Friction Welding of Cast Iron and Phosphor Bronze

Abstract

There is sometimes a need to fabricate machine parts that have the best properties of multiple materials while being economical at the same time. A prime example of such a scenario is with gears. Gears made out of cast iron are a poor choice because cast iron has poor impact resistance and is vulnerable to corrosion. The addition of phosphor bronze as an annulus to the cast iron hub in a composite gear provides the gear with those valuable resistances along with a superior intermeshing with mated gears. However, joining dissimilar materials such as cast iron to phosphor bronze is challenging when conventional welding techniques are employed. To overcome it, applying friction welding to join cast iron to phosphor bronze is focused in this thesis. The obtained results are analyzed and optimized for this particular combination of materials to facilitate their use in gears. The results show that there is an increased accumulation of graphite at the weld joints between cast iron and phosphor bronze for trials at higher (rotational) welding speeds, which leads to less favorable mechanical properties. At lower welding speeds, sound joints with acceptable mechanical and metallurgical properties were obtained.