Microstructures and properties of TC4 ELI alloy with horizontal EBW for submersible manned cabin

The welding was one of the technologies to manufacture manned cabin, which was a significant part of the submersible. To improve the procedure, horizontal EBW was employed on TC4 ELI alloy with 60 mm thickness, and the microstructures and properties of the joints were investigated. The crystals and microstructures of the welds were homogeneous from the top to bottom, and the microhardness of the weld was equivalent, which was harder than that of the base metal. The tensile properties of the joints were homogeneous along the penetration. The tensile strength and yield strength of the joints were higher than those of the base metal, and the percentage elongation after fracture was 80% of the base metal, which indicated the strength mis-match as overmatching. The impact toughnesses of the welds were equivalent along the penetration, which reached 80% of the base metal. The joint specimens were bended to 180° with no cracks. The investigation verified the excellent procedure and properties of horizontal EBW, which would make China become one of the countries with the capacity of manufacturing submersible cabin.