1. What Is S890Q?
S890Q is the EN 10025-6 designation for a high-strength fine-grain structural steel delivered in the quenched and tempered condition. The letter S means structural steel, the number 890 is the minimum yield strength in MPa for thicknesses up to 50 mm, and Q denotes quenching and tempering. The quench-and-temper cycle produces a fine-grained microstructure of bainite and tempered martensite that combines high strength with good toughness, which is what allows very heavily loaded structures to be built in lighter sections.
2. Typical Application Fields
S890Q is used wherever extreme load capacity must be combined with low weight: heavy construction and mining equipment such as excavators, dumpers and drill rigs; cranes and lifting gear, where reduced boom weight increases lifting capacity; offshore structures including drilling platforms and wind turbine support structures; bridges and heavily loaded structural members; and transport machinery, vehicle components and mobile equipment. In these fields the strength-to-weight ratio of the grade translates directly into more payload, longer spans or smaller sections.
3. Key Characteristics
The defining properties of S890Q are its strength, toughness and weldability. The minimum yield strength is 890 MPa up to 50 mm thickness, the tensile strength is in the range 940–1100 MPa, and impact energy is typically required at 30 J at -20°C for the standard Q grade, with the L and L1 variants covering lower impact temperatures. The steel can be welded with standard arc processes in accordance with EN 1011-2, usually with preheating for thicker sections or cold-formed edges to avoid cold cracking.
4. Chemical Composition (Heat Analysis, Max %)
The composition of S890Q is controlled to balance strength and weldability. Typical heat analysis maxima are: carbon 0.20, silicon 0.80, manganese 1.70, phosphorus 0.025, sulfur 0.015, nitrogen 0.015, boron 0.005, chromium 1.50, copper 0.50, molybdenum 0.70, niobium 0.06, nickel 2.0, titanium 0.05, vanadium 0.12 and zirconium 0.15. These limits should be verified against the current edition of EN 10025-6 and the mill certificate, since editions differ slightly.
5. Mechanical Properties by Thickness
The guaranteed mechanical values depend on plate thickness. Common published values for S890Q are: for 3–50 mm, minimum yield 890 MPa and tensile 940–1100 MPa; for 50–100 mm, minimum yield 830 MPa and tensile 880–1100 MPa; for thickness above 100 mm, reduced values apply and must be read from the governing standard edition. The grade is supplied with third-party approvals under classification societies and notified bodies such as ABS, DNV, GL, CCS, LR, RINA, KR, TUV and CE, which reflects its use in certified structures.
Frequently Asked Questions
What does the designation S890Q mean? S denotes structural steel, 890 the minimum yield strength of 890 MPa, and Q the quenched and tempered delivery condition.
Where is S890Q mainly used? In heavy machinery, cranes and lifting equipment, mining and construction machinery, offshore structures, bridges and heavily loaded transport components.
What is the tensile strength of S890Q? Typically 940–1100 MPa for thicknesses up to 50 mm, with slightly lower values for thicker sections per EN 10025-6.
Is S890Q weldable? Yes, with standard arc welding practice per EN 1011-2; preheating is often required for thicker sections or cold-formed edges, and low-hydrogen consumables should be used.
What is the impact requirement for S890Q? The standard Q grade is commonly tested at 30 J at -20°C; the L and L1 variants specify lower test temperatures.
What is S890Q equivalent to? Within the same strength class, Chinese Q890 (GB/T 16270) is the closest parallel; ASTM A514 (690 MPa yield) is a lower-strength family and should not be treated as equivalent.
