Development of Low-Carbon, Copper-Strengthened HSLA Steel Plate for Naval ShipConstruction

摘要

Modern warships designs require an increased utilization of high strength, alloysteel plate for weight reduction, stability, increased payload, and increased mobility. Naval ship structures are subjected to a complex spectrum of loads and service environments, and the structural steels and welding materials used in hull fabrication must demonstrate high fracture toughness for these extreme service conditions. The welding of HY-series high strength steels, traditionally used in Navy ship construction, requires a number of fabrication controls to prevent weld cracking, which result in high fabrication costs. The Navy initiated the HSLA steel program with a goal of reducing ship-building costs. This report describes the development and certification of Cu-strengthened HSLA steels which are weldable with reduced parameter control (particularly preheat,), and provide high strength, high toughness, and high quality weldments. HSLA-80 steel (MIL-S-24645) was certified for use in ship construction after an extensive program demonstrated that the low carbon, copper precipitation strengthened steel met the performance requirements of HY-80 steel, but was readily weldable without preheat. Lower fabrication costs and higher productivity in construction were realized. Keywords: HSLA-80 steel; HSLA-100 steel; Mechanical properties; Welding; Weldability; Fracture toughness; Impact toughness; Alloy development. (jes)