Flat bulb steel is a kind of medium profile mainly used in shipbuilding and bridge construction, among which Marine flat bulb steel is an auxiliary medium profile for shipbuilding. In recent years, with the rapid development of shipbuilding industry, the demand for Marine flat ball steel is strong. Generally, the main hull of larger ships and regular ships is designed with marine bulb flat steel, and the bulb flat steel with the same thickness and material as the connecting plate is used as the frame material (also called tendon or keel).