JPH10291094A - Joining method for coil stock for spiral steel tube with outer face rib - Google Patents

Abstract

PROBLEM TO BE SOLVED: To conduct joining welding with a high efficiency by lifting up a butted part between a tail end of a preceding coil and a front end of a succeeding coil from a lower side with a flux accommodating container, pressing a rear face with flux and conducting one pass one side welding from the upper face so as to prevent generation of a welding defect. SOLUTION: Tail/front ends of preceding/succeeding coils 25, 26 having outer face ribs 25a, 26a are butted. There both ends are lifted up with a flux accommodating container 3 serving as a backing to eliminate a difference in levels. Successively, the flux 1 in the flux accommodating container 3 is pushed up by supplying compressed air to an air hose having an insulation material 4 to expand, is pressed to rear faces of the coils 25, 26 and is filled in between the outer ribs 25a, 26a. At this state from a coil supper face side, a butted part between a tail end of the preceding coil 25 and a front end of the succeeding coil 26, both leveled, are subjected to one pass one side welding. By this method, a weld metal is prevented from flowing down during welding, a back bead is sufficiently formed, joining welding of a coil stock having an outer face rib is obtained without welding defect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of splicing a material coil for a spiral steel pipe with an external rib, which is welded to a material coil being formed and then spliced when manufacturing a spiral steel pipe with an external rib. .

[0002]

2. Description of the Related Art When manufacturing a spiral steel pipe, a spiral steel pipe is manufactured while the tip of the next material coil is connected to the rear end of the material coil being formed by welding (hereinafter referred to as "relay"). In particular, when manufacturing a large-diameter spiral steel pipe, the length of the spiral steel pipe that can be manufactured per coil becomes short. The relay frequency increases.

For this reason, it is necessary to perform welding for joining a coil with high efficiency. 2. Description of the Related Art Conventionally, as a method for performing a relay welding of a coil with high efficiency, there is a method of performing one-pass single-side welding from the upper surface side of the coil. However, this method does not allow sufficient formation of a backwash and causes poor welding, so the surface opposite to the surface to be welded (this surface is the outer surface side of the spiral steel pipe) is formed. Off-line care had to be taken after the tube, which required an extra step.

[0004] Therefore, it is necessary to provide a method of relay welding of a coil which can perform sufficient one-side welding on a single pass and which can sufficiently produce a reverse wave. Japanese Patent Application Laid-Open No. 63-299861 discloses a method of relay welding such a coil. There is a method disclosed in Japanese Patent Publication No.

In this method, the joint welding groove is set to 5 to 20.
°, the root gap width is set to be equal to or larger than the diameter of the welding wire used for the relay welding, and the cut wire is scattered and filled into the groove to a height of 30 to 50% of the coil thickness. This is to perform single pass welding.

[0006]

However, the welding method disclosed in JP-A-63-299861 has the following problems. That is, in this method, as shown in FIG. 3, the cut wire 22 filled in the groove 21 is prevented from falling from the groove 21.
The backing metal 24 filled with the packing flux 23 needs to be applied to the back surfaces of the leading coil 25 and the trailing coil 26 with the groove 21 interposed therebetween. At this time, since the back surface of the coil is flat in a normal coil, the cut wire 22 and the packing flux 23 are sufficiently in contact with each other so that the molten metal does not flow out during welding. In this case, since the rib is located on the lower surface side of the coil to be joined, the backing metal 24 is placed on the back surface side of the leading coil 25 and the succeeding coil 26 with the groove 21 interposed therebetween, as shown in FIG. Even if it hits, the upper end of the backing metal 24
As shown in FIG. 4B, which is a view taken along the line AA in FIG. 4A, the packing flux 2 is in contact with the lower end portions of the ribs 25a and 26a formed on
3 is not filled in the space 27 formed between the adjacent ribs 25a (26a), and the molten metal is filled in this space 2 during welding.
7, there is a problem that sufficient backwash is not formed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and has a splicing material for a spiral-steel pipe material coil with an outer rib in which a backwash is sufficiently formed even in one-pass single-side welding. It is intended to provide a way.

[0008]

According to the present invention, there is provided a method for splicing a material coil for a spiral steel pipe with external ribs according to the present invention, comprising the steps of: A method of performing one-pass single-side welding and joining during forming and welding of a spiral steel pipe with ribs, in which a rear end of a leading coil and a leading end of a succeeding coil that are abutted for joining are joined with a coil from below. Over the entire width, the flux is stored inside and lifted by a flux storage container that also serves as a backing metal, eliminating the step between the rear end of the preceding coil and the front end of the following coil, and then placed in the flux storage container The flux is pressed against the rear surface of the rear end of the preceding coil and the rear surface of the front end of the following coil by the applied flux pressing means, and the flux is applied to the back of the coil. After filled between a plurality of ribs formed on, is the butt portion between the distal end of the rear end and the trailing coils of the preceding coil from the upper surface side of the coil intended to one-pass one-side welding.

When the push-up surfaces of the pair of push-up portions of the flux storage container are made to have the same height, when the rear end of the preceding coil and the tip of the succeeding coil are pushed up by the pair of push-up surfaces, the leading end of the preceding coil is lifted. The height of the rear end of the coil is the same as the height of the front end of the following coil.

Next, the flux pressing means
When the flux in the flux storage container is pressed against the back surface of the coil, the flux enters between the ribs formed on the back surface of the coil, and the space between the ribs is filled with the flux. You. Then, one-pass single-side welding is performed from the surface side of the coil.

[0011] Since the method of splicing a coil material for a spiral steel pipe with external ribs according to the present invention is performed as described above, the molten metal does not flow out from between the ribs, and one-pass single-side welding is performed. A sufficient backlash can be produced, and high-efficiency relay welding of a material coil for a spiral steel pipe with external ribs can be performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for splicing a coil for a spiral steel pipe with external ribs according to an embodiment of the present invention will be described with reference to FIG. FIG. 1A is a side view showing a method of splicing a material coil for a spiral steel pipe with external ribs, and FIG. 1B is a view taken along the line BB of FIG. 1A.

As shown in FIG. 1 (a), an air hose 2 for pressing the flux 1 against the back surface of the coil is disposed inside the air hose 2 just above the U-shaped backing metal 3 filled with the flux 1. The two coils 25 and 26 are positioned such that the rear end of the preceding coil 25 and the front end of the following coil 26 are in a state of abutment.

Then, the backing metal 3 is moved up and down (not shown).
To raise the leading coil 25 on one side wall 3a of the backing metal 3 and raise the following coil 26 on the other side wall 3b of the backing metal 3.

The backing metal 3 is arranged so that the upper surface of the side wall 3a and the upper surface of the side wall 3b are located on the same horizontal plane.
When the backing metal 3 is raised as described above, the leading coil 25
And the lower surface of the rib 25a on the rear surface (lower surface) of the following coil 26 has the same height as the lower surface of the rib 26a on the rear surface of the succeeding coil 26. Therefore, before the backing metal 3 is applied, even if the height at which the preceding coil 25 is positioned and the height at which the following coil 26 is positioned are different due to coil twist or the like, the backing metal 3 is applied. Both heights will be the same.

Next, compressed air is sent to the air hose 2 arranged inside the backing metal 3 to inflate the air hose 2. When the air hose 2 is inflated, the flux 1 in the backing metal 3 is removed because the backing metal 3 is in contact with the lower surfaces of the respective ribs 25a and 26a of both coils 25 and 26, respectively.
As shown in (b), the gaps between the adjacent ribs 25a and the gaps between the adjacent ribs 26a are pushed up, and the gap 1 is filled with the flux 1.

Therefore, even if one-pass single-side welding is performed from the upper surface side of the coil in this state, the deposited metal does not flow down during welding.

Reference numeral 4 in the figure denotes a heat insulating material for preventing the influence of heat from the flux 1 on the air hose 2.

Since the method of splicing a coil coil for a spiral steel pipe with an external rib according to the present invention is performed as described above, welding is performed with high efficiency and no welding defects occur.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the sectional view of FIG.
m, the width w is 50 mm, the plate thickness t ₁ on both sides is 35 mm, and the bottom plate thickness is 20 mm. And the particle size is 12 ~
A 65-mesh flux 1a is filled in the lower layer with a flux 1b having a melting temperature of 1272 ° C. and a particle size of 32 to 100 mesh, and the backing metal 3 is ribbed (thickness 2.m) by a hydraulic device (not shown). 5 to 4 mm) are brought into contact with the ribbed coils 25 and 26 on the lower surface side, and compressed air having a pressure of 1 kg / cm ² is sent to the air hose 2 so that the flux 1
a while filling the gap between the ribs
One pass single side welding was performed from the upper surface side of Nos. 5 and 26.

At this time, the distance e between the ribbed coil 25 and the ribbed coil 26 was 0 to 5 mm.

The welded coil has a thickness t of 6 to 30 mm.
And the plate width of the coil is also 1280 mm, 1474 mm,
Wide range of 1695mm and 1845mm,
In each case, good welding without any welding defects could be performed by one-pass single-sided welding.

[0023]

According to the present invention, it is possible to carry out the relay welding of the coil for spiral steel pipe with external ribs at high efficiency without generating welding defects.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram of a method of splicing a material coil for a spiral steel pipe with an external rib according to an embodiment of the present invention;
(A) is a side view of the coil during welding, (b) is B of (a).
FIG.

FIG. 2 is a side view of a coil and a backing metal for explaining an embodiment of the present invention.

FIG. 3 is an explanatory view when a conventional splice of a coil for spiral steel pipe is performed.

FIG. 4 is an explanatory view when the splicing of a coil for spiral steel pipe with external ribs is performed by a conventional splicing method;
(A) is a side view of the coil during welding, (b) is A of (a).
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flux 2 Air hose 3 Backing metal 4 Insulation material

Claims (1)

[Claims] 1. A method in which a rear end of a preceding material coil for a spiral steel pipe with external ribs and a front end of a succeeding coil are joined by one-pass one-side welding during forming and welding of the spiral steel pipe with external ribs. The leading end of the leading coil and the leading end of the trailing coil in a butted state for joining.
The flux is stored from below in the entire width of the coil and is lifted up by a flux storage container which also serves as a backing metal to eliminate a step between the rear end of the preceding coil and the front end of the following coil. After the flux is pressed against the back surface of each of the rear end of the preceding coil and the front end of the following coil by the flux pressing means arranged in the container, the flux is filled between the plurality of ribs formed on the coil back surface. A method of splicing a material coil for an outer ribbed spiral steel pipe, wherein one end of a butted portion between a rear end of a preceding coil and a front end of a following coil is welded from the upper surface side of the coil by one side.