RU2213287C2 - Method of manufacture of pipe with inner anticorrosive coat - Google Patents

Abstract

FIELD: manufacture of pipes with inner anticorrosive coats; erection and repair of pipe lines handling chemically aggressive media. SUBSTANCE: proposed method includes manufacture of multi-layer inserts from corrosion-resistant metal band by spiral winding of several layers inside ends of pipe; outer surface of first layer of insert is secured to inner surfaces of pipe ends and surfaces of subsequent layers of insert are welded together. EFFECT: enhanced reliability of corrosion protection of weld seam area. 2 cl, 1 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 serially produced in the Russian Federation; additional preparation of the edges for welding is required.

 A known method of 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 pressed - thin-walled are pressed at a given distance from the pipe ends 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 prototype is a pipe with an internal protective coating and a method for its manufacture (Pat. 2130147 RF, IPC 6 F 16 L 13/00, 9/00, 1999), which includes a cylindrical insert made of strip corrosion-resistant metal with a wall thickness of 0 , 1-2.0 mm, and inside the cylindrical liner on the side of the pipe end, a second cylindrical liner of strip corrosion-resistant metal with a wall thickness of less than 1.0 mm and a width of more than 5.0 mm is installed.

 The disadvantage of this method is that the outer surface of the liner to the inner surface of the pipe is fastened with only one longitudinal weld, and this does not provide reliable protection of the weld zone from corrosion.

 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 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 multilayer liners of corrosion-resistant metal, fixing them by welding inside the ends of the pipe and applying an anti-corrosion coating to the inner surface of the pipe. What is new is that the liner is made of a tape by spiral twisting it into several layers inside the ends of the pipe, and the outer surface of the first layer of the liner to the inner surface of the ends of the pipe and the surface of the subsequent layers of the liner is fixed to each other by contact welding.

 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 illustrated in the drawing and is carried out as follows.

 Preparation (cleaning, degreasing) of the inner surface of the ends of the pipe 1 to the length of the liners 2. From the corrosion-resistant metal tape by spiral twisting into several layers inside the ends of the pipe 1, make the liner 2. The outer surface of the first layer of the liner 2 to the inner surface of the ends of the pipe 1 and the surfaces of the subsequent layers of the liner 2 are fixed to each other by contact seam welding. Contact seam welding provides full contact and sealing of the contacting surfaces of all layers of the liner and the inner surface of the pipe. After that, an anti-corrosion coating 3 is applied inside the pipe 1, partially covering the liner 2.

 Pipes made with the proposed method with an internal anti-corrosion coating are ready for welding them into 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. Davydov (RF) and others. - 95119761/06. Claimed on 11/21/95; Publ. 01/27/98. Bull. 3.

 2. Patent 2103594 of the Russian Federation, IPC 6 F 16 L 58/02. The method of connecting pipes with an internal anti-corrosion coating / A. K. Voinov, V.F. Olovyanishnikov, P.A. Anisimov (RF) and others - 96111759/06. Stated 06/11/96; Publ. 01/27/98. Bull. 3.

 3. Patent 2130147 of the Russian Federation, IPC 6 F 16 L 13/00, 9/00. A pipe with an internal protective coating and method of its manufacture / V.M. Ayduganov, M.I. Starshov, S.L. Chakheev, L.I. Volkova. - 97111225/06. Claim 07/01/97; Otub. 05/10/99. Bull. thirteen.

Claims (2)

 1. A method of manufacturing a pipe with an internal anti-corrosion coating, including the manufacture of multilayer liners of corrosion-resistant metal, fixing them by welding inside the ends of the pipe and applying an anti-corrosion coating on the inner surface of the pipe, characterized in that the liners are made of tape by spiral twisting into several layers inside the ends of the pipe .  2. The method according to p. 1, characterized in that the outer surface of the first layer of the liner to the inner surface of the pipe and the surface of the subsequent layers of the liner are fixed to each other by contact seam welding.