Vehicle weight reduction has been an important objective in the automotive industry, due to increasingly stringent emission norms and fuel efficiency targets. For achieving this, manufacturers have started the use of lightweight materials such as aluminium and high strength steel. Although, this transition to multi-material design created new challenges for reliable and efficient joining technologies, as many conventional methods (e.g. resistance spot welding, MIG welding) are incompatible or inefficient when used with dissimilar material pairs. The flow forming screw process has emerged as a highly promising solution because of its one-sided access, chipless operation, and strong mechanical performance, especially in aluminium to steel or mixed metal joints.