welding processes6 friction welding
Friction Welding Friction Welding The heat required for the weld is generated through friction at the interface. One component remains stationery The other component is gripped in a chuck and rotated at high constant speed The two members brought together with axial force After sufficient contact, the rotating member is stopped while axial force is increased Oxides & other contaminants at the interface are removed by radial outward movement of hot metal at the interface Friction Welding Friction Welding The shape of the welded joint depends on the rotational speed and axial pressure Friction welding machines are fully automated Low operator skill level required FW can be used to join a wide variety of materials - Provided that one of the components has some rotational symmetry Solid or tubular parts can be joined with good joint strength Because of the combined heat and pressure, the interface develops a flash by plastic deformation of the heated zone. If desired, the flash can be removed by machining or grinding Friction Welding Friction Welding – Ultrasonic Welding Friction Welding – Ultrasonic Welding Friction Welding – Ultrasonic Welding Ultrasonic Welding (a) Lap welds The faying surfaces of the two components are subjected to: Static Normal force (applied through sonotrode) Oscillating shearing (tangential) stresses (applied by tip of transducer) Efficient operation depends on proper coupling between transducer and sonotrode Shearing stresses cause plastic deformation at interface; creating clean surfaces for bonding Temperatures 1/3 – 1/2 melting point (therefore no melting or fusion) Different joining mechanism for plastics because plastics have lower melting point and there is some fusion (b) Seam welding using roller as sonotrode The welding tip is replaced by rotating disks for the seam welding of structures in which one component is sheet, foil or polymer-woven material 6 . grinding Friction Welding Friction Welding – Ultrasonic Welding Friction Welding – Ultrasonic Welding Friction Welding – Ultrasonic Welding Ultrasonic Welding (a). interface Friction Welding Friction Welding The shape of the welded joint depends on the rotational speed and axial pressure Friction welding machines are