RU2177101C2 - Method for manufacturing pipe internally coated with anticorrosive material - Google Patents

Abstract

FIELD: construction engineering; repair and construction of pipelines carrying chemically active substances. SUBSTANCE: pipe has inserts made of anticorrosive metal strips welded to inner ends of pipe and anticorrosive coating applied to inner surface of pipe. Inserts are secured by resistance welding over their entire surface contacting inner surfaces of pipe ends. Thickness of inserts is increased by resistance welding of next turn of corrosive-resistant band over their entire surface contacting inner surface of insert already formed. EFFECT: facilitated manufacture. 2 cl, 2 dwg

Description

 The invention relates to methods for manufacturing pipes with an internal anti-corrosion coating and can be used in the construction and repair of pipelines for various purposes transporting chemically aggressive environments.

 Currently, an important problem in the construction of pipelines with an internal anti-corrosion coating is the connection of pipes by welding, but it requires the complete preservation of the anti-corrosion coating adjacent to the welded joint. In this regard, various designs of pipes with an internal anti-corrosion coating are being developed, which ensure their connection by welding.

 A known method of connecting pipes with an internal anti-corrosion coating (US Pat. 2103593 RF, IPC 6 F 16 L 58/02, 1998), according to which, before connecting the pipes, thin-walled sleeves of corrosion-resistant heat-resistant material are pressed into their ends. First, welding is performed on the lining, then on the material of the pipes. Pressing is carried out by high-speed plastic deformation.

 The disadvantages of this method are: the manufacture of an integral thin-walled sleeve is laborious and expensive; press fitting the sleeve with high-speed plastic deformation requires the use of sophisticated expensive equipment that is not commercially available in the Russian Federation; additional preparation of the edges for welding is required.

 The method for connecting pipes with an internal anticorrosive coating (US Pat. 2103594 RF, IPC 6 F 16 L 58/02, 1998), according to which, when connecting pipes with an internal anticorrosive coating, the inner surface of the pipe ends is preliminarily veneered is pressed in at a predetermined distance from the ends pipe thin-walled bushings. The ends of the sleeve are connected to the pipe with an annular weld. A corrosion-resistant heat-resistant metal material is deposited on the pipe surface between its end and the sleeve. The ends of the pipes are connected by welding in two stages: first, the surfacing material is welded, then the pipe material.

 The disadvantages of this method are: for the manufacture of pipes requires up to six welded operations; pressing the sleeve requires the use of scarce expensive equipment; in the manufacture of pipes requires a large number and a wide range of auxiliary materials.

 The objectives of the invention are to increase productivity in the manufacture of pipes with an internal anti-corrosion coating and the reliability of the anti-corrosion protection of the weld zone.

 The problem is solved in that the manufacture of a pipe with an internal anti-corrosion coating includes the manufacture of liners from strip corrosion-resistant metal, fixing them inside the pipe ends by welding and applying an anti-corrosion coating to the inner surface of the pipe. New is that the liners of corrosion-resistant metal are connected by contact welding along the entire surface of their contact with the inner surface of the ends of the pipe, and the thickness of the liners is increased by welding by contact welding of the next turn of the corrosion-resistant metal tape over the entire surface of their contact to the inner surface of the already formed liner .

 Analysis of the known similar solutions allows us to conclude that there are no signs in them that are similar to differing features in the claimed method, that is, on the compliance of the proposed method with the criterion of "significant differences".

 A method of manufacturing a pipe with an internal anti-corrosion coating is carried out as follows.

 Is the preparation (cleaning, degreasing) of the inner surface of the ends of the pipe 1 to the length of the liners 2 (Fig. 1). From the corrosion-resistant metal strip inside the ends of the pipe 1, the tubes are rolled up, creating inserts 2, and welded to the inner surface of the ends of the pipe 1 by contact welding over the entire area of the liners 2. Contact welding over the entire area of the liners 2 means that one hundred percent of the area, i.e. . each square millimeter of the surface of the liners 2 is connected to the inner surface of the ends of the pipe 1. To strengthen the corrosion protection, the longitudinal edges of the corrosion-resistant metal strip are interconnected by a longitudinal corrosion-resistant weld 3. After that, an anti-corrosion coating 4 is applied inside the pipe 1, partially covering the liners 2. To increase the thickness of the liner 2 (Fig. 2), the next layer 5 of a corrosion-resistant metal strip to the inner surface is already welded by contact welding x inserts 2. Layer 5 is also created by folding tubes from a corrosion-resistant metal strip, and one hundred percent of the contact area of layers 2 and 5 is subjected to contact welding. The longitudinal edges of the subsequent layers 5 of a corrosion-resistant metal tape are connected together by a longitudinal corrosion-resistant weld 6. In this case, the subsequent longitudinal corrosion-resistant weld 6 in the plan may coincide with the previous longitudinal corrosion-resistant weld 3 or not (Fig. 2). After that, an anti-corrosion coating 4 is also applied inside the pipe, partially covering the liner 5.

 Pipes made with the proposed method with an internal anti-corrosion coating are ready for connection to pipelines.

 The manufacture of pipes with an internal anti-corrosion coating according to the proposed method improves the productivity in the manufacture of pipes and increases the reliability of the corrosion protection of the weld zone.

Sources of information
1. Patent 2103593 of the Russian Federation, IPC 6 F 16 L 58/02. A method of connecting pipes with an internal anti-corrosion coating (A.K. Voinov, V.F. Olovyanishnikov, V.A. N 3.

 2. Patent 2103594 of the Russian Federation, IPC 6 F 16 L 58/02. A method of connecting pipes with an internal anti-corrosion coating (A.K. Voinov, V.F. Olovyanishnikov, P.A. Anisimov (RF), etc. - N 96111759/06. Declared June 11, 1996; Publish. January 27, 98. Bull. N 3.

Claims (2)

 1. A method of manufacturing a pipe with an internal anti-corrosion coating, including the manufacture of liners from strip corrosion-resistant metal, fixing them inside the ends of the pipe by welding and applying an anti-corrosion coating to the inner surface of the pipe, characterized in that the liners of corrosion-resistant metal are connected by contact welding throughout the surface of their contact with the inner surface of the ends of the pipe.  2. The method according to p. 1, characterized in that the thickness of the liner is increased by welding by contact welding of the subsequent turn of a corrosion-resistant metal strip over the entire surface of their contact to the inner surface of the already formed liner.

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