JP7352265B1 - rolled steel pipe - Google Patents

Abstract

[Problem] By forming a concave portion spirally along the outer peripheral surface of a hollow steel pipe body, concave portions and protruding portions are alternately formed in the cross section of the steel pipe body, and the length of the protruding portion and the concave portion are A rolled steel pipe with excellent adhesion and bendability is provided by forming the ratio between the length of the part and the length of the part to be 1:1.3 to 1:3.
[Solution] A rolled steel pipe 300, 500, in which a hollow part 303, 503 is formed in a concave shape while continuing spirally along the outer peripheral surface of a hollow steel pipe body part 301, 501. The depressed portions 303, 503 and the protruding portions 305, 505 are alternately formed in the cross section of the body portions 301, 501, and the length D1 of the protruding portions 305, 505 in the cross section of the steel pipe body portions 301, 501 and the depressed portion are formed alternately. The ratio of the lengths 303 and 503 to the length D2 constitutes a rolled steel pipe in a range of 1:1.3 to 1:3.
[Selection diagram] Figure 1

Description

The present invention relates to rolled steel pipes, and more particularly to rolled steel pipes that have excellent adhesion and bendability.

Form rolling is a processing method in which a material is sandwiched between rolling dies and plastically deformed to form a desired shape.

On the other hand, as a device that can perform conventional rolling work, Korean Patent No. 10-1820641 describes a rolling machine that can be applied to various sizes of non-treated pipes and can create grooves at any position from the pipe end. A manufacturing apparatus is disclosed.

The rolling device described in the above-mentioned patent document includes a shaft portion, a first groove excavation portion, a second groove excavation portion, a tube end position determining member, a support member, and the like.

In addition, various devices that can perform rolling operations have been developed, and rolled steel pipes are manufactured using the rolling devices.

However, in the case of conventional rolled steel pipes, breakage frequently occurs at the bending part when the rolled steel pipe is bent, so there is an urgent need to research various conditions for improving the bendability of rolled steel pipes.

At the same time, it is also necessary to study various conditions for improving the adhesion of rolled steel pipes.

Here, adhesion is something that transmits the stress of reinforcing bars to concrete in a reinforced concrete structure, and is a basic condition of a reinforced concrete structure.

Korean registered patent No. 10-1820641

Therefore, the present invention was made against the above-mentioned background, and by forming a concave portion in a spiral arc shape along the outer circumferential surface of a hollow steel pipe body, the cross section of the steel pipe body is By forming depressions and protrusions alternately, and by forming the ratio of the length of the depressions to the length of the protrusions to be 1:1.3 to 1:3, rollability with excellent adhesion and bending properties is achieved. The purpose is to provide steel pipes.

Further, by forming the ratio of the minimum diameter to the maximum diameter in the cross section of the steel pipe body to be 1:1.8 to 1:2.1, it is possible to provide a rolled steel pipe with excellent adhesion and bendability. With the goal.

The objects of the invention are not limited thereto, and other objects not mentioned will be clearly understood by a person of ordinary skill in the art from the following description.

In order to achieve such an object, one embodiment of the present invention provides rolled steel pipes 300, 500 that are spirally continuous along the outer circumferential surface of hollow steel pipe bodies 301, 501 and have an arc-shaped shape. By forming the depressed portions 303, 503 in a concave shape, the depressed portions 303, 503 depressed in the cross-sectional direction of the steel pipe body portions 301, 501 and the protruding portions 305, 505 protruding in the cross-sectional direction are arranged in the longitudinal direction. are formed alternately , and the length (D1) of one longitudinal direction of the recessed portions 303, 503 is the length (D1) of one longitudinal direction of the protruding portions 305, 505 in the cross section of the steel pipe body portions 301, 501. The rolled steel pipe is characterized in that the ratio of D2) is 1:1.3 to 1:3.

Further, the rolled steel pipe is characterized in that the ratio of the maximum diameter (D_max) to the minimum diameter (D_min) of the cross section of the steel pipe body portions 301 and 501 is 1:1.8 to 1:2.1. provide.

Further, the rolled steel pipe is characterized in that the radius of curvature (R) of the circular arc shape of the depressed portions 303 and 503 is one of 8 mm, 12 mm, and 20 mm.

Further, the height of the protruding parts 305, 505 (H, D3 The rolled steel pipe is characterized in that the ratio of the length (D2) of the depressed portions 303, 503 to ) is 1:5.5 to 1: 8.5 .

According to an embodiment of the present invention, a certain ratio between the length of the depression and the length of the protrusion formed in the hollow steel pipe body, a certain ratio between the height of the protrusion and the length of the depression, The adhesion and bending properties of the rolled steel pipe can be improved by adjusting the ratio, a specific ratio between the minimum diameter and the maximum diameter of the steel pipe body, and a specific radius of curvature of the depression.

FIG. 1 is a perspective view of a rolled steel pipe according to an embodiment of the present invention. 2 is a partial cross section and a partially enlarged view of FIG. 1. FIG. FIG. 3 is a perspective view of a rolled steel pipe according to another embodiment of the present invention. 4 is a partial cross section and a partially enlarged view of FIG. 3. FIG. 1 is a photograph showing a state in which a prototype rolled steel pipe according to an embodiment of the present invention was subjected to bending tests at various radii of curvature, and the bent portion was not damaged. 1 is a photograph showing a state in which a prototype rolled steel pipe according to an embodiment of the present invention was subjected to bending tests at various radii of curvature, and the bent portion was not damaged. 1 is a photograph showing a state in which a prototype rolled steel pipe according to an embodiment of the present invention was subjected to bending tests at various radii of curvature, and the bent portion was not damaged. 1 is a photograph showing a state in which a prototype rolled steel pipe according to an embodiment of the present invention was subjected to bending tests at various radii of curvature, and the bent portion was not damaged. 1 is a photograph showing a state in which a prototype rolled steel pipe according to an embodiment of the present invention was subjected to bending tests at various radii of curvature, and the bent portion was not damaged. 1 is a photograph showing a state in which a prototype rolled steel pipe according to an embodiment of the present invention was subjected to bending tests at various radii of curvature, and the bent portion was not damaged. 1 is a photograph showing a state in which a prototype rolled steel pipe according to an embodiment of the present invention was subjected to bending tests at various radii of curvature, and the bending portion was not damaged.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. When adding reference numerals to each component in each drawing, please note that the same numerals are given to the same components as much as possible even if they appear on other drawings. Must. In addition, in describing the present invention, if it is determined that detailed description of related known configurations or functions may obscure the gist of the present invention, the detailed description thereof will be omitted.

Further, in describing the constituent elements of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are used only to distinguish the component from other components, and the term does not limit the nature or order of the component. When one component is described as being "connected," "coupled," or "connected" to another component, that component may be directly connected or connected to the other component, but each component's It should be understood that other components may also be "coupled," "coupled," or "connected" in between.

FIG. 1 is a perspective view of a rolled steel pipe according to an embodiment of the present invention. 2 is a partial cross-sectional view and a partially enlarged view of FIG. 1. FIG. FIG. 3 is a perspective view of a rolled steel pipe according to another embodiment of the present invention. FIG. 4 is a partial cross-sectional view and a partially enlarged view of FIG. 3. FIGS. 5 to 11 are photographs showing that the bent portions were not damaged as a result of bending tests at various radii of curvature of prototype rolled steel pipes according to embodiments of the present invention.

As shown in these drawings, according to the embodiments of the present invention, the rolled steel pipes 300, 500 have an arcuate concave shape that continues spirally along the outer peripheral surface of the hollow steel pipe body 301, 501. By forming the depressed portions 303, 503 in the steel pipe body portions 301, 501, the depressed portions 303, 503 depressed in the cross-sectional direction and the protruding portions 305, 505 protruding in the cross-sectional direction alternate in the longitudinal direction. The ratio of the length (D2) of the depressed portions 303, 503 to the length (D1) of the protruding portions 305, 505 in the cross section of the steel pipe body portions 301, 501 is 1:1.3 to 1:3. It is characterized by

The steel pipe body portions 301, 501 have a hollow space.

The hollow steel pipe body portions 301, 501 have depressed portions 303, 503 formed in an arcuate concave shape while continuing spirally along the outer peripheral surface thereof.

A partial cross section of such a steel pipe body section 301, 501 based on the central axis is shown in FIGS. 2 and 4.

Referring to FIGS. 2 and 4, the cross section of the steel tube body 301, 501 has depressions 303, 503 and protrusions 305, 505 formed alternately in the longitudinal direction .

Here, the ratio of the length (D2) of the depressions 303, 503 to the length (D1) of the protrusions 305, 505 is 1:1.3 to 1:3.

In the embodiment, the length (D1) of the protrusion 305 may be 7.69 mm, the length (D2) of the depression 303 may be 12.31 mm, and the length (D1) of the protrusion 305 may be 7.69 mm. 69 mm, the length (D2) of the depressed portion 303 may be 20 mm, the length (D1) of the protruding portion 505 may be 10.9 mm, and the length (D2) of the depressed portion 503 may be 19.1 mm. It's okay.

Meanwhile, the ratio of the maximum diameter (D_max) to the minimum diameter (D_min) of the cross section of the steel pipe body portions 301 and 501 may be 1:1.8 to 1:2.1.

In the embodiment, the minimum diameter (D_min) of the cross section of the steel pipe body 301 may be 9.5 mm, and the maximum diameter (D_max) may be 19.71 mm, and the minimum diameter (D_min) may be 12.6 mm, and the maximum diameter (D_min) may be 12.6 mm. The diameter (D_max) may be 22.81 mm, and the minimum diameter (D_min) of the cross section of the steel pipe body 501 may be 17.8 mm, and the maximum diameter (D_max) may be 32.42 mm.

Meanwhile, the depth (D3) of the depressions 303 and 503 may be 1.6 mm to 2.4 mm.

In the example, the depth (D3) of the depression 303 may be 1.61 mm, and the depth (D3) of the depression 503 may be 2.31 mm.

Here, the depth (D3) of the depressions 303, 503 is, in other words, the height (H) of the protrusions 305, 505, which is the height (H) of the protrusions 305, 505 from the lowest point of the depressions 303, 503. This corresponds to the length up to the highest point.

On the other hand, in the rolled steel pipes 300, 500 according to the embodiments of the present invention, the height of the protrusions 305, 505 ( The ratio of the length (D2) to the recessed portions 303 and 503 may be 1:5.5 to 1:8.5.

Further, the ratio of the length (D2) of the depressed portions 303, 503 to the height (H, D3) of the protruding portions 305, 505 may be 1:6.1 to 1:13.6.

As an example, the height (H, D3) of the protrusions 305, 505 may be 0.9 mm to 2 mm, and the length (D2) of the recesses 303, 503 may be 12.31 mm.

In the example (experimental object 2), the height (H) of the protrusions 305, 505 may be 1.7 mm, and the length (D2) of the depressed portions 303, 503 may be 10 mm.

In another example (experimental object 3), the height (H) of the protrusions 305, 505 may be 1.9 mm, and the length (D2) of the recesses 303, 503 may be 16 mm.

[Table 1] below shows the adhesion strength of the experimental body 1 in which the height (H) of the protruding parts 305, 505 is 1.6 mm and the length (D2) of the depressed parts 303, 503 is 15.3 mm. The figure shows the adhesion strength of the above-mentioned experimental body 2 and experimental body 3 when the following conditions are met.

As can be confirmed from [Table 1], it can be seen that the adhesion strength of Experimental Body 2 and Experimental Body 3 is superior to that of Experimental Body 1.

Meanwhile, the radius of curvature (R) of the circular arc shape of the depressed portions 303 and 503 may be one of 8 mm, 12 mm, and 20 mm.

In the embodiment, the radius of curvature (R) of the depressed portion 303 may be 8 mm or 12 mm, and the radius of curvature (R) of the depressed portion 503 may be 20 mm.

As a result of fabricating and bending a prototype of the rolled steel pipe according to the present invention as described above, no damage occurred at the bending portion, as shown in FIGS. 5 to 11.

This is because, in the case of the rolled steel pipe according to the present invention, when the pipe is bent, the concave portions 303 and 503 are expanded and folded to dissipate and disperse the stress applied to the bent portion.

As described above, according to an embodiment of the present invention, the specific ratio between the length of the depression and the length of the protrusion formed in the hollow steel pipe body, the height of the protrusion and the length of the depression The adhesion and bendability of the rolled steel pipe can be improved through a specific ratio between the diameter of the steel pipe body, a specific ratio between the minimum diameter and the maximum diameter of the steel pipe body, and a specific radius of curvature of the depressed part. be.

Even though it has been explained above that all the components constituting the embodiments of the present invention are combined into one or operate by being combined, the present invention is not necessarily limited to such embodiments. It's not. That is, within the scope of the present invention, all of the components can be selectively combined with one or more to operate.

The above description is merely an illustrative explanation of the technical idea of the present invention, and a person having ordinary knowledge in the technical field to which the present invention pertains will understand that the technical idea of the present invention is not deviated from the essential characteristics of the present invention. Various modifications and variations may be possible. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by such examples. It's not limited. The scope of protection of the present invention must be interpreted according to the scope of the claims below, and all technical ideas within the scope equivalent thereto should be construed as falling within the scope of rights of the present invention. .

300, 500 Rolled steel pipe 301, 501 Steel pipe body part 303, 503 Depressed part 305, 505 Protruding part

Claims (3)

A rolled steel pipe (300, 500),
A concave portion (303, 503) is formed in an arcuate concave shape while continuing spirally along the outer peripheral surface of the hollow steel pipe body (301, 501). ), the depressed portions (303, 503) depressed in the cross-sectional direction and the protruding portions (305, 505) protruded in the cross-sectional direction are formed alternately in the longitudinal direction ,
The length (D2) of one longitudinal direction of the recessed part (303, 503) with respect to the length (D1) of one longitudinal direction of the protruding part (305, 505) of the steel pipe body (301, 501). In a configuration where the ratio is 1:1.3 to 1:3 ,
The radius of curvature (R) of the circular arc of the depressed portion (303, 503) is one of 8 mm, 12 mm, and 20 mm.
A rolled steel pipe characterized by: 1 . The ratio of the maximum diameter (D_max) to the minimum diameter (D_min) of the cross section of the steel pipe body ( 301 , 501 ) is 1:1.8 to 1:2.1. Rolled steel pipe described in . The length of the protrusion (305, 505) is the length from the lowest point of the depression (303, 503) to the highest point of the protrusion (305, 505) in the cross section of the steel pipe body (301, 501). The ratio of the length (D2) of the depression (303, 503) to the height (H, D3) is 1:5.5 to 1:8.5, according to claim 1. Rolled steel pipe.

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