Production process of high-strength cold-rolled ribbed steel bar

Abstract

The invention belongs to the technical field of reinforcing steel bar production and processing, and particularly relates to a high-strength cold-rolled ribbed reinforcing steel bar production process, which comprises the following specific steps: selecting low-alloy high-strength steel with chemical components containing trace alloy elements, controlling the diameter of a steel billet to be phi 80-120mm, performing flaw detection on the steel billet, and performing cold rolling on the steel billet to obtain the high-strength cold-rolled ribbed reinforcing steel bar. Through fine grain strengthening and progressive cold drawing of low alloy steel, the strength is improved, meanwhile, the toughness of a matrix is reserved, cold brittleness is reduced through warm rolling at the temperature of 600-700 DEG C, impact is buffered through stress dispersion of twisted winding ribs, first reinforcing ribs and second reinforcing ribs in longitudinal ribs are locally strengthened, and overall flexibility and local high strength are achieved; the brittleness caused by cold machining is reduced through tempering, the impact toughness is improved, and the contradiction of hardness and brittleness is solved; the elastic coating and the tough upsetting end ensure that the steel bar is not brittle or invalid during bending and anchoring.

Description

Technical Field

[0001] This invention relates to the field of steel bar production and processing technology, specifically to a production process for high-strength cold-rolled ribbed steel bars. Background Technology

[0002] Cold-rolled ribbed steel bars are a new type of construction steel that has developed rapidly both domestically and internationally in the late 20th century. They are formed by cold-rolling hot-rolled coils through multiple cold rolling processes to reduce their diameter, then pressing ribs and relieving internal stress, resulting in a steel bar with four or six crescent-shaped sides. Due to their high strength, good plasticity, ease of processing, and strong bond with cement, cold-rolled ribbed steel bars can significantly save steel. In prestressed concrete components, they are a replacement for cold-drawn low-carbon steel wire. In cast-in-place concrete structures, they can replace Grade I steel bars, saving steel and making them one of the better cold-worked steel products.

[0003] However, the existing steel bar production process still has the following technical problems during processing:

[0004] Current production processes cannot simultaneously produce steel bars that meet both hardness and flexibility requirements, leading to numerous inconveniences in their practical use.

[0005] Brittle fracture risk: When the hardness of steel bars is too high (e.g., excessively high tensile strength) and their flexibility is insufficient, the structure is prone to brittle fracture when subjected to impact or vibration. For example, high-strength steel bars may suddenly fracture under earthquakes or extreme loads due to a lack of ductility, leading to partial or overall structural failure.

[0006] Limited deformation capacity: Insufficient flexibility results in poor deformation capacity of steel bars under stress, making it unable to effectively disperse local stress. For example, low-ductility steel bars are prone to stress concentration under long-term loads, accelerating crack propagation and structural damage;

[0007] Decreased durability: Excessive hardness may reduce the bond between steel reinforcement and concrete, leading to accelerated corrosion. Insufficient flexibility affects the ability to repair cracks, making concrete more prone to carbonation, water seepage, and other problems, further weakening structural durability.

[0008] Therefore, a high-strength cold-rolled ribbed steel bar production process is proposed to solve the above-mentioned problems. Summary of the Invention

[0009] The purpose of this invention is to provide a high-strength cold-rolled ribbed steel bar production process to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a high-strength cold-rolled ribbed steel bar production process, the specific steps of which are as follows:

[0011] Step 1: Raw material preparation: Select low alloy high strength steel with trace alloying elements in its chemical composition. Control the diameter of the steel billet to Φ80-120mm. Perform flaw detection on the steel billet to remove internal cracks and inclusion defects.

[0012] Step 2, Loading and Mechanical Descaling: The steel billet is fed into the automated loading rack via a conveyor belt, with positioning accuracy controlled within ±0.5mm. High-pressure water jet combined with steel wire wheel grinding is used to remove the oxide scale from the surface of the steel billet, while simultaneously creating tiny bumps and depressions on the surface.

[0013] Step 3, Pretreatment: Immerse the de-scaled steel billet in a 10%-15% hydrochloric acid solution to further remove the residual oxide layer; then enter the phosphating tank to form a 3-5μm phosphating film on the surface, and dry the surface moisture with hot air;

[0014] Step 4, Cold drawing: Multi-pass progressive cold drawing is adopted, with the total cold drawing rate controlled at 8%-12%, and the tensile strength is increased from 300MPa to 450-500MPa. The cold-drawn steel bars are then subjected to one, two, three, and four diameter reductions in sequence.

[0015] Step 5, Heating and Rolling: The cold-drawn and reduced-diameter steel bars are fed into a medium-frequency induction heating furnace and heated to 600-700℃, followed by multi-pass rolling, including roughing, intermediate rolling, and finishing rolling. Roughing uses flat rolls to roll the steel bar body, ensuring a diameter tolerance of ±0.3mm. Intermediate rolling uses toothed rolls to roll longitudinal and transverse ribs on the surface of the steel bar body, with transverse ribs at an angle of 45°-60°. At the same time, the first reinforcing rib is extruded and formed in the inner cavity of the longitudinal ribs through a die inside the rolls. Finishing rolling uses a composite die, and the high-strength steel bars are rolled a second time in the inner cavity of the steel bar body through a rotating traction device to form the third and fourth heated ribs. The prestressed high-strength ribs CRB800 are formed by four extrusions on the outside of the longitudinal ribs.

[0016] Step 6, Finishing and Straightening: A multi-roll straightener is used to cold straighten the rolled steel bars to control the straightness ≤1mm / m, remove irregular ends from the rolling process, and adjust the height and spacing deviation of the longitudinal and transverse ribs by laser detection.

[0017] Step 7, Heat Treatment and Surface Treatment: Send the steel bars into the tempering furnace and hold them at 200-300℃ for 1-2 hours to eliminate the internal stress generated by cold rolling / rolling through diffusion annealing; Upset both ends of the steel bars or weld circular anchor plates; Apply hot-dip galvanizing or epoxy coating to evenly cover the steel bar body, longitudinal ribs, transverse ribs and anchor end surfaces, with coating adhesion ≥5N / mm;

[0018] Step 8: Marking and Rolling: Marking the longitudinal ribs of the steel bars by pressing with rollers, including the strength grade, specifications, and production batch number, with a rolling depth ≤ 0.3mm.

[0019] Preferably, in step one, the low-alloy high-strength steel selected is HRB500E grade steel billet, which contains trace alloying elements including vanadium, niobium, and titanium.

[0020] Preferably, in step two, the high-pressure water jet pressure is 30-50 MPa; after forming tiny irregularities on the surface, its roughness is Ra1.6-3.2 μm.

[0021] Preferably, the hydrochloric acid solution used in step three is at a temperature of 40-50°C; the phosphating tank is filled with zinc phosphate solution; and the temperature of the hot air is controlled at 80-100°C when drying the surface moisture with hot air.

[0022] Preferably, in step four, the single-pass cold drawing rate is ≤5%.

[0023] Preferably, in step five, the height of the longitudinal ribs rolled on the surface of the body is 2-3 mm, and they are distributed along the axial direction; the transverse ribs are crescent-shaped, spaced 5-10 mm apart, and perpendicularly intersect the longitudinal ribs; the diameter of the first reinforcing rib is 0.8-1.2 mm, and it is distributed along the axial direction of the longitudinal rib; the pitch of the four high-strength steel wires wound in a twisted manner is 10-15 mm; the winding angle of the first to fourth winding ribs is 30°-45°; the second reinforcing rib is formed to be distributed around the longitudinal rib, with a triangular cross-section and a height of 1-1.5 mm.

[0024] Preferably, in step six, the multi-roller straightener is a 6-8 roll type; the winding tightness of the longitudinal and transverse ribs is ≥95%.

[0025] Preferably, in step seven, hot-dip galvanizing is used, with a zinc layer thickness of 80-120 μm and an epoxy coating thickness of 60-100 μm.

[0026] Preferably, in step eight, the height of the characters for the roll pressing marking is 3-5mm.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] This application achieves overall flexibility and localized high strength by using fine-grained strengthening and progressive cold drawing of low-alloy steel to enhance strength while retaining the toughness of the matrix. Warm rolling at 600-700℃ reduces cold brittleness, and the twisted reinforcing bars buffer impact by dispersing stress. The first and second reinforcing bars in the longitudinal ribs provide localized strengthening. Tempering reduces the brittleness caused by cold working, thereby improving impact toughness and resolving the contradiction between hardness and brittleness. The elastic coating and tough upsetting at the coarse end ensure that the reinforcing bar does not break brittlely or fail when bent or anchored. Attached Figure Description

[0029] Figure 1 This is a flowchart of the production process. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example:

[0032] Please see Figure 1 The present invention provides a technical solution:

[0033] A production process for high-strength cold-rolled ribbed steel bars, the specific steps of which are as follows:

[0034] Step 1: Raw material preparation: Select low-alloy high-strength steel with trace alloying elements in its chemical composition. The strength is improved through fine grain strengthening while retaining the toughness of the ferrite-pearlite matrix. The billet diameter is controlled at Φ80-120mm to ensure uniform cold rolling deformation. The billet is subjected to flaw detection to remove internal cracks and inclusions. Defects can cause local stress concentration during cold working, leading to brittle fracture. This ensures the purity of the raw materials.

[0035] Step 2, Loading and Mechanical Descaling: The steel billet is fed into the automated loading rack via a conveyor belt, with positioning accuracy controlled within ±0.5mm to avoid force deviation during subsequent processing; high-pressure water jet combined with wire wheel grinding is used to remove the oxide scale from the surface of the steel billet, while creating micro-uneven surfaces to enhance the adhesion of metal flow during subsequent cold rolling and prevent peeling during the formation of longitudinal and transverse ribs;

[0036] Step 3, Pretreatment: Immerse the de-scaled steel billet in a 10%-15% hydrochloric acid solution to further remove the residual oxide layer; then enter the phosphating bath to form a 3-5μm phosphating film on the surface, which enhances the lubricity during cold drawing and reduces local overheating caused by friction, which can make the material brittle; dry the surface moisture with hot air to avoid oxidation and corrosion during cold rolling.

[0037] Step 4, Cold drawing: Multi-pass progressive cold drawing is adopted, with the total cold drawing rate controlled at 8%-12%, and the tensile strength is increased from 300MPa to 450-500MPa. The cold-drawn steel bars are then subjected to one, two, three, and four diameter reductions in sequence.

[0038] Step 5, Heating and Rolling: The cold-drawn and reduced-diameter steel bars are fed into a medium-frequency induction heating furnace and heated to 600-700℃ to maintain a certain degree of plasticity and prevent brittle fracture during cold rolling. This is followed by multi-pass rolling, including roughing, intermediate rolling, and finishing rolling. Roughing uses flat rolls to roll the steel bar body, ensuring a diameter tolerance of ±0.3mm, providing a benchmark for subsequent structural forming. Intermediate rolling uses toothed rolls to roll longitudinal and transverse ribs onto the surface of the steel bar body. The transverse ribs have an angle of 45°-60° to enhance the anchoring force with concrete. Simultaneously, the first reinforcing rib is extruded into the longitudinal rib cavity through a die inside the roll cavity. Finishing rolling uses a composite die, and a rotating traction device rolls the high-strength steel bar a second time within the steel bar body cavity to form the third and fourth heated reinforcing ribs. Finally, through four extrusion passes on the outside of the longitudinal ribs, prestressed high-strength reinforcing ribs (CRB800) are formed.

[0039] Step 6, Finishing and Straightening: A multi-roller straightener is used to cold straighten the rolled steel bars, controlling the straightness to ≤1mm / m, avoiding local stress concentration caused by bending, removing irregular ends during rolling, and preparing for the formation of the anchoring end structure. The height and spacing deviation of the longitudinal and transverse ribs are adjusted by laser detection to ensure that the wound bars are not loose and the winding tightness is ≥95%.

[0040] Step 7, Heat Treatment and Surface Treatment: The reinforcing bars are placed in a tempering furnace and held at 200-300℃ for 1-2 hours. Diffusion annealing eliminates internal stress generated during cold rolling / rolling, reducing internal stress by 40%-60%. This maintains high strength while increasing impact toughness (impact energy ≥30J at -20℃) by 20%-30% (solving the brittleness problem caused by cold working). The ends of the reinforcing bars are upset or welded with circular anchor plates to ensure anchor strength ≥1.2 times the tensile strength of the reinforcing bar, and the end toughness is consistent with the body, avoiding embrittlement caused by upset treatment. Hot-dip galvanizing or epoxy coating is used to evenly cover the reinforcing bar body, longitudinal ribs, transverse ribs, and anchor end surfaces. The coating adhesion is ≥5N / mm, providing rust prevention without affecting the flexibility of the reinforcing bar. The coating's elastic modulus matches the substrate, preventing cracking during bending.

[0041] Step 8: Marking the structural rolling: Mark the longitudinal ribs of the steel bars by pressing them with rollers, including the strength grade, specifications, and production batch number. The rolling depth should be ≤0.3mm to avoid weakening the local strength.

[0042] In step one, a low-alloy high-strength steel billet of grade HRB500E is selected, which contains trace alloying elements including vanadium, niobium, and titanium.

[0043] In step two, the high-pressure water jet pressure used is 30-50 MPa; after forming minute irregularities on the surface, its roughness is Ra 1.6-3.2 μm; its function is as follows:

[0044] The function of high-pressure water jet (30-50MPa):

[0045] Highly efficient oxide scale removal: The oxide scale (Fe2O3, Fe3O4, etc.) on the surface of steel billets is hard and tightly bonded to the substrate. High-pressure water jets of 30-50MPa can directly peel off the oxide scale through impact force. Combined with the mechanical friction of the steel wire wheel grinding, the oxide scale is completely removed (removal rate ≥99%). This pressure range ensures the removal effect while avoiding micro-cracks or plastic deformation on the surface of the steel billet due to excessive pressure (e.g., >50MPa), thus protecting the integrity of the substrate.

[0046] Preliminary surface roughening: The impact of high-pressure water flow will form uniform micro-pits on the surface of the billet, laying the foundation for subsequent roughness control, while avoiding indentation defects during cold rolling caused by residual oxide scale.

[0047] The role of surface roughness (Ra 1.6-3.2μm):

[0048] Enhancing phosphate coating adhesion: The phosphate coating (3-5μm) in the pretreatment stage needs to adhere tightly to the billet surface to provide lubrication. A roughness of Ra1.6-3.2μm creates microscopic anchor points on the surface, allowing the phosphate solution to penetrate into the pits and react fully with the substrate, significantly improving the bonding strength of the phosphate coating (adhesion increased by 30%-50%), and preventing surface scratches or die wear caused by lubrication layer detachment during cold rolling;

[0049] Optimizing the uniformity of cold rolling deformation: During cold drawing and rolling, the surface roughness of the billet can reduce the risk of slippage during metal flow. Microscopic irregularities of Ra1.6-3.2μm make the deformation force distribution more uniform, reduce local stress concentration, and avoid cracks or necking of steel bars during cold working (especially in the forming stage of irregular structures such as longitudinal ribs and transverse ribs);

[0050] Improving the anchorage performance of steel reinforcement and concrete: The transverse and longitudinal ribs of the final product need to interlock with the concrete, and the surface roughness of the steel billet indirectly affects the forming accuracy of the ribs during subsequent rolling. Appropriate roughness (Ra 1.6-3.2μm) ensures moderate friction between the rolls and the steel billet, making the height, angle, and other parameters of the longitudinal and transverse ribs more precise, ultimately enhancing the mechanical interlocking force between the steel reinforcement and concrete and improving the structural load-bearing capacity.

[0051] The hydrochloric acid solution used in step three is at a temperature of 40-50℃; the phosphating tank contains a zinc phosphate solution; when drying the surface moisture with hot air, the temperature of the hot air is controlled at 80-100℃; its function is as follows:

[0052] The purpose of maintaining the hydrochloric acid solution temperature at 40-50℃ is:

[0053] Enhanced rust removal efficiency: At 40-50℃, the hydrogen ion activity of 10%-15% hydrochloric acid solution is significantly enhanced, which can quickly dissolve residual oxide scale and micro-rust on the surface of steel billet. The reaction rate is 40%-60% higher than that at room temperature (25℃), ensuring thorough rust removal (residual oxide layer thickness ≤5μm).

[0054] Avoid excessive corrosion: Temperatures above 50°C will cause the corrosion rate of hydrochloric acid on the steel substrate to increase sharply, which may form over-corrosion pits; while below 40°C, the oxide layer cannot be completely removed. The range of 40-50°C can achieve a balance between efficient rust removal and protection of the substrate, ensuring that the surface of the steel billet is smooth and free of defects.

[0055] The role of zinc phosphate solution in the phosphating tank:

[0056] Formation of a dense protective film: The zinc phosphate solution reacts chemically with the iron ions on the surface of the steel billet to generate a 3-5μm phosphate film composed of zinc iron phosphate. This film is uniform and dense (porosity ≤1%), which can isolate air and moisture and prevent the steel billet from rusting again in subsequent processes.

[0057] Improved cold working lubricity: The phosphating film has a porous structure that can adsorb the lubricant in the subsequent cold drawing process, forming a stable lubricating layer during cold drawing and rolling, reducing the coefficient of friction between the roll and the steel bar surface (from 0.3 to below 0.15), reducing surface scratches and die wear, while ensuring uniform deformation.

[0058] Enhanced coating adhesion: The zinc phosphate phosphate film has strong adhesion to the steel substrate (adhesion ≥3N / mm), and its porous structure can provide an anchoring effect for subsequent surface treatments (such as hot-dip galvanizing, epoxy coating), thereby increasing the adhesion of the final coating by 20%-30% and meeting the requirement of ≥5N / mm.

[0059] The purpose of controlling the hot air drying temperature at 80-100℃ is:

[0060] Rapid moisture removal: Hot air at 80-100℃ can accelerate the evaporation of moisture on the surface of the phosphate film, shortening the drying time to 3-5 minutes (80% more efficient than air drying at room temperature), avoiding moisture residue that could cause the phosphate film to become damp or powdery, and ensuring the integrity of the film layer.

[0061] Promotes phosphate film curing: This temperature range can promote the stable binding of crystal water in the phosphate film, increase the hardness of the film layer, enhance its anti-friction ability in the subsequent cold drawing process, and prevent the film layer from falling off.

[0062] Controlling the heat effect: When the temperature is below 80℃, moisture evaporation is incomplete, while above 100℃, the phosphating film may become brittle due to over-drying. 80-100℃ ensures effective drying while avoiding negative impacts on the performance of the phosphating film.

[0063] In step four, the single-pass cold drawing rate is ≤5%.

[0064] In step five, the height of the longitudinal ribs rolled on the surface of the body is 2-3 mm, and they are distributed along the axial direction; the transverse ribs are crescent-shaped, spaced 5-10 mm apart, and intersect the longitudinal ribs perpendicularly; the diameter of the first reinforcing rib is 0.8-1.2 mm, and it is distributed along the axial direction of the longitudinal rib; four high-strength steel wires are wound in a twisted manner with a pitch of 10-15 mm; the winding angle of the first to fourth winding ribs is 30°-45°; the second reinforcing rib is formed and distributed around the longitudinal rib, with a triangular cross section and a height of 1-1.5 mm.

[0065] In step six, the multi-roller straightener is a 6-8 roll type; the winding tightness of the longitudinal and transverse ribs is ≥95%; its function is as follows:

[0066] Ensuring the stability of the mechanical properties of reinforcing bars: Longitudinal and transverse ribs are key structures for cold-rolled ribbed steel bars to withstand external forces. Their tight bond with the steel bar body directly affects the core mechanical properties of the steel bar, such as tensile strength and bond strength. A winding tightness of ≥95% ensures that there are no obvious gaps or loosening between the ribs and the body, avoiding stress concentration caused by rib detachment or deformation under load. This ensures that the steel bar can uniformly transfer the load in the concrete, improving the overall load-bearing capacity of the structure.

[0067] Enhanced bond strength with concrete: The longitudinal and transverse ribs on the surface of the steel bar are mechanically interlocked with the concrete, which is the core of ensuring the coordinated work of the steel bar and the concrete. The high tightness can prevent gaps between the ribs and the body, prevent water from seeping into the gaps after the concrete is poured, which would cause the steel bar to rust. At the same time, it ensures the integrity of the rib outline, increases the contact area and friction with the concrete, significantly improves the bond strength, and reduces the risk of slippage when the structure is under stress.

[0068] In step seven, hot-dip galvanizing is used, with a zinc layer thickness of 80-120 μm; the epoxy coating thickness is 60-100 μm; its function is as follows:

[0069] By employing hot-dip galvanizing, long-term corrosion protection is achieved. The zinc layer acts as a sacrificial anode, preferentially corroding through electrochemical action to protect the reinforcing steel substrate from corrosive media such as water, oxygen, and chloride ions. A thickness of 80-120 μm forms a continuous, dense protective layer, providing 15-20 years of corrosion protection in ordinary atmospheric environments. Even in humid or industrial environments, the uniform dissolution of the zinc layer slows down steel corrosion.

[0070] The function of epoxy coating (thickness 60-100μm): Epoxy coating is an inert organic material that can physically isolate steel bars from corrosive media (especially suitable for environments with high chloride ion concentration, such as coastal projects and bridges). Its dense properties effectively block the penetration of moisture and oxygen, forming a dual anti-corrosion system with the galvanized layer, which combines electrochemical protection and physical barrier.

[0071] In step eight, the height of the characters marking the roll pressing is 3-5mm.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or basic characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0073] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A production process for high-strength cold-rolled ribbed steel bars, characterized in that, The specific steps of the steel bar production process are as follows: Step 1: Raw material preparation: Select low alloy high strength steel with trace alloying elements in its chemical composition. Control the diameter of the steel billet to Φ80-120mm. Perform flaw detection on the steel billet to remove internal cracks and inclusion defects. Step 2, Loading and Mechanical Descaling: The steel billet is fed into the automated loading rack via a conveyor belt, with positioning accuracy controlled within ±0.5mm. High-pressure water jet combined with steel wire wheel grinding is used to remove the oxide scale from the surface of the steel billet, while simultaneously creating tiny bumps and depressions on the surface. Step 3, Pretreatment: Immerse the de-scaled steel billet in a 10%-15% hydrochloric acid solution to further remove the residual oxide layer; It then enters the phosphating tank to form a 3-5 μm phosphating film on the surface, and the surface moisture is dried by hot air. Step 4, Cold drawing: Multi-pass progressive cold drawing is adopted, with the total cold drawing rate controlled at 8%-12%, and the tensile strength is increased from 300MPa to 450-500MPa. The cold-drawn steel bars are then subjected to one, two, three, and four diameter reductions in sequence. Step 5, Heating and Rolling: The cold-drawn and reduced-diameter steel bars are fed into a medium-frequency induction heating furnace and heated to 600-700℃, followed by multi-pass rolling, including roughing, intermediate rolling, and finishing rolling. Roughing uses flat rolls to roll the steel bar body, ensuring a diameter tolerance of ±0.3mm. Intermediate rolling uses toothed rolls to roll longitudinal and transverse ribs on the surface of the steel bar body, with transverse ribs at an angle of 45°-60°. At the same time, the first reinforcing rib is extruded and formed inside the longitudinal rib cavity through a die inside the roll cavity. Finishing rolling uses a composite die, and the high-strength steel bar is rolled a second time inside the steel bar body through a rotating traction device to form the third to fourth heated ribs. The prestressed high-strength ribs CRB800 are formed by four extrusions on the outside of the longitudinal ribs. Step 6, Finishing and Straightening: A multi-roll straightener is used to cold straighten the rolled steel bars to control the straightness ≤1mm / m, remove irregular ends from the rolling process, and adjust the height and spacing deviation of the longitudinal and transverse ribs by laser detection. Step 7, Heat Treatment and Surface Treatment: Send the steel bars into the tempering furnace and hold them at 200-300℃ for 1-2 hours to eliminate the internal stress generated by cold rolling / rolling through diffusion annealing; Upset both ends of the steel bars or weld circular anchor plates; Apply hot-dip galvanizing or epoxy coating to evenly cover the steel bar body, longitudinal ribs, transverse ribs and anchor end surfaces, with coating adhesion ≥5N / mm; Step 8: Marking and Rolling: Marking the longitudinal ribs of the steel bars by pressing with rollers, including the strength grade, specifications, and production batch number, with a rolling depth ≤ 0.3mm.

2. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: In step one, the low-alloy high-strength steel selected is HRB500E grade steel billet, which contains trace alloying elements including vanadium, niobium, and titanium.

3. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: In step two, the high-pressure water jet pressure used is 30-50 MPa; after forming tiny bumps on the surface, its roughness is Ra1.6-3.2 μm.

4. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: The temperature of the hydrochloric acid solution used in step three is 40-50℃; the phosphating tank is filled with zinc phosphate solution; when drying the surface moisture with hot air, the temperature of the hot air is controlled at 80-100℃.

5. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: In step four, the single-pass cold drawing rate is ≤5%.

6. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: In step five, the height of the longitudinal ribs rolled on the surface of the body is 2-3 mm, and they are distributed along the axial direction; the transverse ribs are crescent-shaped, spaced 5-10 mm apart, and intersect the longitudinal ribs perpendicularly; the diameter of the first reinforcing rib is 0.8-1.2 mm, and it is distributed along the axial direction of the longitudinal rib; four high-strength steel wires are wound in a twisted manner with a pitch of 10-15 mm; the winding angle of the first to fourth winding ribs is 30°-45°; the second reinforcing rib is formed and distributed around the longitudinal rib, with a triangular cross section and a height of 1-1.5 mm.

7. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: In step six, the multi-roller straightener is a 6-8 roll type; the winding tightness of the longitudinal and transverse ribs is ≥95%.

8. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: In step seven, hot-dip galvanizing is used, with a zinc layer thickness of 80-120μm; the epoxy coating thickness is 60-100μm.

9. The production process of high-strength cold-rolled ribbed steel bars according to claim 1, characterized in that: In step eight, the height of the characters marking the roll pressing is 3-5mm.

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