Because of its high efficiency, low cost and simple equipment, gas cutting is widely used in steel plate blanking and welding groove. Therefore, it is inaccurate to say that gas cutting cannot cut complex parts on steel plates. Gas cutting refers to the use of gas flame to preheat the cut metal to the melting point, so that it burns violently in pure oxygen flow, forming slag and releasing a lot of heat. Under the blowing force of hyperbaric oxygen, the oxide slag is blown away: the released heat further preheats the next layer of metal to reach the melting point. The gas cutting process of metal is a continuous process of preheating, combustion and slag blowing, and its essence is the process of metal burning in pure oxygen, not melting.