What Is S890Q Steel
S890Q is an ultra-high-strength structural steel grade specified in EN 10025-6, supplied in the quenched and tempered condition, the Q in the designation. The grade delivers a minimum yield strength of 890 MPa for thicknesses from 3 to 50 mm, with the yield requirement reducing to 830 MPa for sections above 50 mm. It is intended for welded load-bearing structures subject to extreme static and dynamic loads where weight reduction and compact section design are decisive.
Chemical Composition
The heat analysis limits are carbon 0.20 percent, silicon 0.80 percent, manganese 1.70 percent, phosphorus 0.025 percent, sulfur 0.015 percent, nitrogen 0.015 percent, boron 0.005 percent, chromium 1.50 percent, copper 0.50 percent, molybdenum 0.70 percent, niobium 0.06 percent, nickel 2.0 percent, titanium 0.05 percent, vanadium 0.12 percent, and zirconium 0.15 percent, all maximums. The tightly controlled impurity levels, particularly sulfur, nitrogen, and boron, are essential for achieving the toughness and weldability expected from this strength class.
Mechanical Properties
For thicknesses from 3 to 50 mm the minimum yield strength is 890 MPa and the tensile strength is 940 to 1100 MPa. For thicknesses from 50 to 100 mm and above 100 mm the minimum yield strength is 830 MPa and the tensile strength is 880 to 1100 MPa. The quenched and tempered delivery condition produces a tempered martensite microstructure with a fine, uniform grain size that balances strength with acceptable toughness.
Fabrication and Welding
Steels of this strength class have limited weldability in the sense that weld quality depends strongly on material thickness, joint geometry, restraint, and service conditions. General requirements for arc welding follow EN 1011-2, with preheating, controlled heat input, interpass temperature management, and post-weld heat treatment evaluated case by case. Low-hydrogen welding consumables and qualified procedures are mandatory, and the carbon equivalent must be reviewed before welding.
Applications
S890Q is typically used in structures bearing extreme loads: mining and heavy construction equipment, crane booms and undercarriages, offshore drilling rigs, support structures for offshore wind turbines, and bridge and trestle construction. It is also specified for mobile machinery, lifting equipment, and pressure-bearing structural components where the high strength-to-weight ratio reduces dead load and transportation cost.
Selection and Supply Considerations
When selecting S890Q, verify the required impact test temperature and energy, typically agreed between purchaser and supplier, and confirm the plate thickness bands for yield and tensile values. Plates are commonly supplied in thicknesses up to 100 mm or more, with flame cutting, laser cutting, and edge preparation available to support fabrication. Contact our technical team with your drawings and service conditions to receive a documented quotation and delivery program.
Frequently Asked Questions
Q: What does the Q in S890Q mean?
A: Q indicates the quenched and tempered delivery condition required by EN 10025-6.
Q: What is the minimum yield strength of S890Q?
A: 890 MPa for thicknesses from 3 to 50 mm, reducing to 830 MPa above 50 mm.
Q: Is S890Q suitable for welding?
A: Yes, with qualified low-hydrogen procedures, preheating, and controlled heat input per EN 1011-2.
Q: What applications use S890Q?
A: Crane structures, mining equipment, offshore rigs, wind turbine supports, and heavy bridges.
Q: What standard governs S890Q?
A: EN 10025-6, hot rolled structural steel products in the quenched and tempered condition.
Q: What thickness ranges are available?
A: Typically 3 to 100 mm, with heavier sections available on request subject to testing.
Q: How is S890Q delivered?
A: In the quenched and tempered condition with mill test certificates and optional ultrasonic inspection.
Contact us for pricing, stock availability, and custom processing for your S890Q plate requirements.