Spectrochemical Analysis of Carbon Steel and Low-Alloy Steel by the Point-to-Plane Spark and Ignited A.C.Arc Techniques Using a Recording Photoelectric Spectrometer

Abstract

Using the point-to-plane spark and ignited a.c.arc techniques, with a JACO Ebert convertible plane grating spectrograph and a typewriter read-out system, the photoelectric emission analysis of carbon steel and low-alloy steel is studied, as a rapid and accurate method for the routine work which should take the place of the chemical method in the authors' Laboratory.In preparing the calibration curves of twelve elements (Si, Mn, Cu, Ni, Cr, Mo, V, Ti, Co, Al, Sn and W), fortyseven NBS and BS standard samples of carbon steel and low-alloy steel are used.The results show that the accuracy of these spectrometric methods is as good as that of the chemical analysis and each element is measurable with in an error of 20% when the concentration is of the order of 0.01%.Though the spark method is superior to the ignited a.c.arc method in linearity of the calibration curves and in the freedom from the influence of interfering lines and CN-band, the latter is superior to the former in the intensity of spectral lines of aluminium, cobalt, tin and tungsten.The influence of the shape of the graphite counter electrode on the intensity of the arc or spark spectrum lines is also discussed.