JP2005169455A - Manufacturing apparatus for electric resistance welded tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus capable of manufacturing an electric resistance welded tube from a wide thick steel plate as the base material, at a low cost by merely applying a simple device to an existing facility. <P>SOLUTION: In the manufacturing apparatus for the electric resistance welded tube, there are successively arranged, on the traveling line of a steel strip, an uncoiler for unwinding a coiled steel strip, a leveler for smoothing the unwound steel strip, a connecting means 14 for connecting by welding the trailing end of a preceding steel strip and the leading end of a succeeding steel strip, an edge mirror for straightening both ends in the width direction of the steel strip, a group of forming rolls for cylindrically forming the steel strip after the connection, and a joining means for welding both abutting ends in the width direction of the cylindrical steel strip. This manufacturing apparatus is improved in such a manner that, on the traveling line 15 between the leveler and the connecting means 14, a delivering means 17 is installed which successively feeds a steel cast slab 16, in place of a coiled steel strip, from the direction orthogonally crossing the traveling line, and that a width setting means 19 is installed which parallelizes the center line of the fed steel cast slab 16 to the traveling line. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electric resistance steel pipe manufacturing apparatus, and more particularly, to a technique for manufacturing an electric resistance steel pipe made of a wide and thick steel plate at low cost using existing equipment.

    In general, ERW steel pipes are formed by rolling a coiled steel strip as a raw material with an uncoiler and continuously forming it into a cylindrical shape with a group of forming rolls. It is manufactured by welding. That is, for the production, as a raw material, for example, a steel slab obtained by continuously casting molten steel is heated to a predetermined temperature (usually 1200 to 1300 ° C.) in a heating furnace, and then hot rolled to a constant width. A coiled steel strip wound up is used. Then, as shown in FIG. 2, the coiled steel strip 1 is rewound by the uncoiler 2, smoothed by the leveler 3, and both ends in the width direction are adjusted by the edge mirror 4, and then rolls having various shapes are formed. The steel strip surface is horizontal and fed at a constant speed to a group of forming rolls 5 arranged in multiple stages. The tubular body processed by this forming roll and made into a cylindrical shape (referred to as an open tube since the abutted width direction end portions are unjoined) continues the abutted width direction both end portions of the induction coil 6 or Heating is performed by using a power supply means such as a contact tip, and pressing with a squeeze roll 7 and press-bonding and welding are performed to obtain a steel pipe 8 (hereinafter referred to as a base pipe 8). Since the protrusions called beads are formed on the inner and outer surfaces of joint portions (hereinafter referred to as seam portions) extending substantially linearly continuously in the longitudinal direction of the base tube 8, the beads are bead cutting means 9. Remove by cutting. Further, the raw tube 8 is sized by a multi-stage drawing mill 12 such as a sizer, cut to a predetermined length by a running cutting machine 10 and inspected to have a desired size and characteristics, It becomes ERW steel pipe 13 as a product.

  A connecting means 14 for connecting the rear end of the preceding steel strip and the front end of the subsequent steel strip is provided between the leveler 3 and the edge mirror 4. Usually, the connecting means 14 is a welding machine that moves in synchronization with the traveling steel strip speed, but this enables an operation to continuously supply the coiled steel strip sequentially, thereby improving productivity. It can be planned.

  By the way, conventionally, the largest ERW steel pipe manufactured using such a manufacturing apparatus has an outer diameter of 660.4 mmΦ × thickness of 25.4 mm. It is constrained by the width of the coiled steel strip used as a raw material (maximum 2200 mm). Furthermore, steel strips having a width larger than that are not suitable for the processing capacity of uncoilers and levelers, and cannot be manufactured. It was.

  However, recently, in order to meet cost reduction demands and short delivery time demands, there is a need to manufacture and supply steel pipes with larger diameters with highly productive ERW steel pipes. As large diameter steel pipes manufactured by welding, there are so-called “UO steel pipes” and “spiral steel pipes”, which are not only low in productivity but also expensive. Therefore, it is desired to manufacture an electric resistance welded steel pipe having a larger diameter than before by using an existing electric resistance welded pipe manufacturing apparatus as inexpensively as possible.

  In view of such circumstances, an object of the present invention is to provide an ERW steel pipe manufacturing apparatus capable of manufacturing an ERW steel pipe made of a wide and thick steel plate at a low cost by simply applying a simple device to an existing apparatus. .

  In order to achieve the above-mentioned object, the inventor diligently reviewed the conventional apparatus and embodied the result in the present invention.

  That is, the present invention welds an uncoiler that unwinds a coiled steel strip as a raw material, a leveler that smoothes the unwound steel strip, and a rear end of a preceding steel strip and a front end of a subsequent steel strip. Connecting means for connecting with each other, edge mirrors for adjusting both ends in the width direction of the steel strip, a group of forming rolls for forming the steel strip after connection into a cylindrical shape, and both end portions in the width direction where the cylindrical steel strips are butted against each other In an electric resistance welded steel pipe manufacturing apparatus in which welding means for welding are sequentially arranged on a traveling line of a steel strip, a wide width is provided instead of the coiled steel strip on a traveling line between the leveler and the connecting means. There are provided a means for carrying in a wide thick steel plate that sequentially feeds the thick steel plate from a direction orthogonal to the travel line, and a width determining means for making the center line of the fed wide thick steel plate parallel to the travel line. It is a manufacturing apparatus of a sewn steel pipe. In this case, the means for carrying in the wide thick steel plate is composed of a moving skid on which the wide thick steel plate is placed and moved in a direction perpendicular to the travel line, or the size of the wide thick steel plate is 1000 mm wide. ˜2500 mm × thickness 6.0 to 30.5 mm × length 13,000 to 25000 mm.

  In the present invention, since a wide and thick steel plate can be used as a raw material, an electric resistance welded steel pipe having an outer diameter of 26 inches or more can be manufactured at a low cost only by applying a simple device to an existing manufacturing apparatus.

  Hereinafter, the best mode for carrying out the present invention will be described based on the circumstances leading to the invention.

  First, the inventor examined in detail why an ERW steel pipe larger than 26 inches in diameter cannot be manufactured with an existing apparatus for manufacturing an ERW steel pipe. As a result, it is difficult to manufacture a coiled steel strip used as a normal material with existing equipment, and in the manufacturing apparatus shown in FIG. 2, the means disposed on the upstream side processes a steel strip having a width of 2200 mm or more. I found it impossible. That is, in order to manufacture an ERW steel pipe having a diameter of 26 inches or more, the width of the steel strip is required to be at least about 2250 mm. At the same time, the uncoiler and the leveler were not able to process steel strips of greater width. However, a line on which the unwound steel strip downstream from the leveler travels (actually, a roller is installed), a joining means for joining the rear end of the preceding steel strip and the front end of the subsequent steel strip, It has been found that a group of forming rolls and the like can be used by changing the size and shape of the roll even if the steel strip width is further increased.

  Therefore, the inventor thinks that ERW steel pipes with larger diameters can be manufactured at low cost and stably if a simple device is devised on the upstream side of the material and existing manufacturing equipment, and specific means are studied earnestly. Thus, the present invention has been completed.

  That is, in the present invention, the material is supplied to the connecting means 14 without passing through the uncoiler 2 and the leveler 3 for smoothing the rewound steel strip. Therefore, it was decided to use a wide and thick steel plate (hereinafter referred to as a wide thick steel plate) that is shorter than the steel strip but does not require rewinding. The wide steel plate is not limited to a steel type, but a steel plate manufactured separately in a hot rolling factory or the like may be used. Moreover, it is preferable that the size is width 1000-2500mm x thickness 6.0-30.5mm x length 13000-25000mm. This is because if the width exceeds 2500 mm, the pipe forming process cannot be performed by the travel line, the connecting means 14, the forming roll 5, or the like. Moreover, the upper limit of the thickness of the wide and thick steel plate is 30.5 mm and the lower limit is 6.0 mm for the convenience of forming into a cylindrical shape. Further, the length is preferably 13,000 to 25000 mm. This is because if it exceeds 25000 mm, it is too long to be fed into the existing travel line 15, and if it is less than 13000 mm, the length is too short and there is no point in manufacturing.

  In the present invention, the wide and thick steel plate is used as a raw material, on the traveling line 15 between the leveler and the connecting means, instead of the coiled steel strip 1, sequentially from the direction orthogonal to the traveling line 15. I sent it in.

  As the means for carrying in the wide thick steel plate, any means can be used as long as it can accept the wide thick steel plate and move the wide thick steel plate to an existing travel line. Therefore, in the present invention, as shown in FIG. 1, the received wide and thick steel plate 16 is placed and moved in a direction perpendicular to the existing travel line 15 so as to be carried into the travel line 15. It is preferable to use a carrying-in means constituted by the skid 17. Moreover, a crane, a roller conveyor, etc. should just be utilized for acceptance of the wide thick steel plate in the movement skid 17. FIG.

  Further, the wide steel plates 16 sequentially fed to the travel line 15 need to have their center lines parallel to the travel line 15 before being processed by the downstream means. Therefore, in the present invention, width determining means 19 such as a side roller whose axis is movable in a direction perpendicular to the travel line is provided on both sides of the travel line (roller array) 15.

  Thus, if the wide thick steel plate 16 is used, and its carrying-in means and positioning means 19 are used, the wide thick steel plate 16 can be continuously supplied to the running line 15 of the existing ERW steel pipe manufacturing apparatus.

  Next, the continuously supplied wide thick steel plate 16 needs to connect the rear end of the preceding wide thick steel plate and the rear end of the following wide thick steel plate. This is because the length of the material is increased to increase the efficiency of the pipe making process, and the portion to be cut and removed as scrap (crop) is reduced to improve the yield of the material. For the connection, also in the present invention, connection means 14 composed of a welding machine such as used in the manufacture of small diameter electric resistance welded steel pipes can be used. However, since the length of the wide and thick steel plate 16 that is a material is much shorter than the length of the coiled steel strip, care must be taken in the operation of the connecting means. In other words, in order to bring the leading end of the following wide thick steel plate into contact with the trailing end of the preceding wide thick steel plate, on the upstream side of the connecting means 14, it is necessary to frequently control the rotation speed of the roller of the traveling line 15; Further, the frequency of approaching and separating the welding torch from the wide and thick steel plate 16 increases.

  As shown in FIG. 2, the wide and thick steel plates 16 connected as described above are thereafter formed into a cylindrical shape with an existing forming roll, joined at a butt (seam portion), and bead cutting. After that, the diameter of the pipe does not exist in the past. Depending on the steel type of the material, there is a steel pipe that performs heat treatment of the seam portion after the bead cutting. Then, after being drawn to a desired diameter by a drawing mill such as a sizer and cut at the spot-welded portion in the longitudinal direction, the product is made into an electric resistance steel pipe. However, it is necessary to change the shape and size of each roll disposed on the forming roll to a value that achieves a desired diameter. In addition, about the wide thick steel plate 16 used by connecting, you may connect a normal coiled steel strip.

  In addition, it is not necessary to completely weld the end surfaces of the leading end of the following wide thick steel plate and the trailing end of the preceding wide thick steel plate, and spot welding is sufficient. The reason for this is that when cutting to the steel pipe length of the product with the running cutting machine 10, it is possible to cut with the spot weld as the extra length, and further to cut and remove that part in the subsequent process. This is because the connected part is not a product. That is, it is sufficient that the connection between the preceding material and the following material has a bonding force that resists the external tension generated in the manufacturing process.

  Steel slabs of normal carbon steel cast by a continuous casting machine were rolled into various sizes of steel sheets at a hot rolling mill. And the electric-resistance-welded steel pipe which has various diameters and thickness was manufactured using this steel plate as a raw material using the manufacturing apparatus of the electric-resistance-welded steel pipe which concerns on this invention. Table 1 shows the target steel size, the diameter and thickness of the electric resistance welded steel pipe to be manufactured.

  As shown in Table 2, the results were evaluated by the material yield and the product pass rate. The material yield (%) is defined as (product weight / material weight used) × 100, and the product pass rate (%) is defined as (number of products that passed the inspection such as bag and size / number of products) × 100. It is. From Table 2, it is clear that an electric resistance welded steel pipe using a wide and thick steel plate can be manufactured inexpensively and stably using the electric resistance welded pipe manufacturing apparatus according to the present invention. In addition, according to the present invention, not only a large-diameter pipe, but also an ERW steel pipe having a size that has been manufactured using a coiled steel strip as a raw material can be manufactured without any difference in quality.

It is a top view explaining the principal part in the manufacturing apparatus of the ERW steel pipe which concerns on this invention. It is a schematic diagram which shows the manufacturing apparatus of the conventional ERW steel pipe.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coiled steel strip 2 Uncoiler 3 Leveler 4 Edge mirror 5 Forming roll 6 Feeding means, such as an induction coil or a contact tip 7 Squeeze roll 8 Element steel pipe (element tube)
9 Bead cutting means 10 Running cutting machine 12 Drawing mill (sizer etc.)
DESCRIPTION OF SYMBOLS 13 ERW pipe 14 Connection means 15 Traveling line 16 Wide and thick steel plate 17 Moving skid 19 Positioning means

Claims (3)

An uncoiler that rewinds the coiled steel strip that is the material, a leveler that smoothes the unrolled steel strip, and a connecting means that connects the rear end of the preceding steel strip and the front end of the subsequent steel strip by welding. An edge mirror for adjusting both ends of the steel strip in the width direction, a group of forming rolls for forming the joined steel strip into a cylindrical shape, and a joining means for welding the opposite ends of the cylindrical steel strip in the width direction In the manufacturing equipment for ERW steel pipes arranged sequentially on the running line of the steel strip,
On the running line between the leveler and the connecting means, the wide-thick steel plate is brought in, and the wide-thickness fed in, in order to feed the wide-thick steel plate instead of the coiled steel strip sequentially from the direction perpendicular to the running line. An apparatus for manufacturing an electric resistance welded steel pipe, comprising: a width determining means for making a center line of a steel plate parallel to a running line. 2. The electric-welded steel pipe manufacturing method according to claim 1, wherein the means for carrying in the wide-thick steel plate comprises a moving skid on which the wide-thick steel plate is placed and moved in a direction perpendicular to the travel line. apparatus. The size of the said wide-thick steel plate is width 1000-2500mm x thickness 6.0-30.5mm x length 13000-25000mm, The manufacturing apparatus of the electric-resistance-welded steel pipe of Claim 1 or 2 characterized by the above-mentioned.

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