A new multi-scenario, low-cost, high-efficiency, medium-assisted continuous laser cleaning of corrosion layers was developed. By comparing the roughness and cleaning depth of rust layers cleaned under conditions of liquid-assisted, solid-assisted, and mixed solid–liquid-assisted laser cleaning, simultaneously establishing a three-dimensional finite element model to study the variations during the cleaning process, and conducting a comparative analysis of the results of both, the cleaning mechanism is elucidated. The experimental results indicate that under conditions of water-assisted cleaning, the depth of rust layer increases initially and then decreases with varying water layer heights. The maximum cleaning depth is achieved at a water layer height of 0.1 mm, while the optimal surface roughness occurs at a water layer height of 0.2 mm, indicating a change in cleaning mechanism. The cleaning pattern with SiO₂ activator assistance follows a similar trend to a water medium, reaching maximum cleaning depth at 0.1 mm height, with a slight improvement in surface roughness compared to water-assisted cleaning. Finally, solid–liquid mixing can achieve cleaning completion and improve surface roughness under conditions where water-assisted cleaning alone fails to reach a clean state. Therefore, the active agent can be used for laser cleaning to promote the cleaning process, and solid–liquid mixing to assist the laser cleaning can be a theoretical guide for the field of laser cleaning.

This study proposes a novel high-frequency flat-top longitudinal magnetic field-assisted tungsten inert gas (HF-FTLMF TIG) welding method to improve arc constriction and weld penetration. The effects of magnetic field intensity and frequency on arc morphology, weld appearance, and microstructure were systematically investigated. The results show that, compared with conventional TIG welding, when the frequency of the FTLMF exceeds 1000 Hz, the arc becomes noticeably constricted, the conical angle decreases, and the heat input becomes more concentrated. Under appropriate magnetic field conditions, the arc pressure increases from 251.3 Pa for the free arc to 452.9 Pa, and the weld penetration depth increases from 0.84 mm to 1.09 mm. In addition, HF-FTLMF reduces surface unevenness and improves weld uniformity. Compared with low-frequency FTLMF (<1000 Hz), HF-FTLMF exhibits more stable arc behavior and better weld formation. SEM and EDS results further indicate that the application of HF-FTLMF affects the fusion-zone microstructure and elemental redistribution, and a relatively finer microstructure was observed under the 2000 Hz condition. These findings suggest that HF-FTLMF provides an effective approach for regulating TIG arc behavior and improving weld formation through magnetic field assistance.