What is a needle point on the tungsten electrode primarily used for?

A needle point on the tungsten electrode is primarily used for welding thin metals. The sharp point of the needle configuration allows for a concentrated arc, which is essential when working with thinner materials. This focused arc minimizes heat affected zone (HAZ) and helps prevent burn-through, which is a common issue when welding thin sections.

In contrast, thicker metals typically require a broader arc, which can be achieved with a blunted tungsten electrode. Using a needle point on thick materials could result in excessive heat concentration, leading to distortion or burn-through. Additionally, high-current situations do not necessitate a needle point; rather, a larger, more robust tungsten electrode is preferable to handle the increased thermal load effectively. Lastly, while joining dissimilar metals can have unique requirements, the use of a needle point tungsten is specifically advantageous for managing the delicate balance of heat input and arc control needed for thin metal applications.