Measurement of Thermal Diffusivity of Steels at Elevated Temperature by a Laser Flash Method.

In order to obtain thermal diffusivity of steels at elevated temperature with sufficient reliability using a laser flash method, an accurate value of specimen thickness is essentially required. Accordingly, a linear thermal expansion coefficient of steels was systematically measured in the temperature range from room temperature to 1 676 K. Since the decrease in specimen thickness was detected after the measurement of thermal diffusivity under vacuum at high temperature close to solidus, such a factor was quantitatively estimated from the thickness values of quenched specimens. Combining these two results, the thermal diffusivity values were successfully determined for ultra low carbon, low carbon, medium carbon, 1.2% silicon, 9% nickel and 13 % chromium steels in the temperature range from room temperature to 1676 K using the laser flash method.