Upset Pressure Generation
Upset pressure generation is a process in friction welding where an axial force is applied to the plasticized faying surfaces at the end of the friction phase. This leads to welding and consolidation of the weld.
Physical-Chemical Working Mechanism
During friction welding, the faying surfaces are plasticized by the rubbing between the workpieces. At the end of the friction phase, an axial force is applied to these plasticized surfaces, which leads to additional welding and consolidation.
Metallurgical Relevance & Welding Risks
Creating forging pressure improves the mechanical strength of the weld and prevents cracks or deformations. If the forging force is too high, the material can get overworked and you get an uneven weld. If the forging force is too low, the joint won't be strong enough and might fail under load.
Workshop Practice & How-To
Set the forging force so it's between 100 and 200 N/mm². The time for forging typically runs 5 to 10 seconds. Keep an eye on the forging force and adjust it if needed to ensure the best weld.