S890QL is a European standard (EN 10025-6) high-strength structural steel, known for its exceptional yield strength (890 MPa), achieved through quenching and tempering (the 'Q'), and good low-temperature impact toughness (the 'L' signifies testing at -40°C). It's used in demanding applications like cranes, bridges, and heavy transport, offering strength and durability while remaining weldable and formable, allowing for lighter, stronger designs.
Key Characteristics
S: Structural Steel
890: Minimum yield strength of 890 Megapascals (MPa)
Q: Quenched and Tempered (a heat treatment process)
L: Low temperature impact toughness (tested at -40°C)
Properties & Applications
High Strength: Over three times stronger than basic structural steels, ideal for load-bearing structures.
Good Weldability: Despite its strength, it's relatively easy to weld and fabricate.
Durable: Performs well in extreme conditions due to its low-temperature impact resistance.
Applications: Cranes, mobile platforms, bridges, heavy transportation, lifting equipment, and specialized containers.
How to machine S890QL steel?
Machining S890QL steel is a challenging and specialized process due to its extreme hardness (typically 280–360 HBW) and very high strength (890 MPa yield). Success requires optimized tooling, rigid setups, and strict parameter control to avoid excessive tool wear, poor surface finish, or workpiece damage.
1. Key Challenges
Rapid Tool Wear: High hardness and abrasive alloy carbides cause fast edge degradation.
High Cutting Forces: Demands maximum machine and fixture rigidity to prevent chatter/vibration.
Heat Generation: Intense friction creates high heat, risking tool failure and potential alteration of the steel's heat-treated properties.
Work Hardening: Improper machining (e.g., low feed, worn tools) can harden the surface further, making subsequent passes more difficult.
2. Tooling Selection
Material: Use premium-grade carbide (micro‑grain grades like C3/C4) with TiAlN‑ or AlCrN‑based coatings. For heavy roughing, ceramic inserts (Si₃N₄ or Al₂O₃‑based) may be used under stable, high‑speed conditions.
Geometry: Positive rake angles, sharp edges, and polished flutes to reduce cutting forces and heat. Robust tool holders (e.g., hydraulic or shrink‑fit) are critical for stability.
3. Cutting Parameters (General Starting Points)
Cutting Speed (Vc): Low to moderate – typically 60–120 m/min for turning with carbide. Start at the lower end.
Feed Rate: Use adequate feed (e.g., 0.1–0.3 mm/rev for turning) to avoid rubbing and work hardening.
Depth of Cut: Sufficient to cut beneath any hardened surface layer (≥0.5 mm for finishing).
Note: Parameters must be adjusted based on tool wear and machine rigidity. Always refer to tool‑supplier recommendations.
4. Coolant & Lubrication
High‑pressure coolant (≥70 bar) is highly recommended to dissipate heat, improve chip evacuation, and extend tool life.
Use emulsion or oil‑based coolants with good lubrication properties.
5. Process‑Specific Tips
Turning: Use consistent, light‑to‑medium depths of cut. Ensure the workpiece is securely chucked.
Milling: Prefer climb milling (down‑milling) to reduce heat and work hardening. Use tools with a reduced number of flutes for better chip clearance.
Drilling & Tapping:
Drilling: Use carbide drills with internal coolant channels. Peck drilling is essential for deep holes.
Tapping: Avoid if possible; prefer thread milling for better control and tool life. If tapping is necessary, use premium-grade high‑strength taps and ensure perfect alignment.
6. Preparation & Setup
Remove Hard Surface Scale: The as‑delivered plate often has a hard, decarburized skin. Remove it via grinding or rough machining before finish operations.
Maximize Rigidity: Use the most robust machine available. Minimize overhang of tools and workpieces. Dampened tool holders can help reduce vibration.
Technical data
EN10025-6 S890QL quenched and tempered steel plate Chemical composition
| Grade | C % | Si % | Mn % | P % | S % | N % | B % | Cr % |
| S890QL | 0.200 | 0.800 | 1.700 | 0.020 | 0.010 | 0.015 | 0.005 | 1.500 |
| Cu % | Mo % | Nb % | Ni % | Ti % | V % | Zr % | ||
| 0.500 | 0.700 | 0.060 | 2.000 | 0.050 | 0.120 | 0.150 |
EN10025-6 S890QL quenched and tempered steel plate mechanical properties
| Grade | Thickness(mm) | Min Yield (Mpa) | Tensile(MPa) | Elongation (%) | Min Impact Energy | |
| S890QL | 8mm-50mm | Min 890Mpa | 940-1100Mpa | 11% | -40 | Min 30J |
| 51mm-100mm | Min 830Mpa | 880-1100Mpa | 11% | -40 | Min 30J | |
| 101mm-150mm | Min 800Mpa | 820-1000Mpa | 11% | -40 | Min 30J |
For more information in EN10025-6 S890QL quenched and tempered steel plate quality certificate or inquiry in competitive official quotation, please contact us.
1. What is S890QL steel?
S890QL is a very high-strength quenched and tempered structural steel with a minimum yield strength of 890 MPa, designed to maintain good toughness at low temperatures down to -40°C.
2. What are the main applications of S890QL?
It is used in ultra-heavy mobile crane booms, advanced mining drill rigs, military vehicle frames, and specialized offshore components where maximum strength-to-weight ratio is critical in cold climates.
3. How does S890QL differ from S690QL?
S890QL offers higher yield strength (890 MPa vs. 690 MPa) but lower toughness and weldability, making it suitable for more weight-critical yet more demanding applications.
4. What is the chemical composition of S890QL?
It contains low carbon, manganese, silicon, and micro-alloys like niobium, vanadium, and boron, along with nickel, chromium, and molybdenum for hardenability and toughness.
5. Can S890QL be welded easily?
No, welding S890QL is difficult and requires strict procedures: low-hydrogen consumables, preheating (often 150-200°C), controlled heat input, and usually post-weld heat treatment.
6. What standards apply to S890QL steel?
It is primarily governed by the European standard EN 10025-6 for quenched and tempered high-strength structural steels.
7. Is S890QL corrosion resistant?
No, S890QL is not corrosion-resistant and requires protective coatings such as painting, galvanizing, or specialized plating for use in corrosive environments.
8. How to machine S890QL steel?
Machining S890QL is challenging due to its high hardness; it requires robust carbide tooling, slow cutting speeds, high-pressure coolant, and rigid setup.
9. What is the price of S890QL steel plate?
S890QL is significantly more expensive than lower-grade steels, with prices varying based on thickness, quantity, and certification, often ranging from €2,500 to €4,500+ per ton.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
