Some Thermophysical Properties of Liquid Cr-Mn-Ni-Steels

In the last years new Cr-Mn-Ni-TRIP/TWIP steels have been developed at the Institute of Iron and Steel Technology, Freiberg University of Mining and Technology. Within the Collaborative Research Center SFB 799, the ZrO2-ceramic-TRIP-steel composite materials are produced using the infiltration of open foam ceramics with liquid steel and using powder metallurgy with small additions of ceramic powder before sintering. The thermophysical properties of liquid steel play an important role in both production routes. They affect the infiltration efficiency in one process and the produced powder size in the other, and therefore finally determine the composite properties. In this work some of these properties were estimated, as they are not available in literature. The investigated steels contain approximately 16% chrome, 7% manganese and 3% to 9% nickel. The surface tension was estimated using two methods: the drop weight method and the maximum bubble pressure method. In the drop weight method similar conditions at the gas/metal interface exist as during the atomization or the infiltration process, where liquid metal is exposed to high volume of inert gas. In all these cases the evaporation of manganese affects the surface tension. For comparison of results and for estimation of the liquid steel density the maximum bubble pressure method was used where the evaporation of manganese is limited. The wettability on partially MgO-stabilized ZrO2 ceramic substrates and its change with contact time was determined using the sessile drop method.