Determination of the thermal shock resistance of graphite by arc discharge heating

This paper presents a technique to determine the thermal shock resistance of graphite by a basic analysis of non-steady thermal stress in a circular disk heated by an arc discharge at its central part. The thermal shock resistance is defined as Δ = σ θk Eα , α θ , circumferential tensile thermal stress; κ, thermal conductivity; E, Young's modulus; α, thermal expansion coefficient) and is determined en bloc only measuring the electric power of the arc discharge using the specific non-dimensional thermal stress S ∗ which is calculated theoretically as the maximum saturation stress in the non-dimensional diffusion time τ > 1 4 . This technique is also available to measure simultaneously the thermal diffusivity k = k cp ( c, specific heat; ρ, density) using the specific non-dimensional diffusion time τ ∗ calculated theoretically as the heat reaching time from the center to the periphery of the disk after the arc discharge is started. The experimental studies for several kinds of graphite were carried out and the results are compared with the values of σ θk Eα and k cp estimated indirectly from the individual mechanical and physical properties.