S960Q is a high-yield, ultra-high-strength structural steel plate produced according to the EN 10025-6 European standard. It is delivered in a quenched and tempered (Q+T) state, which provides a unique combination of exceptional mechanical strength and toughness.
Key Specifications & Meaning
The designation "S960Q" provides specific details about the material's properties:
S: Denotes structural steel.
960: Indicates the minimum yield strength of 960 MPa (megapascals).
Q: Signifies the delivery condition as Quenched and Tempered. It also indicates that the material has specified minimum impact energy values at temperatures not lower than -20°C.
Steel Number: 1.8941.
Primary Applications
S960Q is used for demanding load-bearing structures where weight reduction is critical without sacrificing safety or durability.
Heavy Machinery: Cranes, excavators, and mining equipment.
Construction: High-rise buildings, highway bridges, and large-scale engineering projects.
Transportation: Truck chassis, trailers, and railway components to create lightweight yet robust systems.
Offshore & Marine: Oil rigs, shipbuilding, and offshore platforms.
How to machine S960Q steel?
Machining S960Q steel is extremely challenging due to its ultra-high strength (960 MPa yield) and high hardness (typically 300–400 HBW). It requires specialized tooling, rigid setups, and precise parameter control to avoid excessive tool wear, workpiece damage, or failure. Below are key guidelines:
1. Key Challenges
Very High Cutting Forces: Demands maximum machine stability to prevent vibration/chatter.
Rapid Tool Wear: The high hardness and abrasive alloy carbides cause fast edge degradation.
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 rates, worn tools) can harden the surface further, making subsequent passes even more difficult.
2. Tooling Selection
Material: Use premium-grade micro‑grain carbide (C4/C5 grades) with TiAlN/AlCrN/TiSiN coatings. For 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. Robust tool holders (e.g., hydraulic, shrink‑fit) are essential for rigidity.
Tool Monitoring: Inspect tools frequently for wear; replace at first signs of edge deterioration.
3. Cutting Parameters (General Starting Points)
Cutting Speed (Vc): Low to moderate – typically 50–100 m/min for turning with carbide. Start at the lower end.
Feed Rate: Use adequate feed (e.g., 0.1–0.25 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: These are starting points; always refer to tool‑supplier recommendations and conduct test cuts.
4. Coolant & Lubrication
High‑pressure coolant (≥80 bar) is essential to dissipate heat, improve chip evacuation, and extend tool life.
Use emulsion or oil‑based coolants with excellent lubrication and thermal conductivity.
5. Process‑Specific Tips
Turning: Use light‑to‑medium depths of cut. Ensure the workpiece is securely chucked to minimize deflection.
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 mandatory for deep holes.
Tapping: Avoid if possible; thread milling is strongly recommended for better control and tool life. If tapping is unavoidable, use premium 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.
Secure Workholding: Use hydraulic or mechanical clamping to prevent movement under high cutting forces.
1. What is S960Q steel?
S960Q is an ultra-high-strength quenched and tempered structural steel with a minimum yield strength of 960 MPa, offering exceptional strength-to-weight ratio but requiring strict fabrication controls.
2. What are the main applications of S960Q?
It is used in extreme weight-critical components like advanced crane booms, high-performance military vehicles, specialized mining equipment, and heavy-duty offshore lifting systems.
3. How does S960Q differ from S690Q?
S960Q has significantly higher yield strength (960 MPa vs. 690 MPa) but lower toughness and weldability, making it suitable only for the most demanding lightweight designs.
4. Can S960Q be welded easily?
No, welding S960Q is very difficult and requires strict procedures: low-hydrogen consumables, high preheat (often 150-200°C+), controlled heat input, and usually post-weld heat treatment.
5. What is the chemical composition of S960Q?
It contains low carbon with micro-alloys like niobium, vanadium, titanium, and boron, plus alloying elements such as nickel, chromium, and molybdenum for hardenability and strength.
6. What standards apply to S960Q steel?
It is primarily governed by the European standard EN 10025-6 for quenched and tempered high-strength structural steels.
7. Is S960Q corrosion resistant?
No, S960Q is not corrosion-resistant and requires protective coatings (e.g., painting, galvanizing) for use in exposed or corrosive environments.
8. How to machine S960Q steel?
Machining S960Q is extremely challenging due to its high hardness; it requires premium carbide tools, high-pressure coolant, rigid setups, and optimized cutting parameters.
9. What is the price of S960Q steel plate?
S960Q is among the most expensive structural steels, typically ranging from €4,000 to €8,000+ per ton, depending on thickness, quantity, and certification requirements.
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.
