1965 Volume 51 Issue 2 Pages 226-231
It has been recognized that the protective atmosphere, such as RX or DX gas, is necessary to prevent the oxidation and decarburization of steels under heat treatment.
Previously, we have used the popular analysing instruments, viz. Orsat's and dew point apparatus, though the quantitative and qualitative analysis of the specimens containing hydrocarbons was difficult and time-consuming by them.
Gas chromatography possesses inherent advantages that make it particularly favourable for the characterization and quantitative analysis of complex mixtures.
In addition to providing a direct method of analysis for unknown specimens, it has proved to be a powerful adjunct to ultraviolet, infrared and spectroscopic techniques.
From the preliminary experiment, we found silica gel and molecular sieve to be moderate column packings for our objects.
But, it was necessary to know the reliability of this application. So, we analyzed the results by simple statistical treatment.
From the results obtained in the analysis of RX gas, it was concluded that
1) accuracy of results depends upon sample size, and the smaller the sample size, the better;
2) the results obtained from oxygen, carbon monoxide and methane have 95% confidence coefficient and±10 mm2 accuracy of profile area in the case of 1 to 5 times repetition but the results from carbon dioxide, nitrogen and hydrogen are worse; and
3) the carrier gas flow rate from 25 to 30 ml/min. is appropriate to this study.