TOUGHNESS REQUIREMENTS FOR OFFSHORE STRUCTURAL STEELS

This paper reviews the fracture control procedures available in establishing the toughness requirements for offshore structural steels. The transition temperature based on Charpy tests and other empirical relationships is evaluated. The limitation and subjectivity of this method are discussed. The use of fracture mechanics for establishing toughness requirements, in terms of COD values, related to the service environments is illustrated. Fracture data for a typical offshore structural steel (BS 4360-50 D) are used to compare the toughness requirement based on the two fracture control methods. The use of fracture mechanics in selecting fabrication and inspection criteria is discussed. Factors affecting toughness and quality control are addressed.