The influence of the melting regime on oxygen deposition from powders of naturally alloyed iron

Temperature dependences of kinematic viscosity of naturally alloyed iron in a liquid state have been studied. Temperatures, the heating to which transforms the melt into a homogeneous state have been assigned. The polytherm has a complicated type showing the presence of several stages of structural transformations. It was established that the maximum temperature of the heating melt during the experiment greatly affects the type of the polytherm hysteresis. Based on the quasi-chemical model of micro-inhomogeneous melt structure, physical substantiation of transformations occurring during heating and cooling of liquid metal was offered. The results obtained were used in the production of powders from naturally alloyed iron. Pilot melting during which liquid metal was heated above and below its structural reorganizations was carried out. In addition, the temperature of liquid metal spraying by nitrogen was varied. The influence of the melting regimes of naturally alloyed iron on the oxygen content in the obtained powder was studied. Research by the method of vacuum melting using the equipment “O-N-mat 822” showed that the process of oxygen deposition from powder particles has a complicated type. It was found out that the oxygen content in iron powder depends on the particle size and conditions of melt preparation to spraying. Formation of the homogeneous condition during melting leads to the decrease of oxygen concentration in the powder and to the change of its deposition spectrum. It turns out that in such melts oxygen is in a solid solution or is bound in iron oxides.