Determination of carburized layer thickness by GDOES method

Abstract

The aim of this paper is to consider the possibility of using Glow Discharge Optical Emission Spectroscopy (GDOES) for determination of carburized layer thickness. Carburized layer increases the hardness of basic material (low carbon steels with carbon content of 0.2%), thereby it increases its wear and abrasion resistance and it decreases forming of oxidation layer too. The thickness of this layer is usually determined by hardness measuring according to the ČSN EN ISO 2639 standard. The results of this standardized method are compared with the results obtained by two methods of GDOES and with pictures of optical microscopy. It has been found that the method of “Bulk” GDOES analysis with gradual grinding is suitable for determining the thickness of carbon enriched layers, while carburized layers which would correspond to standardized hardness 550 HV 1 may be only guessed from the graph of dependence of carbon content on the depth, in which analysis was performed. The pictures from the optical microscope in cross section do not have sufficient predictive value.

Keywords

• carburizing
• case-hardening
• hardness
• thickness of carburized layer
• optical microscopy
• GDOES