SAE International Advancements in Powder Forged Connecting Rod Technology to Facilitate Downsizing of Direct Injection Turbocharged Engines 2015-01-1722

The advent of more efficient direct injection turbocharged engines has increased the need for higher performance connecting rods, able to withstand in particular higher compressive loads in operation. In this respect, new high strength materials for powder forged connecting rods were developed and introduced in production with excellent results. Among them, HS170M is currently used to manufacture connecting rods for several high performance engines, which not only have higher strength, but have less variation in their mechanical properties. The results of numerous benchmark studies have shown that powder forged connecting rods manufactured with HS170M are stronger than their steel forged counterparts manufactured with microalloyed steels, are easier to machine and fracture split, and represent a cost effective way to manufacture this important high reliability automotive component. In addition, advancements in design and manufacturing of powder forged connecting rods, such as design optimization, post-delubrication shot peening, enhanced shot peening, forged-in-notch to facilitate the fracture split process, pin coating to eliminate the use of bushings, etc., make powder forged connecting rods a very attractive option to the automotive industry. These improvements have resulted in higher performance of powder forged connecting rods in engines and, as a result, in mass reductions, thus further contributing to fuel economy and reduced emissions.