Inconel 625 Alloy Tubes: Manufacture and Applications

Oil production in the deep sea is a challenge for the oil industry. The pipeline through which the oil flows is subjected to a high tensile load by its own weight and is exposed to an aggressive environment by the crude oil. The use of rigid jacketed pipe strikes a balance between the mechanical strength of low alloy steel pipe and the corrosion resistance of Inconel 625. The manufacturing process involves inserting an Inconel 625 pipe into a mechanical low alloy steel pipe. This tube is expanded by hydro-expansion, which creates hydrostatic pressure inside, causing plastic deformation and anchoring in the mechanical tube. A weld is made at both ends using an Inconel 625 consumable. In the next stage of industrialization, the rigid pipe is delivered to a supplier who applies a thermal coating to the outer surface to reduce heat exchange between the pipe and the marine environment. The temperature loss affects the flow by increasing the viscosity of the fluid. While at the coating supplier, the pipe is stored in an uncovered yard and is exposed to contaminants that can enter the interior. The contaminants can come from rain, wind, and handling. The storage yard is lined with gravel. In this article, we would like to explain the manufacturing process and the application of this material in the oil industry. In doing so, we hope to give you an understanding of the phenomena that occur during manufacturing and a brief assessment of the corrosion process caused by the impurities.