When sourcing 3mm welding rods, the price is heavily influenced by the material composition (e.g., Carbon Steel, Stainless Steel, or Cast Iron) and the coating type (e.g., Rutile, Cellulosic, or Basic). You must ensure the rods meet AWS (American Welding Society) or ISO standards, such as AWS A5.1 for carbon steel. Always verify the tensile strength and yield strength specifications, as these directly impact the structural integrity of the weld. For 3mm rods, the current range (Amperage) typically falls between 90A and 130A, so ensure the product's performance stability within this range is documented.