Anchor rod body continuous forming process and equipment

Abstract

The invention discloses an anchor rod body continuous forming process and equipment. The anchor rod body continuous forming process comprises the steps that a base material is heated and subjected to perforation treatment, and a hollow pipe blank is obtained; primary annealing treatment is conducted on the hollow pipe blank, and primary straightening is conducted on the annealed hollow pipe blank; the hollow pipe blank subjected to primary straightening is subjected to acid pickling so as to remove oxide skin on the surface of the hollow pipe blank; a finishing mill is adopted for conducting multi-pass finish rolling forming on the hollow pipe blank obtained after acid pickling, and the rolled anchor rod is obtained; the rolled anchor rod is subjected to secondary annealing treatment, the annealed rolled anchor rod is subjected to secondary straightening, and the temperature of secondary annealing is lower than that of primary annealing; the rolled anchor rod subjected to secondary straightening is subjected to fixed-length cutting; and performing cold rib rolling and thread rolling processing on the rolled anchor rod subjected to fixed-length cutting. According to the embodiment, on the premise that energy consumption is controlled, cold-state precision forming is achieved, and good comprehensive mechanical performance is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of anchor rod processing, and particularly relates to a continuous forming process and equipment for an anchor rod body. BACKGROUND

[0002] In the related art, a "quenching and tempering treatment + hot rolling / hot rolling process" is usually used to obtain the required strength and toughness in the forming process of high-strength hollow anchor rods (for example, 40Cr alloy anchor rods). High-strength performance is obtained through high-temperature rolling above 1100 DEG C, quenching and tempering at 850 DEG C. The rod body is processed using a hot rolling process. However, this method has high energy consumption, large residual stress and poor cold working adaptability. Although some improved schemes reduce the rolling temperature, the whole process is not optimized, the process is complex and is not conducive to the stability control of the structure. SUMMARY

[0003] The present application is based on the discovery and understanding of the inventors of the following facts and problems: The inventors have realized that the anchor rods in the related art usually use high-energy-consumption processes such as hot rolling + quenching and tempering or hot rolling + tempering, the production process is complex, the equipment investment is large, and the consistency control ability of the product is poor. The quenching and tempering treatment process is particularly energy-consuming and time-consuming, which is not conducive to the construction of an efficient processing line. Hot rolling is dangerous and difficult to maintain, and the application effect is not ideal. The whole process usually includes hot piercing, high-temperature heating, hot rolling, hot rolling ribs, hot rolling wires, normalizing or quenching and tempering heat treatment, straightening and detection, which results in high energy consumption of the processing flow, high requirements for equipment, poor processing flexibility, which is not conducive to small-batch customized processing, and the product consistency is poor due to the difficulty in controlling the hot processing temperature.

[0004] The inventors have also realized that the energy consumption of hot rolling and quenching and tempering in the related art is high, especially the rapid heating and quenching in the quenching and tempering stage requires a large amount of energy supply and cooling system; high-temperature rolling and quenching can induce a large amount of residual stress, which can lead to cracking risk in subsequent cold working deformation, affecting the processing adaptability; the phase change structure in the quenching and tempering process is complex and difficult to control, and problems such as overburning and uneven structure are prone to occur, affecting the stability of the final performance; some schemes propose to reduce the hot rolling temperature, but the overall process still relies on the heat treatment path, and the high energy consumption and forming control problem have not been fundamentally solved.

[0005] The present application aims to at least partially solve one of the technical problems in the related art.

[0006] To this end, an embodiment of the present application proposes a continuous forming process for an anchor rod body, which realizes cold precision forming and obtains good comprehensive mechanical properties under the premise of controlling energy consumption.

[0007] An embodiment of the present application also proposes a continuous forming equipment for an anchor rod body.

[0008] The anchor rod body continuous forming process of the embodiment of the present application comprises: heating the base material and performing a piercing process on the base material to obtain a hollow pipe blank; performing a first annealing process on the hollow pipe blank and performing a first straightening on the hollow pipe blank after the annealing process is completed; performing an acid pickling on the hollow pipe blank after the first straightening to remove the oxide skin on the surface of the hollow pipe blank; performing a multi-pass precision rolling forming on the hollow pipe blank after the acid pickling by using a precision rolling mill to obtain a rolled anchor rod; performing a second annealing process on the rolled anchor rod and performing a second straightening on the rolled anchor rod after the annealing process is completed, wherein the temperature of the second annealing is lower than the temperature of the first annealing; performing a fixed-length cutting on the rolled anchor rod after the second straightening; performing a cold rib rolling and thread rolling on the rolled anchor rod after the fixed-length cutting.

[0009] The anchor rod body continuous forming process of the embodiment of the present application realizes a cold precision forming and obtains good comprehensive mechanical properties under the premise of controlling energy consumption, without using high-energy-consumption processes such as quenching and tempering and hot rolling, and the process is simple, green and energy-saving; the grain structure is uniform and small, the tensile strength and yield strength are stable on the premise of greatly improving the elongation rate, meeting the use requirements; the elongation rate is kept at 21-26%, with excellent stability; the annealing process is performed in time after cold rolling, which can effectively release the residual stress induced by cold working, avoid delayed cracking and deformation instability caused by internal stress concentration, improve the reliability and fatigue life in the service stage, and at the same time, benefit from the uniform structure and small cold rolling stress to reduce the risk of cracking during processing.

[0010] In some embodiments, in the step of heating the base material and performing a piercing process on the base material, the temperature of the base material is heated to 1050-1100 degrees Celsius, and then a piercing machine is used to perform the piercing process on the base material.

[0011] In some embodiments, the piercing machine is a three-roll piercing machine, the diameter of the roll in the three-roll piercing machine is 350-450 mm, the length of the roll is 280-330 mm, the inclination angle of the roll is 6-10 degrees, and the rotation speed of the roll is 110-135 r / min.

[0012] In some embodiments, the step of performing a first annealing process on the hollow pipe blank comprises: feeding the hollow pipe blank into an electric annealing furnace, the annealing temperature in the electric annealing furnace is 780-820 degrees Celsius, the holding time is 3.5-6 hours, and then slow cooling is performed.

[0013] In some embodiments, in the step of straightening the annealed hollow tube blank, a straightening machine is used to perform cold straightening on the annealed hollow tube blank. And / or, in the step of secondary straightening of the rolled anchor rod after annealing, a straightening machine is used to perform cold straightening of the rolled anchor rod after secondary annealing; And / or, a 15-roll composite straightener is used in both the primary straightening and the secondary straightening.

[0014] In some embodiments, in the step of using a finishing mill to perform multi-pass finishing rolling on the pickled hollow tube blank, the rolling reduction rate of the finishing mill is 10% to 15%, the diameter of the rolls of the finishing mill is 160 mm to 200 mm, the length of the rolls is 300 mm to 400 mm, the material of the rolls is 50Mn, and the rotational speed of the rolls is 700 r / min to 780 r / min; And / or, the finishing mill uses 50 rolls for multi-pass finishing rolling.

[0015] In some embodiments, the step of performing secondary annealing on the rolled anchor bolt includes: The rolled anchor rod is sent into an electric annealing furnace. The annealing temperature in the electric annealing furnace is 580 degrees Celsius to 620 degrees Celsius, and the heating rate in the electric annealing furnace is less than or equal to 150 degrees Celsius per hour. The heat preservation time is 3.5 to 6 hours; The power was then cut off and the furnace cooled down at a rate of less than or equal to 80 degrees Celsius per hour.

[0016] In some embodiments, a hole-expanding process is also included, in which the rolled anchor rod is expanded after being cut to a fixed length, so that the inner diameter of the rolled anchor rod reaches a preset size.

[0017] In some embodiments, the substrate is 40Cr alloy round steel; And / or, the power of the annealing equipment used for primary and secondary annealing is less than or equal to 80KW, and the power of the cold working equipment used for cold rib rolling and thread rolling is less than or equal to 80KW.

[0018] This invention discloses a continuous forming equipment for anchor bolt bodies, including a piercing machine, a straightening machine, an electric annealing furnace, a pickling device, a finishing mill, a cutting device, and a cold rolling mill. The continuous forming equipment for anchor bolt bodies is used to process and form anchor bolts according to the continuous forming process of anchor bolt bodies described in any of the above embodiments. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the continuous forming process of the anchor rod body according to an embodiment of the present invention.

[0020] Figure 2This is a complete process flow diagram of the continuous forming process of the anchor rod body according to an embodiment of the present invention. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] See Figure 1 and Figure 2 The continuous forming process of the anchor rod body according to an embodiment of the present invention includes: S1. The substrate is heated and perforated to obtain a hollow tube blank. During the perforation stage, the substrate undergoes a hot deformation process, and the internal structure of the substrate changes from the initial state to a coarse columnar austenite structure, providing a basis for subsequent heat treatment and microstructure reconstruction.

[0023] S2. The hollow tube blank is subjected to a first annealing treatment, and the annealed hollow tube blank is straightened once. The annealing treatment adopts medium-temperature annealing. In the first annealing stage, the austenite can be transformed into granular pearlite + ferrite. At the same time, annealing can refine coarse grains, release residual stress initially, make the microstructure more uniform, improve the plasticity of the material, and establish a microstructure softening foundation for subsequent cold working.

[0024] During the first straightening stage, the cold deformation of the rod can play a "stress pre-adjustment" role in the structural direction, so that the residual stress is slightly redistributed along the axial direction, providing morphological stability for subsequent processing.

[0025] S3. Pickling is performed on the hollow tube blank after the first straightening to remove the oxide scale on the surface of the hollow tube blank. The pickling stage can remove the oxide scale generated on the surface after annealing, so that the subsequent finishing rolling process is not affected by oxide inclusions, and at the same time avoid the initiation of microcracks, which is conducive to maintaining the integrity of the interface structure after processing.

[0026] S4. The pickled hollow tube blank is precision rolled in multiple passes using a precision rolling mill to obtain the rolled anchor rod. The material undergoes multiple rounds of low-temperature strong plastic deformation, which elongates and refines the pearlite lamellae, and causes deformation twinning and dislocation density in the ferrite grains. The microstructure gradually transforms into a state of "deformation fine grains + metastable metastructure", which improves the strength and cold working stability, while controlling heat accumulation to avoid recrystallization.

[0027] S5. The rolled anchor bolt undergoes a second annealing treatment, followed by a second straightening process. The temperature of the second annealing is lower than that of the first annealing. During the second annealing process, the high-density dislocation substructure from the previous step partially dissipates, microscopic grain boundary stress is released, and some lamellar pearlite is tempered into an equiaxed fine-grained structure. The internal structure of the ferrite recovers and tends to a stable state. This step is a key point in controlling the uniformity of the microstructure and residual stress, determining the anchor bolt's toughness, fatigue life, and service reliability.

[0028] In the secondary straightening process, the rod is straightened again in a cold state. Under the action of micro-strain, the grain orientation is slightly adjusted, and morphological deviations are corrected. This step is carried out under a stable microstructure, without introducing new stress concentrations, ensuring that the macroscopic geometry and microscopic residual stress of the rod are under excellent control.

[0029] S6. Cut the rolled anchor rods to length after secondary straightening.

[0030] S7. After the anchor rods are cut to length, they undergo cold rib rolling and thread rolling. The ribs and threads are formed using cold rolling. Because the rod structure is already stable and has good plasticity, the rolling deformation is more uniform. Microscopically, local dislocation density and work hardening occur in the rib and thread areas, forming a strong and tough bonding zone, improving local tensile strength and connection performance, while maintaining overall plasticity and structural density.

[0031] The continuous forming process for anchor rods in this invention achieves cold precision forming and obtains good comprehensive mechanical properties while controlling energy consumption. It eliminates the need for high-energy-consuming processes such as tempering and hot rolling, making the process simple, green, and energy-saving. The grain structure is uniform and fine, and the tensile strength and yield strength remain stable while the elongation is greatly improved, meeting the application requirements. The elongation is maintained at 21-26%, exhibiting excellent stability. Timely annealing after cold rolling can effectively release residual stress induced by cold working, avoiding delayed cracking and deformation instability caused by internal stress concentration, thus improving reliability and fatigue life during service. At the same time, thanks to the uniform structure and low cold rolling stress, the risk of cracking during processing is reduced.

[0032] The following describes a continuous forming process for the anchor rod body in a specific embodiment of the present invention.

[0033] See Figure 1 and Figure 2 A continuous forming process for anchor rod bodies, using 40Cr alloy round steel with a diameter of 50mm and a length of 1000 to 3000mm as the base material, is used to manufacture anchor rods with an outer diameter of 25mm, a wall thickness of 7mm, and an inner diameter of 11mm. The continuous forming process for anchor rod bodies includes: S1. Heating the substrate and piercing it to obtain a hollow tube blank. Specifically, after heating the substrate to 1050°C to 1100°C, a piercing mill is used to pierce the substrate. The piercing mill can be a skew-roll three-roll piercing mill, wherein the diameter of the rolls in the skew-roll three-roll piercing mill is 350mm to 450mm, the length of the rolls is 280mm to 330mm, the inclination angle of the rolls is 6 degrees to 10 degrees, and the roll speed is 110r / min to 135r / min. For example, in a skew-roll three-roll piercing mill, the motor power is 320KW, the diameter of the rolls is 400mm, the roll length is 300mm, the inclination angle of the rolls is 8 degrees, the roll speed is 120r / min, and the inner diameter of the prepared hollow tube blank is 11mm, with an error not exceeding 0.1mm.

[0034] The piercing process in this embodiment adopts a three-roll skew rolling + mandrel jacking collaborative process to ensure uniform metal flow and high concentricity of the inner hole during the forming process, and avoid defects such as folding and center cracks.

[0035] During the perforation stage, the substrate undergoes a hot deformation process. The internal structure of the substrate changes from the initial state (the initial structure is coarse lamellar pearlite + ferrite with low internal stress but poor plasticity) to coarse columnar austenite. At this time, the grains coarsen and partially recrystallize, forming inhomogeneous columnar crystals, which provides a basis for subsequent heat treatment and microstructure reconstruction.

[0036] S2. The hollow tube blank undergoes a first annealing treatment, followed by a straightening process. The annealing process employs medium-temperature annealing. Specifically, the hollow tube blank is fed into an electric annealing furnace at a temperature of 780°C to 820°C, with a holding time of 3.5 to 6 hours, followed by slow cooling. This effectively releases piercing stress, reduces hardness, and improves adaptability to subsequent cold rolling. The initial 800°C medium-temperature annealing significantly reduces material hardness and improves ductility, enabling subsequent cold rolling and cold rib rolling processes, laying the foundation for fully cold-processed manufacturing.

[0037] In a single annealing stage, austenite can be transformed into granular pearlite + ferrite. At the same time, annealing refines coarse grains, releases residual stress initially, makes the microstructure more uniform, improves the plasticity of the material, and lays the foundation for microstructure softening for subsequent cold working.

[0038] After annealing, the hollow tube blank is cold-straightened to correct its curvature and ensure its stability in subsequent processes. The straightening machine uses a small roller system with a roller diameter of 230 mm and a roller spacing of 250 mm, and a large roller system with a roller diameter of 340 mm and a roller spacing of 400 mm. The arrangement of transition rollers further improves the straightening accuracy.

[0039] A straightening machine is used to perform cold straightening on hollow tube blanks that have undergone one-time annealing. In the first straightening stage, the cold deformation of the tube can play a "stress pre-adjustment" role in the structural direction, so that the residual stress is slightly redistributed along the axial direction, providing morphological stability for subsequent processing.

[0040] S3. Pickling is performed on the hollow tube blank after the first straightening to remove the oxide scale on the surface of the hollow tube blank. The pickling stage can remove the oxide scale generated on the surface after annealing, so that the subsequent finishing rolling process is not affected by oxide inclusions, and at the same time avoid the initiation of microcracks, which is conducive to maintaining the integrity of the interface structure after processing.

[0041] S4. The pickled hollow tube blank is subjected to multiple passes of precision rolling using a precision rolling mill to obtain the rolled anchor rod.

[0042] The finishing mill uses 50 rolls for multi-pass finishing rolling. The rolling reduction rate of the finishing mill is 10% to 15%. The diameter of the rolls of the finishing mill is 160mm to 200mm, the length of the rolls is 300mm to 400mm, the material of the rolls is 50Mn, and the rotation speed of the rolls is 700r / min to 780r / min.

[0043] For example, the pickled hollow tube blank (around 60 degrees Celsius) is fed into the finishing mill 50 unit for multi-pass finishing rolling. The roll diameter is 180 mm, the length is 350 mm, the material is 50Mn, the motor power is 180 kW, the roll speed is 750 r / min, the outer diameter is controlled at 25 mm, the wall thickness is 7 mm, and the rolling reduction rate is within 15%, to obtain the rolled anchor rod.

[0044] In this embodiment, the material undergoes multiple rounds of low-temperature strong plastic deformation, which elongates and refines the pearlite lamellae, and causes deformation twinning and dislocation density in the ferrite grains. The microstructure gradually transforms into a state of "deformation fine grains + metastable substructure", which improves the strength and cold working stability, while controlling heat accumulation to avoid recrystallization.

[0045] S5. The rolled anchor rod undergoes a second annealing treatment, followed by a second straightening process. The temperature of the second annealing is lower than that of the first annealing. Specifically, in the second annealing, the rolled anchor rod is placed in an electric annealing furnace at a temperature of 580°C to 620°C, with a heating rate of less than or equal to 150°C per hour. The holding time is 3.5 to 6 hours. Subsequently, the furnace is cooled with the power off at a rate of less than or equal to 80°C per hour. This releases residual stress from cold working and stabilizes the microstructure, preventing stress concentration that could lead to cracking. The second low-temperature annealing at 580~620°C eliminates residual stress induced by cold rolling, optimizes the distribution of pearlite and ferrite microstructure, and effectively improves the toughness, processing stability, and fatigue life of the finished product.

[0046] The cold deformation of the anchor bolt after finishing mill rolling induces lattice distortion, subgrain structure formation, increased dislocation density, enhanced strength, and decreased plasticity. During the secondary annealing process, the high-density dislocation substructure from the previous step partially dissipates, microscopic grain boundary stress is released, and some lamellar pearlite is tempered into an equiaxed fine-grained structure. The internal structure of ferrite recovers and tends to a stable state. This step is a critical point for controlling the uniformity of the microstructure and residual stress, determining the anchor bolt's toughness, fatigue life, and service reliability.

[0047] In this embodiment, a 15-roll composite straightener is used in both the primary and secondary straightening processes.

[0048] This embodiment employs a 15-roll composite straightening machine to perform cold straightening on the rolled anchor rod after secondary annealing, further improving the straightness and dimensional consistency of the rod body, ensuring that the straightness meets the requirements, and satisfying the accuracy requirements of the final cold rolling process. The rod body is straightened again in the cold state; under the action of micro-strain, the grain orientation is slightly adjusted, and morphological deviations are corrected simultaneously. This step is performed under a stable microstructure, without introducing new stress concentrations, ensuring that the macroscopic geometry and microscopic residual stress of the rod body are under excellent control.

[0049] S6. Cut the rolled anchor rods to length after secondary straightening. Cut the material to length according to the anchor rod product length specifications.

[0050] S7. After the anchor rods are cut to length, they undergo cold rolling for rib and thread forming. Cold rolling is used to form ribs and threads. Because the rod's structure is already stable and has good plasticity, the rolling deformation is more uniform. Microscopically, local dislocation density and work hardening occur in the rib and thread areas, forming a strong and tough bonding zone, improving local tensile strength and connection performance while maintaining overall plasticity and structural density. At this stage, fine equiaxed pearlite and uniform ferrite can be formed, resulting in a dense structure, combining strength and plasticity, and stable performance. Cold rolling equipment has a fast response speed, eliminating the need to wait for the entire rod to heat up and slowly pass through. The forming speed is increased by approximately 25% or more compared to hot rolling, resulting in a shorter processing cycle, which is beneficial for batch continuous production.

[0051] Furthermore, if synchronous hole enlargement is required, the rolled anchor rod after being cut to length can be enlarged to make the inner diameter of the rolled anchor rod reach the preset size.

[0052] Finally, the finished anchor bolts can be subjected to mechanical performance tests, including tensile strength, hardness, thread precision, and other items.

[0053]

[0054] As shown in Table 1, this invention avoids the large amount of heat treatment energy required by traditional tempering (quenching + tempering) through the path of "medium-temperature softening annealing (first annealing) + low-temperature stabilizing annealing (second annealing)". The peak heat treatment temperature does not exceed 800℃, and the total heat consumption can be reduced by more than 30%. The overall process of this embodiment eliminates the high-temperature tempering process, reducing production complexity and the risk of quality instability, and improving product dimensional consistency and process repeatability. The cold rolling equipment of this embodiment has a fast response speed and does not require waiting for the entire rod to be heated and slowly passed through. The forming speed is increased by more than 25% compared with the hot rolling process, and the processing cycle is shorter, which is conducive to batch continuous production. In the process of cold rolling ribs and thread rolling of this embodiment, due to the better plasticity and moderate hardness of the material, smaller deformation and tighter tolerance control can be achieved compared with hot rolling, which is convenient for high-precision assembly with accessories such as trays, washers, and nuts. At the same time, the temperature rise in the cold rolling process is limited, avoiding safety hazards such as equipment jamming and worker misoperation in high-temperature environments. The overall processing process is more stable and reliable, and has higher operational safety. This invention enables a low-energy manufacturing path for the entire cold working process by means of annealing hardness control and stress management, without the need for tempering heat treatment. It is suitable for the large-scale stable preparation of high-precision, high-strength hollow anchor bolts.

[0055]

[0056] As shown in Table 2, the metallographic structure of the anchor bolt in the embodiment of the present invention is more prominent than that of the anchor bolt produced by the hot working method in the related technology.

[0057]

[0058] As shown in Table 3, the embodiments of the present invention, by optimizing the annealing process and cold working path, achieve excellent mechanical properties for anchor bolts without tempering and hot rolling processes. These properties include higher tensile strength, yield strength, elongation, and stable hardness, making them suitable for applications such as coal mines and tunnels where high strength and toughness of support components are required. The embodiments of the present invention are based on a continuous forming process using double annealing and a cold working path. By eliminating the tempering and hot rolling processes, efficient forming and excellent mechanical properties of the anchor bolts are achieved under a fully cold-working state.

[0059] This invention discloses a continuous forming equipment for anchor bolt bodies, including a piercing machine, a straightening machine, an electric annealing furnace, a pickling device, a finishing mill, a cutting device, and a cold rolling mill. The continuous forming equipment for anchor bolt bodies is used to process and form anchor bolts according to the continuous forming process of anchor bolt bodies described in any of the above embodiments.

[0060] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0064] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0065] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A continuous forming process for anchor bolt bodies, characterized in that, include: The substrate is heated and perforated to obtain a hollow tube blank; The hollow tube blank is subjected to one annealing treatment, and the annealed hollow tube blank is straightened once. Pickling is performed on the hollow tube blank after the first straightening to remove the oxide scale on the surface of the hollow tube blank; A precision rolling mill is used to perform multiple passes of precision rolling on the pickled hollow tube blank to obtain the rolled anchor bolt; The rolled anchor bolt is subjected to secondary annealing and secondary straightening, wherein the temperature of the secondary annealing is lower than that of the primary annealing. The rolled anchor rods, after secondary straightening, are cut to length. The rolled anchor rods after being cut to length are then subjected to cold rib rolling and thread rolling.

2. The continuous forming process for the anchor rod body according to claim 1, characterized in that, In the step of heating the substrate and perforating the substrate, the substrate is heated to 1050 to 1100 degrees Celsius, and then perforated using a perforating machine.

3. The continuous forming process for the anchor rod body according to claim 2, characterized in that, The piercing mill is a skew-roll three-roll piercing mill, wherein the diameter of the rolls is 350 mm to 450 mm, the length of the rolls is 280 mm to 330 mm, the inclination angle of the rolls is 6 degrees to 10 degrees, and the speed of the rolls is 110 r / min to 135 r / min.

4. The continuous forming process for the anchor rod body according to claim 1, characterized in that, The step involves annealing the hollow tube blank once, including: feeding the hollow tube blank into an electric annealing furnace, where the annealing temperature is 780 degrees Celsius to 820 degrees Celsius, the holding time is 3.5 hours to 6 hours, and then slow cooling.

5. The continuous forming process for the anchor rod body according to claim 1, characterized in that, In the first straightening step of the annealed hollow tube blank, a straightening machine is used to perform cold straightening on the hollow tube blank after the first annealing. And / or, in the step of secondary straightening of the rolled anchor rod after annealing, a straightening machine is used to perform cold straightening of the rolled anchor rod after secondary annealing; And / or, a 15-roll composite straightener is used in both the primary straightening and the secondary straightening.

6. The continuous forming process for the anchor rod body according to claim 1, characterized in that, In the process of using a finishing mill to perform multi-pass finishing rolling on the pickled hollow tube blank, the rolling reduction rate of the finishing mill is 10% to 15%, the diameter of the rolls of the finishing mill is 160mm to 200mm, the length of the rolls is 300mm to 400mm, the material of the rolls is 50Mn, and the rotation speed of the rolls is 700r / min to 780r / min; And / or, the finishing mill uses 50 rolls for multi-pass finishing rolling.

7. The continuous forming process for the anchor rod body according to claim 1, characterized in that, The step of performing secondary annealing on the rolled anchor bolt includes: The rolled anchor rod is sent into an electric annealing furnace. The annealing temperature in the electric annealing furnace is 580 degrees Celsius to 620 degrees Celsius, and the heating rate in the electric annealing furnace is less than or equal to 150 degrees Celsius per hour. The heat preservation time is 3.5 to 6 hours; The power was then cut off and the furnace cooled down at a rate of less than or equal to 80 degrees Celsius per hour.

8. The continuous forming process for the anchor rod body according to claim 1, characterized in that, It also includes a hole-expanding process, which expands the holes of the rolled anchor rod after it has been cut to a fixed length, so that the inner diameter of the rolled anchor rod reaches the preset size.

9. The continuous forming process for the anchor rod body according to claim 1, characterized in that, The substrate is 40Cr alloy round steel; And / or, the power of the annealing equipment used for primary and secondary annealing is less than or equal to 80KW, and the power of the cold working equipment used for cold rib rolling and thread rolling is less than or equal to 80KW.

10. A continuous forming equipment for anchor bolt bodies, characterized in that, The equipment includes a piercing machine, a straightening machine, an electric annealing furnace, a pickling device, a finishing mill, a cutting device, and a cold rolling mill. The continuous forming equipment for anchor rods is used to process and form anchor rods according to any one of claims 1 to 9.

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