Benchmarking the Industry: Powder Forging Makes a Better Connecting Rod

The main requirement for the satisfactory function and service life of a connecting rod is the fatigue strength, which is dependent on design, material, microstructure, and surface condition. Much work has been accomplished to study and optimize these factors in the case of powder forged connecting rods [1-8]. To meet the current and increasing performance specifications required by the next generation of diesel and gasoline engines, new high strength powder forged materials have been introduced into production to successfully compete with wrought steels [9-12]. Currently, there are two main processing technologies available to manufacture connecting rods: fracture-split drop forging and fracture-split powder forging. The cost effectiveness of each one of these technologies is another main consideration, other than performance, in high volume production. Higher performance, superior raw material utilization and lower total cost of the finished machined and assembled product are the main reasons why the use of powder forged connecting rods has significantly increased in the last twenty years, taking away market share from the drop forged connecting rods. The goal of this work was to present new data in the debated issue regarding the comparison of these two technologies. Static and dynamic tests were carried out on specimens and on series production components of the same design, manufactured through both drop forging and powder forging processes. Machinability, crackability, weight control, deformation from fracture splitting, and cost were evaluated as well in order to complete the side by side evaluation. The results of this study and results obtained and reported from Bankovic and Yeager [13] clearly show that powder forging makes a better connecting rod in every aspect.