Five-slitting rolling process for phi14mm threads

Abstract

The invention discloses a five-slitting rolling process for phi14mm threads, which belongs to the technical field of rolling and comprises the following steps: heating a steel billet by a heating furnace, and rolling the steel billet in a rolling mill; the number of the rolling mills is 18, and the rolling mills are eight roughing rolling mill sets, seven intermediate rolling mill sets and three finishing rolling mill sets which are sequentially arranged from front to back. A 16.50 m steel billet is adopted for sizing; the intermediate rolling unit comprises a pre-cutting rolling mill, and a 2 # flying shear is arranged behind the pre-cutting rolling mill. The 16.50 m ultra-long steel billet is adopted for sizing, and the 8 + 7 + 3 rolling mill arrangement form is adopted, so that the problem of low production efficiency is solved, the production efficiency is improved, the production stability is ensured, and the economic and technical indexes are improved. The pre-cutting rolling mill moves forwards to medium rolling, the second flying shear is arranged after pre-cutting, the second flying shear can shear off the pre-cutting front part, the front quality is guaranteed, and therefore good conditions are provided for cutting sortie incoming materials, the cutting guide and guard failure rate is reduced, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of rolling, in particular to a five-section rolling process for a φ14mm thread. Background Art

[0002] In the modern steel industry, metal rolling technology, as a key link in steel production, plays a vital role in improving production efficiency, reducing costs and ensuring product quality. Slit rolling technology came into being. This technology uses the hole type to roll the rolled piece into multiple parallel rolled pieces during the hot rolling process, and then uses slitting equipment (such as rollers, guides, slitting wheels, etc.) to cut it into multiple single rolled pieces longitudinally, and finally roll it into finished steel products. Slit rolling technology has been widely used in the steel industry due to its significant energy-saving effect and efficient production capacity.

[0003] As far as the rolling production of φ14mm thread is concerned, the currently commonly used four-cut rolling process has exposed many problems in the actual production process. With the continuous development of steelmaking continuous casting technology, the production capacity of continuous casting equipment has gradually increased, and higher hourly output can be achieved. However, the hourly output of the existing φ14mm thread four-cut rolling machine is difficult to match the timely output of steelmaking continuous casting. This mismatch leads to the incoordination of the production process. The steel billets produced in the continuous casting link cannot be rolled in time, which not only causes the backlog of steel billets, but also increases storage costs and management difficulties.

[0004] From the perspective of production efficiency, the low efficiency of the four-cut rolling process seriously restricts the overall production efficiency of the enterprise. Due to the limitations of rolling speed and output, the enterprise needs to invest more time and resources to complete the established production tasks, which undoubtedly increases production costs and reduces the competitiveness of the enterprise in the market. Moreover, in the inefficient production process, the frequent start and stop of equipment and long-term operation will also lead to increased wear of the equipment, increase the cost and frequency of equipment maintenance and repair, and further affect the stability and continuity of production.

[0005] In addition, as the market's requirements for steel quality and performance continue to increase, the traditional four-cut rolling process has gradually become incapable of controlling product quality. For example, during the rolling process, due to uneven force on the rolled piece and insufficient cutting accuracy, it is easy to cause product dimensional deviation and surface quality defects, which not only affects the product's pass rate, but also increases the scrap rate, resulting in a waste of resources.

[0006] In summary, the existing φ14mm thread four-section rolling process has problems in production efficiency, output matching and product quality, which seriously affects the economic benefits and market competitiveness of enterprises, and an innovative rolling process is urgently needed to solve these problems. Based on this background, the present invention is committed to developing a φ14mm thread five-section rolling process to meet the needs of modern steel production. Summary of the invention

[0007] In order to solve the problems existing in the existing φ14mm thread four-section rolling process in production efficiency, output matching and product quality, the present invention provides a φ14mm thread five-section rolling process.

[0008] The present invention is achieved through the following technical solutions: A five-cut rolling process for φ14mm thread, comprising: a steel billet is heated in a heating furnace and then enters a rolling mill for rolling; the rolling mill is provided with 18 frames, which are 8 rough rolling mill groups, 7 intermediate rolling mill groups and three finishing rolling mill groups arranged in sequence from front to back; the steel billet adopts a 16.50m steel billet length; the intermediate rolling mill group includes a pre-cutting rolling mill, and a 2# flying shear is arranged behind the pre-cutting rolling mill.

[0009] A further improvement of the present invention is that the steel billet is semi-headless rolled using a 165mm×165mm×165000mm steel billet.

[0010] A further improvement of the present invention is to use a 34000mm×17400mm rod heating furnace.

[0011] A further improvement of the present invention is that the 13th rolling mill is a flat roll structure, and the roll gap is set to 21.4 mm.

[0012] A further improvement of the present invention is that the 14th rolling mill has a vertical box hole type, the groove bottom width is 19mm, the groove mouth width is 25.5mm, the fillet is R3.5mm; the hole height is 85mm.

[0013] A further improvement of the present invention is that the 15th rolling mill is a pre-cut hole type, the roll gap is 4.3mm, the middle hole width is 19.2mm, the total width is 95.5mm, the base circle radius of the two side lines is 8.5mm, and the base circle radius of the middle three lines is 8.8mm.

[0014] A further improvement of the present invention is that the 16th rolling mill is a split hole type, the roll gap is 1.0mm, the middle hole width is 19.2mm, the total width is 96.5mm, the base circle radius of the two side lines is 8.0mm, and the base circle radius of the middle three lines is 8.2mm.

[0015] A further improvement of the present invention is that the 17th rolling mill has an elliptical hole profile, a slot width of 24 mm, a base circle radius of 25.5 mm, and a hole profile height of 10.2 mm.

[0016] A further improvement of the present invention is that the final rolling speed of the finishing mill group is 14.5-15.0 m / s.

[0017] It can be seen from the above technical solutions that the beneficial effects of the present invention are: The 16.50m ultra-long billet length is used, which is 37.5% longer than the traditional billet. The longer billet reduces the tapping gap, making the rolling process more continuous, reducing the time loss caused by frequent loading and changing of materials, and greatly improving production efficiency. At the same time, since the number of cutting heads and tails is reduced, the waste of steel is reduced, the yield rate is improved, and the production cost is reduced. Moreover, the continuous and stable rolling process is conducive to maintaining the operating stability of the rolling mill, reducing the wear of equipment caused by frequent start and stop, and extending the service life of the equipment. The "8 + 7 + 3" rolling mill layout is adopted to reasonably allocate the rolling tasks at each stage; the 8 rolling mills of the roughing mill can carry out preliminary large deformation rolling on the heated steel billet, and quickly roll the steel billet into suitable intermediate billet, providing a good foundation for subsequent rolling; the 7 rolling mills of the intermediate rolling mill further refine the size and shape of the rolled piece in preparation for finishing rolling; the 3 rolling mills of the finishing mill focus on the final high-precision rolling of the rolled piece to ensure the dimensional accuracy and surface quality of the finished rebar; this layout with clear division of labor makes the entire rolling process more efficient and orderly, and improves the quality stability of the product. The pre-cutting mill is moved forward to the intermediate rolling mill, which can pre-cut the rolled pieces in advance, creating better conditions for subsequent cutting and rolling; the 2# flying shear set after pre-cutting can cut off the pre-cut front part in time, effectively ensuring the quality of the front and avoiding subsequent rolling failures caused by front quality problems; at the same time, good front quality provides stable and reliable conditions for the incoming materials of the cutting frame, reducing the failure rate of the cutting guide; the reduction of the failure rate of the cutting guide not only improves production efficiency, but also reduces downtime and maintenance costs caused by equipment failure, ensuring the stable operation of the entire rolling production line. These processes and equipment settings cooperate with each other, and have brought significant advantages to the five-cut rolling process of φ14mm thread from multiple aspects such as improving production efficiency, ensuring product quality, and reducing equipment failure rate, which has effectively promoted the improvement of enterprise production efficiency and market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0019] Figure 1 This is a schematic diagram of the 1H~4V hole structure.

[0020] Figure 2 This is a schematic diagram of the 5H~8V hole structure.

[0021] Figure 3 It is a structural diagram of the hole type of the 14H frame box.

[0022] Figure 4 It is a schematic diagram of the structure of the pre-cut hole type of the 15H frame.

[0023] Figure 5 It is a structural diagram of the 16H frame cutting hole type.

[0024] Figure 6 It is a structural diagram of the 17H ​​frame cutting hole type. DETAILED DESCRIPTION

[0025] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent.

[0026] like Figure 1-6 As shown, the present invention discloses a five-cut rolling process for φ14mm thread, comprising: a steel billet is heated in a heating furnace and then enters a rolling mill for rolling; the rolling mill is provided with 18 frames, which are 8 rough rolling mill groups, 7 intermediate rolling mill groups and three finishing rolling mill groups arranged in sequence from front to back; the steel billet adopts a 16.50m ultra-long steel billet cut length; the intermediate rolling mill group includes a pre-cutting rolling mill, and a 2# flying shear is arranged after the pre-cutting rolling mill.

[0027] The 16.50m ultra-long billet length is used, which is 37.5% longer than the traditional billet. The longer billet reduces the tapping gap, making the rolling process more continuous, reducing the time loss caused by frequent loading and changing of materials, and greatly improving production efficiency. At the same time, since the number of cutting heads and tails is reduced, the waste of steel is reduced, the yield rate is improved, and the production cost is reduced. Moreover, the continuous and stable rolling process is conducive to maintaining the operating stability of the rolling mill, reducing the wear of equipment caused by frequent start and stop, and extending the service life of the equipment. The "8 + 7 + 3" rolling mill layout is adopted to reasonably allocate the rolling tasks at each stage; the 8 rolling mills of the roughing mill can carry out preliminary large deformation rolling on the heated steel billet, and quickly roll the steel billet into suitable intermediate billet, providing a good foundation for subsequent rolling; the 7 rolling mills of the intermediate rolling mill further refine the size and shape of the rolled piece in preparation for finishing rolling; the 3 rolling mills of the finishing mill focus on the final high-precision rolling of the rolled piece to ensure the dimensional accuracy and surface quality of the finished rebar; this layout with clear division of labor makes the entire rolling process more efficient and orderly, and improves the quality stability of the product. The pre-cutting mill is moved forward to the intermediate rolling mill, which can pre-cut the rolled pieces in advance, creating better conditions for subsequent cutting and rolling; the 2# flying shear set after pre-cutting can cut off the pre-cut front part in time, effectively ensuring the quality of the front and avoiding subsequent rolling failures caused by front quality problems; at the same time, good front quality provides stable and reliable conditions for the incoming materials of the cutting frame, reducing the failure rate of the cutting guide; the reduction of the failure rate of the cutting guide not only improves production efficiency, but also reduces downtime and maintenance costs caused by equipment failure, ensuring the stable operation of the entire rolling production line. These processes and equipment settings cooperate with each other, and have brought significant advantages to the five-cut rolling process of φ14mm thread from multiple aspects such as improving production efficiency, ensuring product quality, and reducing equipment failure rate, which has effectively promoted the improvement of enterprise production efficiency and market competitiveness.

[0028] Among them, the billet is semi-headless rolled with 165mm×165mm×165000mm billet, and the single weight of the billet reaches 3.5 tons. And a 34000mm×17400mm ultra-long and ultra-wide bar heating furnace is used. Compared with the traditional billet, the length is increased by 37.5%, which reduces the steel tapping gap and the number of head and tail cutting, so that the machine hour output is increased by 40%, effectively improving production efficiency and production rhythm. During the rolling process of large-size billets, the metal deformation is more uniform and the internal structure is more compact, which helps to improve the mechanical properties of the product. The ultra-long and ultra-wide design of the heating furnace ensures that the billet is heated evenly, avoiding rolling defects caused by local temperature differences, such as cracks and uneven deformation, thereby improving the stability and consistency of product quality. It effectively reduces the number of billet replacements and heating time, and reduces energy consumption and equipment wear.

[0029] Among them, the 13th rolling mill is a flat roll structure with a roll gap set to 21.4mm. The flat roll structure can provide uniform rolling force for the rolled piece and avoid uneven force on the rolled piece due to the roll shape. The 21.4mm roll gap setting works closely with the previous and subsequent processes to effectively ensure the reduction of the 14th rolling mill. A stable reduction is the key to ensuring that the rolled piece is deformed according to the predetermined size and shape. It enables the 14th rolling mill to accurately process the rolled piece and ensure the stability of the material shape. The stable material shape provides a reliable foundation for subsequent rolling processes, especially the vertical box hole rolling of the 14th rolling mill, ensuring that the rolled piece can be evenly deformed during the subsequent rolling process, reducing product size deviations and surface defects caused by unstable material shapes, thereby improving product quality and production stability.

[0030] Furthermore, the 14th rolling mill is a vertical box pass, with a groove bottom width of 19mm, a notch width of 25.5mm, a fillet of R3.5mm, and a pass height of 85mm. The precisely set groove bottom width and notch width can enable the rolled piece to obtain just the right lateral constraint and extension space when passing through the pass, ensuring the lateral dimensional accuracy of the rolled piece and avoiding deviations in the width direction. The reasonable fillet design effectively reduces the stress concentration phenomenon of the rolled piece during the rolling process, reduces the risk of defects such as cracks on the surface of the rolled piece, and thus improves the surface quality of the product. The 85mm pass height provides a stable and suitable material basis for the subsequent rolling. It can ensure that the rolled piece has a uniform material shape when entering the subsequent frame, making the metal flow in the subsequent rolling process more reasonable and ensuring the fullness requirements of the transverse ribs. By strictly controlling the rolling load and ensuring it is above 12%, the advantages of the pass can be fully utilized, the rolling process can be stabilized, and product quality problems caused by unstable rolling load can be reduced, thereby improving the overall production efficiency and product quality.

[0031] Furthermore, the 15th rolling mill is a pre-cutting hole type, with a roll gap of 4.3mm, a middle hole width of 19.2mm, a total width of 95.5mm, a base circle radius of 8.5mm on both sides, and a base circle radius of 8.8mm on the middle three lines. It can make fine size adjustments to the rolled piece. The 4.3mm roll gap ensures accurate thinning of the rolled piece in the thickness direction, so that the rolled piece has a suitable thickness when entering the subsequent process, preparing for cutting. The design of the middle hole width and the total width ensures the dimensional accuracy of the rolled piece in the transverse direction, ensures that the shape of the rolled piece meets the requirements of subsequent cutting, avoids uneven cutting or cutting failure due to dimensional deviation, and improves the success rate of cutting and the consistency of product quality. It can also optimize the stress distribution of the rolled piece during the rolling process; the reasonable base circle radius makes the metal flow more uniform in the pre-cutting stage of the rolled piece, reduces the stress concentration point, which not only reduces the risk of defects such as cracks and tears in the rolled piece, but also ensures that the rolled piece maintains a good internal organizational structure in the subsequent cutting and rolling process, and improves the mechanical properties of the product. The parameter setting of the pre-cutting hole type is the key link of the entire five-cut rolling process. It provides the best incoming material conditions for the cutting hole type of the 16th rolling mill. After the pre-cutting treatment of the 15th rolling mill, the rolled piece has a preliminary cutting shape, which enables the 16th rolling mill to perform the cutting operation more smoothly, improves the cutting accuracy and efficiency, and further ensures the efficient operation of the entire rolling process and the stability of product quality.

[0032] Furthermore, the 16th rolling mill is a slitting hole type, with a roll gap of 1.0mm, a middle hole width of 19.2mm, a total width of 96.5mm, a base circle radius of 8.0mm on both sides, and a base circle radius of 8.2mm on the middle three lines. The 16th rolling mill is a key link in slitting. The 1.0mm roll gap setting ensures that precise longitudinal slitting can be achieved when the rolled piece is subjected to rolling force. The extremely narrow roll gap causes stress concentration at a specific position of the rolled piece, so that it can be smoothly slit according to the preset path, ensuring the accuracy and consistency of the slitting, avoiding the problem of incomplete slitting or slitting deviation, and greatly improving the success rate of the five slitting. The design of the middle hole width of 19.2mm and the total width of 96.5mm further standardizes the size of the individual pieces after slitting during the slitting process; ensuring that each individual piece after slitting meets the rolling requirements of the φ14mm thread in the width direction, ensuring the dimensional accuracy when it is subsequently rolled into a finished product, and reducing defective products caused by dimensional deviation. The design of 8.0mm base circle radius on both sides and 8.2mm base circle radius on the middle three lines makes the metal flow more reasonable at the moment of cutting; effectively avoids the damage to the internal structure of the rolled piece caused by excessive stress concentration during the cutting process, ensures the uniformity of the internal organizational structure of the rolled piece after cutting, improves the mechanical properties of the product, and makes the φ14mm thread reach better standards in terms of strength and toughness. The precise setting of the cutting hole parameters enables the rolled piece after cutting to smoothly enter the subsequent finishing process; it provides a good foundation for further processing of the finishing mill, ensures the continuity and efficiency of the entire rolling process, reduces the stagnation of the production line caused by cutting problems, and improves production efficiency.

[0033] Furthermore, the 17th rolling mill adopts an elliptical hole type, with a slot width of 24mm, a base circle radius of 25.5mm, and a hole height of 10.2mm. Optimizing the shape of the rolled piece: The 17th rolling mill adopts an elliptical hole type, with a slot width of 24mm, a base circle radius of 25.5mm, and a hole height of 10.2mm. This design can further optimize the shape of the rolled piece after cutting. The elliptical hole type can make the metal distribution of the rolled piece more uniform during the rolling process, avoid stress concentration caused by irregular shape, thereby improving the internal quality of the rolled piece and providing better billets for subsequent finishing. The precise setting of the slot width and base circle radius ensures that the dimensional accuracy of the rolled piece is further improved when the rolled piece is rolled in this rolling mill. The slot width of 24mm and the base circle radius of 25.5mm ensure that the rolled piece is closer to the standard requirements of the finished product φ14mm thread in width and curvature, providing a guarantee for the final finished product dimensional accuracy and reducing the scrap rate caused by dimensional deviation. The hole height setting of 10.2mm matches the rolling process of the subsequent 18th rolling mill, providing a suitable material type for the subsequent rolling process. The appropriate hole height enables the rolled piece to smoothly undergo the final thread forming rolling when entering the 18th rolling mill, ensuring the continuity and smoothness of the entire rolling process and improving production efficiency.

[0034] Among them, the final rolling speed of the finishing mill is 14.5-15.0m / s. The production efficiency is greatly improved, and the output is increased by 70t / h compared with the original four-cut process machine, so that more φ14mm rebar can be produced per unit time.

[0035] According to the billet positioning and multiple-length shearing scheme in the heating furnace, the billet length corresponding to the φ14mm thread is designed, as shown in Table 1.

[0036] Table 1

[0037] According to the “8+7+3” process layout, the reduction is redistributed. The rolling schedule is shown in Table 2.

[0038] Table 2

[0039] According to the above-mentioned five-cut rolling process of φ14mm thread, the output of φ14mm thread machine reaches 280t / h, which is 70t / h higher than that of four-cut machine. The heat delivery rate is increased from 75% to 93%, and the heat delivery rate is increased by 18%. The production efficiency is increased by 33%, the rolling process is more stable, the product appearance quality is better, and the negative difference rate and yield rate indicators are better.

[0040] The five-cut rolling process of the φ14mm thread adopts 16.50m super-long billet length, optimized rolling mill layout (8+7+3) and hole type system to solve the problem of low production efficiency, improve production efficiency, ensure production stability, and improve economic and technical indicators. The pre-cutting mill is moved forward to the middle rolling, and the 2# flying shear is set after the pre-cutting. The 2# flying shear can cut off the pre-cutting front part, ensuring the quality of the front part, thus providing good conditions for the incoming materials of the cutting frame, reducing the failure rate of the cutting guide, and improving production efficiency.

[0041] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A five-section rolling process for φ14mm thread, characterized in that: The steel billet is heated in a heating furnace and then enters a rolling mill for rolling; the rolling mill is set up with 18 frames, including 8 rough rolling mills, 7 intermediate rolling mills and three finishing rolling mills arranged from front to back; the steel billet adopts a 16.50m billet length; the intermediate rolling mill includes a pre-cutting mill, and a 2# flying shear is set after the pre-cutting mill.

2. The five-section rolling process of φ14mm thread according to claim 1, characterized in that: The steel billet is semi-headless rolled using 165mm×165mm×165000mm steel billet.

3. The five-cut rolling process of φ14mm thread according to claim 2, characterized in that: A 34000mm×17400mm bar heating furnace is used.

4. The five-section rolling process of φ14mm thread according to claim 1, characterized in that: The 13th rolling mill has a flat roll structure and the roll gap is set to 21.4 mm.

5. The five-section rolling process of φ14 mm thread according to claim 4, characterized in that: The 14th rolling mill has a vertical box hole type with a groove bottom width of 19mm, a groove mouth width of 25.5mm, a corner radius of R3.5mm, and a hole height of 85mm.

6. The five-cut rolling process of φ14 mm thread according to claim 5, characterized in that: The 15th rolling mill has a pre-cut hole type, a roll gap of 4.3mm, a middle hole width of 19.2mm, a total width of 95.5mm, a base circle radius of both sides of 8.5mm, and a base circle radius of the middle three lines of 8.8mm.

7. The five-section rolling process of φ14 mm thread according to claim 6, characterized in that: The 16th rolling mill has a split hole type, with a roll gap of 1.0mm, a middle hole width of 19.2mm, a total width of 96.5mm, a base circle radius of 8.0mm on both sides, and a base circle radius of 8.2mm for the three middle lines.

8. The five-cut rolling process of φ14 mm thread according to claim 7, characterized in that: The 17th rolling mill has an elliptical hole profile with a slot width of 24mm, a base circle radius of 25.5mm and a hole profile height of 10.2mm.

9. The five-section rolling process of φ14 mm thread according to claim 1, characterized in that: The final rolling speed of the finishing mill is 14.5-15.0m / s.

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