In response to the challenges associated with weld treatment during the on-site corrosion protection of hydraulic steel gates, this paper proposes a method utilizing a magnetic adsorption climbing robot to perform corrosion protection operations. Firstly, a magnetic adsorption climbing robot with a multi-wheel independent drive configuration is proposed as a mobile platform. The robot body consists of six joint modules, with the two middle joints featuring adjustable suspension. The joints are connected in series via an EtherCAT bus communication system. Secondly, the kinematic model of the climbing robot is analyzed and a PID trajectory tracking control method is designed, based on the kinematic model and trajectory deviation information collected by the vision system. Subsequently, the proposed kinematic model and trajectory tracking control method are validated through Python3 simulation and actual operation tests on a curved trajectory, demonstrating the rationality of the designed PID controller and control parameters. Finally, an intelligent software system for weld defect detection based on computer vision is developed. This system is demonstrated to conduct defect detection on images of the current weld position using a trained model.

The development of clean energy resources, including hydro power, plays an important role in protecting the global environment. Multi-layer bellows are key components and are widely used in hydro power plants. Due to the special multi-layer structures, conventional arc welding is prone to the defects of pores and insufficient fusion when fabricating or repairing such bellows. Precise laser welding with a high energy density and a low heat input has the potential to join multi-layer bellows in a high-quality manner. In this study, a comparative investigation was conducted on the arc welding and laser welding of multi-layer 316L stainless steel sheets and B610CF high-strength steel plates regarding the weld quality, microstructure and tensile properties. The results show that laser-welded joints produced a narrower heat-affected zone and a full weld without visible defects. Compared with arc welding, laser welding had more equiaxed grain regions in the fusion zone and a homogeneous elemental distribution in the heat-affected zone. This led to a more reliable welded joint using laser welding.

Galvanic corrosion between 42CrMo steel and 410 stainless steel in low-conductivity Yangtze River freshwater was investigated using electrochemical measurements and secondary current distribution modeling. Experimental polarization data were used to establish the electrode kinetics, and the numerical model was calibrated against the measured galvanic current. The effects of cathode-to-anode area ratio (A_c/A_a) and electrode separation (d) were evaluated across 20 geometric configurations. At d = 50 mm, increasing A_c/A_a from 0.5 to 4 increased the total galvanic current from 1.57 × 10⁻⁴ to 4.97 × 10⁻⁴ A and the maximum local anodic current density from 0.078 to 0.270 A m⁻². At A_c/A_a = 1, increasing electrode separation from 10 to 100 mm reduced the total galvanic current by approximately 41%, while the current-localization factor increased. These results demonstrate that electrode geometry governs both the overall galvanic corrosion intensity and the spatial distribution of anodic current. The findings provide a basis for identifying high-risk configurations and optimizing the geometric design of dissimilar-metal connections in hydropower structures.