What is the impact of using a small cup size in GTAW?

Using a small cup size in Gas Tungsten Arc Welding (GTAW) leads to restricted gas coverage and increases the risk of contamination. The size of the cup, which is part of the torch assembly, plays a critical role in protecting the weld pool from atmospheric contaminants such as oxygen and nitrogen. A smaller cup creates a narrower gas flow, which can lead to inadequate shielding, particularly in situations where movement or wind could disrupt the gas coverage. This limited coverage can expose the molten weld pool to the surrounding environment, resulting in defects like porosity and oxidation, ultimately compromising the quality of the weld.

Additionally, a smaller cup can make it challenging to maintain a stable arc and proper heat distribution across the weld area, which would further affect the integrity and mechanical properties of the completed weld. Therefore, while small cups may offer some benefits in terms of visibility and access in tight spaces, the overall impact on gas coverage and contamination risk is detrimental.