Mild steel also called plain-carbon steel is the most common form of steel because its price is relatively low while it provides material properties that are acceptable for many applications, Mild steel has a relatively low tensile strength and malleable; surface hardness can be increased through carburizing. This material is also electrically conductive, easily available and flexible in design. It can be machined by using many non-conventional methods like laser cutting, water jet machining and plasma arc machining. Among them Plasma arc machining is a widely used industrial process due to its high accuracy, finishing, ability of machining any hard materials and to produce intricate shape increases its demand in market. This process is considered a challenging technology compared to its main competitors: Oxy-fuel and laser cutting, in particular for cutting of mild steel for thickness 8-40 mm.