KR20130071094A - Manufacturing method of big steel pipe - Google Patents

Manufacturing method of big steel pipe Download PDF

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Publication number
KR20130071094A
KR20130071094A KR1020110138422A KR20110138422A KR20130071094A KR 20130071094 A KR20130071094 A KR 20130071094A KR 1020110138422 A KR1020110138422 A KR 1020110138422A KR 20110138422 A KR20110138422 A KR 20110138422A KR 20130071094 A KR20130071094 A KR 20130071094A
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KR
South Korea
Prior art keywords
steel pipe
bending
welding
open steel
manufacturing
Prior art date
Application number
KR1020110138422A
Other languages
Korean (ko)
Inventor
이계봉
Original Assignee
서광기연 주식회사
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Application filed by 서광기연 주식회사 filed Critical 서광기연 주식회사
Priority to KR1020110138422A priority Critical patent/KR20130071094A/en
Publication of KR20130071094A publication Critical patent/KR20130071094A/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
    • B21D5/01—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments
    • B21D5/015—Bending sheet metal along straight lines, e.g. to form simple curves between rams and anvils or abutments for making tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D51/00—Making hollow objects
    • B21D51/02—Making hollow objects characterised by the structure of the objects
    • B21D51/10—Making hollow objects characterised by the structure of the objects conically or cylindrically shaped objects
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
    • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
    • B21C37/08—Making tubes with welded or soldered seams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D45/00—Ejecting or stripping-off devices arranged in machines or tools dealt with in this subclass
    • B21D45/02—Ejecting devices

Abstract

PURPOSE: A manufacturing method of a thick steel pipe is provided to reduce the capacity of a pressure roller and to prevent the surface damage of a thick steel pipe and the damage of a pressurization roller. CONSTITUTION: A manufacturing method of a thick steel pipe comprises the following steps: chamfering left and right ends of a thick steel pipe in the width direction(S1); bending the surrounding area of the ends(S2); pressurizing the pre-bent thick steel pipe at one side to gradually bend(S3); molding a secondary open steel pipe to adjacently face upper and lower chamfer parts(S4); track-welding the faced chamfer parts after the adjacent bending step(S5); and performing regular welding and correcting(S6,S7). [Reference numerals] (S1) Chamfering step; (S2) Pre-bending step; (S3) Main bending step; (S4) Adjacent bending step; (S4-1) Transfer step; (S4-2) Positioning step; (S4-3) Stroking step; (S4-4) Discharging step; (S5) Track-welding step; (S6) Regular welding step; (S7) Correcting step

Description

MANUFACTURING METHOD OF BIG STEEL PIPE}

The present invention relates to a technique for manufacturing a large diameter thick tube to increase the production efficiency and to ensure the stability of the quality.

There are various methods of making metal pipes, and appropriate methods are used in consideration of the diameter of the pipe and the thickness of the material. Typically, the pipe can be manufactured by extrusion and bending after welding.

In the case of large diameter thick pipes with a thick thickness and a diameter of about 400 mm or more, most of the large diameter pipes are gradually bent to form thick walls by welding the opposite ends.

Large diameter thick pipes widely used in industry are about 400 ~ 1800mm in diameter, the general working process is as follows.

The thick plate 10 having a predetermined width and length is prepared and the thick plate is introduced into the bending machine.

The bending machine includes a lower mold and an upper mold, and the upper mold is formed of an elongate member corresponding to the length of the thick plate 10. When the upper mold is lowered to press the thick plate, the thick plate is bent according to the degree of falling of the upper mold. The upper mold is commonly referred to as a bending knife, and the lower end of the bending knife B-2 includes a curved head portion B-2a and a body portion B-2b extending vertically upward from the head portion.

When bending is made from one end of the thick plate in the width direction, and bending is performed to some extent, bending is performed at the other end of the thick plate and finally bending is performed in the center of the width direction. Is made.

Both ends of the preliminary thick tube 1 face each other to form a predetermined distance, and weld to both ends to form a complete thick tube.

However, when the thick tube is formed using the bending knife B-2 as shown in FIG. 1, both ends of the preliminary thick tube 1 due to the basic shape of the bending knife B2 have a body portion B- of the bending knife B-2. 2b) The separation distance is over the thickness. The thickness of the body portion B-2b is usually about 100 mm or more.

Therefore, in order to perform welding prior to the main welding, both ends of the preliminary thick tube 1 should be as close as possible. In this case, a plurality of press rollers 2 are arranged at the outer circumference of the preliminary thick tube 1 and pressurized after Allow both ends of the tube 1 to be in contact with each other, and then perform temporary welding.

However, in order to apply force to both ends of the preliminary thick tube 1, a very large force is required, and the capacity of the pressurized cylinder must also correspond, and the press roller 2 is in contact with the outer surface of the preliminary thick tube 1 Since the preliminary thick tube 1 is fed little by little, breakage of the pressure roller 2 occurs frequently, and many scratches occur on the surface of the preliminary thick tube 1.

This phenomenon is due to the presence of elastic restoring force due to bending due to the material characteristics of the thick steel pipe, and in order to minimize the action force through the pressing roller, the distance between both ends of the preliminary thick pipe should be bent to a minimum. However, as mentioned, there is a fundamental problem that the distance between both ends of the preliminary thick tube must be larger than the thickness of the body of the bending knife due to the structural characteristics of the bending knife.

As a related art of the present invention, there is a "method of manufacturing a large steel pipe" of Republic of Korea Patent Publication No. 10-2011-0022613.

2 is a schematic view showing the steps of manufacturing a large steel pipe according to the prior art.

As shown, the forming process (a) is gradually formed into the bent portion 1.1 by the forming apparatus 30 by the forming tool as the sheet metal plate 4 proceeds, and finally formed into a bent tube 1.2. The tubular body 1.2 is then closed in the welding process (b) by means of longitudinal welding seams in the welding apparatus 40 with opposite edges prepared in advance for welding. Subsequent steps (d) such as calibration process (c) and hydrotest are then carried out.

The prior art is also welded after forming the sheet metal plate in the form of a tube by using a bending knife or the like, there is a problem that both ends of the tube due to the bending knife always have a certain distance.

1. Republic of Korea Patent Publication No. 10-2011-0022613 (2011.03.07 published)

Therefore, the present invention is to provide a method for manufacturing a thick tube that can improve the productivity and improve the quality of the product by solving the original problem of bending by using a bending knife as a method for manufacturing a large diameter thick tube.

Method for producing a large thick tube of the present invention for achieving the problem as described, the chamfering step of chamfering the width direction left and right ends of the thick plate material; A pre-bending step of bending the left and right end portions of the thick plate material chamfered using a pre-bender; Pressing the prebending thick plate material from either side in the width direction to gradually bend using a bending knife, but finally pressurizing the central portion in the width direction of the thick plate material to bend close to a circle to face the chamfer facing each other to form an opening. A main bending step of forming the primary open steel pipe; Rotating the primary open steel pipe so that the opening is directed in the horizontal direction, then by applying a force from the top to the upper chamfered into the lower chamfered portion to form an overlapping portion and then remove the force applied to the upper chamfered portion And a close bending step of forming a secondary open steel pipe to be elastically restored to face each other at a closer distance from the upper chamfer portion and the lower chamfer portion.

The method for manufacturing a large thick tube of the present invention is characterized in that the welding process for the chamfers facing each other after the close bending step is continued, and the welding step and the calibration step are performed after the welding process. .

And in the present invention, the welding step is characterized in that the partial welding is made in a state that the two chamfers spaced apart by a plurality of pressure rollers for pressing the outer surface of the secondary open steel pipe contact.

And in the present invention, the close bending step, the transfer step of allowing the opening of the primary open steel pipe is put on the support in a state facing vertically upward; A positioning step of rotating the primary open steel pipe by operating the rotating rollers of the support such that the opening faces the horizontal direction; A stroking step of lowering the pressing block located above the support by a predetermined stroke and then raising again so that the upper chamfer and the lower chamfer face each other more closely; And a discharge step of taking out the molded second open steel pipe by operating the feeding rollers of the support.

According to the manufacturing method of the large thick tube according to the present invention, the distance between both chamfers of the first open steel pipe is minimized through the close bending step after the main bending step, so that the welding can be performed immediately, and the pressing force using the pressure roller is Since it is not much required, it is possible to prevent the surface damage of the thick tube or breakage of the pressure roller, and to reduce the capacity of the pressure roller.

In addition, since the pressing force using the pressure roller is not required much, the productivity can be improved, and in some cases, there is an effect that the main welding can be performed immediately without welding.

1 is a manufacturing process of the thick tube according to the prior art.
2 is a schematic view showing the steps of manufacturing a large steel pipe according to the prior art.
Figure 3 is a flow chart for the manufacturing method of a large thick tube according to the present invention.
Figure 4 is a work flow chart for the manufacturing method of a large thick tube according to the present invention.
5 is an illustration of a schematic prevendor;
6 is a schematic conceptual view of a bending machine.
7 is a perspective view of a press.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention in the drawings, portions not related to the description are omitted, and like reference numerals are given to similar portions throughout the specification.

Whenever a component is referred to as "including" an element throughout the specification, it is to be understood that the element may include other elements, not the exclusion of any other element, unless the context clearly dictates otherwise.

3 is a flowchart illustrating a method of manufacturing a large thick tube according to the present invention, and FIG. 4 is a flowchart of a method of manufacturing a large thick tube according to the present invention.

The method for manufacturing a large thick tube according to a preferred embodiment of the present invention includes a chamfering step (S1), a pre-bending step (S2), a main bending step (S3) and a close bending step (S4), the welding process step (S5) ) And the main welding step S6 and the calibration step S7.

Chamfering step (S1) means to chamfer the width direction left and right ends of the thick plate 10 having a predetermined length and width. Chamfering treatment is preferably made to the upper and lower surfaces of the left and right ends of the thick plate 10. Each portion chamfered is referred to as a first chamfer (C1) and a second chamfer (C2).

After the chamfering step S1, the pre-bending step S2 is performed, and FIG. 5 is an exemplary view of a schematic prebender.

The pre-bending step (S2) is to bend the portion near the left and right ends in the width direction of the chamfered thick plate 10. Pre-bending step (S2) may use a predetermined dedicated pre-bender (PB), the left and right ends of the thick plate 10, the upper mold (PB-1) and the lower mold (PB-2) of the pre-bender (PB) By closing the upper and lower molds, the left and right ends in the width direction of the thick plate 10 are bent at a predetermined curvature.

Pre-bending the widthwise left and right ends of the thick plate 10 is to allow both chamfers to be more precisely abutted to form a perfect circle when finally bent in a circular shape.

After the pre-bending step (S2) is followed by the main bending step (S3), the thick plate material 10 is pre-bending is moved to the bending machine is bent close to the circle. 6 is a schematic conceptual view of a bending machine.

The bending machine (B) includes a support (B-1) corresponding to the lower mold and a bending knife (B-2) corresponding to the upper mold, and the pre-bended thick plate (10) is mounted on the support (B-1). Is bent from one of the left and right sides in the width direction and bent close to the circle. The thick plate 10 placed on the support (B-1) is gradually bent while the position is moved to the left and right, and finally the thick plate when pressing the center of the width direction of the thick plate 10 with the bending knife (B-2) The first chamfering portion C1 and the second chamfering portion C2, which are both left and right ends of (10), are bent in a state facing each other with the body portion B-2b of the bending knife B-2 interposed therebetween.

Bending knife (B-2) is composed of a lower portion of the head portion (B-2a) and the body portion (B-2b) protruding above the head portion (B-2a), the thickness of the body portion (B-2b) Due to the first open steel pipe 20 is formed through the main bending step (S3) is formed so that the two chamfer (C1, C2) facing each other to form a primary opening (21).

The left and right lengths of the primary openings 21 of the primary open steel pipe 20 formed by the main bending step S3 are always greater than the thickness of the body portion B-2b of the bending knife B-2. For example, when the thickness of the body portion B-2b of the bending knife B-2 is 100 mm, the left and right lengths of the primary opening 21 may be greater than at least 100 mm.

Therefore, in the present invention, after the main bending step S3, the close bending step S4 is performed.

In the close bending step S4, the opening 21 of the primary open steel pipe 20 formed through the main bending step S3 is formed to form a secondary open steel pipe 30 having a minimum value.

In the close bending step S4, the first open steel pipe 20 is rotated by an appropriate angle so that the opening 21 faces in the horizontal direction, and a force is applied from the upper portion so that the first chamfer C1 is the second chamfer. It enters into (C2) is pressed to form a degree of overlap (K) to some extent and consists of removing the force applied.

That is, in the close bending step S4, each end of the first chamfer C1 and the second chamfer C2 constituting the primary opening 21 is contacted by using the elastic restoring force of the thick plate 10. The first chamfer (C1) and the second chamfer (C2) forming the overlapped portion (K) by the elastic restoring force of the material itself by removing the force after bending more than the first unfolded first opening (21) It is possible to form a secondary opening 31 shorter than the length.

In other words, the close bending step S4 is performed by applying a force through the outer surface of the primary open steel pipe 20 in consideration of the elastic and plastic properties of the material as appropriate, forming the first opening 21 facing each other ( C1) presses to the inside of the second chamfer (C2) to form an overlapping portion (K) and then removes the force, so that the thick plate 10 is partially plastically deformed and the first chamfer (C1) due to the remaining elastic restoring force ) And the second chamfer (C2) to the outside is formed a secondary open steel pipe 30 having a secondary opening 31 of a shorter length without the overlap (K).

Both face chamfers C1 and C2 of the secondary open steel pipe 30 formed by the close bending step S4 are basically both sides of the primary opening 21 of the primary open steel pipe 20 than the length of the primary opening 21. A secondary opening 31 having a short separation distance between the mounting portions C1 and C2 may be formed, and in some cases, both chamfering portions C1 and C2 may be in contact with each other.

Preferably, in consideration of the material properties of the thick plate 10, the test of the first chamfer (C1) into the second chamfer (C2) and the degree of restoration when the force is removed Appropriate secondary openings 31 can be formed.

The proximity bending step S4 will be described in more detail as follows.

Proximity bending step (S4) is carried out using a predetermined press (R), subdividing the proximity bending step (S4) transfer step (S4-1), positioning step (S4-2), stroking step (S4-) 3), the discharge step (S4-4) can be made. 7 is a schematic perspective view of a press.

The transfer step (S4-1) is a process to put the primary open steel pipe 20 formed by the main bending step (S3) onto the support (R1) of the press (R). The primary opening 21 of the primary open steel pipe 20 formed through the main bending step S3 is in a state of pointing upwards, and is supplied onto the support R1 of the press R as it is.

When the primary open steel pipe 20 is placed on the support (R1), the positioning step (S4-2) is performed, the primary open steel pipe so that the primary opening 21 of the primary open steel pipe 20 faces in the horizontal direction. (20) is rotated in the forward and reverse directions. The support (R1) is provided with a plurality of rotating rollers (R2), if the rotary rollers (R2) are rotated in any one direction in contact with the lower surface of the primary open steel pipe 20 also the primary open steel pipe (20) Rotate and rotate until the primary opening 21 is positioned approximately horizontally. In the positioning step S4-2, the primary open steel pipe 20 is rotated to about 70 to 90 degrees so that the primary opening faces the horizontal direction.

After the positioning step S4-2, the stroking step S4-3 is continued, and in the stroking step S4-3, the pressing block R3 positioned above the support R1 is lowered by a predetermined stroke. After the first chamfering portion C1 is bent, the second chamfering portion C2 enters into a predetermined overlapping portion K, and then the lowering pressure block R3 is raised to its original position.

After the stroking step S4-3 by the vertical movement of the pressure block R3, as mentioned, the primary open steel pipe 20 is properly plastically deformed, and the overlapping portion K is formed by the accumulated elastic restoring force. As the first chamfer (C1) and the second chamfer (C2) is pressed to achieve the first chamfer (C1) and the second chamfer (C2) are in close contact with the second open steel pipe ( 30) is molded.

The stroking step (S4-3) is followed by the discharge step (S4-4), the plurality of feeding rollers (R4) provided in the support (R1) is operated to take out the secondary open steel pipe (30). .

After the proximity bending step (S4) is followed by the welding step (S5), preferably in the welding step (S5) using a plurality of pressure rollers (D) that can press the outer surface of the secondary open steel pipe (30). The two chamfers C1 and C2 spaced apart from each other by a predetermined distance are partially welded while being pressed to contact each other.

The usable welding step (S5) is to ensure that the correct welding site is formed before the main welding (S6), in particular, the two chamfers (C1, C2) facing each other through the close bending step (S4) is bent very close Therefore, when a predetermined force is applied to the outer surface of the secondary open steel pipe 30 by using the pressure roller (D), the two chamfered portions C1 and C2 spaced apart to make contact.

According to the conventional method, when pressing by using a pressure roller such that two chamfers forming a separation distance of the thickness of the body portion (B-2b) of the bending knife (B-2) are in contact with each other, the primary open steel pipe (20) Very large force is required because the force must be applied to the two chamfer (C1, C2) in contact in the elastic region, but in the case of the present invention already close the primary open steel pipe 20 to some extent in the close bending step (S4) Since the plastic deformation state and the distance between the two chamfers C1 and C2 constituting the secondary opening 31 have been narrowed, the welding can be performed by contacting the two chamfers C1 and C2 with a relatively small force. have.

In the present invention, since the large force does not act on the plurality of pressure rollers (D) in the welding process (S5), the capacity of the pressure cylinder for operating the pressure roller (D) does not have to be large, and the secondary open steel pipe 30 The possibility of causing damage to the surface of) is also reduced.

After the welding process (S5), the main welding step (S6) is continued, in the main welding step (S6) is continuously welded to the grooves formed on the upper and lower surfaces of the two chamfers making contact with each other.

When the main welding step (S6) is completed through the straightening step (S7) to correct the roundness or straightness of the completed large gymnasium. Since the calibration step is possible through a known method, a description thereof will be omitted.

The method for manufacturing a large thick tube of the present invention as described above can be molded into a thick tube in a thick tube in a continuous process, there is an advantage that can improve the quality of the thick tube.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be.

It is therefore to be understood that the embodiments described above are intended to be illustrative, but not limiting, in all respects. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

The method for manufacturing a large thick tube according to the present invention can achieve high productivity when manufacturing large diameter thick tubes while maintaining the stability of quality, and thus can be widely used for the production of various industrial large steel pipes.

Chamfering stage: S1 Pre-bending stage: S2
Main bending step: S3 Close bending step: S4
Available welding step: S5 Main welding step: S6
Calibration stage: S7 thick board: 10
First chamfer: C1 Second chamfer: C2
Primary open steel pipe: 20 Primary opening: 21
Secondary open steel pipe: 30 Secondary opening: 31

Claims (4)

In the large-size thick tube manufacturing method,
Chamfering step of chamfering the width direction left and right ends of the thick plate material;
A pre-bending step of bending the left and right end portions of the thick plate material chamfered using a pre-bender;
Pressing the prebending thick plate material from either side in the width direction to gradually bend using a bending knife, but finally pressurizing the central portion in the width direction of the thick plate material to bend close to a circle to face the chamfer facing each other to form an opening. A main bending step of forming the primary open steel pipe;
Rotating the primary open steel pipe so that the opening is directed in the horizontal direction, then by applying a force from the top to the upper chamfered into the lower chamfered portion to form an overlapping portion and then remove the force applied to the upper chamfered portion And a close bending step of forming a secondary open steel pipe to be elastically restored to face each other at a closer distance from the upper chamfering portion and the lower chamfering portion. The method of claim 1,
The manufacturing method of the large thick tube,
A method for manufacturing a large thick tube, characterized in that the welding step for the chamfer facing each other after the close bending step is followed, and the welding step and the calibration step are performed after the welding step. 3. The method of claim 2,
The soluble welding step,
Method for producing a large thick tube characterized in that the partial welding is made in a state in which the two chamfers spaced apart by a plurality of pressure rollers for pressing the outer surface of the secondary open steel pipe made contact. 4. The method according to any one of claims 1 to 3,
The close bending step,
A conveying step of allowing the opening of the primary open steel pipe to be introduced onto the support in a vertically upward direction;
A positioning step of rotating the primary open steel pipe by operating the rotating rollers of the support such that the opening faces the horizontal direction;
A stroking step of lowering the pressing block located above the support by a predetermined stroke and then raising again so that the upper chamfer and the lower chamfer face each other more closely;
And a discharge step of taking out the secondary open steel pipe formed by operating the feeding rollers of the support.
KR1020110138422A 2011-12-20 2011-12-20 Manufacturing method of big steel pipe KR20130071094A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112008207A (en) * 2020-07-22 2020-12-01 海洋石油工程（青岛）有限公司 Structural pipe prefabricating method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112008207A (en) * 2020-07-22 2020-12-01 海洋石油工程（青岛）有限公司 Structural pipe prefabricating method

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