1974 Volume 60 Issue 13 Pages 2002-2012
In previous papers described for analysis of Al in steel by emission spectroscopy, the analytical values were affected mainly by the amounts of Al2O3 in the sample, the difference in a situation of the grinding of the sample surface and so on.
For the elimination of these affections, a study has been carried out on the behaviors of integrated photo-current pulses occured from every unit discharge.
As the result of many considerations, it was found that Al in steel has been able to be determined metallographically; Al as in the homogeneous state (acid-soluble Al at chemical analysis) and as in the inhomogeneous one (insoluble Al) respectively. The efficient and appropriate informations used to the metallographic analysis was derived from the distribution of integrated photo-current pulses.
This distribution was obtained by the following techniques. The pulses occured from every unit discharge were shaped and amplified suitably and must be put through multi-channel pulse height analyzer circuit. After treatment in P. H. A., the output pulse amplitude shows the distribution due to the metallographical state of Al in the sample.
The median value shows T. Al, and the shift of the median values during spark time show insol. Al in the sample, respectively.
In this method, the results obtained are 0.0015% Al (δ)(at the range of 0-0.05% Al) for T. Al and 0.0018% Al (δ)(at 0-0.04% Al) for sol. Al respectively.
