Arc melting-gas chromatographic method for the determination of oxygen in metals

Abstract

A simple and convenient apparatus for the determination of gases in metals is studied. Gaseous components in metal samples, i. e. oxygen, hydrogen, nitrogen are extracted in the form of CO, H₂ and N₂, respectively, and are separated by a gas chromatograph to be determined. To enhance rapidity and precision of measuring, a simple digital integrator using oneshot-multivibrator is added to the apparatus. The counting rate of integrator is 2000 count/sec for 10 mV imput voltage. The bias from the linearity between imput voltage and counting rate is less than 1%. Analytical curve for oxygen is obtained by injecting pure carbon monoxide into argon flow. The values of oxygen content in steels obtained by this method are well congruent with those obtained by the vacuum fusion method. The necessary measuring time is 4.5 minutes.