Joining method, punch rivet arrangement, die, and punch rivet tool

A method for joining at least two workpieces using a punch rivet arrangement, the punch rivet arrangement comprising a rivet and a collar, wherein the rivet has at least one radial recess, comprising the steps of:

• placing the rivet on a first side of the workpieces which form a stacked workpiece arrangement;
• placing the collar on a die arranged on a second side of the workpiece arrangement,
• punching the rivet with a punch force through the workpiece arrangement in an axial direction, wherein the workpiece arrangement is supported by a support surface of the collar, and wherein the collar is supported by a first engagement surface of the die;
• and
• modifying the collar by applying a modification force to the collar,
• wherein the modification force is higher than the punch force, and
• wherein the modification of the collar allows a second engagement surface of the die, different of the first engagement surface, to apply a radial swaging force onto the collar so that material of the collar flows into the at least one radial recess of the rivet, and
• wherein the second engagement surface of the die contacts the collar after or during the step of punching the rivet with a punch force through the workpiece arrangement in an axial direction.