Effect of microstructure, residual stresses and distortion in Vacuum carburizing heat treatment with gas and oil as quenchant Media

The quenching process during the carburizing heat treatment has shown to be the main factor which promote distortion during the all chain process of the shafts manufacturing, this because in this stage is where the sample experiment contraction because the cooling and also expansion due to martensitic transformation. In this study two steels alloys with different hardenability used for manufacturing transmission shafts for heavy trucks was treated in vacuum carburizing, and was quenched in two different medias, nitrogen and hot oil, the aim is to observe the effect on the microstructural properties, residual stresses and the distortion in main diameters and tooth gear. An optical measurement system was used to validate the distortion, because this system provides changes in diameters, lengths and also Run out measurements. For tooth profiles measurements a CNC automatic equipment was used, additionally, residual stresses were validated using a X-ray diffractor.