Why is it important to keep the end of the filler rod in the protective zone of shielding gas?

Keeping the end of the filler rod in the protective zone of shielding gas is crucial because it helps prevent oxide formation on the filler material. In Gas Tungsten Arc Welding (GTAW), the shielding gas serves to protect both the weld pool and the filler rod from atmospheric contamination, particularly oxygen and nitrogen. These gases can react with the molten metal, leading to the formation of oxides on the surface. Such oxides can weaken the weld joint and adversely affect the mechanical properties of the finished weld.

When the filler rod is within the shielding gas zone, it maintains a clean surface that's free from contaminants, ensuring that the weld pool remains pure and that the integrity of the weld is upheld. This aspect is particularly important in applications that require high structural strength and corrosion resistance, such as in aerospace and marine industries. By preventing oxide formation through proper shielding, welders can achieve cleaner and stronger welds, enhancing overall weld quality and performance.