Powder forging of a motorcycle connecting rod

A motorcycle connecting rod is one of the major moving parts affecting the engine performance. The traditional manufacturing process results in material waste and excessive machining. A new method of hot forging P/M has been proposed and studied experimentally. In order to achieve uniform density, the punch is divided into three parts to consolidate the loose powder. The multistage movement of the three parts of the punch, called synchronous compaction, results in the desired uniform density. The powder flow during consolidation was illustrated and the density distribution of the compacts was measured. A set of forging dies with flash was used to produce the densification and deformation of the sintered compact. Then a set of flashless forging dies was designed to obtain the desired shape and dimensions of the connecting rod. The effects of forging temperature and initial compact density on densification were evaluated through hot forging experiments. Based on properties achieved, Fe-C-Cu-Mo was selected as the alloy powder. Through testing and metallographic observation, the connecting rod produced by the P/M hot forging was found to be superior to that manufactured by the traditional method in the physical and mechanical properties.