CALIBRATION METHOD FOR DETERMINATION OF NITROGEN-CONTENT IN STEEL BY THERMO-CONDUCTIMETRY AFTER FUSION IN THE CURRENT OF AN INERT-GAS

A calibration method for determining the nitrogen content in steel by a thermo-conductimetric method after fusion in the current of an inert gas is proposed. In this calibration method, a pure chemical substanc e whose nitrogen content can be calculated based on its molecular weig ht is used as a calibrant. The nitrogen recovery and thermostability o f 9 chemical substances in the fusion procedure were investigated; it was found that potassium nitrate is the most suitable as a calibrant. The results of analysis of 9 steel samples of certified reference mate rials demonstrate that the proposed calibration method is applicable t o determination of nitrogen contents between 0.001% and 0.5%.