This leads to plastic deformation of the joining element and welding with the base plate. The cover plate is simply penetrated and fixed between element head and base plate. The connection results from a combination of form-fit, force closure and adhesive bond.
- No pre-hole
- No pre or post treatment of the joining partners
- No brittle intermetallic phases, as there is no thermal adhesive bond between aluminum and steel
- The technology of the joint is a combination of form closure, force closure and adhesive bond control of the linear expansion differences between aluminum and steel induced by temperature changes
- A high number of material thickness combinations can be joined without modifications of the equipment
EJOWELD® Joining Process
The steel friction element penetrates the upper layer (e.g. aluminum) and welds onto the base plate, which is made of high-strength or advanced high- strength steel. The friction, which is generated by appropriate process control and the application of mechanical forces, acts directly on the friction element. The produced frictional heat affects the element and the base plate without reaching the melting temperature. An adhesive bond is only created between the friction element and the base plate. Between the friction element and the upper layer just force and form closure is achieved. When the head of the element has reached the upper plate, the rotation stops and an increased axial force is applied onto the friction element. Only then the friction welding process is completed. The upper layer is now fixed between the head of the friction element and the base plate. The friction element thus fulfills two separate tasks during the joining process. On the one hand, it penetrates the cover sheet without altering its properties, and on the other hand it reliably generates the frictional heat to create a steel- steel bonding.