Verification of the Simulated Carburizing Process in Different Bore Sizes

Abstract

Carburizing is one of the leading surface treatments in the industry. For this study, 20MnCr5 steel was gas carburized and quenched in real circumstances and simulated with Simufact software. The research investigated the dimensions and types of bores. A through and blind bore was used in this study to analyze how the geometry affects the created layer and, additionally, it takes into account the placement in the heat treatment furnace. An optical microscope and Vickers hardness tester were used to detect the changes in microstructure and measure the layer thickness. After the experiments, a simulation calculated the same variables to compare and validate the results to each other. It can be stated that the placement in the chamber did not influence the form of the high carbon content layer. The simulation and the measured results were in good agreement. The maximum hardness difference was 17%, but the calculated layer thicknesses were always between the measured data. For example, in the case of a small blind bore, the calculated layer thickness was 1.68 ± 0.18 mm, while the measured value was 1.54 ± 0.37 mm. Additionally, the hardness change in depth was similar in both cases. After this validation process, the residual stresses and plastic strains were determined. The maximum residual stresses were similar for every case, namely around 1900 MPa, while the maximum plastic strain was measured in a small blind bore with a value of 0.18. The minimum plastic strain was 0.04 in the through bore.