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High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes)

An International Journal

ISSN for PRINT: 1093-3611

Institutional price:	$604.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2005, Volume9

155 pages

DOI: 10.1615/HighTempMatProc.v9.i2

Issue price - $144.00

FROM TRANSFERRED ARC TO PLASMA TORCHES

J. F. Coudert
PCTS -CNRS UMR 6638, University of Limoges, 123 av. A. Thomas, 87060 Limoges cedex, France

C. Chazelas
Laboratoire Sciences des Procédés Céramiques et de Traitements de Surface, ENSIL,16 rue d'Atlantis, 87068 LIMOGES Cedex, France

D. Rigot
Laboratoire Sciences des Precedes Ceramiques et Traitements de Surfaces IJMR 6638, Universite de limoges, 123 avenue Albert Thomas - 87060 Limoges, France

V. Rat
PCTS -CNRS UMR 6638, University of Limoges, 123 av. A. Thomas, 87060 Limoges cedex, France

ABSTRACT

Thermal plasma generated either by transferred arc or by plasma torches are involved in many industrial processes including, for example, cutting, welding, powder synthesis or coating elaboration by plasma spray techniques. The common feature is that electrical energy is converted into thermal energy, which must be transferred differently following the goal of the technique. Cutting requires a high thermal flux density to the anode in order to optimize both the accuracy and the speed of cutting. On the opposite, heat transfer to the anode of a plasma spray torch needs to be reduced, as much as possible, in order to slow down the nozzle erosion which is responsible, among other problems, of the monotonic deviation of the torche performances over a long time scale. This presentation is devoted to a general approach of the physical processes concerning an electric arc, thermally constricted and confined in the channel of a plasma torch nozzle. Experimental results characterizing both stationnary and transient behaviour of the generated plasma flow will be described. General tendancies observed for the shift of the torch performances and connected to the anode erosion, will be commented.