Method for attaching a first tubular component having a threaded portion to a second tubular component having a threaded portion, said method comprising: fitting the first tubular component onto the second tubular component; rotating the first tubular component with respect to the second tubular component to screw the threaded portions (3, 4) together; obtaining a set of points constituting a curve representing the torque applied during the screwing of the first tubular component up to an end position as a function of the number of turns made by the first tubular component relative to the second tubular component; comparing one or more parameters of the curve obtained with one or more reference curve(s) in a database in which each reference curve is associated with an evaluation of the attachment quality of reference first and second tubular components; and evaluating the attachment quality of the first and second tubular components (1, 2) in accordance with the comparison step of comparing the curve obtained with the reference curves, characterized in that the comparison step comprises the comparison of the shape of at least one portion of the curve obtained, and in that the comparison step comprises a comparison of the shape of the portion of the curve obtained from fitting the first tubular component onto the second tubular component until contact is made between a first sealing surface of the first tubular component and a second sealing surface of the second tubular component, and/or of the portion of the curve obtained from contact being made between the first sealing surface of the first tubular component and the second sealing surface of the second tubular component until contact is made between the first shoulder of the first tubular component and the second shoulder of the second tubular component, and/or of the portion of the curve obtained from contact being made between the first shoulder of the first tubular component and the second shoulder of the second tubular component up to the end position. fitting the first tubular component onto the second tubular component; rotating the first tubular component with respect to the second tubular component to screw the threaded portions (3, 4) together; obtaining a set of points constituting a curve representing the torque applied during the screwing of the first tubular component up to an end position as a function of the number of turns made by the first tubular component relative to the second tubular component; comparing one or more parameters of the curve obtained with one or more reference curve(s) in a database in which each reference curve is associated with an evaluation of the attachment quality of reference first and second tubular components; and evaluating the attachment quality of the first and second tubular components (1, 2) in accordance with the comparison step of comparing the curve obtained with the reference curves, characterized in that the comparison step comprises the comparison of the shape of at least one portion of the curve obtained, and in that the comparison step comprises a comparison of the shape of the portion of the curve obtained from fitting the first tubular component onto the second tubular component until contact is made between a first sealing surface of the first tubular component and a second sealing surface of the second tubular component, and/or of the portion of the curve obtained from contact being made between the first sealing surface of the first tubular component and the second sealing surface of the second tubular component until contact is made between the first shoulder of the first tubular component and the second shoulder of the second tubular component, and/or of the portion of the curve obtained from contact being made between the first shoulder of the first tubular component and the second shoulder of the second tubular component up to the end position.