In flame cutting, oxygen is used as the cutting gas. The oxygen is blown into the kerf at pressures of up to 6 bar. There, the heated metal reacts with the oxygen: it begins to burn and oxidizes. The chemical reaction releases large amounts of energy – up to five times the laser energy – and assists the laser beam. Flame cutting makes it possible to cut at high speeds and handle jobs involving thick plates such as mild steel with thicknesses in excess of 30 millimeters.