EJOWELD® friction welding is used to join overlapping work pieces without pre-hole. A requirement for this method is the accessibility of the joining point on both sides.
It is based on a press-welding process and is therefore classified for joining by welding according to process group DIN 8593 part 6.
Advantages EJOWELD® Process
- No pre-hole
- No pre or post treatment of the joining partners
- No brittle intermetallic phases, because the process works without thermal adhesive bond between aluminium and steel
- The active principle of the joining is of a combination of form closure, force closure and adhesive bond
- Control of the linear expansion differences between aluminium 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. aluminium) and welds onto the base plate, which is made of high-strength and 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 acts on 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 to the friction element. Only then is the friction welding process finished.
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 the steel-steel bonding.