JPH03207523A - Manufacture of metallic welded tube - Google Patents

Abstract

PURPOSE:To form the diameter of a through hole on the outlet side at the same time in the form of a tube of the same outer diameter by passing a metallic plate through a die provided with a through hole of a circular section section having a tapered part in which a diameter is reduced from the inlet side to the outlet side thereof. CONSTITUTION:A metallic plate 1 is passed through a through hole 3 of a circular section having a tapered part in which the diameter is reduced from the inlet side of the die to the outlet side thereof. In the process in which this through hole 3 is passed, the metallic plate 1 is bent along the tapered part and elongated in the lengthwise direction, therefore, when the flat metallic plate 1 is passed through the through hole 3 of the die 2, it can be formed at the same time into the form of a pipe having the same outer diameter with the diameter of the through hole on the outlet side. Thereafter, as the tube form is held by squeeze rollers, the butted part of both side edges of the strip is TIG-welded. In this way, when the outer diameter of the metallic pipe to be manufactured is changed, die changing can be performed in a short time and easily.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves forming a metal plate continuously into a tubular shape, and welding the abutted side edges of the metal plate to mainly adjust the wall thickness t and outer diameter D. When manufacturing a metal welded pipe with a ratio t/D of about 3 to 20%, a metal plate is formed into a tube shape at once by passing a flat metal plate through a through hole drilled in a die. The present invention relates to a method for manufacturing a welded pipe.

[Conventional technology]

In order to manufacture a metal tube by bending a metal plate to the product curvature in the width direction and forming it into a tube, conventionally, forming rolls or cages having a large number of calibers arranged in tandem are used as shown in the perspective view of Fig. 8. A metal plate is sequentially bent in three width directions using a roll or shaping machine equipped with a roll 10 to form a tubular shape, and the tubular metal plate is held by a seam guide roll 11 and a squeeze roll 5. metal plate] - both edges]. Generally, a roll forming method has been practiced in which a continuous line is used to join the abutted portions 1b of the abutted parts 1b by butt welding.

However, in such conventional methods, for example, when manufacturing a welded metal tube with a ratio of wall thickness L to outer diameter D of 1, /D of about 3 to 20%, the outer diameter of the metal tube to be manufactured is changed. In this case, the forming roll or cage roll 10, as well as the seam guide roll 11 and the squeeze roll 5, must be replaced with roll sets having the desired dimensions corresponding to the outer diameter of the metal tube to be manufactured. Therefore, roll silk has at least 20 mm for each type of outer diameter.
Since there are multiple sets, it takes a lot of labor and a long time to change the rolls, which reduces the production efficiency of the equipment. It had the disadvantage that it was not economical because it had to be prepared for each day.

Furthermore, when attempting to manufacture thin metal tubes with an outer diameter of 101IR or less, very high precision is required in the installation position of each roll set, the distance between the rolls of each roll set, and the dimensions of the rolls of each roll set. For example, in each set of opposing rolls, the distance between the opposing rolls must be adjusted, and at the same time, the rolls must be installed at accurate positions in front, back, and below with respect to the passing direction on the metal plate. Since it is likely to be installed eccentrically at a position slightly deviated from this position, the opposing roll will be slightly eccentric, especially if the outer diameter of the metal tube to be manufactured is small and the thickness of the metal plate 1 is very thin. When installed with this roll, the butt portions 1b of both side edges 1a of the metal plate 1 formed into a tubular shape are formed by this roll.
A step is created in the abutment part 1 in a state where this step is created.
Since the part b is welded, the cross-sectional shape of the manufactured metal tube does not form a perfect circle, resulting in a defect in the product.

[Problem to be solved by the invention]

The present invention solves the above-mentioned drawbacks of the prior art, and can easily and inexpensively adapt to changes in the outer diameter of the manufactured length metal tube, especially when the outer diameter is changed to . An object of the present invention is to provide a method for manufacturing a metal tube that can easily, inexpensively, and reliably manufacture a metal tube as thin as 0+nm or less.

[Means to solve the problem]

As a result of various studies to solve this problem, the inventors of the present invention have discovered a die that has a through hole with a circular cross section and a tapered portion whose diameter decreases from the entry side to the exit side. By passing the metal plate through the through hole, it is possible to form a flat metal plate into a tube shape with both sides of the plate butted against each other at once, without having to gradually form the metal plate into a tube shape using multiple rolls. They discovered that a metal welded pipe could be manufactured by welding the abutting portions of both side edges of this metal plate, and perfected the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, the manufacturing method of the metal welded pipe based on this invention is demonstrated in detail with drawing.

Figure 2 is an explanatory side view showing a state in which a metal welded pipe is manufactured by the method of the present invention, Figure 2 is an explanatory front view showing an example of the die shown in Figure 1, and Figure 3 is an explanatory view of the die shown in Figure 2. A- in
4 is a sectional view taken along the line A, FIG. 4 is a diagram showing another embodiment of manufacturing a metal welded pipe by the method of the present invention, FIG. 5 is a sectional view taken along the line B-B in FIG. 4, and FIG. 6 (A) , (mouth) and (c)
7 shows the various cross-sectional shapes of the metal plate immediately after passing through the through hole of the die, and FIG.
It is a figure showing the relationship with a diameter.

In order to carry out the method of the present invention, first, a through hole having a circular cross section having a tapered portion whose diameter decreases in the direction of movement of a metal plate for manufacturing a metal welded pipe, that is, from the inlet side to the outlet side. A die 2 in which a hole 3 is bored is prepared. In other words, the through hole 3 is inserted into the flat metal plate.
A die 2 is used to form the die 2 into a tubular shape with both side edges 1a abutted against each other at once by passing it through from the inlet side with a dog diameter through the tapered part to the outlet side with a smaller diameter than the inlet side. prepare. The metal plate 1 to be formed into a tubular shape is not only a normal cold-rolled metal plate, but also a metal plate whose at least one side has been polished by mirror polishing or hairline polishing, or whose at least one side has been etched or chemically colored. It is possible to use a metal plate that has been subjected to the treatments listed in Table 1-1, such as processing, ceramic coating, plating, and painting.

As shown in Figure 1, such a metal sheet work is passed through the through hole 63, which has a circular cross section and has a tapered portion whose diameter decreases from the inlet side to the outlet side of the die 2, and the die 2 is cut all at once. It is formed into a tubular shape with both side edges 1a abutted against each other. At this time, although it varies depending on the outer diameter and material of the welded metal pipe to be manufactured, if the thickness of the metal sheet work is 3 to 20% of the outer diameter of the welded metal pipe to be manufactured, the material width is narrow. If it is too large, the internal pressure due to the compressive force in the circumferential direction will be insufficient and the material will not be sufficiently filled in the die 2, so that after passing through the through hole 3, the deformation near the both side edges 1a will occur as shown in FIG. 6(A). The length of the wall thickness center line of the metal welded pipe to be manufactured from Sano 1.0
It is preferable to have a plate width that is one or more times the width of the plate. Furthermore, if the width of the metal plate 1 is wide with respect to the center line of the wall thickness of the manufactured sized metal tube, when the metal plate J is drawn into the die 2, the both side edges 1a are butted together in the middle of the tapered part. In the process of being further drawn into the tubular shape, the metal plate 1 is subjected to compressive stress in the circumferential direction due to the taper of the die 2 and tensile stress in the longitudinal direction, causing it to contract in the circumferential direction and elongate in the longitudinal direction. If the width of the metal plate 1 is too wide, the compressive stress in the circumferential direction is too large and the metal plate 1
Since buckling may occur near both sides 1i1a of the metal tube, it is desirable to use a metal plate work having a plate width that is 1.35 times or less the length of the wall thickness center line of the metal tube to be manufactured. The occurrence of such a phenomenon is shown in Fig. 7 when a tool made of carbon tool steel SKD-11 has an entrance diameter of 35+n, an exit diameter of 10 mm, and a taper angle of 2.
Stainless steel strips (SUS304) of various thicknesses were passed through the through holes using a solid lubricant in a die with a 2° through hole to form a tube shape, and then held in a tube shape with a squeeze roll. As shown in the results of TIG welding of the butt parts of both side edges of the stainless steel strip, if the thickness of the metal plate 1 is less than 3% of the outer diameter of the welded metal pipe to be manufactured, the thickness of the metal plate ↓ is thin. As a result, the compressive force in the circumferential direction causes misalignment of both side edges 1a of the metal plate king, and the compressive deformation does not proceed further in the width direction, resulting in a defective cross-sectional shape, and the other metal plate 1
- If the plate thickness exceeds 20% of the outer diameter of the welded metal pipe to be manufactured, the thickness of the metal plate 1 will be too thick and the pulling force will be extremely large, causing the metal plate king to break on the exit side of the die or the metal plate to be welded. It has been confirmed that the vicinity of both side edges 1a of the plate ↓ is not sufficiently bent and cannot be shaped into a perfect circle. As mentioned above, the plate width is 1.0 of the length of the wall thickness center line of the metal welded pipe.
1~Eng. A welded metal pipe with a good shape can be manufactured within the range of 35 times, but if you want to completely prevent the occurrence of surface flaws, the plate width must be 1.5 times the length of the center line of the thickness of the welded metal pipe. It is preferable to be in the range of 0.01 to 1.20 times.

In addition, when passing such a metal plate 1 through the through hole 3 of the die 2, the metal plate 1 which has been plastically bent with a small diameter bending roll 8 perpendicular to the longitudinal direction with the surface that will become the inside of the tube as the inside is inserted into the longitudinal direction. By setting the curvature in the direction to zero, the metal plate 1 is bent to a certain extent in the width direction by utilizing the residual curvature in the width direction caused by the plastic bending/unbending.
It is desirable to make the tube penetrate through the through hole 3 in order to reliably form it into a tubular shape. For example, as shown in FIG. 4, the entrance side cylindrical roll 9 and its axis are parallel to each other and are arranged with a gap between them. A cylindrical roll 9 on the exit side rotating in the same direction as the cylindrical roll 9 on the side, a bending roll 8 of small diameter arranged close to these cylindrical rolls 9 and parallel to the axis of this cylindrical roll 9; The metal plate 1 is first placed along the entrance side cylindrical roll 9, then passed through the gap, bent along the small diameter bending roll 8, and then passed through the gap again to make the longitudinal curvature zero. By doing so,
The residual curvature in the width direction caused by the plastic bending and unbending is utilized to pass the metal plate 1 into the through hole 3 of the die 2 while being bent to some extent in the width direction.

The entrance diameter of the through hole 3 of the die 2 that penetrates the metal plate 1 in this way is preferably larger than the width of the metal plate 1, but as shown in FIG. When a metal plate 1 which has been plastically bent with a small-diameter bending roll 8 perpendicular to the longitudinal direction is penetrated with the surface facing inside, the metal plate 1 has already been bent at the entry side of the through hole 3, as shown in FIG. Since the plate width when projected onto a plane is smaller than the actual plate width, the diameter of the entrance side of the through hole 3 is larger than the plate width when the metal plate 1 is projected onto a plane at the entrance side of the through hole 3. It is sufficient if it has a diameter. As shown in FIGS. 1 and 3, an identical diameter section 3a having the same diameter is provided between the entrance and exit sides of the through hole 3 of the die 2, and the same diameter section 3a is provided between the entrance side and the exit side. In the section 3a, it is preferable to perform plastic processing into a tubular shape by maintaining the tubular shape in which both sides 1i1a of the metal plate are abutted against each other.

In this way, the flat metal plate 1 is formed into a tubular shape with both side greens 1a abutted against each other, and the abutting portions 1b of the both sides i1a are welded. Tice 2 as shown in the figure
A metal plate 1 formed into a tubular shape by passing through a through hole 3 is held in a tubular shape by a squeeze roll 5 on both sides, 13.
The abutted portion 1b of the metal plates 1a abutted against each other is arc welded with an arc welding torch 4, or the abutted portion 1b of the metal plate 1 formed into a tubular shape as shown in FIG.
A welding through hole 7 is drilled that penetrates from the outer peripheral edge of the die 2 toward the same diameter section 3a of the die 2 in accordance with At the butt part 1b of both side edges 1a of the
It is also possible to perform laser welding on this abutted portion 1b by irradiating a laser beam. Further, as a means for welding, the metal plate 1 is formed into a tubular shape by passing through the through hole 3 of the die 2, and is held in a tubular shape by a squeeze roll 5, and the abutting portions 1b of both side edges 1a of the metal plate 1 are welded. Needless to say, laser welding may be used as a means for doing so.

[For production]

As described above, the method 12 for manufacturing a metal welded pipe according to the present invention is to use a die 2 in which a through hole 3 having a circular cross section is formed and has a tapered portion whose diameter decreases from the inlet side to the outlet side. Since the metal plate 1 is passed through the through hole 3, the metal plate 1 is bent along the tapered part of the through hole 3 and stretched in the longitudinal direction, so that a flat metal temporary is formed. 1 through the through hole 3 of the die 2, it can be formed into a tubular shape having the same outer diameter as the diameter of the through hole on the exit side.

In addition, when passing the metal plate J through the through hole 3 of the die 2, plastic bending is performed on the metal plate J with a small diameter bending roll 8 perpendicular to the longitudinal direction with the surface that will become the inside of the tube inside. This plastic bending with the longitudinal curvature as zero
Due to the residual curvature in the width direction caused by unbending, the through hole 3 of the die 2 is bent in the width direction to some extent.
If the metal plate 1 is penetrated along the tapered part of the through hole 3,
The stress acting on the die 2 when forming it into a tubular shape can be reduced.

Further, an identical diameter section 3a having the same diameter is provided between the entrance and exit sides of the through hole 3 of the die 2, and the both side edges 1a of the metal plate 1 are provided in the same diameter section 3a.
If the through hole 3 is passed through while maintaining the tubular shape in which the metal plates are butted together, it is possible to reduce the springback that occurs in the metal sheet work formed in the tubular shape. Then, a welding through hole 7 penetrating from the outer periphery of the die 2 to the same diameter section 3a of the die 2 is bored in correspondence with the butt part tb of the metal plate formed into a tubular shape, and this welding through hole A laser beam is irradiated through the metal Fi.7. When the butt portions 1b of 1 are laser welded, the welded tubular metal plate 1 is held in a circular cross-section having the outer diameter of the metal tube to be manufactured until it reaches the exit side, so after passing through the through hole 3. springback is reliably suppressed.

In this way, according to the method of the present invention, the metal plate 1 is passed through the circular through hole 3 of the die 2, so that it can be accurately butted together without creating a step on both side edges 1a of the metal plate work. .

-15 [Example] Example 1 A through hole with an entrance diameter of 35 m, an exit diameter of 10 nn + a taper angle of 22° was bored in a die made of carbon tool steel SKS, and the plate thickness was 1. nwn, a flat austenitic stainless steel strip (S[IS304) with a plate width of 31 strips is passed through the through hole to form a tubular shape, and then held in the tubular shape with a squeeze roll, the edges of both sides of the stainless steel strip are As a result of TIG welding the butt portions, the cross-sectional shape is almost a perfect circle and the wall thickness is 1. wn, outer diameter]. We were able to manufacture one-of-a-kind stainless steel welded pipes.

Example 2 Carbon] A die made of Nigu Steel SK5 with an entrance diameter of 4.0 mm,
A through hole with an outlet diameter of 1.0 mm and a taper angle of 30° was drilled, and a welding through hole with a diameter of 0.51 Wl was further drilled in the same diameter section with a length of 3.0 m as shown in Fig. 4. , plate thickness 0
．． A flat austenitic stainless steel strip (SUS304) with a width of 1 m and a plate width of 3.3 nwn is passed through a through hole to form a tubular shape, and then YAG is applied from a laser irradiation machine to the abutting portions of both side edges of the stainless steel strip through the through hole for welding. (Yttrium Aluminum Garnet 1) As a result of laser irradiation and welding, the cross-sectional shape was a perfect circle and the welding condition was good with a wall thickness of 0. ]. mm, outer diameter]. ．． We were able to manufacture orth stainless steel welded pipes.

Example 3 A through hole with an entrance diameter of 35 m, an exit diameter of 10 m, and a taper angle of 22° was bored in a die made of carbon tool t [sK5, and a flat austenitic stainless steel strip with a thickness of 1 m and a width of 31 mm was prepared. This is caused by plastic bending and unbending by making the longitudinal curvature zero after plastic bending (SUS304) with a small diameter bending roll with a radius of 7ln orthogonal to the longitudinal direction with the surface that will become the inside of the tube being the inside. Utilize the residual curvature in the width direction to bend the stainless steel strip to a certain extent in the width direction and pass it through the through hole to form a tubular shape, and then hold the stainless steel strip in the tubular shape with a squeeze roll until the abutting portions of both side edges of the stainless steel strip are formed. As a result of TIG welding, the cross-sectional shape is almost a perfect circle (thickness m, outer diameter). It was possible to manufacture a stainless steel welded tube of 0 mm.

16 [Effects of the Invention] As detailed above, when a metal welded pipe is manufactured by the metal welded pipe manufacturing method according to the present invention, it is a simple method in which a flat metal plate is passed through a through hole drilled in a die. Since it is possible to form a flat metal plate into a tube shape all at once, it is only necessary to prepare one die that corresponds to the outer diameter of the welded metal tube to be manufactured, so the outer diameter of the metal tube to be manufactured can be changed. When doing so, the dice can be easily replaced in a short time, and it is also economical.

Furthermore, the metal plate that passes through the through hole of the die is formed into a tubular shape with both edges firmly butted against each other, making it easy to carry out high-mix, low-volume production while also supplying high-quality products. be able to.

In addition, providing the same diameter section for the through hole of the die suppresses the springback that occurs in the metal plate after passing through the through hole, and furthermore, if the welding through hole is drilled in the same diameter section, the same Since the butt portions of the metal plates can be welded in the diameter section, a high quality product can be supplied.

Furthermore, the ratio t/ of the wall thickness t and the outer diameter D of the metal welded pipe to be manufactured
When D is 3 to 20%, a flat metal plate having a plate width of 1.01 to 1.35 times the length of the wall thickness center line of the metal welded pipe is used as the metal plate to be passed through the through hole of the die. By using plates, phenomena such as meandering and twisting will not occur in the manufactured metal welded pipes, and it will also prevent the occurrence of wrinkles due to buckling, such as when the edges of the metal plates overlap or near the edges of the metal plates. This makes it possible to manufacture a metal welded pipe with a good shape and no distortion.

Laser welding the butt joints makes it possible to form a good weld by adjusting the laser output to suit the material and width of the metal plates, so even thin metal welded pipes of several meters or less can be easily welded. It can be manufactured.

The metal welding method according to the present invention, which has various advantages as described above, makes it possible to manufacture metal welded pipes cheaply and easily, and even to produce very small diameter metal pipes, which increases its industrial value. It's very big.

[Brief explanation of drawings]

Fig. 1 is an explanatory side view showing a state in which a metal welded pipe is manufactured by the method of the present invention, Fig. 2 is an explanatory front view showing an example of the die shown in the engineering drawing, and Fig. 3 is an explanatory view of the die shown in Fig. 2. A- in
4 is a cross-sectional view taken along the line A, FIG. 4 is a diagram showing another embodiment of manufacturing a metal welded pipe by the method of the present invention, FIG. 5 is a sectional view taken along the line B-B in FIG. 4, and FIG. 6 (A) , (mouth) and (c)
7 shows the various cross-sectional shapes of the metal plate immediately after passing through the through hole of the die, and FIG.
FIG. 8, which shows the relationship with the diameter, is a perspective view showing a state in which a metal welded pipe is manufactured by a conventional method. In the drawings 1...Metal plate 1a...Side edge]b...Butt portion 2...Dice-19-3...Through hole 3a...Same diameter section 4. ... Arc welding torch 5 ... Squeeze roll 6 ... Laser irradiation machine 7 ... Welding through hole 8 ... Small diameter bending roll 9 ... Cylindrical roll 10 ... ... forming roll or cage roll 11
...Seam guide roll patent applicant Nissin Steel Co., Ltd. 20

Claims (1)

[Claims] 1. A metal plate ( By penetrating the flat metal plate (1) through the metal plate (1), both edges (
1a) are formed into a tubular shape in abutted state, and the abutted portion (1b) is welded. 2. In the through hole (3) of the die (2), the same diameter section (3
2. The method of manufacturing a welded metal pipe according to claim 1, wherein the metal plate (1) is formed into a tubular shape in which both side edges (1a) of the metal plate (1) are butted together in the same diameter section (3a). 3 Ratio t/ of the wall thickness t and outer diameter D of the metal welded pipe to be manufactured
When D is 3 to 20%, the metal plate (1) to be penetrated into the through hole (3) of the die (2) is 1.01 to 1.35 times the length of the wall thickness center line of the metal welded pipe. 3. The method for manufacturing a welded metal pipe according to claim 1, wherein a flat metal plate (1) having a plate width of . 4. The method for manufacturing a metal welded pipe according to any one of claims 1 to 3, wherein the butt portions (1b) of both side edges (1a) of the metal plate (1) formed in a tubular shape are laser welded. 5 The butt part (1b) of the metal plate (1) formed into a tubular shape
) from the outer periphery of the die (2).
), a welding through hole (7) penetrating through the same diameter section (3a) is formed, and a laser is irradiated from the welding through hole (7) to laser weld the abutted portion (1b). Item 4. The method for manufacturing a metal welded pipe according to item 4. 6 By making the longitudinal curvature of the metal plate (1), which has been plastically bent with a small-diameter bending roll (8) perpendicular to the longitudinal direction with the surface that will become the inside of the pipe as the inner side, the plastic bending process is reduced to zero. Claims 1 to 5, wherein the metal plate (1) is bent to a certain extent in the width direction by utilizing residual curvature in the width direction caused by bending and unbending, and is then passed through the through hole (3) of the die (2). The method for manufacturing a metal welded pipe according to any one of the preceding items.