Mild steel is black to dark grey unpolished and silvery polished. Mild steel has the same red rust oxide as iron. Mild steel is also ferrous and magnetic. Another name for mild steel is low carbon steel. Mild steel makes yellow sparks when ground down. Mild steels density is about 7.86 g/cm3but it varies since it is an alloy of iron and carbon (low carbon steel). MIld steel melting point is 1350-1530°C (2462-2786°F).