Measurement of thermodynamic properties of tellurium in molten iron by transpiration method

Tellurium is added to sulfur free-cutting steel in order to improve its machinability by inclusion control. However, the thermodynamic properties of the steel and inclusions have not yet been studied. In the present work, the dissolution of tellurium into steel was investigated. First, the equilibrium Te2(g) partial pressure of solid tellurium was determined at 663–693 K by the transpiration method. The equilibration of molten iron under a controlled tellurium partial pressure, prepared by the transpiration method, was then performed at 1823 K. An approximately linear relationship between the tellurium content of the molten iron and the partial pressure of Te(g) was found at mass% Te < 0.01.