Paper Title
Analysis of Properties of Crankshafts Influencing Their Machinability

Abstract
The manufacture of crankshafts in the automotive industry is discussed. In this study, the machinability of crankshafts from different heats was evaluated. To characterize the crankshafts made from two heats, their microstructures were examined, prior austenite grain size measured, titanium particles analysed and chemical compositions determined. All the parameters of interest were found to be the same in both heats, except for sulphur levels and the associated amounts of manganese sulphide inclusions. The sulphur level in the second heat conformed to its material data sheet, whereas that in the first heat was lower than specified in the material data sheet. Since the presence of sulphur in the form of MnS inclusions greatly enhances machinability and even minute variations in sulphur concentration may strongly affect machinability, the absence of sulphur may become the cause of out-of-standard machinability in crankshafts. Keywords - Machinability, Manganese Sulfides, Crankshafts, Metallographic Analysis