Abstract: The present invention relates to a method of sealing an opening in a tubular body (1), comprising at least one through channel (3) extending in the longitudinal direction of the body, an opening (7) of the channel being formed in respective end surface (5) of the body. The method is characterized in that a sealing plug (15) is inserted in the opening (7) and is positioned far enough into the channel (3) that when a stamping tool (19) with an outer diameter which is greater than the inner diameter of the opening (7) is applied perpendicularly to the end surface (5) and concentrically to the opening (7), the portion of the end surface (5) constituting the periphery of the opening (7) is deformed plastically and is pressed into the channel (3) to form a shoulder (21) outside the sealing plug (15) with an inner diameter which is less than the outer diameter of the sealing plug (15).