S890QL
1.8983
High-yield-strength alloy special structural steel, quenched and tempered · EN 10025-6:2019+A1:2022 · EN 10025-1:2004, where applicable for general delivery and conformity requirements
S890QL is an ultra-high-strength, weldable structural steel supplied quenched and tempered under EN 10025-6. It combines a minimum yield strength of 890 MPa at nominal thicknesses up to 50 mm with specified Charpy toughness at −40 °C. Its strength-to-weight potential is substantial, but successful use depends on thickness-specific design values, qualified low-hydrogen welding procedures, controlled heat input and strict protection of the delivered heat-treated condition.
- 890 MPa for 3–50 mm; 830 MPa above 50–125 mmMinimum yield strength · Nominal product thickness governs the specified value.
- 940–1100 MPa for 3–50 mm; 880–1100 MPa above 50–125 mmTensile strength · Room-temperature tensile requirements in the quenched-and-tempered delivery condition.
- QL: 30 J minimum average longitudinal Charpy V at −40 °CLow-temperature quality · Standard-size test pieces; transverse testing and values require the relevant ordering provision.
- Hot-rolled flat products, nominally 3–125 mmStandard product range · EN 10025-6 does not define S890QL bars, forgings, tubes or hollow sections.
- Quenched and temperedDelivery condition · The high strength is microstructure-dependent and can be degraded by uncontrolled heating.
- 0.72% up to 50 mm; 0.82% above 50–100 mm; 0.83% above 100–125 mmMaximum CEV · IIW carbon equivalent based on heat analysis; actual values should be taken from the inspection certificate.
Overview
- Designation system
- Steel name to EN 10027-1; steel number to EN 10027-2
- Product forms
- Hot-rolled plate, Wide flat, Hot-rolled strip, Sheet or plate cut from strip
- Condition
- Quenched and tempered (Q), Direct-quenched after hot rolling and subsequently tempered, where used by the manufacturer
- Density
- 7.85 g/cm³ (Representative density for engineering calculations; not a defining EN 10025-6 requirement.)
What the designation defines
The designation is property- and delivery-condition based. “S” identifies structural steel; “890” is the specified minimum yield strength in MPa for nominal thicknesses up to 50 mm; “Q” requires delivery in the quenched-and-tempered condition; and “L” identifies the quality with specified impact properties at temperatures down to −40 °C.
EN 10025-6 classifies the material as an alloy special steel and covers hot-rolled flat products only. For S890 grades, the standard range is 3–125 mm nominal thickness. A commercially described S890QL bar, tube, forging or casting is therefore not automatically an EN 10025-6 product, even if its chemistry or strength appears similar.
S890QL is not a proprietary grade. Individual mills sell branded products certified to S890QL, but their tighter chemistry, dimensional range, forming guarantees and processing recommendations are producer-specific rather than universal grade requirements.
Mechanical requirements and thickness effects
| Nominal thickness t | Minimum yield strength | Tensile strength | Minimum elongation |
|---|---|---|---|
| 3 ≤ t ≤ 50 mm | 890 MPa | 940–1100 MPa | 11% |
| 50 < t ≤ 100 mm | 830 MPa | 880–1100 MPa | 11% |
| 100 < t ≤ 125 mm | 830 MPa | 880–1100 MPa | 11% |
Yield is reported as the appropriate yield-strength measure under the specified tensile test method. Elongation applies to the proportional gauge length Lo = 5.65√So.
The number 890 must not be used as a universal design value. The specified yield strength falls to 830 MPa above 50 mm, and design resistance can be further affected by the applicable structural design standard, partial factors, stability, fatigue, joint details, temperature and fabrication condition. Elastic modulus is broadly similar to conventional structural steel, so replacing a lower-strength grade does not produce a proportional increase in stiffness or buckling resistance.
| Test-piece orientation | Test temperature | Minimum average energy | Status |
|---|---|---|---|
| Longitudinal | −40 °C | 30 J | Basic EN 10025-6 QL requirement |
| Transverse | −40 °C | 27 J | Applicable when transverse impact testing is specified under the relevant ordering option |
Values refer to standard 10 mm × 10 mm specimens. Reduced-size specimens use reduced energy requirements in accordance with the standard. The test certificate should be checked for specimen size, orientation and temperature.
A Charpy requirement at −40 °C is a material qualification point, not by itself a declaration that every component is safe for service at −40 °C. Service-temperature selection also depends on thickness, stress level, detail category, strain rate, weld condition, flaw tolerance and the governing design or fracture-control rules.
Composition limits and weldability indicator
EN 10025-6 permits a broad alloy-design envelope so that producers can obtain the required hardenability, strength and toughness through different steelmaking and heat-treatment routes. The following values are maximum heat-analysis limits, not a typical commercial composition. Product analysis is subject to separate permitted limits and should not be assessed directly against the heat-analysis table.
| C | Si | Mn | P | S | N | B |
|---|---|---|---|---|---|---|
| 0.20% | 0.80% | 1.70% | 0.020% | 0.010% | 0.015% | 0.0050% |
The steel must be fully killed, fine grained and contain sufficient nitrogen-binding elements.
| Cr | Cu | Mo | Nb | Ni | Ti | V | Zr |
|---|---|---|---|---|---|---|---|
| 1.50% | 0.50% | 0.70% | 0.06% | 4.0% | 0.05% | 0.12% | 0.15% |
Actual mill compositions are commonly much narrower and should be taken from the EN 10204 inspection document.
| Nominal thickness t | Maximum CEV |
|---|---|
| t ≤ 50 mm | 0.72% |
| 50 < t ≤ 100 mm | 0.82% |
| 100 < t ≤ 125 mm | 0.83% |
These are specification ceilings, not recommended welding targets. Welding procedure development should use the actual heat analysis and product-specific guidance.
The potentially high CEV reflects the hardenability needed to obtain an 890 MPa strength class through the plate thickness. The grade is weldable, but it is not as tolerant of uncontrolled welding practice as conventional structural steels. Hydrogen level, restraint, section thickness, joint geometry, heat input, preheat, interpass temperature and cooling time all become significant.
Fabrication and preservation of properties
Welding should be covered by a qualified procedure based on EN 1011-2 or the governing fabrication code and the plate producer’s recommendations. Use controlled low-hydrogen consumables and clean, dry joint surfaces. Preheat and interpass limits should be established from the actual composition, combined thickness, hydrogen level, restraint and heat input rather than from the grade name alone. Excessively rapid cooling raises hydrogen-cracking risk, while excessive heat input or interpass temperature can soften the heat-affected zone and reduce joint strength or toughness.
Matching-strength weld metal may be required where the joint must develop the full parent-metal resistance, but it can impose penalties in toughness, hydrogen sensitivity and fabrication robustness. Purposeful undermatching is used in some designs, provided the joint design and qualified procedure explicitly accommodate the lower weld-metal strength. Consumable selection must therefore be a design and procedure decision, not a simple grade-to-filler lookup.
Mechanical, laser, plasma and oxy-fuel cutting can be used when supported by appropriate procedures. Thermal cutting may create a hardened edge and residual stress; thicker or colder plate may require preheating. Remove notches, drag lines and hardened or damaged zones where they would impair bending, fatigue performance or weld quality. Cut edges in highly stressed or fatigue-critical details deserve particular inspection attention.
Cold forming is possible, but springback, forming force and sensitivity to edge quality are substantially greater than for ordinary structural steel. Minimum bend radius depends on thickness, bend-line orientation, edge preparation and the producer’s product guarantee. EN 10025-6 provides informative bend guidance for a limited thickness and bend-angle range; for production work, use the certified plate producer’s recommendations and validate demanding operations by trials.
Uncontrolled hot forming, flame straightening or post-weld heat treatment can alter the tempered microstructure and invalidate the delivered properties. EN 10025-6 states that stress relief should remain at least 30 °C below the producer’s tempering temperature and should not be held for more than one hour. Because the original tempering temperature is normally not stated in advance, the producer should be consulted before stress relief. Higher temperatures or longer holding times require agreed post-treatment mechanical properties.
Ordering, certification and inspection
| Item | What to state or verify |
|---|---|
| Designation | EN 10025-6 – S890QL or EN 10025-6 – 1.8983, including the required standard edition |
| Product and dimensions | Plate, strip, sheet or wide flat; nominal dimensions; applicable dimensional and tolerance standard |
| Inspection document | Required EN 10204 document type, commonly 3.1 unless the project requires otherwise |
| Impact testing | Temperature, orientation and any requirements beyond the basic longitudinal QL condition |
| Chemical verification | Whether product analysis is required in addition to heat analysis |
| Internal soundness | Required ultrasonic-testing class to EN 10160, if applicable |
| Through-thickness properties | Any Z-quality requirement to EN 10164 for joints susceptible to lamellar tearing |
| Surface and flatness | Required surface class, repair restrictions and any tighter flatness or thickness tolerances |
| Coating route | Any intended hot-dip galvanizing or chemistry control that must be agreed before manufacture |
| Processing restrictions | Required producer limits for welding, forming, thermal cutting, flame straightening or stress relief |
If optional requirements are not stated at the time of order, supply is made to the basic specification.
Review the certificate by heat and product. Confirm the exact designation, standard edition, delivery condition, nominal thickness, heat analysis, calculated CEV, tensile results, impact-test temperature, specimen orientation and specimen size. Do not accept a certificate showing only “S890” or a proprietary 900 MPa class without an explicit conformity statement to S890QL when EN 10025-6 compliance is contractually required.
Standard compliance does not guarantee availability in every thickness, width, flatness class or processing condition. Mill production route and dimensional programme should be confirmed before design details are frozen.
Use and substitution boundaries
S890QL is typically selected for highly loaded structures where mass reduction is valuable, including crane and lifting structures, mobile equipment, transport systems, booms, handling machinery and other welded load-bearing components. Its benefit is greatest where static strength controls. Deflection, local and global buckling, fatigue, connection capacity and fabrication constraints can limit the achievable weight reduction.
Substitution requires more than matching nominal yield strength. Check product form, standard edition, thickness-dependent tensile properties, toughness temperature and orientation, chemistry and CEV, heat-treatment route, dimensional tolerances, inspection level, weld-procedure qualification and design-code acceptance. A branded 900 MPa product is interchangeable only when its certification and all project requirements demonstrate the necessary conformity.
Sources
- EN 10025-6:2019+A1:2022 — Hot-rolled products of structural steels, Part 6European Committee for Standardization / UNI
- SIST EN 10025-6:2019+A1:2023 — Standard previewSlovenian Institute for Standardization
- Declaration of Performance — S890QL / 1.8983Industeel, ArcelorMittal
- DILLIMAX 890 — High-strength fine-grained structural steel, quenched and temperedDillinger
- High Strength Steel Design and Execution Guide, Publication P432Steel Construction Institute
- High-strength quenched and tempered fine-grained steelsvoestalpine Steel Division
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