A method of joining a tubular member and a pipeline configured to convey corrosive products comprises preparing a tubular member with an inner seat; inserting the end of a pipeline inside the inner seat; inserting a sleeve of corrosion-resistant material inside the end of the pipeline; inserting an expandable mandrel inside the sleeve; and expanding the expandable mandrel to join the end of the pipeline and the tubular member, and seal the sleeve and the pipeline to protect parts of the pipeline, sensitive to corrosive products, via the sleeve.