## 1 Introduction  
Low-cost carbon steels, extensively utilized in marine engineering for components like ship decks, pipelines, and drilling platforms, face significant longevity challenges due to corrosion and rust. The economic impact of metal rusting is substantial with an estimated annual cost of approximately 2.4 trillion dollars [1]. This issue is particularly acute for 20 steel, which is commonly used in marine environments. Its low carbon and alloy content makes its surface more susceptible to rust-based contaminants [2], potentially leading to a drastic reduction in the lifespan of ship hulls and creating safety hazards. Consequently, developing low-cost methods for treating rusted metal surfaces to restore their original performance has become a focal point of current research. Presently, the most commonly adopted methods for cleaning metal surfaces include physical cleaning, chemical cleaning, and high-pressure water jet cleaning [3, 4]. However, these techniques often suffer from drawbacks such as low efficiency, imprecision, severe damage to material surfaces, environmental pollution, and potential health risks for personnel [5, 6, 7, 8]. In contrast, laser-cleaning technology offers substantial benefits over traditional processes in terms of flexibility, consumable costs, and environmental impact. It has gained widespread application in diverse fields, including pre-soldering cleaning, metal decontamination, and the restoration of cultural artefacts [9; 10; 11]. [PERSON] et al. [12] identified that at low energy densities, the primary mechanism of laser cleaning of metal oxides is ablation, where high-energy pulsed lasers not only cause phase explosion but also facilitate oxide layer removal through pressure-induced shock effects. [PERSON] et al. [13] employed a fiber laser to remove rust oxides from Q345 steel commonly used in the mining industry and explored the surface integrity at different laser powers to determine the optimum cleaning parameters and confirm the feasibility of laser cleaning. [PERSON] et al. [9] investigated rusty steel using a combination of molten salt pretreatment and laser cleaning, noting an enhanced ease of rust layer removal at lower laser irradiation intensities. [PERSON] et al. [5] reported that laser descaling could reduce the annual corrosion rate of steel surfaces more effectively than acid descaling. Additionally, [PERSON] et al. [14] utilized a nanosecond ultraviolet laser for the removal of microorganisms and contaminants from the rust layer on AH36 steel surfaces. At an energy density of 5.30 J/cm\({}^{2}\), the corrosion resistance of the laser-cleaned surface was found to be threefold higher than that of the microbiologically contaminated surface post-recovery. For the shipbuilding field where steel is in high demand, the cost-effective 20 steel has a natural advantage. The above report shows that the corrosion resistance of the material after laser cleaning has been improved while reducing the cost, providing new ideas for the application of laser cleaning in the shipbuilding field. Despite numerous studies conducted in the field, the primary goal of laser cleaning remains the effective removal of corrosion layers without inflicting damage to the substrate material. Furthermore, understanding how laser treatment can enhance the corrosion resistance of metals by altering the surface structure, composition, and grain size during the corrosion layer removal process is of paramount importance for practical applications. [PERSON] et al. [15] explored how the laser processing speed influences the roughness and hardness of the steel surface, examining the effects of various parameters on surface properties post-laser treatment. Similarly, [PERSON] et al. [16] applied [PERSON]'s method in experimental design for laser cleaning, discovering that adjustments in laser pulse frequency and scanning speed can significantly enhance the cleaning efficiency while concurrently reducing the system's specific energy.