooling. Application No. 201810818442.5 discloses a method for producing cold-rolled steel bars, the method comprising:

[0044] Step 1: Molten steel is poured into a steel mold in a steel furnace, and after it is shaped and cooled, it forms hot-rolled steel bars;

[0045] Step 2: Remove the phosphorus from the steel bars from Step 1 and introduce them into the rolling mill for cold rolling and cold twisting;

[0046] Step 3: The steel bars that have undergone cold rolling and cold twisting in Step 2 are then subjected to a stress relief machine to eliminate the cold rolling stress.

[0047] Step 4: Introduce the steel bars that have had their cold rolling stress eliminated in Step 4 into the complete set of equipment for rust removal, straightening, and coiling into a warehouse.

[0048] The above methods reveal that when producing ribbed steel bars from wire rod using cold rolling, the production process only considers the finished product's specifications, such as grain structure, tensile strength, yield strength, and elongation, without taking into account the inherent characteristics of the purchased product. In other words, current technology relies on heat treatment after cold rolling to meet product requirements, neglecting the characteristics of the product before processing. In fact, directly cold rolling the raw material wire rod destroys its original lattice structure, reducing its plasticity and, to some extent, its strength. Even with subsequent heat treatment, the temperature is far lower than the initial forming temperature, making it difficult for the heat-treated steel bars to regain the original grain structure after quenching. Furthermore, to improve production efficiency during wire rod heat treatment, the wire rod's... The cooling rate is relatively fast, and quenching treatment is required. Rapid cooling reduces the tensile strength of the steel bars, but the elongation is relatively low. However, for high-speed railway viaducts and ballastless tracks, the requirements for the tensile strength, yield strength, and especially the elongation of the steel bars are different from those for general construction. Steel bars used in high-speed railway construction require both higher tensile strength and yield strength, as well as a higher elongation. If cold rolling is performed directly on the original wire rod, even if heat treatment is carried out in the later stage of ribbed steel bar forming, it is difficult to improve the tensile strength and elongation. How to further improve the elongation on the basis of existing product indicators is a new challenge faced by cold-rolled steel bar manufacturers.

[0049] In response to the high requirements for tensile strength and elongation of steel bars in the construction of high-speed railway viaducts and ballastless tracks, this invention takes into account the forming process of wire rod and the high tensile strength and low elongation characteristics of wire rod, and provides a production system and method for high-ductility ribbed steel bars. The purpose is to perform cold rolling processing on the steel bars at a certain temperature, reduce the degree of damage to the lattice structure of the wire rod during cold rolling, reduce the hardness of the steel bars during cold rolling, thereby reducing the cold rolling power required and saving energy. After secondary heat treatment, the elongation is further improved.

[0050] The technical solution of this invention is: a production system for high-ductility ribbed steel bars 20b. Figure 1This is a schematic diagram of the production system of the present invention. The production system includes a wire feeding machine 10, a descaling machine 11, a rolling mill, a looper, a rolling rib pressing machine, a heat treatment device, a take-up machine, and a production line controller, as described in the prior art. The production system includes at least two types of rolling equipment and two types of heat treatment devices. The two types of rolling equipment include a rolling mill and a rolling rib pressing machine. The two types of heat treatment devices include a primary heat treatment device 14 and a secondary heat treatment device. The primary heat treatment device 14 and the secondary heat treatment device are respectively located before and after the rolling rib pressing machine. Temperature detectors 15 are respectively installed after the primary heat treatment device 14 and the secondary heat treatment device. The primary heat treatment device 14, the secondary heat treatment temperature detectors, and the temperature detectors are connected to the production line controller.

[0051] A method for producing high-ductility ribbed steel bar 20b includes a wire feeding process, a descaling process, a rolling and diameter reduction process, a looper process, a rolling and rib-pressing process, a heat treatment process, and a wire take-up process. The ribbed steel bar 20b undergoes at least two heat treatment processes during rolling. The first heat treatment process is performed before the rolling and rib-pressing process, and the second heat treatment process is performed after the rolling and rib-pressing process. The first heat treatment process is a preheating process with a preheating temperature below 200℃, and the second heat treatment process has a heat treatment temperature below 180-700℃. After rolling, the diameter of the wire rod 20a is reduced by 18-28%. The ribbed steel bar 20b produced by this method with a single heat treatment process has a yield strength of 550-580MPa and a tensile strength of 610-660MPa, with an elongation of 13-18%.

[0052] Table 1. Examples comparing product characteristics using the production line of the present invention with those of existing production lines.

[0053]

[0054] The rolling reducing mill includes a left-right rolling reducing mill 13 and a right-up rolling reducing mill 12. The rolling rib pressing mill includes a left-right rolling rib pressing mill 17 and a right-up rolling rib pressing mill 18. Both the rolling reducing mill and the rolling rib pressing mill are equipped with paired rollers. The paired rollers of the last rolling rib pressing mill are paired die rollers with rib pressing and / or markings.

[0055] An orientation device is installed before the rolling reducing mill, the rolling rib pressing mill, and the heat treatment device. The orientation device is one or more pairs of positioning rollers in the vertical and / or horizontal directions or horizontal positioning sleeves. 11a is positioning sleeve one, located in front of the descaling machine 11. Positioning sleeve one 12a is a horizontally oriented trumpet-shaped sleeve structure. This is because the wire rod will sway during the unwinding process, and this structure can stabilize the swaying phenomenon. 12a is positioning roller one, located in the vertical direction... 13a is the front of the vertical rolling mill 12; 13a is the second positioning sleeve, located in front of the horizontal rolling mill 13; 14a is the first stabilizing roller in the direction of the reinforcing bar, located in front of each high-frequency heating coil in the primary heat treatment device 14; 17a is the third positioning sleeve, located in front of the horizontal rolling rib pressing mill 17; 18a is the second positioning roller, located in front of the vertical rolling rib pressing mill 18; 19a is the second stabilizing roller in the direction of the reinforcing bar, located in front of each medium-frequency heating coil in the secondary heat treatment device.

[0056] A looper for adjusting wire slack and a wire guide device 16 are also provided between the rolling mill and the rolling rib-pressing mill.

[0057] The primary heat treatment device 14 and the secondary heat treatment device are each composed of multiple high-frequency and medium-frequency coils. Figure 3 This is a schematic diagram of a single heat treatment device. The primary heating device and the secondary heating device are each composed of multiple individual heat treatment devices. The heating coils 27 of the individual heat treatment devices are arranged in a line and controlled separately as needed. The heating temperature is set in the high-frequency or medium-frequency generator 26 and adjusted accordingly using the controller. 27a is the heat insulation cover of the heating device. Multiple steel moving and stabilizing rollers 28 are respectively set in front of the multiple high-frequency and medium-frequency heating coils 27 arranged in a row. The roller shafts of the multiple steel moving and stabilizing rollers 28 are hollow shafts, and cooling water is installed inside the hollow shafts. 29 is the hollow shaft cooling water pipe. The cooling water circulates in the multiple hollow shaft cooling water pipes to prevent the roller shafts from expanding due to heat and hindering the rolling of the rollers.

[0058] Figure 4 A schematic diagram of the structure within the V-shaped groove on the outer periphery of one of the last pair of mold rollers in the pressure ribs and / or markings. Figure 5 A schematic diagram of the structure within the V-shaped groove on the outer periphery of another roller in the last set of paired mold rollers for pressure ribs and / or markings. Figure 6A longitudinal cross-sectional view of the last set of paired mold rollers with ribs and / or markings. The last set of rollers in the paired mold rollers with ribs and / or markings has a V-shaped groove in the middle of its outer circumference. The V-shaped openings of the pair of rollers are positioned opposite each other. The two sides of the V-shaped groove are concave arc-shaped, specifically V-shaped groove side 1 30a and V-shaped groove side 2 30b. The apex angle of the intersection of the chords of the two concave arcs in the V-shaped groove is 90°. Two alternating willow-leaf-shaped inclined rib grooves are provided within the V-shaped groove, specifically willow-leaf-shaped inclined rib groove 1 31a and willow-leaf-shaped inclined rib groove 2 31b, with the apex angle of their intersection being concave. The angles between the midline 32 of the two willow-leaf-shaped inclined ribs along their rib length direction and the outer circumference of the mold roller are 100-130° and 130-145°, respectively. The midline 32 of the two willow-leaf-shaped inclined ribs along their rib length direction has the greatest depth. Recesses are provided on the circumference formed by the intersection of the chords in the V-shaped groove and on the mold closing line of the upper and lower rollers. 34 is the mold closing recess, and the depth of the recess is less than 2mm. The distance between the midlines of the two willow-leaf-shaped inclined ribs along their rib length direction is less than 10mm. The inclination angles of the two willow-leaf-shaped inclined ribs in the upper and lower rollers differ by 180°.

[0059] The steel bar produced by this roller mold is a tetrahedron with four arc-shaped protrusions. The diagonal protrusions are of the same height as the willow leaf-shaped inclined ribs. The diagonal protrusions intersect with the two inclined willow leaf-shaped ribs. The other two diagonal protrusions are formed by mold-closing recesses and are protruding separately, without intersecting with the willow leaf-shaped inclined ribs.

[0060] The temperature detector 15 is an infrared temperature detector 15.

[0061] The steering device 16 is a 90-degree steering device for reduced-diameter steel bars. Figure 2 This is a schematic diagram of the structure of multiple arched holes in the steering device. The steering device 16 is composed of multiple arched holes 25a. From front to back, the chords of the multiple arched holes 25a gradually change from the horizontal direction to the vertical direction. The arched holes 25a are set on the wear-resistant plate 24.

[0062] The diameter of the wire rod is less than 15mm, and the high-ductility ribbed steel bar 20b includes:

[0063] 1) Place the wire rod on the wire feeding machine 10 and lead it to the descaling machine 11;

[0064] 2) Use descaling machine 11 to remove oxide debris from the surface of the reinforcing bars;

[0065] 3) Use a rolling reduction mill to roll and reduce the diameter of steel wire rods. Rolling reduction includes rolling reduction processes in the left and right directions and rolling reduction processes in the up and down directions.

[0066] 4) The rolled and reduced diameter steel wire is preheated using a primary heat treatment device 14;

[0067] 5) The temperature of the wire after the heat treatment process is detected and the information is fed back to the production line controller, which adjusts the temperature of multiple high-frequency generators.

[0068] 6) The steel wire is rolled using a rib-pressing mill, and rib-pressing and / or scoring are performed simultaneously. The rib-pressing and / or scoring includes rolling processes in the left and right directions and rolling processes in the up and down directions. The rib-pressing and / or scoring processes are located at the end of the rib-pressing mill.

[0069] 7) The secondary heat treatment device performs secondary heat treatment on the rolled and reduced diameter steel wire rod. The secondary heat treatment process includes heating, forced cooling and natural cooling sub-processes.

[0070] 8) The temperature of the ribbed steel bars 20b at the ends of multiple medium-frequency coils in the secondary heat treatment process is detected by temperature detector 15, and the production line controller adjusts the temperature of multiple medium-frequency heaters according to the detected temperature.

[0071] 9) The ribbed steel bar 20b is wound by the take-up machine to form a coil of ribbed steel bar 20b. If necessary, multiple take-up machines of ribbed steel bar 20b in the prior art are equipped with a flying shear machine 21 and a conveyor track switcher 22. The winding is switched between multiple take-up machines under the control of the production line controller.

[0072] In this embodiment, a take-up machine 23a and a take-up machine 23b are provided. The ribbed steel bar 20b is wound alternately on the take-up machine 23a and the take-up machine 23b by the flying shear machine 21 and the conveyor track switcher 22.

[0073] Figure 6 This is a schematic diagram of a single heat treatment device. The heat treatment device consists of multiple such devices. The primary heat treatment process involves high-frequency coil heating, and the secondary heat treatment process involves medium-frequency coil heating. The temperatures of the multiple high-frequency and medium-frequency coils gradually increase. The temperature rise in the primary heat treatment process is 110-200°C / m, and the temperature rise in the secondary heat treatment process is 90-150°C / m.

[0074] The forced cooling in the secondary heat treatment process has a temperature drop of 10-30°C / s and a forced cooling time of 2 seconds.

[0075] By preheating after the rolling reduction process, although the overall properties of the reinforcing steel are not significantly affected, the yield strength under cold rolling conditions can be maintained. This can alleviate the quenching strength of the wire rod to some extent, reduce lattice defects caused by plastic deformation of the steel during the cold rolling process, and reduce lattice defects in the subsequent rib-pressing process. Preheating also facilitates the forming process during rib-pressing, reducing the power required, simplifying the forming process, and saving energy. Furthermore, during the secondary heat treatment, the temperature can be further increased based on the primary heat treatment. Preheating at a temperature below 200°C not only releases… The stress introduced during wire rod manufacturing, without affecting the essential properties of the wire rod and ribbed steel bar 20b, increases the minimum temperature during the secondary heat treatment, shortens the heating time of the secondary heat treatment, and accelerates the speed of the secondary heat treatment; by setting a steel bar wire guide device 16 between the rolling mill and the rolling rib-pressing mill, the wire rod rolled into an elliptical structure after diameter reduction can be rotated 90 degrees and then rolled towards a circular structure; by utilizing this invention, steel bars can be cold rolled at a certain temperature, reducing the degree of damage to the lattice structure of the wire rod during cold rolling, reducing the hardness of the steel bar during cold rolling, thereby reducing the cold rolling power required during cold rolling, saving energy, and further improving the elongation rate after secondary heat treatment.

[0076] Another technical solution provided by the present invention is: a production system for ribbed steel bars, the production system including a wire feeding machine, a descaling machine, a rolling mill, a looper, a rolling rib pressing machine, a heat treatment device, a take-up machine, and a production line controller, as described in the prior art. The production system includes at least two types of rolling equipment. The difference between this system and the high-ductility ribbed steel bar production system described in the above embodiments is that the heat treatment device is not limited to the two types described above: a primary heat treatment device and a secondary heat treatment device. The similarity is that the rolling equipment can be the rolling equipment described in the above embodiments. The rolling reducing mill includes a left-right rolling reducing mill and a top-bottom rolling reducing mill. The rolling rib pressing mill includes a left-right rolling rib pressing mill and a top-bottom rolling rib pressing mill. Both the rolling reducing mill and the rolling rib pressing mill are equipped with paired rollers. The paired rollers of the last rolling rib pressing mill are paired die rollers with ribs and / or markings. The outer periphery of the last pair of paired die rollers with ribs and / or markings is provided with a V-shaped groove. The V-shaped openings of the pair of rollers are arranged opposite each other. The two sides of the V-shaped groove are concave arc-shaped. Two willow leaf-shaped inclined rib grooves are arranged alternately in the V-shaped groove. The apex of the intersection of the chords is concave. The circumference formed by the apex of the intersection of the chords in the V-shaped groove and the parting line of the upper and lower rollers are both provided with concave parts.

[0077] In specific implementation, the included angles between the midline of the two willow-leaf-shaped inclined rib grooves along their rib length direction and the outer circumference of the mold roller are 100-130° and 130-145°, respectively. The apex angle of the intersection of the chords of the two concave arcs in the V-shaped groove is 90°. The depth of the concave part is less than 2mm. The distance between the midline of the two willow-leaf-shaped inclined rib grooves along their rib length direction is less than 10mm. The inclination angles of the two willow-leaf-shaped inclined rib grooves in the upper and lower rollers differ by 180°.

[0078] A method for producing ribbed steel bars includes a wire feeding process, a descaling process, a rolling and diameter reduction process, a looper, a rolling and rib-pressing process, a heat treatment process, and a wire take-up process. The method differs from the high-ductility ribbed steel bar production method described in the above embodiments in that it is not limited to including at least two heat treatment processes. The rolling and rib-pressing process includes: rolling the steel bar wire using a rolling and rib-pressing mill, while simultaneously performing rolling and rib-pressing and / or scoring. The rolling and rib-pressing and / or scoring includes rolling processes in the left-right direction and rolling and rib-pressing and / or scoring processes in the up-down direction. The rolling and diameter reduction mill includes rolling and diameter reduction mills in the left-right direction and up-down direction. The rib-pressing machine includes a left-right rib-pressing machine and a top-bottom rib-pressing machine. Both the rolling reducing mill and the rolling rib-pressing machine are equipped with paired rollers. The paired rollers of the last rolling rib-pressing machine are paired die rollers with rib pressing and / or markings. The outer circumference of the last pair of die rollers with rib pressing and / or markings is provided with a V-shaped groove. The V-shaped openings of the pair of rollers are arranged opposite each other. The two sides of the V-shaped groove are concave arc-shaped. Two willow leaf-shaped inclined rib grooves are arranged alternately in the V-shaped groove. The apex of the intersection of the chords is concave. The circumference formed by the apex of the intersection of the chords in the V-shaped groove and the parting line of the upper and lower rollers are both provided with concave parts.

[0079] In specific implementation, the included angles between the midline of the two willow-leaf-shaped inclined rib grooves along their rib length direction and the outer circumference of the mold roller are 100-130° and 130-145°, respectively. The apex angle of the intersection of the chords of the two concave arcs in the V-shaped groove is 90°. The depth of the concave part is less than 2mm. The distance between the midline of the two willow-leaf-shaped inclined rib grooves along their rib length direction is less than 10mm. The inclination angles of the two willow-leaf-shaped inclined rib grooves in the upper and lower rollers differ by 180°.

[0080] A ribbed steel bar includes: a steel bar body, which is a tetrahedron, each face of the steel bar body being a convex arc shape. The four faces of the steel bar body include a first face, a second face, a third face, and a fourth face. The first face, the second face, the third face, and the fourth face sequentially surround the center line of the steel bar body and form the tetrahedron. The first face and the second face are provided with two alternately arranged willow leaf-shaped inclined ribs, and the third face and the fourth face are provided with two alternately arranged willow leaf-shaped inclined ribs. A convex diagonal portion is formed between each pair of adjacent faces. The diagonal portion between the first face and the second face intersects with the willow leaf-shaped inclined ribs of the first face and the second face, and the diagonal portion between the third face and the fourth face intersects with the willow leaf-shaped inclined ribs of the third face and the fourth face. That is, the ribbed steel bar includes: a steel bar body, which is a tetrahedron, each face of the steel bar body is a convex arc shape, with the diagonal parts protruding. The height of two of the diagonal parts can be consistent with the height of the willow leaf-shaped inclined ribs. The two diagonal parts intersect with two inclined willow leaf-shaped inclined ribs, and the other two diagonal parts are formed by the recess of the mold line and are individually protruding, without intersecting with the willow leaf-shaped inclined ribs.

[0081] In this embodiment of the invention, the ribbed steel bars can be prepared using the aforementioned ribbed steel bar production system, ribbed steel bar production method, high-ductility ribbed steel bar production system, and production method, but are not limited thereto. The ribbed steel bars prepared using the aforementioned ribbed steel bar production system and ribbed steel bar production method have different shape characteristics from the steel bars in the national ferrous metallurgical industry standard YB / T4657-2018 "Reinforced Concrete Four-Sided Ribbed Steel Bars". Compared to the steel bars in the national ferrous metallurgical industry standard YB / T4657-2018 "Reinforced Concrete Four-Sided Ribbed Steel Bars", the ribbed steel bars of this application are more cylindrical in shape, with the transverse ribs forming willow leaf shapes, and two willow leaf-shaped inclined ribs arranged alternately. Due to the different shape and structural characteristics, the ribbed steel bars of this application have the following unique advantages: 1. They are easy to straighten. 2. When using ribbed steel bars to weld steel mesh, the cylindrical ribbed steel bars, regardless of their rotation angle, can be welded effectively, reducing construction difficulty, minimizing construction problems, and improving the reliability of reinforced concrete products. 3. They are easily bendable; during the welding of ribbed steel bars into steel cylinders, steel bars at any angle can be easily bent into a rectangular ring, facilitating construction.

[0082] In specific implementation, the diagonal portion between the second and third surfaces is separated from the willow-leaf-shaped inclined ribs of the first and second surfaces, and the willow-leaf-shaped inclined ribs of the third and fourth surfaces, respectively. The height of the willow-leaf-shaped inclined ribs of the first and second surfaces, and the willow-leaf-shaped inclined ribs of the third and fourth surfaces is less than 2 mm. The height of the willow-leaf-shaped inclined ribs of the first and second surfaces, and the willow-leaf-shaped inclined ribs of the third and fourth surfaces, is the same as the height of the diagonal portion. The apex angle of the intersection of the chords of the two arcs of the willow-leaf-shaped inclined ribs is 90°. The angle between the center line of the longitudinal direction of the two willow-leaf-shaped inclined rib grooves and the axis of the main steel bar body is different, ranging from 40° to 70°.

[0083] The inclination angles of the willow-leaf-shaped inclined ribs on the first and second surfaces and the willow-leaf-shaped inclined ribs on the third and fourth surfaces differ by 180°.

[0084] The spacing between the midlines of the alternating willow-leaf-shaped inclined rib grooves along their length direction is less than 10 mm.

[0085] See Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 The inclined ribs of the ribbed steel bars are in the shape of willow leaves, and each inclined rib should not intersect with other inclined ribs.

[0086] The inclined ribs are evenly distributed around the cross-section of the ribbed steel bar. The inclination angles of the willow leaf-shaped inclined ribs on both sides of the ribbed steel bar should be opposite, that is, the directions of the willow leaf-shaped inclined ribs on opposite sides of the main body of the steel bar are opposite.

[0087] The angles β1 and β2 between the center lines of two adjacent inclined ribs and the longitudinal axis of the ribbed steel bar are different, ranging from 40° to 70°.

[0088] The distance between two adjacent inclined ribs in a ribbed steel bar is l1, and the distance between two inclined ribs separated by one inclined rib is l1+l2, where l1 and l2 are equal, i.e., l1=l2.

[0089] The angle α between any inclined rib of the ribbed steel bar and the surface of the ribbed steel bar shall not be less than 40°, and the inclined rib shall intersect the surface of the ribbed steel bar in an arc shape.

[0090] The total inter-rib spacing of ribbed steel bars should not exceed 25% of the nominal perimeter.

[0091] (∑f i ≤0.25πd).

[0092] The relative inclined rib area fr is determined according to formula (1):

[0093] Where:

[0094] K = 4;

[0095] F R The longitudinal cross-sectional area of ​​a rib, expressed in square millimeters (mm). 2 );

[0096] β: The angle between the inclined rib and the axis of the reinforcing bar, in degrees (°);

[0097] d: Nominal diameter of the steel bar, in millimeters (mm);

[0098] l: Spacing between inclined ribs, in millimeters (mm);

[0099] l = l1 = l2;

[0100] sinβ=(sinβ1+sinβ2) / 2.

[0101] The inner radius R is formed by the protruding arc-shaped edges on each side of the main body of the steel bar.

[0102] In some embodiments, the dimensions, weight, and permissible deviations of the ribbed steel bars are as follows:

[0103]

[0104] In the embodiments of the present invention, due to the characteristics of the arc-shaped four-sided ribs, the phenomenon of steel tipping that is prone to occur when forming the rolling groove during the production of two-sided ribbed steel bars is less common. After adopting the four-sided rib shape, more than 3,000 tons have been produced so far without any steel tipping phenomenon. This is a good factor for the stable operation of the production process, which is a prominent feature.

[0105] For detailed performance statistics of the ribbed steel bars after straightening in this embodiment, please refer to [link / reference needed]. Figure 12 .

[0106] For detailed statistics on the performance of existing double-ribbed steel bars after straightening, please refer to [link / reference needed]. Figure 13 .

[0107] By comparing the strength of the ribbed steel bars of this embodiment before and after straightening with that of the two-sided ribbed steel bars in the prior art, the tensile strength of both the ribbed steel bars and the two-sided ribbed steel bars in this embodiment did not change much after straightening. However, the yield strength of the ribbed steel bars in this embodiment decreased less than that of the two-sided ribbed steel bars. The average yield strength of the ribbed steel bars in this embodiment after straightening was slightly higher than that of the two-sided ribbed steel bars by about 15 MPa. The yield strength decreased to 20-40 MPa after straightening. Among them, the ribbed steel bars in this embodiment were generally 20-30 MPa, while the two-sided ribbed steel bars were generally 25-40 MPa. Some of them exceeded this range and were even greater than 40 MPa.

[0108] This embodiment compares the welding of ribbed steel bars with the welding of steel bars with ribs on both sides:

[0109] Comparison of welding efficiency experiments:

[0110] #2 Welding Mesh Machine:

[0111]

[0112] #1 Welding Mesh Machine:

[0113]

[0114]

[0115] According to experimental statistics, on welding machine No. 2, the production efficiency of ribbed steel bars in this embodiment is increased by approximately 6.9% compared to two-sided ribbed bars. On welding machine No. 1, the increase is approximately 7.5%.

Claims

1. A method for producing ribbed steel bars, comprising a wire laying process, a descaling process, a rolling and diameter reduction process, a looper process, a rolling and rib pressing process, a heat treatment process, and a wire winding process, characterized in that, In the production method of ribbed steel bars, the rolling and rib-pressing process includes: A rib-pressing mill is used to roll steel wire rods, simultaneously performing rib-pressing and / or scoring. The rib-pressing and / or scoring includes rolling operations in the left-right direction and rolling operations in the up-down direction. The rolling reduction mill for the diameter reduction operation includes both left-right and up-down rolling reduction mills. The rib-pressing mill also includes both left-right and up-down rolling reduction mills. Both the diameter reduction mill and the rib-pressing mill are equipped with paired rollers. The paired rollers of the last rib-pressing mill are paired die rollers with rib-pressing and / or scoring features. A V-shaped groove is provided in the middle of the outer circumference of the last pair of die rollers with rib-pressing and / or scoring features. The V-shaped openings are arranged opposite each other. The two sides of the V-shaped groove are concave arcs. Two willow-leaf-shaped inclined ribs are arranged alternately in the V-shaped groove. The apex of the intersection of the chords is concave. The circumference formed by the apex of the intersection of the chords in the V-shaped groove and the mold parting line of the upper and lower rollers are both provided with concave parts. The angle between the midline of the rib length direction of the two willow-leaf-shaped inclined ribs and the outer circumference of the mold roller is 100-130° and 130-145°, respectively. The apex of the intersection of the chords of the two concave arcs in the V-shaped groove is 90°. The depth of the concave part is less than 2mm. The distance between the midline of the rib length direction of the two willow-leaf-shaped inclined ribs is less than 10mm. The inclination angle of the two willow-leaf-shaped inclined ribs in the upper and lower rollers differs by 180°. The heat treatment process includes a primary heat treatment device and a secondary heat treatment device. The primary heat treatment device is located between the rolling diameter reduction process and the rolling rib pressing process, and the secondary heat treatment device is located after the rolling rib pressing process. A steering device is provided between the rolling reducing mill and the rolling rib pressing mill. The steering device is located after the primary heat treatment device. The steering device is composed of multiple arched holes, and the chords of the multiple arched holes from front to back gradually change from the horizontal direction to the vertical direction.

2. A production system for ribbed steel bars, comprising: The rolling equipment includes a reducing mill and a rib-pressing mill. The reducing mill includes both left-right and up-down rib-pressing mills. Both the reducing mill and the rib-pressing mill are equipped with paired rollers. The last pair of rollers in the rib-pressing mill is a pair of die rollers with ribs and / or markings. A V-shaped groove is formed in the middle of the outer circumference of the last pair of die rollers with ribs and / or markings. The V-shaped openings of the pair of rollers are positioned opposite each other. The two sides of the V-shaped groove are concave arc shapes. The mold has two alternating willow-leaf-shaped inclined ribs, with the chords intersecting at a concave apex. The circumference formed by the chords intersecting at the apex of the V-shaped groove and the mold parting line of the upper and lower rollers both have recesses. The angles between the midline of the two willow-leaf-shaped inclined ribs along their rib length direction and the outer circumference of the mold roller are 100-130° and 130-145° respectively. The chords intersecting at the apex of the two concave arcs in the V-shaped groove are 90°. The depth of the recesses is less than 2mm. The distance between the midlines of the two willow-leaf-shaped inclined ribs along their rib length direction is less than 10mm. The inclination angles of the two willow-leaf-shaped inclined ribs in the upper and lower rollers differ by 180°. A primary heat treatment device and a secondary heat treatment device, wherein the primary heat treatment device is located between the rolling mill and the rolling rib-pressing mill, and the secondary heat treatment device is located after the rolling rib-pressing mill; A steering device is provided between the rolling reducing mill and the rolling rib pressing mill. The steering device is located after the primary heat treatment device. The steering device is composed of multiple arched holes, and the chords of the multiple arched holes from front to back gradually change from the horizontal direction to the vertical direction.

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