Special-shaped steel fiber, production device and preparation method thereof

Abstract

The application discloses special-shaped steel fibers, a preparation production device and a preparation method, and is applied to the field of special-shaped steel fiber preparation, and has the technical scheme as follows: the special-shaped steel fiber preparation device comprises a circular arc type steel fiber forming device, a spiral type steel fiber forming device and a double spiral type steel fiber forming device, the circular arc type steel fiber forming device and the spiral type steel fiber forming device comprise an endless hook forming die and a hook end forming die, the circular arc type steel fiber forming device, the spiral type steel fiber forming device and the double spiral type steel fiber forming device are respectively provided with a straightening assembly, a wire feeding assembly, a forming assembly and a cutting assembly along the conveying direction of the steel fibers, and the special-shaped steel fiber preparation device has the technical effects that the dimension of the steel fiber is increased, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of shaped steel fiber preparation, and particularly to shaped steel fibers, preparation equipment and preparation methods. Background Technology

[0002] Steel fibers are a widely used concrete reinforcing material in countries around the world. Adding them to concrete can effectively limit the formation and development of micro and macro cracks inside the concrete, significantly improve the tensile, bending, impact and fatigue resistance of concrete, and enhance its ductility. It has important engineering value and application scenarios in special projects such as national defense and nuclear power, as well as structural reinforcement and new structural systems.

[0003] Currently, various shapes and types of steel fibers are used in concrete, including straight, hooked, corrugated, twisted, and spiral types. However, the reinforcing and toughening effects of some fibers on concrete still need improvement (e.g., straight and hooked fibers), while others lack dedicated, high-efficiency production equipment (e.g., spiral fibers). These factors hinder the further development of steel fibers and steel fiber reinforced concrete. The forming process for spiral fibers involves repeatedly twisting the steel wire into a spiral shape along a machine spindle and then cutting it. For example, Chinese utility model patent CN211965697U discloses an eight-claw machine for automatic steel wire bending. This utility model uses an extrusion head on a telescopic rod to compress the steel wire in the feeding hole, causing the wire to spiral. This device is costly, has low production efficiency for spiral steel wire, and is not designed specifically for concrete. Many problems remain to be solved before directly using this type of fiber in concrete.

[0004] For example, curved steel fibers are arc-shaped steel fibers with "two-dimensional" dimensional characteristics. By pre-laying these curved steel fibers throughout the mold, and through the "interlocking" effect between the fibers and the "double bridging" effect with cracks in the matrix, a closed space is formed within the matrix by two fibers, inhibiting further crack propagation and improving crack control efficiency. This significantly enhances the basic mechanical properties of slurry-infiltrated fiber concrete (SIFCON). However, as disclosed in Chinese invention publication CN113636771B, a mold and manufacturing method for curved steel fibers are described. This invention involves straightening the steel wires before they enter a cutting mold, stamping them, and then unloading them. However, this type of curved steel fiber is a typical planar fiber, providing only in-plane bridging stress. As a planar fiber, the lack of additional winding effects from other dimensions significantly limits the improvement of crack bridging performance by curved steel fibers. Furthermore, this manufacturing method cannot achieve continuous fiber production, which limits the fiber production efficiency. Therefore, it is necessary to provide a new type of irregular steel fiber with out-of-plane dimensions and its preparation method, which can improve the bridging performance of steel fibers in concrete while achieving efficient production. Summary of the Invention

[0005] The primary objective of this invention is to provide shaped steel fibers. Without affecting fiber production efficiency, out-of-plane end hooks are added to arc-shaped fibers. These end hooks provide out-of-plane dimensions, and the out-of-plane winding effect they provide enhances the fiber's bridging effect. Similarly, adding end hooks to helical fibers without affecting production efficiency increases the anchoring performance of the helical fiber ends. Furthermore, a double-helical fiber can be formed by combining a helical structure with another helical structure, which increases the steel fiber's dimensions and improves its anchoring effect.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: shaped steel fiber, wherein the geometric structure of the centerline of the shaped steel fiber in three-dimensional space is as follows:

[0007]

[0008] In this formula:

[0009]

[0010] Where a and b are constants, c is the radius of the helix, t is the angle, and the range of t is [0, 2nπ), n>0, N(t) is the normal vector of the rotation axis, N x (t), N y (t) and N z (t) are the components of the normal vector in the X, Y and Z directions, respectively.

[0011] The present invention is further configured such that: when a≠0, b=0, c=0, the steel fiber shape is an arc; when a≠0, b≠0, c=0, the steel fiber shape is a single helix; and when a≠0, b≠0, c≠0, the steel fiber shape is a double helix.

[0012] The second objective of this invention is to provide an apparatus for preparing shaped steel fibers, which has the advantages of improving production efficiency and reducing production costs.

[0013] The above-mentioned technical objective of this invention is achieved through the following technical solution: a production apparatus for preparing irregularly shaped steel fibers, used to produce irregularly shaped steel fibers as described in any of the above technical solutions; comprising an arc-shaped steel fiber forming device, a spiral steel fiber forming device, and a double-spiral steel fiber forming device, wherein the arc-shaped steel fiber and spiral steel fiber forming devices include a forming mold without end hooks and a forming mold with end hooks. The arc-shaped steel fiber forming device, the spiral steel fiber forming device, and the double-spiral steel fiber forming device are each provided with a straightening component, a feeding component, a forming component, and a cutting component along the steel fiber conveying direction.

[0014] The invention is further configured such that: the arc-shaped and spiral-shaped steel fiber forming molds and the fiber forming device without end hooks are provided with a fiber rotary forming component between the wire feeding component and the cutting component. The fiber rotary forming component includes an inner tube and an outer tube arranged coaxially. The inner tube has a spiral track for advancing the steel fiber, and the outer tube is used to constrain the rebound of the steel fiber. The entrance and exit of the arc-shaped steel fiber spiral track are set at different horizontal heights. This increases the dimensionality of the arc-shaped steel fiber, thereby increasing its anchoring effect, and also prevents the rotary-formed steel fiber from interfering with the entry of the arc-shaped fiber rotary forming component.

[0015] The present invention is further configured such that: the outer tube of the device includes a rotatable outer tube and a non-rotatable outer tube; the rotatable outer tube includes an outer wall and an inner wall that are coaxially arranged and can rotate relative to each other; for the rotatable outer tube, during the forming process of the steel fiber entering the arc-shaped fiber rotary forming assembly, the steel fiber rebounds based on its own elasticity, thereby generating friction with the inner wall of the outer tube of the device; the inner wall of the outer tube of the device rotates relative to the outer wall; and the friction between the steel fiber and the inner wall of the outer tube of the device drives the inner wall to rotate, thereby reducing frictional heat and steel fiber loss.

[0016] The present invention is further configured such that: the arc-shaped and spiral-shaped fiber forming mold with end hooks differs from the end hook-less forming mold in that an end hook pressing component is added between the wire feeding component and the arc-shaped fiber rotary forming component. The end hook pressing component includes a set of interlocking gears. The steel fiber passes through the gap between the interlocking gears to form a concave indentation on the steel fiber. The bottom of the concave indentation is cut off by the cutting component to form an end hook.

[0017] The present invention is further configured such that: the double helical steel fiber forming device is provided with a forming component between the wire feeding component and the cutting component, the forming component including a first helical shaft and a second helical shaft, the second helical shaft being formed along the first helical shaft and having a steel fiber forming channel wound on the second helical shaft.

[0018] The present invention is further configured such that: the outer and inner sides of the molding component are provided with a plurality of passive rollers for reducing resistance during the molding process and active rollers for driving the steel fibers to advance in the steel fiber molding channel.

[0019] The present invention is further configured such that: the number of spiral turns N of the second spiral shaft is (0-2], the spiral diameter C is not less than 2mm, and the pitch P is not less than 2mm.

[0020] The present invention is further configured such that: the number of spiral turns N of the steel fiber forming channel is not less than 1 turn, the spiral diameter C is not less than 2 mm, and the pitch P is not less than 2 mm.

[0021] The present invention is further configured such that the steel fiber forming channel is manufactured based on lathe machining, thermal processing and 3D printing technology.

[0022] The present invention is further configured such that: the diameter of the steel fiber is 0.10mm to 2.00mm, the length of the steel fiber is 10.00mm to 200.00mm, the aspect ratio of the length to the diameter of the steel fiber is 30 to 350, and the tensile strength is not less than 600MPa.

[0023] The present invention is further configured such that the fiber pitch P of the arc-shaped steel fiber, the spiral steel fiber, and the double spiral steel fiber is in the range of [0 mm, 100 mm], the spiral diameter C is in the range of [5 mm, 100 mm], and the number of spiral turns N is in the range of [0, 20].

[0024] The third objective of this invention is to provide a method for preparing irregularly shaped steel fibers, which has the advantages of increasing the dimensionality of steel fibers, improving production efficiency, and reducing production costs.

[0025] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a method for preparing irregularly shaped steel fibers, using a production apparatus for preparing irregularly shaped steel fibers as described in any of the above technical solutions; including a method for forming arc-shaped steel fibers, a method for forming spiral steel fibers, and a method for forming double spiral steel fibers, wherein the methods for forming arc-shaped steel fibers and spiral steel fibers include forming methods without end hooks and forming methods with end hooks.

[0026] The present invention is further configured such that the method for forming the endless hook includes:

[0027] Step 1: The steel fibers are straightened by passing them through the straightening assembly;

[0028] Step 2: The wire feeding assembly feeds the straightened steel fibers into the spiral track opened on the inner tube of the fiber rotary forming assembly for rotation, and the steel fibers are formed during the rotation process.

[0029] Step 3: After the steel fiber is pushed out in the fiber rotation forming assembly, the cutting assembly cuts the steel fiber to complete the preparation of arc-shaped steel fiber and spiral steel fiber. During this process, the wire feeding assembly pushes out the steel fiber at a set rate, and at the same time, the cutting assembly cuts the steel fiber at the corresponding rate to ensure that the prepared steel fiber is consistent with the expected steel fiber size and can be continuously produced.

[0030] The present invention is further configured such that the method for forming the end hook includes:

[0031] Step 1: The steel fibers are straightened by passing them through the straightening assembly;

[0032] Step 2: The wire feeding assembly feeds the straightened steel fiber into the end hook pressing assembly. The end hook pressing assembly drives the steel fiber to be pushed into the fiber rotary forming assembly. In the end hook pressing assembly, the gap between the two meshing gears forms a concave indentation on the steel fiber.

[0033] Step 3: After being pressed by the end hook, the steel fibers are fed into the spiral track opened on the inner tube of the fiber rotary forming assembly and rotated. During the rotation process, the steel fibers are formed.

[0034] Step 4: After the steel fiber is pushed out of the fiber rotation forming assembly, the cutting assembly cuts the steel fiber to complete the preparation of arc-shaped steel fiber and spiral steel fiber. During this process, the wire feeding assembly pushes out the steel fiber at a set rate, and at the same time, the cutting assembly cuts the steel fiber at the corresponding rate to ensure that the prepared steel fiber is consistent with the expected steel fiber size and can be produced continuously.

[0035] The present invention is further configured such that the double-helix steel fiber forming method includes:

[0036] Step 1: The steel fibers are straightened by passing them through the straightening assembly;

[0037] Step 2: The wire feeding assembly feeds the straightened steel fibers into the steel fiber forming channel in the forming assembly to achieve double helix forming of the steel fibers;

[0038] Step 3: After the steel fiber is pushed out of the forming component, the cutting component cuts the steel fiber to complete the preparation of the double helix steel fiber. During this process, the wire feeding component pushes out the steel fiber at a set rate, and at the same time, the cutting component cuts the steel fiber at the corresponding rate to ensure that the prepared steel fiber is consistent with the expected steel fiber size and can be produced continuously.

[0039] The present invention is further configured such that the molding component has multiple molding specifications to achieve rapid molding of double-helix steel fibers of different shapes and sizes.

[0040] In summary, the present invention has the following beneficial effects:

[0041] 1. A novel shaped steel fiber is proposed, which can achieve different fiber shapes from "quasi-one-dimensional" to "quasi-five-dimensional" by changing the fiber's dimensions, including: arc-shaped, spiral, and double-spiral steel fibers. Furthermore, without affecting fiber production efficiency, end hooks are introduced into the arc-shaped and spiral steel fibers to increase their anchorage strength. Applying this steel fiber to concrete can restrict the propagation of internal micro-cracks and macro-cracks in multiple dimensions, improving the ductility and impact resistance of concrete.

[0042] 2. Several fast and convenient methods for forming irregular steel fibers are provided. One method is to use a simple and specific round tube mold to make the steel wire entering the pipe go through a certain length of spiral rotation and cut to form the fiber. The other method is to use a specific fiber forming mold to make the steel wire enter the forming mold through the feeding wire, push it to form the fiber, and finally cut the fiber. The forming part of the mold can be easily replaced with different molds to achieve efficient production of different sizes of irregular steel fibers.

[0043] 3. By introducing gear technology into the manufacturing process of arc-shaped and spiral steel fibers, the production efficiency of arc-shaped steel fibers is accelerated by pressing the end hooks with a pair of interlocking gears in the end hook pressing assembly and then entering the mold of the arc-shaped channel. Furthermore, by changing the interlocking gears of the end hook pressing assembly and the spiral track of the arc fiber rotary forming assembly, and by combining the springback relationship of different steel fibers, the processing cost of producing different types of arc-shaped steel fibers can be reduced, thereby improving processing efficiency and quality. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the anisotropic steel fiber structure in Example 1;

[0045] Figure 2 This is a schematic diagram of the dimensions of the irregular steel fiber in Example 1;

[0046] Figure 3 This is a schematic diagram of the process structure of the endless hook forming mold and the spiral steel fiber forming device in Example 3;

[0047] Figure 4 This is a schematic diagram of the process structure of the forming mold with end hooks in Example 4;

[0048] Figure 5 This is a schematic diagram of the inner tube of the device in the arc-shaped and spiral fiber rotary forming assembly of Example 3;

[0049] Figure 6 This is a schematic diagram of the non-rotatable outer tube in the arc-shaped and spiral fiber rotation molding assembly of Example 3;

[0050] Figure 7 This is a schematic diagram of the rotatable outer tube in the arc-shaped and spiral fiber rotary molding assembly of Example 3;

[0051] Figure 8 This is a schematic diagram of the end hook pressing assembly in Example 4;

[0052] Figure 9 This is a schematic diagram of the molding component of Example 5.

[0053] Reference numerals: 1. Straightening assembly; 11. Guide seat; 12. Straightening roller; 2. Wire feeding assembly; 21. Wire feeding roller; 3. Cutting assembly; 31. Rotary cutter head; 32. Steel fiber cutting blade; 4. Arc-shaped and spiral-shaped fiber rotary forming assembly; 41. Inner tube of the device; 42. Outer tube of the device; 43. Spiral track; 44. Outer wall; 45. Inner wall; 5. End hook pressing assembly; 51. Engaging gear; 6. Forming assembly; 61. First spiral shaft; 62. Second spiral shaft; 63. Steel fiber forming channel; 64. Passive roller; 65. Active roller. Detailed Implementation

[0054] The present invention will be further described in detail below with reference to the accompanying drawings.

[0055] Example 1:

[0056] refer to Figure 1 The geometric structure of the centerline of the irregularly shaped steel fiber in three-dimensional space is as follows:

[0057]

[0058] In this formula:

[0059]

[0060] Where a and b are constants, c is the radius of the helix, t is the angle and the range of t is [0, 2nπ), n>0, N(t) is the normal vector of the rotation axis of the shaped steel fiber center, N x (t), N y (t) and N z (t) are the components of the normal vector in the X, Y and Z directions, respectively.

[0061] When a≠0, b=0, c=0, the steel fiber shape is arc-shaped; when a≠0, b≠0, c=0, the steel fiber shape is single helix-shaped; when a≠0, b≠0, c≠0, the steel fiber shape is double helix-shaped.

[0062] Example 2:

[0063] A production apparatus for preparing irregularly shaped steel fibers, used to produce irregularly shaped steel fibers as shown in Example 1; including an arc-shaped steel fiber forming device, a spiral steel fiber forming device, and a double spiral steel fiber forming device. The arc-shaped and spiral steel fiber forming devices include a forming mold without end hooks and a forming mold with end hooks. The arc-shaped steel fiber forming device, the spiral steel fiber forming device, and the double spiral steel fiber forming device are respectively equipped with a straightening component 1, a wire feeding component 2, and a cutting component 3 along the conveying direction of the steel fibers.

[0064] Specifically, the straightening component 1 includes a fixed guide seat 11, on which several straightening rollers 12 are fixedly arranged. The straightening rollers 12 are arranged alternately to improve the straightening effect of the steel fibers. The wire feeding component 2 includes a set of wire feeding rollers 21 symmetrically fixed on the guide seat 11. The wire feeding rollers 21 rotate actively to drive the steel fibers for conveying. The cutting component 3 includes a rotating cutter disc 31. Steel fiber cutting blades 32 for cutting steel fibers are evenly arranged along the circumference on the rotating cutter disc 31. The steel fibers are pushed forward at a set rate, and at the same time, the rotating cutter disc 31 also cuts the steel fibers at a corresponding rate to cut out steel fibers of a specific length.

[0065] In this embodiment, the diameter of the steel fiber is 0.10mm to 2.00mm, the length of the steel fiber is 10.00mm to 200.00mm, the aspect ratio of the length to the diameter of the steel fiber is 30 to 350, and the tensile strength is not less than 600MPa. The fiber pitch P of the arc-shaped steel fiber, the spiral steel fiber, and the double spiral steel fiber ranges from [0mm to 100mm], the spiral diameter C ranges from [5mm to 100mm], and the number of spiral turns N ranges from [0 to 20].

[0066] Example 3:

[0067] Specifically, the difference between the endless hook forming mold and Embodiment 2 is that the endless hook forming mold has an arc-shaped and a spiral-shaped fiber rotary forming assembly 4 between the wire feeding assembly 2 and the cutting assembly 3. The arc-shaped and spiral-shaped fiber rotary forming assemblies 4 respectively include an inner tube 41 and an outer tube 42 arranged coaxially. A spiral track 43 is opened on the inner tube 41 to serve as a travel channel for pushing steel fibers. The outer tube 42 is used to constrain the rebound of steel fibers. The entrance and exit of the spiral track 43 are set at different horizontal heights to avoid interference between the rotary-shaped steel fibers and the steel fibers about to enter the arc-shaped and spiral-shaped fiber rotary forming assemblies 4. In this embodiment, the arc-shaped and spiral-shaped fiber rotary forming assemblies 4 can be replaced. The diameter of the inner tube 41 and the spiral track 43 opened on the inner tube 41 can be designed according to the forming requirements of steel fibers.

[0068] Specifically, the outer tube 42 of the device includes a rotatable outer tube and a non-rotatable outer tube. The rotatable outer tube includes an outer wall 44 and an inner wall 45 that are coaxially arranged and can rotate relative to each other. For the rotatable outer tube, during the molding process of the steel fiber entering the arc-shaped and spiral fiber rotary molding component 4, the steel fiber rebounds based on its own elasticity, thereby generating friction with the inner wall 45 of the outer tube 42. The inner wall 45 of the outer tube 42 rotates relative to the outer wall 44. Based on the friction between the steel fiber and the inner wall 45 of the outer tube 42, the inner wall 45 is driven to rotate, thereby reducing frictional heat and steel fiber loss.

[0069] Example 4:

[0070] Specifically, compared with the end-hookless forming mold of Embodiment 3, the end-hook forming mold has an additional end-hook pressing component 5 between the wire feeding component 2 and the arc-shaped and spiral-shaped fiber rotary forming component 4. The end-hook pressing component 5 includes a set of interlocking gears 51, and the steel fiber passes through the gap between the interlocking gears 51 to form a concave indentation on the steel fiber.

[0071] Example 5:

[0072] Specifically, the difference between the double helix steel fiber forming device and Embodiment 2 is that the double helix steel fiber forming device has a forming component 6 between the wire feeding component 2 and the cutting component 3. The forming component 6 includes a first helical shaft 61 and a second helical shaft 62. The second helical shaft 62 is formed along the first helical shaft 61 and a steel fiber forming channel 63 is wound on the second helical shaft 62.

[0073] Specifically, the outer and inner sides of the molding component 6 are provided with a number of passive rollers 64 for reducing resistance during the molding process and active rollers 65 for driving the steel fibers to advance within the steel fiber molding channel 63.

[0074] Specifically, the second helical shaft 62 has a helical number N of (0-2), a helical diameter C of not less than 2 mm, and a pitch P of not less than 2 mm. The steel fiber forming channel 63 has a helical number N of not less than 1 turn, a helical diameter C of not less than 2 mm, and a pitch P of not less than 2 mm. The steel fiber forming channel 63 is manufactured based on lathe machining, thermal processing, and 3D printing technology.

[0075] Example 6:

[0076] The method for preparing irregularly shaped steel fibers uses the production apparatus for preparing irregularly shaped steel fibers as shown in Examples 2-5 above; including a method for forming arc-shaped steel fibers, a method for forming spiral steel fibers, and a method for forming double spiral steel fibers. The methods for forming arc-shaped steel fibers and spiral steel fibers include a method for forming without end hooks and a method for forming with end hooks.

[0077] Among them: the method for forming a hook without end includes:

[0078] Step 1: The steel fiber is straightened by passing it through the straightening component 1;

[0079] Step 2: The wire feeding assembly 2 feeds the straightened steel fibers into the spiral track 43 on the inner tube 41 of the fiber rotary forming assembly 4 for rotation, and the steel fibers are formed during the rotation process.

[0080] Step 3: After the steel fiber is pushed out in the fiber rotation forming component 4, the cutting component 3 cuts the steel fiber to complete the preparation of arc-shaped steel fiber and spiral steel fiber. During this process, the wire feeding component 2 pushes out the steel fiber at a set rate, and at the same time, the cutting component 3 also cuts the steel fiber at the corresponding rate to ensure that the prepared steel fiber has a consistent size.

[0081] Example 7:

[0082] The difference between the forming method with end hooks and the forming method without end hooks in Example 6 is as follows:

[0083] An end hook pressing step is added between step 1 and step 2. The end hook pressing step is as follows:

[0084] The wire feeding assembly 2 feeds the straightened steel fiber into the end hook pressing assembly 5. The end hook pressing assembly 5 drives the steel fiber to be pushed into the fiber rotation forming assembly 4. In the end hook pressing assembly 5, the gap between the two meshing gears 51 is used to form a concave indentation on the steel fiber.

[0085] In this embodiment, taking a steel fiber body length of 25mm as an example: the body length is 25mm, the first bending angle is 135°, and the bending is 2.5mm. The second bending angle is in the opposite direction, bending at 135°, and bending is 2.5mm. Different body lengths and bending angles can also be obtained by changing the wire pressing die.

[0086] Example 8:

[0087] The difference between the double-helix steel fiber forming method and the endless hook forming method in Example 6 is as follows:

[0088] Step 2 of the double helix steel fiber forming method is as follows: the wire feeding assembly 2 feeds the straightened steel fiber into the steel fiber forming channel 63 in the forming assembly 6 to achieve double helix forming of the steel fiber;

[0089] In this embodiment, the molding component 6 is equipped with a variety of molding specifications to achieve rapid molding of double helical steel fibers of different shapes and sizes.

[0090] Example 9:

[0091] The difference between this embodiment and embodiment 2 is that:

[0092] When using steel wire with a nominal tensile strength of not less than 1100MPa and a diameter of 0.55mm, fibers are prepared according to the above steps, wherein the pitch P is 0mm, the spiral diameter C is 6mm, and the number of spiral turns N is 1 / 2, resulting in arc-shaped steel fibers with a fiber length of 14mm.

[0093] When steel wire with a nominal tensile strength of not less than 1100MPa and a diameter of 0.55mm is used, fibers are prepared according to the above steps, wherein the pitch P is 2mm, the spiral diameter C is 6mm, and the number of spiral turns N is 2, resulting in spiral steel fibers with a fiber length of 32mm.

[0094] When using steel wire with a nominal tensile strength of not less than 1300MPa and a diameter of 0.80mm, fibers are prepared according to the above steps, wherein the spiral diameter C of the spiral shaft 2 is 10mm, the pitch P is 20mm, the number of spiral turns N is 1, the spiral diameter C of the forming channel is 5mm, the pitch P is 5mm, and the number of spiral turns N is 4, a double-helix steel fiber with a fiber length of 40mm is obtained.

[0095] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make inventive modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A production apparatus for preparing shaped steel fibers, characterized in that, The device includes an arc-shaped steel fiber forming device, a spiral steel fiber forming device, and a double spiral steel fiber forming device. The arc-shaped steel fiber and spiral steel fiber forming devices include a forming mold without end hooks and a forming mold with end hooks. The arc-shaped steel fiber forming device, the spiral steel fiber forming device, and the double spiral steel fiber forming device are respectively provided with a straightening component (1), a wire feeding component (2), and a cutting component (3) along the conveying direction of the steel fiber. The endless hook forming mold is provided with an arc-shaped and a spiral-shaped fiber rotary forming assembly (4) between the wire feeding assembly (2) and the cutting assembly (3). The arc-shaped and spiral-shaped fiber rotary forming assembly (4) respectively includes an inner tube (41) and an outer tube (42) arranged coaxially. The inner tube (41) is provided with a spiral track (43) for serving as a travel channel for steel fiber propulsion. The outer tube (42) of the device includes a rotatable outer tube and a non-rotatable outer tube. The rotatable outer tube includes an outer wall (44) and an inner wall (45) that are coaxially arranged and can rotate relative to each other. For the rotatable outer tube, during the forming process of the steel fiber entering the arc-shaped and spiral fiber rotary forming assembly (4), the steel fiber rebounds based on its own elasticity, thereby generating friction with the inner wall (45) of the outer tube (42). The inner wall (45) of the outer tube (42) rotates relative to the outer wall (44). Based on the friction between the steel fiber and the inner wall (45) of the outer tube (42), the inner wall (45) rotates, thereby reducing frictional heat and steel fiber loss.

2. The apparatus for preparing and producing shaped steel fibers according to claim 1, characterized in that, The outer tube (42) of the device is used to constrain the rebound of the steel fiber. The entrance and exit of the spiral track (43) are set at different horizontal heights to avoid interference between the rotating steel fiber and the arc-shaped and spiral fiber rotation forming components (4) that are about to enter.

3. The apparatus for preparing and producing shaped steel fibers according to claim 1, characterized in that, Compared to the forming mold without end hooks, the forming mold with end hooks adds an end hook pressing component (5) between the wire feeding assembly (2) and the arc-shaped and spiral-shaped fiber rotary forming assembly (4). The end hook pressing component (5) includes a set of interlocking gears (51) that mesh with each other. The steel fiber passes through the gap between the interlocking gears (51) to form a concave indentation on the steel fiber.

4. The apparatus for preparing and producing shaped steel fibers according to claim 1, characterized in that, The double-helix steel fiber forming device is provided with a forming component (6) between the wire feeding assembly (2) and the cutting assembly (3). The forming component (6) includes a first spiral shaft (61) and a second spiral shaft (62). The second spiral shaft (62) is formed along the first spiral shaft (61) and a steel fiber forming channel (63) is wound on the second spiral shaft (62).

5. The apparatus for preparing and producing shaped steel fibers according to claim 4, characterized in that, The molding component (6) is provided with a number of passive rollers (64) on its outer and inner sides to reduce resistance during the molding process, and active rollers (65) to drive the steel fibers to advance in the steel fiber molding channel (63).

6. The apparatus for preparing and producing shaped steel fibers according to claim 4, characterized in that, The number of spiral turns N of the second spiral shaft (62) is (0, 2], the spiral diameter C is not less than 2 mm, and the pitch P is not less than 2 mm.

7. The apparatus for preparing and producing shaped steel fibers according to claim 4, characterized in that, The steel fiber forming channel (63) has a spiral number of not less than 1 turn, a spiral diameter C of not less than 2 mm, and a spiral pitch P of not less than 2 mm.

8. The apparatus for preparing and producing shaped steel fibers according to claim 4, characterized in that, The steel fiber forming channel (63) can be manufactured based on lathe machining, hot working and 3D printing technology.

9. The apparatus for preparing and producing shaped steel fibers according to any one of claims 1-8, characterized in that, The steel fiber has a diameter of 0.10mm to 2.00mm, a length of 10.00mm to 200.00mm, an aspect ratio of length to diameter of 30 to 350, and a tensile strength of not less than 600MPa.

10. The apparatus for preparing shaped steel fibers according to any one of claims 1-5 or 8, characterized in that, The fiber pitch P of spiral steel fibers and double spiral steel fibers ranges from 0 mm to 100 mm, the spiral diameter C ranges from 5 mm to 100 mm, and the number of spiral turns N ranges from 0 to 20.

11. A method for preparing shaped steel fibers, using the apparatus for preparing shaped steel fibers as described in any one of claims 1-10; characterized in that, The methods include arc-shaped steel fiber forming methods, spiral steel fiber forming methods, and double spiral steel fiber forming methods. The arc-shaped steel fiber and spiral steel fiber forming methods include end-hook-less forming methods and end-hook-with forming methods.

12. The method for preparing shaped steel fibers according to claim 11, characterized in that, The method for forming the endless hook includes: Step 1: The steel fiber is straightened by passing it through the straightening assembly (1); Step 2: The wire feeding assembly (2) feeds the straightened steel fiber into the spiral track (43) on the inner tube (41) of the arc fiber rotary forming assembly (4) for rotation, and the steel fiber is formed during the rotation process. Step 3: After the steel fiber is pushed out in the fiber rotation molding assembly (4), the cutting assembly (3) cuts the steel fiber to complete the preparation of arc-shaped steel fiber and spiral steel fiber. During this process, the wire feeding assembly (2) pushes out the steel fiber at a set rate, and the cutting assembly (3) also cuts the steel fiber at the corresponding rate to ensure that the prepared steel fiber is consistent with the expected steel fiber size and can be continuously produced.

13. The method for preparing shaped steel fibers according to claim 11, characterized in that, The method for forming the end hook includes: Step 2: The wire feeding assembly (2) feeds the straightened steel fiber into the end hook pressing assembly (5). The end hook pressing assembly (5) drives the steel fiber to be pushed into the fiber rotary forming assembly (4). In the end hook pressing assembly (5), the gap between the two meshing gears (51) forms a concave indentation on the steel fiber. Step 3: The steel fibers after being pressed by the end hook are fed into the spiral track (43) on the inner tube (41) of the fiber rotary forming assembly (4) for rotation, and the steel fibers are formed during the rotation process. Step 4: After the steel fiber is pushed out in the fiber rotation molding assembly (4), the cutting assembly (3) cuts the steel fiber to complete the preparation of arc-shaped steel fiber and spiral steel fiber. During this process, the wire feeding assembly (2) pushes out the steel fiber at a set rate, and the cutting assembly (3) also cuts the steel fiber at the corresponding rate to ensure that the prepared steel fiber is consistent with the expected steel fiber size and can be continuously produced.

14. The method for preparing shaped steel fibers according to claim 11, characterized in that, The double-helix steel fiber forming method includes: Step 2: The wire feeding assembly (2) feeds the straightened steel fibers into the steel fiber forming channel (63) in the forming assembly (6) to achieve double helix forming of the steel fibers; Step 3: After the steel fiber is pushed out in the forming component (6), the cutting component (3) cuts the steel fiber to complete the preparation of the double helix steel fiber. During this process, the wire feeding component (2) pushes out the steel fiber at a set rate, and at the same time, the cutting component (3) also cuts the steel fiber at the corresponding rate to ensure that the prepared steel fiber is consistent with the expected steel fiber size and can be continuously produced.

15. The method for preparing shaped steel fibers according to claim 14, characterized in that, The molding component (6) is equipped with a variety of molding specifications to achieve rapid molding of double helical steel fibers of different shapes and sizes.

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