Viscosity measurement of molten metal

We developed a simple viscosity measurement method to directly evaluate the period and logarithmic decrement of oscillation. The viscosity of a molten metal is an important thermophysical property for production at high temperatures. However, the viscosities of molten metals are relatively low and difficult to measure because of challenges involved in their handling. Among several methods available for meas-uring viscosity, the oscillating crucible method is generally used with molten metals. The conventional method involves an approximation using a multistep iteration to determine the viscosity. In this study, we developed a simple viscosity measurement method based on the principle of least squares to derive the period and logarithmic decrement of oscillation. To confirm the reproducibility of the proposed method, the viscosity of molten nickel was measured and found to be in good agreement with those reported in the literature. The measurement error was less than ±3%. Resently, we have been systematically measured the viscosities of stainless steels and nickel superalloys.

Thermal conductivity measurement of molten silicate

Thermal conductivities of silicate melts are essential for understanding the melting and crystallization processes of metallurgical slag, industrial glass melts, and magmatic liquid. Moreover, these thermal conductivities are important for improving the manufacturing process of steels. However, because the measurement of the thermal conductivities of silicate melts at a high temperature is difficult, experimental data of thermal conductivities are very limited owing to the experimental difficulty. In the present study, we prepared silicate glass samples. The thermal effusivities of molten silicate were evaluated using the front-heating front-detection laser flash method, and their thermal conductivities were calculated using this thermal effusivity data in addition to their specific heat capacity and density.