Investigation of material flow in forging bi-metal components

High performance components, such as poppet valves, connecting rods, and pistons are manufactured from materials that provide the necessary performance characteristics to withstand tough operating conditions. These materials usually possess high values of yield strength, Young's modulus, fatigue strength, and maintain them over a range of temperatures. Low density is also useful in components subjected to rapid speed changes. However, high performance materials, such as titanium alloys and stainless steels usually have a high density or are too costly to be used extensively. In many applications, high performance properties are required on particular surfaces or contact points, and are not necessary throughout the entire body of the component. One way of achieving this is to make components with more than one strategically located material. For practical reasons, normally the maximum number of alloys would be two. The work described in this paper is a preliminary investigation of the use of forging to produce bi-metallic components, through the production of a spur gear form. The experimental and simulation work described in this paper, provides knowledge of the effects of process variables on the outcome of forging bimetallic gears.