JPH05154545A - Production of clad steel welded pipe - Google Patents

Abstract

PURPOSE:To manufacture an inner surface clad steel welded pipe while keeping the high workability of a welding work by electric welding a butting part of clad material of a tubular body which a raw plate of clad steel is formed and the inner surface is made to the clad material, and thereafter, executing build up welding to a butting unwelded part. CONSTITUTION:The raw plate or a raw coil of the clad steel is continuously formed so that the inner surface becomes clad material 2 by roll-forming to manufacture a tubular body 1 and the electric welding is executed while contact- pressurizing the butting part 2a of the clad material 2 to form the electric welded part 4. Thereafter, the butting unwelded part of the base material 3 made of the ordinary steel is build up welded to manufacture the clad steel welded pipe. Formation of the raw pipe 1 is executed at high efficiency and also as the welding of the clad material 2 is executed with the electric welding and the ordinary steel welding of the base material 3 is executed with the build up welding from the outer surface side, the workability to the welding work can be kept high and the inner surface clad welded pipe can be manufactured at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a clad steel welded steel pipe, and more particularly to a method for producing a clad steel welded steel pipe having an inner surface as a composite material.

[0002]

2. Description of the Related Art Clad steel welded steel pipe whose inner surface side is a composite material of alloy steel can be manufactured at a lower cost than a seamless steel pipe of alloy steel alone. Therefore, as a means for transporting oil or gas containing a corrosive component, Used in the field of oil development.

Conventionally, a method of manufacturing a clad steel welded steel pipe having an inner surface side made of a composite material of alloy steel has been carried out by a roll bender, a press, a UOE method or the like so that the clad steel original plate is made of the alloy material of the inner surface side. After forming into a tubular shape, the cladding is welded from the inner side mainly with the welding rod made of the same material as the cladding, and the ordinary steel is mainly welded from the outside with the welding rod made of the same material as the ordinary steel. A method of overlay welding or a method in which the welding sequence is reversed is adopted.

Further, as a method for increasing the production efficiency of welded clad steel pipe, there is a technique described in Japanese Patent Publication No. 2-24197. The method according to this technique is to bend a clad steel plate or steel strip into a tubular shape, heat both opposite edges of the bent steel plate or steel strip, and then apply butt welding by applying a lateral pressure. The bead is cut and removed to a depth reaching the base material, and a welded portion having the same properties as the mating material is applied to the cut and removed portion.

[0005]

However, the conventional method for welding the butt portion of the cladding material portion of the welded clad steel pipe from the inner surface has the following problems.

That is, a field in which a large amount of clad steel welded steel pipe whose inner surface is a composite material (hereinafter referred to as "inner surface clad steel welded steel pipe") is used is a field related to oil development. When the inner surface clad steel welded steel pipe is used for the unrefined crude oil gas transportation up to, the pipe diameter is 4 to 8 inches (101.6 to 203.
Most of them have a relatively small diameter of 2 mm).

In the case of producing such a small-diameter inner surface clad steel welded steel pipe, when attempting to perform overlay welding of the mating material portion from the inner surface, a welding wire feeding device, a power feeding device, and gas feeding in the case of gas shield welding are used. It is necessary to arrange a welding head composed of a feeder, a shield device around the welded portion, a flux feeder in the case of submerged arc welding, a flux disperser and, if necessary, a flux collector, in the pipe.

When the steel pipe has a small diameter, it is impossible to arrange such a welding head in the pipe,
Even if it can be arranged, the welding wire feeding part is unstable at the tip of the welding wire supply part due to unstable feeding of the wire etc. However, there has been a problem that the repair work is increased and the work efficiency is lowered, and the defective portion is cut off to reduce the yield.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and a clad steel welded steel pipe which can be easily manufactured without deteriorating the quality even of a small diameter inner clad steel welded steel pipe. It is intended to provide a manufacturing method.

[0010]

A method for producing a clad steel welded steel pipe according to the present invention is a method for producing a clad steel welded steel pipe having an inner surface as a composite material, which comprises forming an original plate or coil of clad steel to form an inner surface. At least a part of the butting of the joining material of the tubular body with the joining material as the joining material is electric resistance welded, and then the unbutted butted portion is overlay welded.

Further, in the method for producing a clad steel welded steel pipe as an embodiment of the above invention, in the above invention, the base plate or coil of the clad steel to be used is such that the side end surface of the base material is more entire than the side end surface of the laminated material. The width is narrowed by 5 to 30% of the plate thickness.

[0012]

In the method for producing a clad steel welded steel pipe according to the present invention, at least a part of the abutting portion of the abutting material is electro-resistance welded to the abutting material on the inner surface side. The welding quality can be improved and the welding quality can be maintained at high quality. Furthermore, welding work for inserting a welding device into the inner surface of the steel pipe is not required. Since the base material is welded by overlay welding from the outer surface, the workability of this portion can be maintained high.

The reason why the electric resistance welding is carried out while the tubular body is restrained in a state where at least a part of the mating material butt portion of the raw pipe is contact-pressurized is as follows.
That is, as in the case of manufacturing the normal electric resistance welded steel pipe shown in FIG. 5, when the butt portion 22a of the mating material portion 22 of the raw pipe 21 and the butt portion 23a of the ordinary steel portion 23 are brought into contact at the same time, electric resistance welding is performed. As shown in FIG. 6, the molten steel 23b of the ordinary steel portion 23 passes through the abutting portion 22a of the mating material portion 22 and is extruded toward the inner surface of the pipe by the pressure applied by the upset pressurization. Since the abutting portion 22a is in a state where the alloy steel joining material 22 does not exist, the corrosion resistance cannot be maintained. In this respect, the laminated material 2 as in the present invention
If only two parts are welded first, the above does not occur and therefore the corrosion resistance does not decrease.

Further, in the method for producing a clad steel welded steel pipe as an embodiment of the above invention, the base plate or coil of the clad steel to be used has a base material side end surface having a total plate thickness of 5 to 10 The reason why the cutting process is performed so as to be located 30% rearward is as follows. This is because if it is less than 5%, the effect of suppressing the intrusion of the molten normal steel at the time of contact with the laminated material is the same as that in the case where no cutting is performed, and no further effect can be obtained, and if it exceeds 30%, the effect disappears.

[0015]

EXAMPLE A method of manufacturing a welded clad steel pipe according to an example of the present invention will be described with reference to FIGS. A method for manufacturing a clad steel welded steel pipe according to an embodiment of the present invention is a method for manufacturing a clad steel welded steel pipe in which an inner surface side is a composite material of alloy steel, and an inner surface side of a clad steel original plate or coil is formed by roll forming. The tubular body 1 is manufactured by continuous molding so that the tubular body 1 is constrained in a state in which at least a part of the butting portion 2a of the laminated material 2 of the manufactured tubular body 1 is contact-pressurized. The electric resistance welding is performed to form the electric resistance welding portion 4.

FIGS. 1 (a) to 1 (c) are transverse sectional views of the shell 1 showing the contact pressure state of the butting portion 2a of the joining material 2 at that time. FIG. 1 (a) shows a case in which one point 2b on the innermost surface side of the abutting portion 2a of the mating material 2 is in contact with the mating material 2
The abutting portion 2a of the base metal 3 and the abutting portion 3a of the base material 3 of ordinary steel are aligned with each other.
It spreads in a fan shape starting from. In this case, both end faces of the clad original plate or the original coil are cut so as to be perpendicular to the plate surface.

FIG. 1 (b) shows a case where the abutting portion 2a of the mating material 2 is in contact at one point 2b on the innermost surface side. In this case, the abutting portion 2a of the mating material 2 and ordinary steel are also shown. The abutting portion 3a of the base material 3 is curved, and the abutting portions on both sides extend in an arc shape starting from the point 2b. In this case, both end surfaces of the clad original plate or the original coil are cut so as to be inclined toward the base material 3 side of ordinary steel with respect to the plate surface.

FIG. 1 (c) shows the case where the abutting portions 2a of the mating material 2 are in full contact with each other. In this case, both side end surfaces of the clad original plate or the original coil, and the mating material 2 is made into the plate surface. On the other hand, the base material 3 is cut so as to be inclined toward the laminated material 2 side, and the base material 3 is cut so as to be perpendicular to the plate surface.

When electric resistance welding is performed in the above-described state, only the alloy steel composite material 2 is welded as shown in FIG. 2, and the molten portion of the base material 3 near the composite material 2 is the molten steel of the composite material 2. Is pushed up by. Due to this, a slight mixed portion of alloy steel and ordinary steel is recognized near the boundary between the composite material 2 and the base material 3, but the material of the composite material 2 of the alloy steel on the inner surface side of the steel pipe is reduced. is not.

FIG. 3 shows the welded and unwelded portion of the raw pipe 1 after electric resistance welding that is welded as it is or with a groove, and the welded welded portion 5 is welded from the outside. Can be welded to.

In FIG. 4, the distance (L) between the side end surface 13a of the ordinary steel base material 13 and the side end surface 12a of the alloy steel composite material 12 is shown as the whole of the clad steel plate or coil used. It is cut so as to be 5 to 30% of the plate thickness (t).
The ordinary steel base material 13 is less likely to melt during electric resistance welding, and therefore the mixed portion of alloy steel and ordinary steel is reduced, so that the quality can be further improved.

[0022]

EFFECTS OF THE INVENTION According to the present invention, the raw pipe can be formed with high efficiency, and the welding of the joining material is performed by the electric resistance welding and the welding of the ordinary steel is performed by the overlay welding from the outer surface side. Therefore, the inner clad steel welded steel pipe can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a tubular body showing a contact pressure state of a butt portion of a mating material.

FIG. 2 is a transverse cross-sectional view of a shell showing a state in which a butt portion of a tubular body is electric resistance welded.

FIG. 3 is a cross-sectional view of an inner clad steel welded steel pipe after overlay welding.

FIG. 4 is a cross-sectional view showing a processed state of both end surface portions of a clad steel original plate or an original coil.

FIG. 5 is a transverse cross-sectional view showing a butted state of a butted portion when an ordinary electric resistance welded steel pipe is electric resistance welded.

FIG. 6 is a transverse cross-sectional view showing a state in which the inner surface clad steel welded steel pipe is electric resistance welded in the same butt state as when a normal electric resistance welded steel pipe is electric resistance welded.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tubular body 2 Laminated material 2a Laminated portion of the laminated material 2b Contact point of the abutted portion of the laminated material 3 Base material 3a Butted portion of the base material 4 ERW welded portion 5 Overlay welded portion 12 Raw material or raw coil laminated material 12a Or side end surface of the mating material of the original coil 13 base material of the original plate or original coil 13a end surface of the original plate or original coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Michiaki Yoshida Marunouchi 1-2-2, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Yutaka Nagahama 1-2-1 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Takayuki Otake 1-2 1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (2)

[Claims] 1. A method for producing a clad steel welded steel pipe having an inner surface as a joining material, wherein at least a part of a joining material butt of a tubular body having an inner surface as a joining material is formed by electroforming a clad steel original plate or coil. A method for producing a clad steel welded steel pipe, which comprises welding and then overlay welding the butt-unwelded portions. 2. A clad steel original plate or original coil, wherein the side end surface of the base material has a total plate thickness of 5 to 3 than the side end surface of the laminated material.
The method for producing a clad steel welded steel pipe according to claim 1, wherein the width is narrowed by 0%.