A method of friction welding

1,188,583. Welding by pressure. AZERBAIDZHANSKY NAUCHNO - ISSLEDOVATELSKY INSTITUT NEFTYANOGO MASHINOSTROENIYA. 11 April, 1967, No. 16549/67. Heading B3R. In friction welding two workpieces having abutting end portions of different cross-sectional areas the axial lengths of the workpieces being greater than their respective external radii, the external upsetting of the end portion of smaller cross-sectional area is confined and shaped by a sleeve about the end portion of smaller crosssectional area and having an internal diameter slightly larger than the external diameter of the end portion of larger cross-sectional area. A pipe 1, Fig. 1, is held in a fixed clamp 2 with a sleeve 3 rigidly secured about the end of the pipe and a tubular connecting piece 4 with an end piece of larger cross-sectional area is secured in a clamp 5 connected to a spindle 6. The spindle 6 is rotatable in bearings 7 in a body 8 acted on by an hydraulic ram 9 and a mandrel 11 arranged to rotate with spindle 6 is positioned within the workpieces 1, 4 on a shaft 12. The workpiece 4 which has a frustoconical surface engaging a frusto-conical surface on the pipe 1 is rotated and urged forwards by the ram 9 and the pipe 1 plastically deforms to fill the space within the sleeve 3. When welding temperature is reached rotation is stopped and an upsetting force is applied. The sleeve may be in one piece with the clamp 2 and the mandrel may be freely fitted on the shaft 12. In a modification the connecting piece may have a spigot projecting within the pipe end to function as a mandrel. In another embodiment a pipe 16, Fig. 3, and connecting piece 17 of similar external diameters are friction welded with a sleeve 18 to limit the external upset of pipe 16 and with a shaped mandrel 19 to permit controlled internal upset of the pipe 16. The mandrel and casing may be cooled and internal and external upsetting may be allowed simultaneously and solid bodies may be welded.