Abstract: The invention relates to a process for producing a multilayer pipe (1) from a tubular element having a metallurgical bond comprising at least one outer pipe (10) of metallic material and one inner pipe (20) of metallic material arranged within the outer pipe, the inner surface of the outer pipe (10) being mechanically bonded to the outer surface of the inner pipe (20) at least in parts of their interface, in which, in a production line, the tubular element is simultaneously heated and drawn, wherein each portion of the tubular element is submitted to heating by induction and then to hot-drawing, wherein the tubular element is drawn with a mandrel located therein. Through this process, the existing mechanical connection between the pipes is trans-formed in a metallurgical connection. The invention also relates to a multilayer pipe (1) produced for this process, wherein the outer pipe (10) is made of a carbon manganese steel alloy and the inner pipe (2) is made of a corrosion-resistant alloy.

Abstract: A process for producing a multilayer pipe by expansion is disclosed, with or without heating, in which a multilayer pipe (1) comprises at least one outer pipe of metallic material (10) and an inner pipe of metallic material (20), the inner pipe of metallic material (20) having a yield strength lower than the yield strength of the outer pipe (23) and an external diameter smaller than the internal diameter of the outer pipe. The process for producing the multilayer pipe comprises a mounting step (34) between the pipes (10, 20), wherein the inner pipe is inserted inside the outer pipe, and at least one mechanical expansion step (36), comprising moving a mandrel (2) longitudinally and internally in the inner pipe (20) while the outer pipe and the inner pipe are held at a fixed position, wherein at least part of the mandrel (2) has a greater external diameter than the internal diameter of the inner pipe.

Abstract: The invention relates to a process for producing a multilayer pipe (1) from a tubular element having a metallurgical bond comprising at least one outer pipe (10) of metallic material and one inner pipe (20) of metallic material arranged within the outer pipe, the inner surface of the outer pipe (10) being mechanically bonded to the outer surface of the inner pipe (20) at least in parts of their interface, in which, in a production line, the tubular element is simultaneously heated and drawn, wherein each portion of the tubular element is submitted to heating by induction and then to hot-drawing, wherein the tubular element is drawn with a mandrel located therein. Through this process, the existing mechanical connection between the pipes is trans- formed in a metallurgical connection. The invention also relates to a multilayer pipe (1) produced for this process, wherein the outer pipe (10) is made of a carbon manganese steel alloy and the inner pipe (2) is made of a corrosion-resistant alloy.

Abstract: A process for producing a multilayer pipe by expansion is disclosed, with or without heating, in which a multilayer pipe (1 ) comprises at least one outer pipe of metallic material (10) and an inner pipe of metallic material (20), the inner pipe of metallic material (20) having a yield strength lower than the yield strength of the outer pipe (23) and an external diameter smaller than the internal diameter of the outer pipe. The process for producing the multilayer pipe comprises a mounting step (34) between the pipes (10, 20), wherein the inner pipe is inserted inside the outer pipe, and at least one mechanical expansion step (36), comprising moving a mandrel (2) longitudinally and internally in the inner pipe (20) while the outer pipe and the inner pipe are held at a fixed position, wherein at least part of the mandrel (2) has a greater external diameter than the internal diameter of the inner pipe.