Comparative Assessment of Mechanical Properties and Fatigue Life of Conventional and Multistep Rolled Forged Connecting Rods of High Strength AISI/SAE 4140 Steel

This paper aims to improve the mechanical properties and fatigue life of AISI/SAE 4140 alloy steel connecting rods (CRs). Conventional CRs are typically manufactured through open die forging/hammering, blocking, hot forging processes. In present work, a modification process route has been proposed such that forging/hammering was completely replaced with multistep asymmetrical reducer rolling technique. Four passes were introduced achieve desired preform shape size. The effect each pass on grain size, properties, investigated. Samples from rolling, stage subjected impact, hardness, tensile, testing. Metallography using optical scanning electron microscopes also conducted reveal metallurgical changes. Fatigue testing fractography performed R.R. Moore Rotating-Beam machine microscope, respectively, evaluate fracture behavior both conventional rolled forged CRs. It observed that, unlike process, gradually reduces size as progresses improves yield, impact strengths, ductility. comparison forging, led an almost 33% 29% increase in yield tensile respectively. Moreover, CR increased by more than five times compared CR.