Nanosecond Laser Cleaning of 10CrNi2Mo3Cu2V Steel: Surface Cleaning, Oxidation Control and Welding Performance

High-strength steels often require surface pretreatment before welding to remove contaminants and ensure weld quality. Compared with conventional mechanical grinding, which is time-consuming, labor-intensive, environmentally unfriendly, and potentially damaging to the substrate, laser cleaning offers a contact-free alternative to conventional surface-treatment methods and may reduce the use of abrasive or chemical cleaning agents. In this study, nanosecond laser cleaning of oxide films on 10CrNi2Mo3Cu2V steel was investigated in air and argon to determine the optimal process window. A 1064 nm, 100 ns pulsed fiber laser was employed for single-pass scanning at fluences of 5.10-10.19 J/cm². The cleaned surfaces were characterized by SEM, EDS, XPS, laser confocal microscopy, microhardness testing, and vacuum electron-beam welding. In argon, the optimal fluence was 7.64 J/cm², at which the oxide-related surface products were effectively removed in the analyzed area, the oxygen content decreased to 2.11 wt.%, the roughness reached 5.2 μm, and the hardness became comparable to that of the ground sample. At higher fluences, secondary oxidation increased and surface quality deteriorated. The optimized laser-cleaned joints were pore-free and achieved a tensile strength of 881.4 MPa, exceeding that of both the untreated and ground controls.