Developed by Lockheed Martin, for the George C. Marshall Space Flight Center, the Ternary Gas Plasma Welding Torch provides a faster, more efficient means of joining thicker materials with relatively low heat inputs. In addition, due to the patented design, there is less dependency on the technician's skills to achieve quality results. The increase in performance that the Ternary Gas Plasma Welding Torch achieves is attributed to a secondary inert gas acting in conjunction with the primary inert gas to provide a substantially "stiffer" arc from the electrode of the torch than a typical single inert gas provides.

Benefits

Potential Commercial Uses

The Technology

The Ternary-Gas Plasma Arc Welding (TGPAW) torch functions by utilizing three gases: a primary inert plasma gas, a secondary inert plasma gas, and an inert shielding gas. The primary inert plasma gas is directed through the body of the welding torch and out of the body across the tip of a welding electrode disposed at the forward end of the body. The second plasma gas is disposed for flow through a longitudinal bore in the electrode. It is directed through the electrode to co-act with the arc to produce equivalent defect free welds in types and thickness of metals (ferrous and non-ferrous) with less total heat input per inch of weld (i.e. less current/voltage output and/or high travel speeds). The completed weld is narrower with greater penetration at any given electrical current setting, thereby producing a more desirable Heat Affected Zone (HAZ) and greater ultimate tensile strength values. In addition, the secondary inert plasma gas compliments the primary inert gas to provide a "stiffer" arc, less subject to becoming skewed and unequal in dimensional shape. This characteristic aids alleviating weld "cutting" defects caused by an asymmetrical arc and subsequent asymmetrical heating pattern at the weld joint. The secondary plasma gas may be any of the inert gases or semi-reactive gases or a mixture of two or more of these, however the choice is dependent on the material being welded and the results desired. The process can be applied to Direct Current Straight Polarity and Variable Polarity Welding Modes. The third inert plasma gas is "shield" gas that is directed through the torch body for circulating around the head of the torch adjacent to the electrode tip. The following diagram illustrates the Ternary Gas system: