THE EFFECT OF PERCENTAGE OF NITROGEN IN PLASMA GAS ON NITROGEN SOLUTION FROM AN ARC PLASMA INTO LIQUID IRON

Abstract

The effect of percentage of nitrogen in plasma gas on nitrogen solution from an arc plasma into liquid iron has been investigated by melting iron in an atmosphere of nitrogen and argon using an arc plasma. Results show that both the rate of nitrogen absorption and the steady-state (plateau) solubility are increased as the percentage of nitrogen in the plasma gas increased from 2% to 35%. Both effects are seen to become less pronounced as the percentage nitrogen in the plasma gas approaches 35%. Increase in nitrogen percent in the plasma gas results in increased content of dissociated nitrogen and molecular nitrogen possessing excess vibrational energy and therefore the increased solution of nitrogen in the liquid iron. It would appear that above 35% nitrogen in the plasma gas, frequency of collisions of species in the plasma gas create conditions for recombinations of species into molecular nitrogen, thus decreasing the effect of percent nitrogen in plasma gas on nitrogen absorption and plateau solubility.