Assessment of Microalloying effect to the New Automotive Forged Steel Parts

Microalloyed steel has been widely used mainly for cost saving and weight reduction by optimizing the component design. Numerous experimental works for microalloyed and alloyed steels carried out. The optimum designs of preform for the busting and blocking stages during forging were investigated. Various parameters were evaluated by FE analysis such as temperature, strain and strain rate for hot forming. It is found that a new type of microalloyed crankshaft exhibits a similar fatigue limit compared to the alloy steel. Fatigue tests have been carried out with standard samples from forged crankshafts, and rig tests have been performed with machined crankshaft of different materials. We also analyzed the actual stress by applying strain gauges on the crankshaft. From the above evaluation results, we can determine the safety factor of crankshaft and thus, enable to optimize the design and materials for maximizing the engine performance.