A PROCESS TO IMPROVE FATIGUE STRENGTH OF MICRO ALLOY STEELS, FORGED PARTS MADE FROM THE PROCESS AND AN APPARATUS TO EXECUTE THE PROCESS

摘要

The present invention describes a process to make enhanced fatigue strength micro-alloy steel. In the process of the present invention, the soaking temperature is maintained in the range of 900 °C to 1050 °C and soaking time in the range of 30-60 minutes depending on size of crankshaft to get refined grain size. Distortion of the components is prevented from occurring with provision of adequate supports especially designed for the process. Forged parts made using the process, such as crankshafts, have a refined grain pattern and result into 20 to 25% enhancement in torsion fatigue strength & 10-25% enhancement in bending fatigue strength. The present invention thus provides an enhanced ratio of the strength to material density and a micro-alloy whose torsion fatigue strength and bending fatigue strength are greater than the currently available micro-alloy steels.