Special steel profiles are increasingly being used for commercial and warship construction to reduce production and life cycle costs. In particular, bulb flats (Holland profiles), manufactured by special profiles businesses, are increasingly being used for plate stiffening in warships and naval auxiliaries. Examples are the UK's Type 23 Frigates, the LPH HMS Ocean, Watson Class Sealift ships and the Dutch LPD HrMs Rotterdam, as well as, looking to the future, the UK Type 45 Destroyer. Some comparison will be made of naval vessel construction on both sides of the Atlantic, particularly looking at the advantages that bulb flats can bring to naval vessel construction. This paper will discuss the challenge of introducing new shapes, examine the state of the art in the production of special steel shapes and describe metallurgical developments that enable the delivery of shapes with required structural performance and suitability for production. Shipbuilding developments such as laser welding are being addressed with a view to the manufacture of special profiles, particularly where tolerance and chemical composition issues need to be addressed. Future lightweight vessel construction may involve a mix of aluminium, steel and composite structures. Special profiles can be developed to assist in the joining of these different construction materials.
Morphology Study on Inclusion Modifications Using Mg–Ca Treatment in Resulfurized Special Steel
