Abstract
A method to measure the erosion of electrodes which occurs in a low voltage condenser spark in air is studied and applied to the case of cast iron samples having various metallurgical histories.The. erosion of pure iron, M (mg), is calculated by substituting the measured values of crater depth, a0, . and electrode radius, b0, into the following equation.
M=4.12 a0 (a02+3b02).
This method is thought useful, since it has been ascertained that the amount of erosion in pure iron is proportional to the iron line intensity.For the calculation of iron grow away from a cast sample containing x percent of iron, the following equation is employed.
MFe=π/6xρa0 (a02+3b02),
where, ρ (density, g/cm3) =8.10-0.22 C%-0.09 Si%-0.07 P%.
Though the erosion of Fe-C alloys increases with the carbon content, the iron line intensity does not increase proportionally to it.While large variation is found in the erosion of white cast iron samples, the intensities of iron lines observed are always low and almost constant.It is also clarified that grey cast irons having high saturation value of carbon show remarkably higher intensities than those expected from the amount of erosion.
