Eco Friendly and Cost Effective Manufacturing Technique for Automotive Drive Shafts

In general, the automotive drive shafts are being manufactured by one of the conventional manufacturing process sequence i.e. Hot Forging, Normalizing & subsequently case hardening and tempering to achieve the desired functional strength requirements. The case hardening process like induction hardening or gas carburizing shall be decided based on geometry, material chemistry and functional requirements. The part like drive shafts which are subjected to torsional load at the surface and bending load at core during application.

As per CAE analysis, the torsional and bending stress will act upon 40-50% of the shaft diameter from the surface. These property requirements are achieved through normalizing followed by induction hardening process. The study has been done to eliminate the normalizing process by increasing the case depth around 20% without affecting the functional requirements as mentioned. Comparative Microstructural study has been done on normalized and non normalized shaft and found to be at par. This paper deals with the new manufacturing technique that will be cost effective and eco-friendly without compromising the fatigue performance. In this technique, Normalizing process is eliminated and hence it saves substantial amount of electrical energy which is required to reach normalizing process temperature around 850-900°C. It saves approximately 40kwh energy per shaft and also results in eliminating the generation of gases and fumes in normalizing furnaces to the environment.