Mild steel is a type of low-carbon steel with a carbon content of 0.05% to 0.25% by weight. It is one of the most commonly used steels in the world due to its versatility, affordability, and availability. Mild steel is characterized by its low tensile strength, making it ideal for a variety of applications that don't require high strength or toughness.  Some of the common uses of mild steel filler wires include construction, manufacturing, pipes and tubes, and DIY projects. It can be easily fabricated and welded, making it a popular choice for many industries.