DNV Grade F500
DNV Grade F500 is an extra-high-strength shipbuilding steel plate certified by the classification society DNV (Det Norske Veritas). The F designation indicates impact testing at -60 degrees Celsius, and 500 refers to the minimum yield strength level of 500 MPa. The grade offers a minimum yield strength of 500 MPa, a tensile strength of 610-770 MPa, and a minimum elongation of 16 percent. It is designed for applications requiring extra-high strength and durability, such as ship cranes and offshore structural projects.
Chemical Composition
The chemical composition of DNV F500 is specified with maximum limits of carbon 0.18 percent, silicon 0.55 percent, manganese 1.60 percent, phosphorus 0.020 percent, sulfur 0.020 percent, and nitrogen 0.020 percent. The tight control of phosphorus, sulfur, and nitrogen is essential for achieving the -60 degrees Celsius impact toughness required by the F designation, while the manganese content provides the strength needed for the 500 MPa yield level.
Mechanical Properties
The mechanical properties of DNV F500 are uniform across the covered thickness ranges. For thickness up to 50 mm, above 50 mm up to 70 mm, and above 70 mm up to 150 mm, the minimum yield strength is 500 MPa, the tensile strength is 610-770 MPa, and the elongation is at least 16 percent. The Charpy V-notch impact energy at -60 degrees Celsius is at least 33 J for energy 1 and 50 J for energy 2 across all three thickness ranges.
Applications
DNV Grade F500 plates are used in shipbuilding projects and ocean offshore structural projects where extra-high strength is essential. Typical applications include ship cranes and lifting equipment, where the combination of high strength and low-temperature toughness supports heavy lifting in marine environments, and offshore structures that must resist dynamic wave and wind loads. The grade is selected where the structural weight must be minimized without compromising load capacity.
Fabrication Considerations
As an extra-high-strength quenched and tempered plate, DNV F500 requires strict welding control. Preheat and interpass temperature limits, low-hydrogen consumables, and qualified welding procedure specifications are mandatory to prevent hydrogen-induced cracking and to preserve the mechanical properties of the heat-affected zone. Cutting and forming should follow the manufacturer's recommendations for high-strength steel.
Frequently Asked Questions
What does 500 mean in DNV F500? It refers to the minimum yield strength level of 500 MPa; the F prefix indicates impact testing at minus 60 degrees Celsius.
What are the mechanical properties? Minimum yield strength 500 MPa, tensile strength 610-770 MPa, elongation at least 16 percent, and impact energy 33/50 J at minus 60 degrees Celsius.
Where is F500 used? Ship cranes, offshore structural projects and other applications requiring extra-high strength and low-temperature toughness.
What is the impact test temperature? Minus 60 degrees Celsius.
What thickness ranges are covered? Up to 50 mm, 50-70 mm and 70-150 mm, with the same property requirements across all ranges.
What welding precautions apply? Preheat and interpass temperature control, low-hydrogen consumables and qualified welding procedures.
