Forming process of hot-rolled bent and closed angle section steel

Abstract

The present application relates to a kind of hot roller bending sharp corner closed section steel forming process, to solve the problems of large residual stress in the existing cold bending sharp corner section steel process, severe work hardening, complex process and high cost etc..The present application utilizes the high temperature of hot-rolled steel plate to directly perform roller bending forming, processes four bending corners of the steel plate in two groups, the first bending corner is formed and finished to a sharp corner with an outer fillet radius close to zero, and then the second bending corner is formed and finished.The process includes the following steps: first bending corner initial forming, first bending corner finishing, second bending corner initial forming, finishing, welding, weld cooling, second bending corner finishing, sizing, cooling and fixed-length cutting, etc..The process effectively shortens the process, reduces production cost, improves the quality of sharp corner section steel, especially solves the problem of residual stress in the bending corner area, and improves its applicability in high-rise buildings.

Description

Technical Field

[0001] This invention belongs to the field of steel forming technology and relates to a forming process for hot-roll bending of sharp-cornered closed-section steel. Background Technology

[0002] With the widespread adoption of prefabricated building structures, the demand for closed-section steel, especially square and rectangular tubes, is increasing. Conventional cold-formed closed-section steel suffers from thinning in the rounded corner areas, large corner radii, and high residual stress, limiting its application in high-rise buildings. Furthermore, if cold-formed sharp-corner steel is used, the corner areas undergo work hardening, exacerbating the risk of cracking.

[0003] Existing methods for forming sharp-angle steel sections involve either cold bending followed by heating the rounded corners for extrusion sizing, or cold bending followed by overall heating for extrusion sizing of the sharp corners. This process adds a heating step, increasing the cost of the sharp-angle steel. Furthermore, residual stress remains in the bend areas of sharp-angle steel formed in this way, limiting its application in high-rise buildings. Summary of the Invention

[0004] In view of this, the purpose of this invention is to solve the above problems and provide a forming process for hot roll bending of sharp-corner closed steel sections. This process utilizes the high temperature of the hot-rolled steel plate to directly roll bend the steel into sharp-corner closed steel sections, thereby shortening the process flow, reducing the cost of the steel sections, and improving the product quality of the sharp-corner steel sections.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A forming process for hot roll bending of sharp-corner closed-section steel involves dividing the four sharp corners of the steel section into two groups: a first bend and a second bend. The first bend consists of the two bends on the outer side of the unfolded steel plate, and the second bend consists of the two bends on the inner side of the unfolded steel plate. The sharp-corner closed-section steel is directly roll-bent using the high temperature of the hot-rolled steel plate. The roll bending process includes the following steps:

[0007] S1. Initial forming of the first bend: The high-temperature steel plate is hot-rolled at the two first bends to obtain a U-shaped open steel section.

[0008] S2, First bend corner finishing: Finishing the first bend corner of the open steel section to make the first bend corner into a sharp corner;

[0009] S3, Initial forming of the second bend: Forming the two second bend portions on the inner side of the high-temperature steel plate;

[0010] S4. Precision forming: Further forming of the first and second bends of the open steel section;

[0011] S5. Welding: Welding and fusion are performed on the closed sections of the open-section steel to form a closed-section steel.

[0012] S6. Weld cooling: Cool the weld of the closed-section steel.

[0013] S7. Second bend corner sharpening: The two corresponding second bend corners on the closed steel section are finely shaped into sharp corners.

[0014] S8. Sizing: Sizing the closed-section steel to form a qualified product.

[0015] S9. Cooling: Cool the closed-section steel after sizing.

[0016] S10, Cut to length: Cut the cooled steel sections to length.

[0017] S10. Collection and warehousing: Collect the completed steel sections to the finished product warehouse.

[0018] Furthermore, the initial angle of the first bend in S1 is 85° to 92°.

[0019] Furthermore, in S2, a slanted roller is used to finish the first bend of the open-end steel, and the bend of the first bend after initial forming is finished into a sharp corner with an outer radius close to zero.

[0020] Furthermore, the initial angle of the second bend in S3 is 65° to 75°.

[0021] Furthermore, in S7, a combination of flat and vertical rollers is used to refine the bend of the second bend in the closed-end steel into a sharp corner with an outer radius close to zero.

[0022] Optionally, the second bend and sharp corner finishing process can be carried out simultaneously with the sizing process.

[0023] The beneficial effects of this invention are as follows:

[0024] This invention efficiently utilizes the deformation advantage of high-temperature steel plates to deform the bends of the steel profiles into sharp angles. The first bend deforms to 85°–92° during the initial forming stage, which is beneficial for subsequent sharp angle finishing processes and edge fusion during welding. The second bend's sharp angle finishing and sizing processes are performed simultaneously, which helps improve forming efficiency.

[0025] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0027] Figure 1 This is a schematic diagram illustrating the implementation process of the hot roll bending of the closed-angle steel profile in this invention.

[0028] Figure 2 Schematic diagram of the first bend angle and sharp corner finishing.

[0029] Figure 3 Schematic diagram of the second bend angle sharpness finishing.

[0030] Figure reference numerals: 1-High temperature steel plate; 11-First bend; 12-Second bend; 21-Open section steel; 22-Sharp-corner open section steel; 23-Slanted roll. Detailed Implementation

[0031] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0033] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0034] Please see Figures 1-3This describes a hot roll bending forming process for sharp-corner closed-section steel. The four sharp corners of the steel section are divided into two groups: a first bend (11) and a second bend (12). The first bend consists of the two outer bends on the unfolded steel plate, and the second bend consists of the two inner bends on the unfolded steel plate. The sharp-corner closed-section steel is directly formed by roll bending using the high temperature of the hot-rolled steel plate. Taking hot roll bending of square and rectangular tubes as an example, the forming method is "direct square forming." The roll bending process includes the following steps:

[0035] S1. Initial forming of the first bend: The high-temperature steel plate 1 is hot-rolled to form the first bend 11 part of the two bends. The angle of the first bend 11 after initial forming is 85°~92°, resulting in a U-shaped open steel section 21.

[0036] S2. First bend corner finishing: The first bend corner 11 of the open steel 21 is finished by using the inclined roller 23 to finish the first bend corner of the open steel 21, and the bend corner of the first bend corner after initial forming is finished into a sharp corner with an outer radius close to zero, thus obtaining the sharp corner open steel 22.

[0037] S3. Initial forming of the second bend: The two second bends 12 on the inner side of the high-temperature steel plate 1 are formed. The angle of the second bend after initial forming is 65°~75°.

[0038] S4. Precision forming: Further forming of the first and second bends of the open steel section 22;

[0039] S5. Welding: High-frequency welding is used to weld and fuse the closed positions of the open section steel 22 to form a closed section steel.

[0040] S6. Weld cooling: Use air cooling, water cooling or other methods to cool the weld of closed-section steel.

[0041] S7. Second bend corner finishing: The two corresponding second bend corners on the closed steel section are finished into sharp corners. The bend corners of the second bend corners in the closed steel section are finished into sharp corners with an outer radius close to zero by using a combination of flat and vertical rollers.

[0042] S8. Sizing: Sizing the closed-section steel to form a qualified product.

[0043] S9. Cooling: Cool the closed-section steel after sizing.

[0044] S10, Cut to length: Cut the cooled steel sections to length.

[0045] S10. Collection and warehousing: Collect the completed steel sections to the finished product warehouse.

[0046] The sizing process is carried out simultaneously with the finishing of the second bend angle.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A forming process for hot-roll bending sharp-angle closed-section steel, characterized in that, The four sharp corners of the closed-section steel are divided into two groups: the first bend and the second bend. The first bend consists of the two bends on the outer side of the unfolded steel plate, and the second bend consists of the two bends on the inner side of the unfolded steel plate. The closed-section steel is then directly roll-formed using the high temperature of the hot-rolled steel plate. The roll-forming process includes the following steps: S1. Initial forming of the first bend: The high-temperature steel plate is hot-rolled at the two first bends to obtain a U-shaped open steel section. S2. First bend corner finishing: The first bend corner of the open-section steel is finished to form a sharp corner; the first bend corner of the open-section steel is finished by using a slanted roller to finish the bend corner of the first bend corner after initial forming to a sharp corner with an outer radius close to zero. S3, Initial forming of the second bend: Forming the two second bend portions on the inner side of the high-temperature steel plate; S4. Precision forming: Further forming of the first and second bends of the open steel section; S5. Welding: Welding and fusion are performed on the closed sections of the open-section steel to form a closed-section steel. S6. Weld cooling: Cool the weld of the closed-section steel. S7. Second bend corner finishing: The two corresponding second bend corners on the closed steel section are finished into sharp corners; the bend corners of the second bend corners in the closed steel section are finished into sharp corners with an outer radius close to zero by using a combination of flat and vertical rollers. S8. Sizing: Sizing the closed-section steel to form a qualified product. S9. Cooling: Cool the closed-section steel after sizing. S10, Cut to length: Cut the cooled steel sections to length. S11. Collection and warehousing: Collect the completed steel sections to the finished product warehouse.

2. The forming process of hot-roll bending pointed-angle closed-section steel according to claim 1, characterized in that: The initial angle of the first bend in S1 is 85° to 92°.

3. The forming process of hot roll bending pointed-angle closed-section steel according to claim 1, characterized in that: The initial angle of the second bend in S3 is 65° to 75°.

4. The forming process of hot-roll bending sharp-angle closed-section steel according to claim 1, characterized in that: The second bend and sharp corner finishing process is carried out simultaneously with the sizing process.

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