Overcoming Manufacturing Challenges in Mass Production of Vanadium Micro-Alloyed Steel Connecting Rods

With recent advancements to create light weight engines and therefore, to design stronger and lighter connecting rods, automobile manufacturers have looked upon vanadium micro-alloyed steels as the material of choice. These materials have been developed keeping in mind the strength and manufacturing requirements of a connecting rod. Since, 36MnVS4 has been the most popular of this category, the same has been discussed in this paper.

The transition of manufacturers from the traditional C70S6 grade to the new 36MnVS4 must be dealt with in-depth study and modification of processes to adapt to new properties of the latter. C70S6 is a high carbon grade with superior fracture split whereas 36MnVS4 is a medium carbon grade with superior strength and ductility owing to the presence of vanadium. This paper deals with the study of challenges in mass production of connecting rod using 36MnVS4 grade and overcoming the same using optimization of processes like controlled cooling, stress-relief annealing, notch scribing and fracture-splitting. Latest trends in scribing techniques and their effects on fracture behavior have also been studied in detail with the help of scanning electron microscopy.