Nickel-based double-metal composite pipe all-position automatic welding method

Abstract

The invention discloses a nickel-based double-metal composite pipe all-position automatic welding method. The method includes the steps that (1), pipe ends of two composite pipes are machined into platform-shaped beveled edges; (2), the two composite pipes are in butt joint through internal clamps in the pipes; (3), coating layer backing welding and transition layer welding are performed in sequence through TIG welding or hot wire TIG welding; (4), base layer welding is performed through TIG or MIG welding. The same nickel-based alloy welding material is adopted for the coating layer welding, the transition layer welding and the base layer welding, and the Ni content of the nickel-based alloy welding material is higher than or equal to that of the coating layer. By means of the machined platform-shaped beveled edges, it is avoided that coating layer nickel-based metal and base layer metal dilute each other, and the corrosion performance of a nickel-based composite pipe circumferential weld is guaranteed; and the same nickel-based alloy welding material is adopted for all layers of welding, the requirements for coating layer metal corrosion and base layer toughness are met, and it is avoided that the nickel-based alloy base layer ring welding generates hot crack defects.

Description

[0001] Technical field: [0002] The invention relates to an all-position welding method for a bimetal composite pipe, in particular to an all-position automatic welding method for a nickel-based bimetal composite pipe. [0003] Background technique: [0004] Contain high H 2 S, high CO 2 , high Cl-, and high salinity oil and gas gathering and transportation pipelines put forward higher and more stringent corrosion resistance requirements for pipeline corrosion resistance, and the use of corrosion-resistant bimetallic composite pipes is the best solution. On the one hand, the bimetallic composite pipe has the good mechanical properties of carbon steel pipes and the corrosion resistance of corrosion-resistant alloys, giving full play to the characteristics of different materials; on the other hand, it greatly saves rare and precious metal materials and reduces the cost of pipelines. [0005] In recent years, with the development of highly corrosive oil and gas fields, nickel-b...

AI Technical Summary

Problems solved by technology

In this method, the gap between the butt pipes is not greater than 0.5mm, and the groove angle is 3-6.5°. This small gap and groove angle reduce the filling amount of welding materials, but the processing cost of the J-shaped groove is high; the whole ring welding TIG welding is used in the process, and the welding efficiency is lower than that of MIG; moreover, the cost of this welding method is too high. Stainless steel welding wire can be used for the ring welding of stainless steel composite pipes, and the use of 625 welding wire may double the cost of stainless steel composite pipes

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