S690QL & S700MC High Strength Steel
High Yield Structural Steel Plates & Sheets – 690 / 700 MPa Class
Introduction
S690QL and S700MC are high strength structural steels with a minimum yield strength of around 690–700 MPa — roughly three times that of ordinary mild steel (E250). They allow designers to cut section thickness and weight while carrying the same or higher loads.
Although their strength levels are similar, the two grades are produced differently and serve different purposes. S690QL is a quenched and tempered plate for heavy welded structures, while S700MC is a thermomechanically rolled steel made for cold forming in thinner gauges. At Sharoff Steel Suppliers, we help customers choose the right grade for their design, fabrication method and service conditions.
What Is S690QL?
S690QL is a high yield strength, quenched and tempered (Q&T) structural steel specified under EN 10025-6. The grade name breaks down as:
• S – Structural steel
• 690 – Minimum yield strength of 690 MPa (for thicknesses up to 50 mm)
• Q – Quenched and tempered condition
• L – Guaranteed impact toughness at low temperature (–40°C)
The quench-and-temper process gives a fine, uniform microstructure, delivering high strength, good toughness and reliable weldability even in thick plates.
What Is S700MC?
S700MC is a high strength, low alloy steel for cold forming, specified under EN 10149-2. The grade name breaks down as:
• S – Structural steel
• 700 – Minimum yield strength of 700 MPa
• M – Thermomechanically rolled
• C – Suitable for cold forming
Its low carbon content and micro-alloying (Nb, V, Ti) give excellent bendability, press-brake formability and weldability, making it ideal for lightweight vehicle and machine components.
Mechanical Properties
S690QL – EN 10025-6
| Thickness (mm) | Min. Yield Strength (MPa) | Tensile Strength (MPa) | Min. Elongation |
|---|
| 3 – 50 | 690 | 770 – 940 | 14% |
| > 50 – 100 | 650 | 760 – 930 | 14% |
| > 100 – 150 | 630 | 710 – 900 | 14% |
Impact energy (Charpy V-notch): minimum 30 J at –40°C (longitudinal) / 27 J at –40°C (transverse).
S700MC – EN 10149-2
| Thickness (mm) | Min. Yield Strength (MPa) | Tensile Strength (MPa) | Min. Elongation |
|---|
| ≤ 8 | 700 | 750 – 950 | 10% (A80, t < 3) / 12% (A5, t ≥ 3) |
| > 8 | 680 | 750 – 950 | 12% (A5) |
Impact testing is optional and can be ordered — typically 40 J at –20°C (longitudinal) for thicknesses of 6 mm and above.
Chemical Composition (Ladle Analysis, Max %)
| Element | S690QL | S700MC |
|---|
| Carbon (C) | 0.20 | 0.12 |
| Silicon (Si) | 0.80 | 0.60 |
| Manganese (Mn) | 1.70 | 2.10 |
| Phosphorus (P) | 0.020 | 0.025 |
| Sulphur (S) | 0.010 | 0.015 |
| Chromium (Cr) | 1.50 | – |
| Molybdenum (Mo) | 0.70 | 0.50 |
| Nickel (Ni) | 2.00 | – |
| Niobium (Nb) | 0.06 | 0.09 |
| Vanadium (V) | 0.12 | 0.20 |
| Titanium (Ti) | 0.05 | 0.22 |
| Boron (B) | 0.005 | 0.005 |
| Aluminium (Al) | – | 0.015 (min) |
For S700MC, the sum of Nb + V + Ti shall not exceed 0.22%. Values are indicative as per EN standards; actual chemistry is confirmed by the mill test certificate.
S690QL vs S700MC – Which One Do You Need?
| Parameter | S690QL | S700MC |
|---|
| Standard | EN 10025-6 | EN 10149-2 |
| Production route | Quenched & tempered | Thermomechanically rolled |
| Typical form | Heavy plates | Hot-rolled sheets, coils & strips |
| Thickness range | Up to 150 mm | Mostly up to 10–12 mm |
| Low-temperature toughness | Guaranteed at –40°C | Optional, by agreement |
| Cold forming | Moderate | Excellent – tight bends possible |
| Weldability | Good, preheat usually needed | Very good, low carbon equivalent |
| Best suited for | Heavy load-bearing welded structures | Lightweight formed components |
Typical Applications
S690QL
• Mobile and crawler crane booms
• Heavy lifting equipment and spreader beams
• Earthmoving and mining machinery
• Offshore structures and heavy platforms
• Bridges and high-load structural members
• Penstocks and pressure-bearing structures
S700MC
• Truck and trailer chassis frames
• Tipper bodies and lightweight vehicle structures
• Truck-mounted crane arms and loader cranes
• Agricultural and forestry machinery
• Cold-formed sections and press-braked profiles
• Material handling equipment
Fabrication Guidelines
Welding
• Use low-hydrogen consumables matched to the strength level
• Control heat input to preserve strength and toughness in the heat-affected zone
• S690QL generally requires preheating, depending on plate thickness and carbon equivalent
• S700MC can often be welded without preheat in thinner sections
Forming & Cutting
• S700MC is designed for tight-radius cold bending on a press brake
• S690QL can be cold formed, but needs larger bend radii and higher press capacity
• Both grades can be cut by plasma, laser or oxy-fuel; avoid excessive heating of Q&T plate, as it can lower strength
Why Use High Strength Steel?
Compared with conventional structural steels such as E250 or E350, S690QL and S700MC offer:
• Weight savings of up to 30–50% for the same load
• Higher payload for vehicles, trailers and cranes
• Less welding due to thinner sections
• Lower transport and handling costs
• Reduced material consumption and carbon footprint
Choosing the right high strength grade directly improves performance, efficiency and lifecycle cost.
Why Choose Sharoff Steel Suppliers for S690QL & S700MC?
• Over six decades of experience in special and high-performance steels
• Supply of plates and sheets with mill test certificates (EN 10204 3.1)
• Cut-to-size supply as per drawing
• Technical guidance on grade selection, welding and forming
• Experience supporting crane, trailer, earthmoving and heavy engineering manufacturers
We don't just supply high strength steel — we help you use it correctly.
Integration with Our Steel Portfolio
S690QL and S700MC fit naturally alongside our other offerings:
• Abrasion resistant plates (SAIL Hard, Hardox, TISCRAL)
• Structural steel sections
• EN 10025 grades such as S355J2W+N
• Alloy steels like EN19 and C45
• MS and chequered plates
This enables single-source procurement for complete machine and structure builds.
Procurement Checklist (For High Strength Steel)
Before placing your order, confirm:
• ✅ Required grade and standard (EN 10025-6 / EN 10149-2)
• ✅ Thickness, width and length
• ✅ Impact test requirement and test temperature
• ✅ Fabrication route (welding, bending, cutting)
• ✅ Inspection and third-party testing needs
• ✅ Documentation & traceability (EN 10204 3.1 / 3.2)
Early material clarity avoids fabrication issues, rejections and delays.
FAQs – S690QL & S700MC
What is the difference between S690QL and S700MC?
S690QL is a quenched and tempered plate for heavy, thick welded structures with guaranteed toughness at –40°C. S700MC is a thermomechanically rolled sheet designed for cold forming in thinner gauges.
Can S690QL and S700MC be welded?
Yes. Both are weldable using low-hydrogen consumables and controlled heat input. S690QL usually needs preheating; S700MC often does not in thin sections.
Is S700MC a replacement for S690QL?
Only in some cases. S700MC suits thin, formed parts, while S690QL is preferred for thick plates and heavy structures. Selection should follow your design specification.
Do you supply cut-to-size material?
Yes. Plates and sheets can be supplied cut to size as per your drawing, along with mill test certificates.
Conclusion
S690QL and S700MC bring 700 MPa-class strength to structures and machines where weight, payload and durability matter. S690QL is the choice for heavy-duty welded structures, and S700MC for lightweight formed components.
At Sharoff Steel Suppliers, high strength steel supply is backed by material expertise, application understanding and complete traceability. Send us your enquiry for current availability and pricing.
