Research on Influence Mechanism of Nozzle Structure on Properties of Thick Carbon Steel Plate by Laser Cutting

Abstract Aiming at problems such as slow cutting speed, poor cutting quality and inability to cut thick plates effectively with traditional single-layer nozzle structure, it is proposed to add an outer ring core to form a double-layer nozzle structure on the basis of the single-layer nozzle structure to improve its cutting performance. The three-dimensional entity of single- and double-layer nozzle is established, and the simulation model of auxiliary gas flow field is established by using N-S equation and SST k-ω turbulence model assisted by laser cutting in this paper. The simulation results show that under the same cutting parameters, the auxiliary gas flow rate, oxygen concentration, mass flow rate, shear force and dynamic pressure of the double-layer nozzle structure are higher than those of the single-layer nozzle structure. In addition, compared with the single-layer nozzle structure, the double-layer nozzle structure can effectively improve the attenuation of oxygen concentration in the direction of sheet thickness. Two nozzle structures were used to laser cutting carbon steel plates with a thickness of 20 mm in the experiment, and the experimental parameters of cutting speed were 1.2–1.6 m/min. The comparison results show that the cutting speed and cutting section quality of the double-layer nozzle are better than those of the single-layer nozzle, and the results of simulation analysis are consistent with the cutting test results.