Higher Fatigue Strength Materials for Powder Metal Forged Connecting Rods

The automotive industry is being challenged to continuously improve the performance of components used in vehicles and to reduce manufacturing costs. As a result, automotive components manufacturers are looking for lower cost materials which can perform better in service. The most widely used material for a powder metal forged connecting rod is P/F-10C50 (FC-0205) admixed with manganese sulfide (MnS) to enhance the machinability. A main requirement for a satisfactory function and service life of a powder metal forged connecting rod is the fatigue strength. Fatigue strength mainly depends on design, material, microstructure, and surface condition. Much work has been accomplished to study and optimize these factors [1, 2, 3, 4, 5, 6, 7 and 8], but the industry is still under pressure to further optimize them. The goal of this research work was to engineer powder metal mixtures with higher strength, good machinability and at reasonable cost. Several powder metal mixtures were considered to manufacture powder metal forged connecting rods. Static and dynamic tests were carried out on specimens and on real components. Machinability tests were not complete at this point in time for all of the mixtures under review, but results reported elsewhere were considered. From the results of this study, improvements of close to 19% in fatigue strength were achieved.