Design and welding method for high-strength steel structure using laser-arc hybrid welding

The study intended for rational usage of high-strength steel in structure by applying laser-arc hybrid welding has been conducted. Key design requirements and improvement target have been clarified considering their key performances as structural members. The evaluation methods for risk of brittle fracture and cold cracking have been established for quality control. Safety of welded joint has been confirmed and their fatigue strength has been improved by optimizing welding process.