Bulb flat for shipbuilding are being used as plate stiffeners especially in the shipbuilding industry. Ball flat steel is a kind of main type which is mainly used in the field of shipbuilding and bridge construction. Among them, marine ball flat steel is used in shipbuilding auxiliary medium, generally larger ships and regular ships are designed in the main hull. , Using the same thickness with the plate and the material of the ball flat steel as a bone (also known as bones or keel).