The invention concerns a method and a machine for weld-bonding a valve seating ring (34) in an annular recess (30) of a cylinder head (20). The machine comprises an electrode tool (14) on which the ring is located and an overhead support (18, 40, 44, 46) for mounting the cylinder head above the tool. In use the tool is moved upwards into the recess while a welding current is passed across the cylinder head and the tool, whereby the ring is weld-bonded into the recess, without process spatter entering the cylinder head. There may be two separate tools (14, 16) which operate simultaneously on respective recesses (30 or 32) although the weld current may be applied sequentially.