Improved Assembly for Gas Shielding During Welding or Brazing

Inert gas is distributed evenly over the region surrounding the weld joint.

An improved assembly for inert-gas shielding of a metallic joint is designed to be useable during any of a variety of both laser-based and traditional welding and brazing processes. The basic purpose of this assembly or of a typical prior related assembly is to channel the flow of a chemically inert gas to a joint to prevent environmental contamination of the joint during the welding or brazing process and, if required, to accelerate cooling upon completion of the process.

In a typical prior welding gas-shielding assembly, depicted in the left part of the figure, the inert gas is fed to the joint through a central nozzle in the welding torch. This arrangement does not always provide adequate protection against contaminants because the inert gas flows turbulently into the joint region and is not evenly distributed in the heated region surrounding the joint. The lack of inert gas in some places in the region surrounding the joint can result in oxidation, which, in turn, can lead to porosity and ultimately to cracking. Improper distribution of shielding gas can also lead to the formation of plasma and to insufficient cooling of portions of the region surrounding the joint that are meant to be protected against excessive heating.

The present improved welding gas-shielding assembly, depicted in the right part of the figure, provides a column of evenly distributed gas flow directly surrounding the pool of molten metal in the weld joint to prevent oxidation and formation of plasma.