Indepth Investigations into the Capability of Plazma Arc Cutting of Mild Steel Tubes

Abstract

Plasma Arc cutting (PAC) is a process of cutting steel and other metals (or sometimes other materials) using a plasma torch. In this method, an inert gas (in some units, compressed air) is blown at high speed out of a nozzle. At the same time an electrical arc is formed through that gas from the nozzle to the surface being cut, turning some of that gas to plasma. The plasma is sufficiently hot to melt the metal being cut and moves sufficiently fast to blow molten metal away from the cut. Plasma can also be used for plasma arc welding and other applications. In Plasma Arc Cutting (PAC), the plasma gas flow is enhanced so that the intense and deeply penetrating plasma jet cuts through the material and molten material is removed as cutting dross. PAC differs from oxy-fuel cutting in that the plasma process operates by using the arc to melt the metal whereas in the oxy-fuel process, the oxygen oxidizes the metal and the heat from the exothermic reaction melts the metal. Unlike oxy-fuel cutting, the PAC process can be applied to cutting metals which form refractory oxides such as stainless steel, cast iron, aluminum, and other non-ferrous alloys. In this paper the deviations in the thickness of the cut profile of the square tubes are critically analyzed for assessment of the deviations in the cut surface of the square tubes of structural steel due to the phenomena like top edge rounding, dross, cut surface bevel angle, top spatter and extended kerf width etc.