Abstract :
To understand the effect of surface materials on metallic arc welding electrodes, something must be known as regards the fundamental theory of arc heat distribution, arc vapor resistance and similar matters which are modified by the presence of surface materials. The character of the arc may be changed by chemical and structural variations in the surface materials. Stability is one such arc characteristic. Two types of stability are recognized, — chemical and electrical. Surface materials have a significant influence on the brittleness or ductility of weld metal. They also can be used to control the arc type, four such types being recognized. The influence of surface materials on the heating of electrodes is another phase of the matter of practical significance. Surface materials may be employed to control both the operating characteristics of the electrode and the resultant weld properties. Among the operating characteristics might be mentioned stability and rate of melting. Among the weld properties are included freedom from blow-holes and tensile strength. These and other practical applications of a comprehensive knowledge of surface materials are cited in this paper.
