RU2493927C2 - Method of tube production - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to tube rolling and may be used in production of wrought tubes. In carbon-arc gouging, sheet lengthwise edges are cut at oblique angle or at double angle to sheet plane, sheet edges tucking in, pre- and final forming. After final forming, billet is produced with its lengthwise edges overlapped without alignment. Then, billet lengthwise edges are aligned by application of expansion force inside the billet to cause prestressed state and to weld lengthwise seam.

EFFECT: higher reliability.

3 cl, 5 dwg

Description

The proposed method of manufacturing a pipe relates to the field of transport infrastructure, the pipe is designed to transport liquid and gaseous substances, as well as solid fuel and other solid substances in the form of a solution under the influence of pressure differences in the cross sections of the pipe. The inventive method of manufacturing a pipe can be used in the design, construction and operation of pipelines for the petrochemical and gas industries. In connection with the expansion of oil and gas production, the need for high-strength thick-walled pipes has increased significantly, therefore, the task of obtaining high-quality, high-strength thick-walled large-diameter pipes has become urgent.

According to the well-known technology of the Chelyabinsk Tube Rolling Plant, a pipe is made of two billets, the method includes preliminary and final molding of two pipe halves and welding of two longitudinal seams in a welding mill.

In the manufacture of pipes by this method, two longitudinal welds are obtained, which significantly reduces the bearing capacity and, as a result, the disadvantages of this technical solution are the low strength of the pipe being manufactured, and the low reliability of the welds.

A known method of forming pipes of large diameter, including sequentially performed preliminary U-molding, final molding on the press by giving the U-shaped workpiece a cylindrical shape in one stroke of the press using a punch tool and subsequent welding of the longitudinal seam (see V.Ya. Osadchy, A . S. Vavilin et al. Technology and equipment for pipe production, Moscow, Intermet Engineering, 2001. “Technological scheme for the production of large-diameter pipes from one sheet with molding on presses (UOE)”, Fig. 11.4, p. 416, as well as the above brochure SMS MEER, p.16-18).

The disadvantages of this technical solution are the low strength of the manufactured pipe, low reliability of the weld.

The technical result of the proposed method of manufacturing a pipe is to increase the reliability of the weld, increase the bearing capacity of the pipe, resistance to avalanche damage, increase reliability under shock loads, high wear resistance.

The specified technical result is achieved by the fact that the method of manufacturing the pipe includes gouging the sheet, bending the edges of the sheet, preforming, final molding and welding of the seam according to the invention when gouging, the longitudinal edges of the sheet are cut at an oblique angle or at a double angle to the plane of the sheet, after the final molding a blank is obtained , the longitudinal edges of which go against each other without their combination, for welding the longitudinal seam combine the longitudinal edges of the workpiece by applying a distributing force inside otovki ensuring prestressed condition in the tube; and / or a number of “pockets” are installed inside the pipe; and / or a tape of elastic material with transverse ribs is installed inside the pipe.

Due to the fact that when gouging, the longitudinal edges of the sheet are cut at an oblique angle or at a double angle to the plane of the sheet, after the final molding, a workpiece is obtained, the longitudinal edges of which come on top of each other without their combination, for welding the longitudinal seam, the longitudinal edges of the workpiece are combined by applying a distributing efforts inside the workpiece to ensure a prestressed state in the pipe; and / or a number of “pockets” are installed inside the pipe; and / or a tape of elastic material with transverse ribs is installed inside the pipe, the reliability of the weld increases, the load-bearing capacity of the pipe increases, the reliability under impact loads increases, and the wear resistance increases.

Thus, the combination of the claimed features allows you to increase the reliability of the weld, increase the bearing capacity of the pipe, increase reliability under shock loads, increase wear resistance.

The inventive method has novelty, differing from the prototype of the above features, and ensures the achievement of the perceived by the applicant technical result.

The inventive method of manufacturing a pipe can be widely used in the manufacture of long tubular billets of large diameter. The essence of the proposed method of manufacturing a pipe is illustrated by drawings:

figure 1 - processing of the edges of the sheet at an oblique angle;

figure 2 - processing of the edges of the sheet at a double angle;

figure 3 is a schematic diagram of the final molding and welding;

figure 4 - "pocket" in the third embodiment;

figure 5 - tape in the fourth embodiment.

A method of manufacturing a pipe 1 is carried out on the equipment of a pipe rolling plant. The method includes gouging a sheet in which the longitudinal edges 2 of the sheet are cut not at a right angle to the plane of the sheet stock but at an oblique angle (FIG. 1) or a double angle (FIG. 2). Next, bending of the edges 2 of the sheet, preliminary U-molding and final molding on the press are carried out by giving the U-shaped workpiece a cylindrical shape, and after final forming, the longitudinal edges 2 of the workpiece after being removed from the bending mill are not aligned with each other. The longitudinal edges of the workpiece go against each other. Those. after the final molding, a billet is obtained, the longitudinal edges of which come into each other without combining them. For welding the longitudinal seam 3 in the welding mill, a dispensing force is applied to the workpiece, the longitudinal edges 2 are combined and the weld 3 is welded. Thus, in the finished form, the pipe 1 has internal compressive stresses, which increases its reliability. The pipe 1 can be molded by any known method, including step-by-step molding, in which the section of pipe 1 is formed by stepwise longitudinal bending of the workpiece.

Also on the inner surface of the pipe 1 it is possible to install "pockets" 4 and / or tape 5 with transverse ribs. This is necessary for whipping the bottom of the jet stream of the transported product during operation of the pipeline and holding the suspension at the bottom, which reduces jet corrosion.

The inventive method of manufacturing a pipe allows us to increase the reliability of the weld of the finished product, increase the bearing capacity of the pipe, resistance to avalanche damage, increase the reliability of the pipe under shock loads, provide high wear resistance due to the fact that when gouging, the longitudinal edges of the sheet are cut at an oblique angle or at a double angle to the sheet plane, after the final molding, a workpiece is obtained, the longitudinal edges of which come against each other without their combination, for welding the longitudinal seam, the longitudinal to fittin g workpiece by applying a force inside the dealer workpiece ensuring prestressed condition in the tube; and / or a number of “pockets” are installed inside the pipe; and / or a tape of elastic material with transverse ribs is installed inside the pipe.

Claims (3)

1. A method of manufacturing a pipe, including gouging the sheet, bending the edges of the sheet, pre-forming, final molding and welding of a longitudinal seam, characterized in that when gouging, the longitudinal edges of the sheet are cut at an oblique angle or at a double angle to the plane of the sheet, after the final molding a blank is obtained , the longitudinal edges of which go against each other without their combination, combine the longitudinal edges of the workpiece by applying a dispensing force inside the workpiece with a pre-stressed state and weld a longitudinal seam. 2. The method according to claim 1, characterized in that a number of "pockets" are installed inside the pipe. 3. The method according to claim 1, characterized in that a tape of elastic material with transverse ribs is installed inside the pipe.

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