The overall pressure to reduce costs drives the automotive market to develop new material and methods to simplify the manufacturing process. The connecting rod material change in the Ford Zetec-Rocam engine family is an action being taken to improve overall engine performance and reduce costs.
The current conrod is manufactured by traditional lamination, hot forging, quenching, and tempering using manganese steel SAE1541. The newly designed conrod is produced by cross-wedge rolling, hot forging, and controlled cooling with the forging temperature using microalloyed steel DIN27MnSiVS6.
The component modifications are discussed in detail considering the design and manufacturing of the following topics - operational requirements, metallurgy, forging, and machinability. Both conrod configurations are compared in respect to their performance, using mechanical tests to evaluate behavior differences. The expected life of the parts under different engine operational conditions have been computer simulated based on the finite element method.
The study shows cross-wedge rolled microalloyed conrods fulfill the engine operational conditions. They also have longer fatigue live and better mechanical properties. CAE simulations have good correlation to experimental data.