Effect of post carburizing treatments on residual stress distribution in plain carbon and alloy steels- A numerical analysis

This work focuses on finding the residual stress distribution in post carburized steels. Ini-tially, three different steel specimens (EN 3, 20MnCr5 and EN 353) were carburized with gascarburizing technique. For post carburizing treatment, one set of the samples was air-cooled(normalizing treatment) and others were quenched in water (hardening treatment). Scan-ning electron microscope (SEM) was used to study the microstructure of post carburizedsteels. The normalized steels displayed pearlite and bainite structures and hardened steelsdisplayed low and high carbon martensite along with retained austenite. In few samples,the residual stresses were measured with the X-ray stress analyzer. A Finite Element Anal-ysis (FEA) model was established using the varied material properties and thermophysicalparameters of different steels. Later the measured and experimental data from the FEA werecompared, there were in a good fit and the FEA model was validated. It was observed thatthe residual stress in normalized and hardened steels were dependent on the carbon gradi-ent as well as the temperature difference from the core (center) to the case (surface) of thesteels. The formation of martensite and retained austenite in the hardened steels led themto attain high magnitude stresses than normalized steels.