This 690MPa high-strength quenched and tempered steel plate is specifically developed for the leg structures of offshore jack-up platforms (Jack-up Rig / Jack-up Wind Farm Installation Vessel), including racks, chords, and large welded composite structures. The material features an optimized low-carbon chemical composition and stringent heat treatment process, ensuring high strength, excellent low-temperature impact toughness, and outstanding weldability even at ultra-thick plate thicknesses up to 210 mm.

The steel plate maintains an impact absorption capacity of >50 J at low temperatures as low as –60°C, making it suitable for high-safety applications in extremely cold marine environments and compliant with offshore engineering standards such as DNV, ABS, and ASTM. Its enhanced weldability and cuttability significantly improve manufacturing efficiency, reducing the overall cost of offshore equipment fabrication and maintenance.

Key applications include: leg structures of jack-up platforms, truss legs of offshore wind installation vessels, rack structures, chord materials, and thick plate welded assemblies, making it an ideal material for large-load-bearing structures in the offshore engineering industry.