Studies on Thermal Shock Resistance of Several Kinds of Graphite

Abstract

This paper presents a technique to determine the thermal shock resistance of graphite by the basic analysis of nonsteady thermal stress in a circular disk heated by an arc discharge at its central area. The thermal shock resistance, defined as Δ=σ_θk/Eα, (σ_θ: circumferential tensile thermal stress, k: thermal conductivity, E: Young's modulus, α: thermal expansion coefficient), can be determined en bloc only by measuring the arc discharge electric power using the specific non-dimensional thermal stress S_* which is calculated theoretically as the maximum saturation stress in the nondimensional diffusion time τ>1/4. This technique is also applicable to measure simultaneously the thermal diffusivity κ=k/cρ (c: specific heat, ρ: density). The experimental studies for several kinds of graphite were carried out and the results were compared with the values of σ_θk/Eα and k/cρ estimated indirectly from these individual mechanical and physical properties.