This invention relates to consumable welding rods or welding electrodes. More particularly, the invention relates to welding rods or welding electrodes of the type comprising a tubular metallic sheath enclosing a core or filling composed of grains or granules of inorganic welding materials belonging to one or more of the following groups: Alloying agents, fluxing agents, slag-forming agents, gas-forming agents and arc-stabilizing or electron-emitting agents.
Tubular welding wire or rods of the kind referred to are used in gas welding and in arc welding with nonconsumable electrode (carbon arc welding and TIG welding) as well as in the electroslag welding process (ES welding) and the consumable electrode welding process, in which last-mentioned processes the tubular wire or rod does itself constitute the consumable electrode. In automatic or semiautomatic consumable-electrode welding the wire is usually supplied as a coil, while in manual welding usually rod-shaped electrodes are employed. The wires or rods may be either bare or coated.
With the tubular wires or rods referred to, it is important to prevent material from dropping out at the electrode tip and to prevent voids from forming within the electrode. To secure this result it has been suggested to submit the core material to a high degree of compaction in the course of the manufacture, in order to convert it into a virtually solid body. This method does, however, not always secure the desired result. Also, it imposes particular restrictions on the manufacturing process. It has also been suggested to mix the powered material with a liquid bonding agent, for instance a sodium silicate solution, to a paste and to deposit or extrude a string of said paste in the trough-shaped strip. This method introduces, however, other complications.
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