Laser cutting of carbon steel is usually carried out with the use of oxygen as the cutting gas. When oxygen reacts with the heated laser beam, the metal oxidation reaction is exothermic and the heat evolved in the oxidation of iron is typically 3-5 times stronger than the input power of the laser radiation. The products of combustion (oxides) are blown out with the same oxygen jet. The cutting width is determined by the diameter of the focused beam as well as the speed of the cut, and can be lowered to values of around 0.15mm.
One of the main concerns of working with laser flame is a possibility that the cutting process transitions into an uncontrollable autogenous mode. In this mode, the metal outside the laser beam’s zone of impact is heated to the combustion temperature, increasing the width of the cut and its roughness. During laser-oxygen cutting of steel, difficulties may arise with the presence of cut-out parts and sharp edges of small-diameter holes. In these cases, it is better to use a high-pressure inert gas for cutting. Air can also be used, however laser cutting with air can potentially form a burr that is difficult to remove.
Laser-oxygen cutting ensures a high quality of the cut’s end surface and only minor burr on its lower edge.