Experimental study of an oxygen plasma cutting torch: II. Arc-material interaction, energy transfer and anode attachment

A study of are-material interaction and energy transfer in the case of plasma cutting is presented. A fast CCD camera moving with the torch is used to estimate the anodic arc root location inside the kerf. Temperature measurements on the cut-front surface and on the kerf edges are performed by infrared pyrometry. Temperature fields inside the workpiece obtained with inserted thermocouples are compared with the theoretical results of an analytical model to estimate heat conduction losses Q(HCL) (W) dissipated in the plate. For various sets of operating parameters (voltage, inlet oxygen pressure and cutting speed), a complete energy balance of the process is performed with the calculation of the device efficiency on the basis of the various power terms implicated in the cutting tool: the power lost above the workpiece, heat conduction losses, the power involved in melting steel, the energy released by chemical oxidation reactions, the power available for cutting and losses under the plate in the extinguishing plasma.