KR100814863B1 - Steel pipe, method of making the same, and tool of making the same - Google Patents

Abstract

A steel pipe, and a method and an apparatus of making the same are provided to achieve improved work efficiency by forming a ring insertion groove at a roller during a bending process. A method of making a steel pipe includes a step of uncoiling a steel coil for manufacturing a steel pipe(100), a step of welding a plurality of reinforcement members(120) to the uncoiled steel plate, a step of bending the steel plate in a pipe shape, a step of welding ends of the reinforcement members and the steel pipe, and a step of performing heat treatment on the welded parts and cooling the heat-treated parts.

Description

Steel pipe, its manufacturing method and its manufacturing apparatus {Steel pipe, Method of making the same, and Tool of making the same}

1 is a perspective view showing a state before and after deformation of a general steel pipe used as a pipe for a plastic house,

Figure 2a is a partial cutaway perspective view of a steel pipe according to an embodiment of the present invention,

FIG. 2B is a cross-sectional view taken along the line A-A 'of FIG. 2A;

3 is a partial cutaway perspective view of a steel pipe according to another embodiment of the present invention;

4 is a partial cutaway perspective view of a steel pipe according to another embodiment of the present invention;

5 is a flow chart of a steel pipe manufacturing method according to an embodiment of the present invention,

6 is a plan view of a steel pipe is partially bent after the first welding step,

7 is a front view of the bending step,

8 is a cross-sectional view of the steel pipe after the second welding step.

<Description of Symbols for Main Parts of Drawings>

100, 200, 300-Steel pipe 120-Reinforcement ring

220-Reinforcement Plate 320-Reinforcement Spring

B-Base Roll R-Roller

G-Ring Insertion Groove

The present invention relates to a steel pipe, a method for manufacturing the same, and a device for manufacturing the same, and more particularly, by inserting a reinforcing member such as a ring, a spring, a plate, and the like into a hollow of a steel pipe used in a plastic house, the shear strength, the torsional strength, and the bending strength. It relates to a steel pipe and a manufacturing method for improving the steel pipe manufacturing apparatus that can improve the work efficiency by forming a ring insertion groove in the roller in the bending process of the manufacturing process of the steel pipe.

Steel pipes used for structural pillars, truss or pipes in vinyl houses are generally hollow. Production methods of such steel pipes include an electric resistance welding (ERW) method, a spiral method, and a roll bending method. In particular, a pipe having a small cross section mainly uses an ERW (electric resistance welding) method, which is manufactured by unwinding a steel pipe coil at room temperature, bending it in the shape of a pipe on a roller, and then welding by using heat generated by electrical resistance as a high frequency. In addition, the steel pipe is formed in a circular, polygonal or the like in cross section depending on the use. As a material of the steel pipe, carbon steel plated with aluminum, stainless steel, zinc, etc. is mainly used in consideration of the fact that high strength and high elasticity are required when used for structural purposes.

1 is a perspective view showing a state before and after deformation of a general steel pipe used as a pipe for a plastic house.

The pipe for the vinyl house at the time of installation in Figure 1 has the shape of a steel pipe 10 of the normal form. However, when an external force is applied due to a natural disaster such as a typhoon or heavy snow, the shape of the steel pipe 30 is in the shape of 휜. In particular, during heavy snow, the upper load is excessively applied, and a concentrated moment is applied to the central portion M and the lateral mount portions S1 and S2 on both sides thereof, and thus is easily deformed as shown in FIG. 1. Referring to the enlarged portion of the deformation part 35, since the inside of the steel pipe is empty, the cross section of the pipe is pressed and the outer diameter and the inner diameter are reduced while being folded. In general, since the vinyl house is installed in an arch shape due to its characteristics, it is difficult to bend when using a high-strength steel pipe so that a hot rolled steel pipe is used. Hot rolled steel pipes are sagging or bent due to their weak strength and elasticity. In particular, in recent years, the abnormal climate frequently occurs globally, the risk of summer typhoons and winter snowfall is increasing.

In general, galvanized steel pipes with an inner diameter of 22 to 32 mm are used as pipes for agricultural vinyl houses. These steel pipes were made up of 22mm inside and 1.2mm thick until a few years ago. However, as described above, the phenomenon that the vinyl house falls frequently during natural disasters every year, and the current diameter is 25 ~ 27mm, larger 32mm and 1.8mm thickness is currently used. However, increasing the standard of steel pipes increases the cost and increases the burden on farmers, which may lead to a weakening of agricultural competitiveness. Therefore, it is urgent to develop a technology that can improve the shear strength, the torsional strength and the bending strength while maintaining the standard of the steel pipe.

The present invention has been made to solve the above problems, in particular, by inserting a reinforcing member, such as a ring, spring, plate, etc. in the hollow of the steel pipe used for vinyl housing, etc., to improve the shear strength, torsional strength, bending strength It is an object of the present invention to provide a steel pipe manufacturing apparatus that can improve the work efficiency by forming a ring insertion groove in the roller in the bending process of the steel pipe and its manufacturing method and the manufacturing process of the steel pipe.

Steel pipe according to the present invention devised to achieve the above object is characterized in that in the structural steel pipe, the reinforcing member is inserted into the steel pipe.

In addition, the reinforcing member may be joined to the steel pipe by welding. In addition, the reinforcing member may be any one of a reinforcing ring, reinforcing plate material, reinforcing spring.

In addition, the reinforcing ring or the reinforcing plate member may be formed a plurality of spaced apart from each other by a predetermined interval. In addition, the predetermined interval is preferably a length within 10 times the cross-sectional inner diameter of the steel pipe.

In addition, the method of manufacturing a steel pipe according to the present invention comprises the steps of: uncoiling a steel pipe coil for steel pipe manufacturing; A first welding step of welding a plurality of reinforcing members at predetermined intervals to the uncoiled steel pipe plate; Bending the steel pipe plate welded to the reinforcing member into a tubular shape; A second welding step of welding one end and the other end of the reinforcing member and the steel pipe plate; And heat treating and cooling the welded portion.

In addition, the reinforcing member may be any one of a reinforcing ring, reinforcing plate material, reinforcing spring.

In addition, the first welding step may be by electro-pressure welding, the second welding step may be by the slash welding.

In addition, the steel pipe manufacturing apparatus according to the present invention includes a base roll (base roll); And a roller for placing the steel pipe on the base roll and bending the steel pipe, wherein the roller is formed with a ring insertion groove for fixing the position of the reinforcing ring welded to the steel pipe.

In addition, the ring insertion groove may be formed on one side of the roller to a depth less than the thickness of the reinforcing ring.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible, even if shown on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the following will describe a preferred embodiment of the present invention, but the technical idea of the present invention is not limited thereto and may be variously modified and modified by those skilled in the art.

First, a steel pipe according to an embodiment of the present invention will be described.

Figure 2a is a partially cutaway perspective view of a steel pipe according to an embodiment of the present invention, Figure 2b is a cross-sectional view taken along line AA 'of Figure 2a.

Steel pipe 100 according to an embodiment of the present invention, referring to Figure 2a, the reinforcing ring 120 is inserted therein. The reinforcing ring 120 is bent (vending) of a substantially rectangular plate material is formed in a substantially cylindrical shape. The reinforcing ring 120 is attached to the inner circumferential surface of the steel pipe 100 by welding. The welding may be performed by resistance welding, laser welding, or the like. However, the welding is preferably performed by electric pressure welding, that is, electric arc welding. Referring to FIG. 2B, the welding part is preferably both central portions 130 of the reinforcing member 120. On the other hand, the welding of both ends of the reinforcing ring 120 and the steel pipe 100 is preferably made by fillet welding. In the case of butt welding, butt welding is a welding method in which two welding teeth are not at one plane but at a predetermined angle. The welded portions of electro-welding and slag welding face each other. The reinforcing ring 120 may be formed of the same or similar material as the steel pipe 100, it is preferable that the galvanized carbon steel excellent in flexural strength. The manufacturing method of the steel pipe 100 will be described later.

Referring to FIG. 2B, the reinforcing ring 120 is formed to be spaced apart from each other by a predetermined interval. Preferably, the reinforcing ring 120 is spaced apart from each other by a distance within 10 times the inner diameter of the cross section of the steel pipe (100). In order to determine the appropriate interval, the following experiment was conducted using bamboo. Since the vinyl house is installed in an arch shape, it is common for the top or both sides to sit down in case of typhoon or heavy snowfall. Applicant has come up with the idea from bamboo, which maintains the shape flexibly without breaking even in the harsh natural environment such as strong wind or heavy snow. Nodule spacing and cross section diameter measurements were made using several bamboo specimens, and the average nodule spacing was within approximately 10 times the inner diameter of the bottom of the bamboo. If the same applies to the steel pipe, the spacing between the reinforcing ring 120 is also preferably arranged and attached within 10 times the inner diameter of the steel pipe (100). However, the above intervals need not be all the same, and it is preferable that the interval is adjusted and arranged according to the strength of the shear force. For example, when the steel pipe 100 is used for the vinyl house pipe, since the center portion and both the base portions are easily deformed, the reinforcing ring 120 will be arranged in such a portion.

As such, when the reinforcing ring 120 is inserted into the inside of the steel pipe 100 at predetermined intervals, the initial stiffness is increased by 26 to 30% compared to the general steel pipe having an empty interior. In addition, the steel pipe 100 has a maximum strength of about 20% increased, showing a result of improved bending strength.

Next, a steel pipe according to another embodiment of the present invention will be described.

3 is a partial cutaway perspective view of a steel pipe according to another embodiment of the present invention. The embodiment of FIG. 3 is similar to the embodiment of FIG. 2A except that the reinforcing plate 220 is inserted into the steel pipe 200 instead of the reinforcing ring 120, and thus, the difference will be described.

Steel pipe 200 according to another embodiment of the present invention, referring to Figure 3, the reinforcing plate 220 is inserted therein. At this time, the reinforcing plate 220 is formed to be substantially perpendicular to the inner peripheral surface of the steel pipe (200). The reinforcing plate material 220 is formed in a substantially disk shape. However, when the cross-sectional shape of the steel pipe is a polygonal shape rather than a circular shape, the reinforcement plate may also be formed in a polygonal shape. The reinforcing plate 220 is welded to the inner surface of the plate-shaped steel pipe 200 by electric pressure, and then bend the steel pipe 200 in a cylindrical shape, the both ends of the steel pipe 200 and the reinforcing plate 220 It is attached by carrying out the thermal welding of the contact part. On the other hand, the reinforcing plate material 220 may be attached in such a way that the cylindrical steel pipe 200 is cut and bisected in the longitudinal direction, and then inserted and welded therein. At this time, after the welding of the reinforcing plate material 220, of course, the process of welding the bisected steel pipes 200 are further required.

The reinforcing plate 220 is also inserted into a plurality of spaced apart from each other by a predetermined interval, preferably the separation distance is within about 10 times the inner diameter of the steel pipe (200). By doing so, the steel pipe 200 is improved in shear strength, flexural strength and torsional strength, so that the steel pipe 200 can be firmly maintained without being deformed even when external force is applied.

Next, a steel pipe according to another embodiment of the present invention will be described.

Figure 4 is a partial cutaway perspective view of a steel pipe according to another embodiment of the present invention. The embodiment of FIG. 4 is similar to the embodiment of FIG. 2A except that the reinforcing spring 320 is inserted into the steel pipe 300 instead of the reinforcing ring 120.

Steel pipe 300 according to another embodiment of the present invention, referring to Figure 4, the reinforcement spring 320 is inserted therein. The reinforcement spring 320 is made in advance, and is attached to the steel pipe 300 by inserting and welding. The reinforcement spring 320 may also be formed to be spaced apart from each other by a predetermined interval as in the case of the reinforcement ring 120 and the reinforcement plate 220. On the other hand, the reinforcement spring 320 may be inserted into the entire steel pipe 300, of course. At this time, the elastic modulus of the reinforcing spring 320 is preferably large enough to withstand even a significant load is applied by external force. Preferably, the reinforcing spring 320 is pre-welded at least two places inside the steel pipe 300, and when the both ends of the bent steel pipe 300 are connected to each other, it is preferable that the welding is made.

By doing so, the steel pipe 300 is improved by the inserted reinforcement spring 320 shear strength, bending strength and torsional strength and exhibits excellent restoring force even during deformation.

Next, a method of manufacturing a steel pipe according to an embodiment of the present invention will be described.

5 is a flow chart of a steel pipe manufacturing method according to an embodiment of the present invention. 6 is a plan view of a steel pipe, a part of which is being bent after the first welding step. 7 is a front view of the bending step. 8 is a cross-sectional view of the steel pipe after the second welding step. Hereinafter, a method of manufacturing a steel pipe (when a reinforcing ring is used as a reinforcing member) according to the embodiment of FIG. 2A will be described as an example.

Steel pipe manufacturing method according to an embodiment of the present invention, referring to Figure 5, uncoiling (S10), leveling (S20), cutting step (S30), reinforcing member insertion step ( S40), the first welding step (S50), the bending step (S60), the second welding step (S70), and the welding region heat treatment and cooling step (S80) is made.

The uncoiling step (S10) is a step of unfolding the steel pipe manufacturing coil for manufacturing the steel pipe (100). Sheets for the production of steel pipes are wound in a cylindrical form in consideration of their ease of handling and transport. Therefore, in order to manufacture a steel pipe, the coil must be unfolded into a flat plate shape. Although not shown, the steel pipe manufacturing coil may be uncoiled using a pair of rollers facing each other.

The leveling step (S20) is a step of flattening the steel pipe manufacturing plate released through the uncoiling step (S10) into a flat plate shape. Although not shown, the leveling step S20 may be performed by passing a steel pipe manufacturing plate between a plurality of rollers arranged in a zigzag form.

The cutting step (S30) is a step of cutting to meet the standard to manufacture the flattened steel pipe manufacturing plate through the leveling step (S20). The cutting step (S30) may vary depending on the use of the steel pipe. For example, when manufactured for a vinyl house pipe, the cutting specification is determined in consideration of the inner and outer diameters of the final pipe.

The reinforcing member insertion step (S40) is a step of arranging the reinforcing member 120 on the surface to be the inner circumferential surface of the steel pipe 100 cut to the appropriate standard through the cutting step (S30). The reinforcing member 120 is arranged a plurality of spaced apart from each other at appropriate intervals, the interval is preferably as mentioned above that less than 10 times the inner diameter of the steel pipe (100).

Referring to FIG. 6, the first welding step S50 is a step of welding the reinforcing members 120 arranged at appropriate intervals through the reinforcing member insertion step S40 to the steel pipe 100. In the first welding step (S50), the welding is preferably made on both sides of the central portion 130 of the reinforcing member 120, it is preferable that the electric pressure welding. However, the welding method and the welding location and recovery may be made differently.

7, the bending step S60 is a step of bending the steel pipe 100 welded to the reinforcing member 120 through the first welding step S50 in a tubular shape. The bending step S60 may be made through a steel pipe manufacturing apparatus including a base roll B and a roller R, which will be described later.

In the second welding step (S70), referring to FIG. 8, after the bending of the reinforcing member 120 and the steel pipe 100 are formed in a tubular shape through the bending step (S60), the reinforcing member 120 and the steel pipe are formed. It is a step of welding one end and the other end of (100). The second welding step (S70) is preferably made of a woolen welding. When the second welding step (S70) is completed as shown in Figure 8 one end and the other end of the reinforcing member 120 and the steel pipe 100 is connected to form a connecting portion 140, the cross section is formed in a concentric circle shape.

The welding region heat treatment and cooling step (S80) is a step of heat-treating the welding region including the connection part 140 of the steel pipe 100 formed in a tubular shape through the second welding step (S70) and then cooling it. Since the welding part is formed by heating the electrode at a high temperature and then cooling, the other part and the metal microstructure are in a different state. Therefore, when used as it is, the welded site may act as a weak spot due to different physical properties such as strength and other sites. In order to prevent this, various heat treatment methods may be introduced to make the entire steel pipe 100 into a homogeneous microstructure. After this heat treatment, a cooling process is required. Cooling preferably consists of air cooling and water cooling sequentially.

By doing this, it is possible to manufacture by adding only a small process to the existing steel pipe production process without changing the specifications of the steel pipe, it is possible to produce at a low cost compared to the strength improvement effect.

Next, a steel pipe manufacturing apparatus according to an embodiment of the present invention will be described.

Steel pipe manufacturing apparatus may be various under various processes as described above, but those skilled in the art can be easily selected and used will be described below the apparatus used in the bending process of FIG.

Steel pipe manufacturing apparatus according to an embodiment of the present invention, referring to Figure 7, is formed including a base roll (B) and the roller (R). Moreover, the groove | channel for pressing by the roller R is formed in the said base roll B. As shown in FIG. In addition, the roller (R) includes a central axis (C), the ring insertion groove (G).

The base roll (B) is a part that serves as a workbench for bending the steel pipe 100 and the reinforcing member 120 welded together. The upper and lower surfaces of the base roll (B) is formed with a groove having a substantially semi-cylindrical shape so that the steel pipe 100 and the reinforcing member 120 may be fixed. Of course, the groove may be formed only on one surface of the base roll (B). Steel pipe 100 and the reinforcing member 120 is placed in the groove.

The roller R is a portion for bending the steel pipe 100 and the reinforcing member 120 placed on the base roll B by applying pressure downward. The roller R may be formed symmetrically with respect to the central axis C as shown in FIG. 7. The ring insertion groove G is a portion formed for fixing the position of the reinforcing member 120, in particular, the reinforcing ring 120. Only the reinforcing ring 120 is inserted into the ring insertion groove G, and the steel pipe 100 is not inserted. The ring insertion groove (G) is preferably formed on one side of the roller (R) to a depth less than the thickness of the reinforcing ring (120). When the ring insertion groove G is formed to be deeper than the thickness of the reinforcing ring 120, the reinforcing ring 120 is inserted into the ring insertion groove G so deeply that the steel pipe 100 is severely separated from the reinforcing ring 120. There is a problem that can be. When the rounding shape is formed in the steel pipe 100 and the reinforcing ring 120 by the roller R and the base roll B, it is processed into a complete pipe shape by another rotating roller.

By doing so, the welding portions of the reinforcing ring 120 and the steel pipe 100 may be bent in an integrated state without being detached during the bending process.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

The steel pipe according to the present invention has the effect of improving the shear strength, flexural strength and torsional strength while maintaining economic efficiency by maintaining the standard of the steel pipe as before.

In addition, the steel pipe manufacturing method according to the present invention has the effect of improving the strength by adding only a few simple processes to the existing process.

In addition, the steel pipe manufacturing apparatus according to the present invention has the effect of improving the work efficiency by allowing the work of the steel pipe and the reinforcing member to be integrated with each other while avoiding detachment during the bending process.

Claims (10)

delete delete delete delete delete Uncoiling a steel pipe coil for steel pipe manufacturing; A first welding step of welding a plurality of reinforcing members at predetermined intervals to the uncoiled steel pipe plate; Bending the steel pipe plate welded to the reinforcing member into a tubular shape; A second welding step of welding one end and the other end of the reinforcing member and the steel pipe plate; And Heat-treating and cooling the welded portion Steel pipe manufacturing method comprising a. The method of claim 6, The reinforcing member is a steel pipe manufacturing method, characterized in that any one of the reinforcing ring, reinforcing plate, reinforcing spring. The method of claim 6, Said first welding step is by electro-pressure welding, and said second welding step is by steel-welding. Base roll; And A roller for bending the steel pipe by placing a steel pipe on the base roll In the steel pipe manufacturing apparatus comprising a, The roller is a steel pipe manufacturing apparatus, characterized in that the ring insertion groove is formed for fixing the position of the reinforcing ring welded to the steel pipe. The method of claim 9, The ring insertion groove is a steel pipe manufacturing apparatus, characterized in that formed on one side of the roller to a depth less than the reinforcing ring thickness.

Images