Which material is commonly used as a filler rod in TIG welding?

In TIG (Tungsten Inert Gas) welding, the choice of filler rod material is crucial as it must be compatible with the base metal being welded. The correct answer identifies that stainless steel, aluminum, or copper alloys are commonly used as filler rods in TIG welding. This is because TIG welding is a versatile process that accommodates a wide variety of materials.

Stainless steel filler rods are widely used when welding stainless steel materials, ensuring a strong and durable joint. Aluminum filler rods are essential for joining aluminum components, which is common in many industries, including automotive and aerospace. Copper alloys are also compatible with TIG welding, allowing for effective joining of copper parts.

In contrast, the other options are limited in scope. Copper only applies to specific situations and does not include the diversity of materials necessary for many TIG applications. Aluminum exclusively excludes other common fillers, and iron and steel alloys might be used in different welding processes like MIG (Metal Inert Gas) welding rather than TIG. Therefore, the inclusion of various materials in the correct answer reflects the adaptability of TIG welding in a range of applications.