Paper Title
Analysis of Properties of Crankshafts Influencing Their Machinability

Abstract
The article deals with the problem of crankshafts production in the automotive industry. The different machinability of the crankshafts was evaluated depending on the melting from which they were made. On the analyzed crankshafts from two heats with different machinability the hardness was measured, the microstructure was evaluated including the measurement of the original austenitic grain size, the titanium particles were analyzed and the chemical composition was measured.In all performed analyzes the monitored parameters of both melts were identical, the only exception was the sulfur content and consequently also the amount of manganese sulfide inclusions. While the prescribed values for the sulfur content in the first melting process corresponded to the material sheet, the sulfur content was found to be lower in the second melting process compared to material sheet. Since the presence of sulfur in the form of MnS inclusions significantly improves machinability and very small deviations in concentration can have a major impact on machinability, the absence of sulfur is therefore a cause for poor crankshafts machinability. It is recommended to strictly comply the prescribed sulfur content, because even a slight deviation has the potential to cause a significant deterioration in machinability. Keywords - Machinability, Manganese sulfides, crankshafts,metallographicanalysis.