A method for producing a steel underwater pipe that is able to carry corrosive fluids, particularly water, the internal wall of which is partially lined by a protective coating of plastic material of the liner type wherein the assembly by welding directly together the ends of at least two pipe elements (10, 10-1, 10-2) is provided for, comprising the steps wherein are produced successively: a) the application, preferably by welding, of a layer of corrosion-resistant steel alloy on a terminal part (10a1) of length L1 of the internal wall of each pipe element (10, 10-1, 10-2) from its end to be welded; b) the machining on the pressure side surface of the layer of corrosion-resistant steel alloy, c) the application of a said protective coating of plastic material, preferably in the form of a tubular shell, directly on the internal wall of each pipe element (10-1, 10-2); and covering a first part of length L2 of said layer of corrosion-resistant steel alloy, a second, adjacent part of length L3 of said layer of corrosion-resistant steel alloy on the side of the end to be welded of each pipe element not being covered by said protective coating of plastic material, d) the coaxial (XX') insertion of a compression ring of corrosion-resistant steel alloy inside said terminal part (10a1) of each pipe element and the crimping of a first annular part of length L4 of said compression ring against the pressure side face of the terminal part of said protective coating of plastic material covering a first part of said layer of corrosion-resistant steel alloy, and the welding of the free end of a second annular part of said compression ring against a second part of said layer of corrosion-resistant steel alloy not covered by said protective coating of plastic material, said first annular part of the compression ring comprising an outer side face which is corrugated, over a part at least of its length, preferably in the form of a plurality of first parallel circular peripheral grooves, said second annular part of said compression ring continuing said first annular part, said second annular part being applied against a part of said second part of the layer of corrosion-resistant steel alloy not covered by said coating of plastic material and extending over a length L5 less than L3, from and against the end of said coating of plastic material until said free end of said compression ring closest to the end to be welded of the pipe element, and e) the assembly by welding directly together the ends to be welded of two pipe elements (10-1, 10-2) by a corrosion-resistant steel alloy weld. a) the application, preferably by welding, of a layer of corrosion-resistant steel alloy on a terminal part (10a1) of length L1 of the internal wall of each pipe element (10, 10-1, 10-2) from its end to be welded; b) the machining on the pressure side surface of the layer of corrosion-resistant steel alloy, c) the application of a said protective coating of plastic material, preferably in the form of a tubular shell, directly on the internal wall of each pipe element (10-1, 10-2); and covering a first part of length L2 of said layer of corrosion-resistant steel alloy, a second, adjacent part of length L3 of said layer of corrosion-resistant steel alloy on the side of the end to be welded of each pipe element not being covered by said protective coating of plastic material, d) the coaxial (XX') insertion of a compression ring of corrosion-resistant steel alloy inside said terminal part (10a1) of each pipe element and the crimping of a first annular part of length L4 of said compression ring against the pressure side face of the terminal part of said protective coating of plastic material covering a first part of said layer of corrosion-resistant steel alloy, and the welding of the free end of a second annular part of said compression ring against a second part of said layer of corrosion-resistant steel alloy not covered by said protective coating of plastic material, said first annular part of the compression ring comprising an outer side face which is corrugated, over a part at least of its length, preferably in the form of a plurality of first parallel circular peripheral grooves, said second annular part of said compression ring continuing said first annular part, said second annular part being applied against a part of said second part of the layer of corrosion-resistant steel alloy not covered by said coating of plastic material and extending over a length L5 less than L3, from and against the end of said coating of plastic material until said free end of said compression ring closest to the end to be welded of the pipe element, and e) the assembly by welding directly together the ends to be welded of two pipe elements (10-1, 10-2) by a corrosion-resistant steel alloy weld.