Methodology of Higher Fatigue Strength and Lighter weight of Connecting Rod for Diesel Engines

To reduce weight of the Connecting Rod for diesel engines, it is needed to increase the fatigue strength of the Rod. For this purpose, a methodology to increase the strength of the Rod which is subject to the cyclic load of stress ratio R≤0 was proposed. That is 1) Increase the hardness of the Rod as high as possible. 2) Introduce the compressive residual stress, such as the sum of compressive residual and loaded stresses equals to the compressive yield stress, if, possible. 3) Obtain a fain grain size. Therefore, the authore made the material development for the high strength an process improvement of the Rod. As the result, the weight of the Rod 20% lighter than that of the conventional Rod.