The Development of an In-Situ Sensor for Measuring the Hydrogen Content of Liquid Iron

For in-situ measurement of the hydrogen content of liquid iron, a new inert gas probe technique has been developed which consists of injection of inert gas into molten iron through a nozzle, collection of the ascending bubbles in which hydrogen partial pressure is in equilibrium with the iron, instantaneous determination of hydrogen concentration in the gas using a mass spectrometer, and conversion of the concentration to hydrogen content in iron by Sievert's law. The experimental result is in good agreement with the theoretically calculated hydrogen content. Response is quite rapid (̃ 1.5 min). The efficiency of hydrogen recovery by a bubble is affected by the bubble size, the hydrogen concentration, and the ascending distance. The bubble size is determined by the flow rate and the nozzle size.