JPS61279392A - Production for longsized thick pipe - Google Patents

Abstract

PURPOSE:To shorten the set up time and welding time and to make the production of a long size thick pipe efficient by electro-welding the joint part in the bus direction with opposite abutting of a long semicircular cylinder after forming a steel plate in short semicircular cylinder and forming in a long semicircular cylinder with its semiperipheral welding by arranging in the necessary number. CONSTITUTION:A thick steel plate is formed in semicircular shape and made in a short semicircular cylinder 3. The short semicircular cylinder 3a, 3b are abutted and born freely rotatably respectively and semicircular rack 4a, 4b are fitted as well and pinion 5a, 5b are fitted to the rack 4a, 4b. A rail 6 is then laid, an electro-welding machine 7 is held at the position that the tangent of the joint part 9 becomes vertical and a long semicircular cylinder is produced with the electro-welding from the lower end of the joint part 9. It is then abutted so as to slip the position of the joint part 9a, 9b in the peripheral direction of long semicircular pipe 10a, 10b, a rail 12 is laid along the joint part 11, an electro-welding machine 7 is arranged and with a vertical electro-welding toward the upper part from the lower end of the joint part 11 a long sized pipe is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing thick-walled long tubes for use in boiler drums, jackets, and the like.

[Prior Art] A conventional method of manufacturing a thick-walled long tube is as shown in FIGS. 4 and 5. That is, after forming a thick steel plate into a cylindrical shape, a short cylinder 2 is manufactured by multi-layer welding a joint part 1 extending in the generatrix direction by submerged arc welding, and then the short cylinders 2a and 2b are assembled into a joint part 1a.
, 1b are placed in different positions, 1C are butted together, and the entire circumference joint is welded in multiple layers by nub merge arc welding. This operation is repeated one after another to produce a thick-walled long tube.

[Problems to be Solved by the Invention] However, the conventional method described above requires welding a plurality of buses to join the joint, resulting in a long welding time.

The present invention aims to weld joints in a short time and efficiently manufacture thick-walled long pipes.

[Means for Solving the Problems] The present invention involves forming a steel plate into short semi-cylinders, arranging the required number of short semi-cylinders in the generatrix direction, butt welding them around half the circumference to produce a long semi-cylinder, and then forming a long semi-cylinder. The semi-cylindrical cylinders are placed facing each other, and the joint part in the generatrix direction extending in the vertical direction is welded with an electric or mouth weld.

[Function] (Since the joints in the generatrix direction are welded in one bus, welding time and setup time required for welding are significantly reduced.)

[Implementation example] The present invention will be described in detail below with reference to the drawings.

A thick steel plate is formed into the semi-cylindrical shape shown in Fig. 1 by roll or press forming to form the short semi-cylindrical shape 3, and the short semi-cylindrical cylinders 3a and 3b shown in Fig. 2 are butted together to form both short semi-cylindrical cylinders 3a and 3b, respectively. While being rotatably supported, semicircular racks 4a and 4b are attached to both short semicylindrical cylinders 3a and 3b, and both short semicylindrical cylinders 4a,
Binions 5a and 5b for rotating 4b are attached to rack 4a.
, 4b. Further, a rail 6 is laid on one of the short semi-cylinders, and an electro welding machine (electro gas arc welding machine or electro slab welding machine 1) 7 is placed on the track so that it can run freely.

8 in the figure indicates an auxiliary plate.

The electro-welding machine 7 holds the joint part 9 in a position where the tangent line is vertical, rotates both short semi-cylinders 3a and 3b from the lower end of the joint part 9, and vertically electro-welds them to produce a long cylinder. When the circumferential welding is completed, the rails and racks 4a, 4
b is removed, and the longitudinal cylinders 10a and 10b (not shown in FIG. 3) are connected to the circumferential joint portion 9a.

Butt so that the position of 9b is shifted. A rail 12 is attached along a joint portion 11 extending in a generatrix (vertical) direction, and an electrowelding machine 1 is disposed on the rail 12 so as to be freely movable. Vertical electrowelding is performed upward from the lower end of the joint part 11 to produce a long pipe.

According to the present invention, since the electrogas arc welding method is adopted and each joint is completed by one bus welding, the setup and welding time in the welding work can be significantly reduced.

Incidentally, electrowelding may be applied only to the joint portion of the longitudinal cylinder in the l'' line direction, or three or more short semi-cylinders may be butted together to form a longitudinal cylinder.

[Effect of the Invention 1] As described above, according to the present invention, both the welding setup time and the welding time can be significantly shortened, and thick-walled long pipes can be manufactured with high efficiency.

[Brief explanation of drawings]

FIGS. 1 to 3 are explanatory views showing the manufacturing process of the method according to the present invention, and FIGS. 4 and 5 are explanatory views showing the conventional process. 3.3a and 3b are short semi-cylinders, 7 is an electro welding machine, 1
1 indicates a joint part. Patent application Hitoshi Kawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1) Form a steel plate into short semi-cylinders, arrange the required number of short semi-cylinders in the generatrix direction, butt and weld half the circumference to produce a long semi-cylinder, then butt the long semi-cylinders facing each other and weld them in the generatrix direction extending vertically. A method for manufacturing a thick-walled long pipe, characterized by electrowelding a joint part.