Abstract: A pipe end is expanded with the aid of an expander tool (1). The expander tool (1) comprises a plurality of jaws (10) that are radially movable between a retracted and an expanded position. The jaws (10) have outer jaw surfaces which are intended for engagement with the inner surface of the pipe end and which lie adjacent to one another in the retracted position of the jaws (10) and have an at least generally circular arcuate shape in cross-section. The expander tool (1) further comprises a piston (2) or cone with a tapered end for moving the jaws (10) between the retracted and the outer expanded positions and the piston (2) is moved in a reciprocating manner in the axial direction before expanding the pipe end gradually in the stages. The axial reciprocating movement of the piston (2) is guided to rotate the jaws (10) to a certain extent in a circumferential direction after each expansion stage.

Abstract: A pipe end is expanded with the aid of an expander tool (1). The expander tool (1) comprises a plurality of jaws (10) that are radially movable between a retracted and an expanded position. The jaws (10) have outer jaw surfaces which are intended for engagement with the inner surface of the pipe end and which lie adjacent to one another in the retracted position of the jaws (10) and have an at least generally circular arcuate shape in cross-section. The expander tool (1) further comprises a piston (2) or cone with a tapered end for moving the jaws (10) between the retracted and the outer expanded positions and the piston (2) is moved in a reciprocating manner in the axial direction before expanding the pipe end gradually in the stages. The axial reciprocating movement of the piston (2) is guided to rotate the jaws (10) to a certain extent in a circumferential direction after each expansion stage.