This is a picture of a large gear with a ring welded into it. The ability to weld the ring into the gear with little or no distortion and no change to the heat treatment allowed the manufacturer to through broach the gear teeth on the I.D. of the assembly at a considerable cost saving.
The picture on the left shows a family of gears that service the mining industry. After assembly and welding they are shown in the right hand picture.
This picture shows silver contacts welded to aluminum for use in the electrical transmission service sector.