摘要 |
A welding machine for weld bonding a valve seating ring in an annular recess of a cylinder head (20) includes 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 electrode tool is moved upwards into the recess while a welding current is passed across the cylinder head and the electrode tool, so that the ring is weld bonded into the recess, without process spatter entering the cylinder head. There can be two separate electrode tools which operate simultaneously on respective recesses although the weld current may be applied sequentially. |