Polar ships sail in low-temperature Polar Regions all year round and are often collided with floating ices. The welding joints of polar ships therefore demand high comprehensive performance. The microstructure and mechanical properties, residual stress and deformation of the electrogas welding (EGW) are systematically analyzed for the polar ship equipment. The optimization of the welding process of the EGW, improvement of the reliability of the welding joints and reduction of the welding deformation and residual stress promote the application of efficient welding processes for polar ships. The results show that with the increase of groove gap, the linear energy increases, the low-temperature toughness stability of the weld decreases, and the low-temperature toughness of the heat-affected zone decreases significantly, as well as the residual stress and deformation of the weld increase significantly. The large heat input steel plate developed by the technologies of oxide metallurgy or oxidation metallurgy can effectively improve the low-temperature toughness of the heat-affected zone and the reliability of the welding joints.

In recent years, the polar navigation equipment is of increasing concern with the decreasing coverage and thickness of the arctic sea ice. Compared to traditional navigation areas, the sea ice will interact frequently with the ships in arctic regions, which is also one of the main causes of the fatigue damage of the hull structure. It is therefore of significant importance for the prediction of the dynamic structural response of ships sailing in Polar Regions to simulate the dynamic process of the ship-ice collision and analyze the influencing factors. The ice material parameters that can be applied to the commercial software LS-DYNA are proposed, with feasibility verification according to the P-A curve of ISO. The modeling of the bow is then established to simulate the collision between the bow and the floating ice under the operation conditions with bow speeds of 5kn, 6kn and 7kn, respectively, and a floating ice size of 10m×10m×0.6m, and then analyze the impact of the parameters.