Investigation of influences by the process and the steel on the extent of internal oxidation during gas carburizing

摘要

In the frame of this work the influence on the internal oxidation by different gas carburizing atmospheres, particularly during initial stage of the heat treatment cycle, and also by varying carburizing duration was investigated in a sealed quench furnace. Furthermore, a standard carburizing process was examined and jugded in respect of the amount and form of internal oxidation for different steel types and melt compositions. One result was, that the average internal oxidation depth obtained at the end of the heat treatment cycle is influenced very little by the efforts made to minimize the level of oxygen in the atmosphere during heating up. Furthermore it could be shown, that a comparison of internal oxidation depths is not possible if they are taken from steel samples with different compositions. This is due to the different levels of oxidizing alloy elements, whereas the oxidation of the silicon can be taken as a measure of internal oxidation depth and the intensity of internal oxidation is mainly determined by the oxidation of manganese.