Friction Welding Upset Pressure
The friction welding upset pressure is the axial force applied at the end of the friction phase to join the plasticized parts under pressure and expel contaminants.
Physical-Chemical Mechanism of Action
The upset pressure presses the plasticized joint partners together, resulting in a material bond. Impurities such as dirt and dust are squeezed out in the process.
Metallurgical Relevance & Risks in Welding
Too low upset pressure can cause the joint partners not to press together well and impurities not to be completely removed. This can lead to poor mechanical properties and cracks in the welded joint. Too high pressure can coarsen the microstructure and impair material toughness.
Workshop Practice & Instructions
The upset pressure should be set to meet the specific requirements of the welding material and component geometry. A typical value is between 50 and 100 MPa. It is important to control the pressure time and ensure impurities are completely removed.