EN 10025-6 · High yield strength

S690 QL Plate 690 MPa strength

High yield strength structural steel according to EN 10025-6. Reduce the weight of your structures by up to 40% while maintaining the same load capacity. Stock available 4-80 mm.

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Certificate 3.1
Technical advice
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S690 QL Specifications
Yield strength (ReH) ≥ 690 MPa
Tensile strength (Rm) 770-940 MPa
Elongation (A5) ≥ 14%
Charpy test 30 J @ -40°C
Stock thicknesses 4 - 80 mm
Formats 2000×6000 / 2500×8000
Certification EN 10204 3.1
Equivalents Strenx 700, Weldox 700
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⚠️ PWHT Prohibited on S690 QL

Post-weld heat treatment destroys the mechanical properties of quenched and tempered steel.

!
DO NOT APPLY PWHT - Risk of property destruction

Post-weld heat treatment (PWHT) is STRICTLY PROHIBITED on S690 QL steels. Applying PWHT at 550-650°C causes over-tempering of the material, reducing the yield strength from 690 MPa to ~355 MPa, completely invalidating the purpose of using high-strength steel. Design joints so that PWHT is not required.

Effect of PWHT on mechanical properties

Parameter Original S690 QL After PWHT Variation
Yield strength (MPa) ≥690 ~350-400 ↓ -48%
Tensile strength (MPa) 770-940 ~500-550 ↓ -35%
Hardness (HV10) 250-320 ~180-220 ↓ -30%
Microstructure Quenched + Tempered (QT) Ferrite + Pearlite Destroyed

Mechanical properties S690 QL

Values according to EN 10025-6 for thicknesses ≤50 mm. Please consult for greater thicknesses.

Property Value Unit
Yield strength (ReH) ≥690 MPa
Tensile strength (Rm) 770 - 940 MPa
Elongation (A5) ≥14 %
Charpy V-notch impact energy (KV) ≥30 at -40°C J
Brinell hardness (HBW) 250 - 320 -

Welding guide S690 QL

Recommended parameters to maintain the mechanical properties of the material.

Recommended welding parameters

Parameter Recommendation Notes
Heat input 0.5 - 2.0 kJ/mm Never exceed 2.5 kJ/mm
Interpass temperature 100 - 150°C max. Measure with IR thermometer
MMA electrodes AWS E11018-G Dry at 350°C before use
MIG/MAG wire AWS ER110S-G Gas Ar/CO2 82/18
TIG wire AWS ER110S-G Argon gas shielding
PWHT PROHIBITED Destroys QT properties

Formats

Thickness (mm) Available formats Availability
6 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
8 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
10 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
12 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
15 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
20 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
25 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
30 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
40 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
50 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
60 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
70 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
80 2.000×6.000–12.000 / 2.500×6.000–12.000 ✓ Immediate
100 2.500×length on request → On request
120 2.500×length on request → On request
150 2.500×length on request → On request

Where is S690 QL used?

Industrial applications where weight reduction is critical for performance.

🏗️

Cranes and lifting equipment

Extendable booms, counterweights, load-bearing structures. Weight reduction that enables greater reach and capacity.

✓ Up to 35% less weight
🚛

Heavy industrial vehicles

Dump trucks, excavator buckets, aerial work platforms. Higher payload with lighter chassis.

✓ +15% payload
⛏️

Mining equipment

Chassis of haul trucks, machinery components. Resistance to wear and fatigue.

✓ Extended service life
🌉

Mobile and military bridges

Folding structures, Bailey bridges, military engineering components. Fast transport and assembly.

✓ Rapid deployment
🚜

Agricultural machinery

Combine harvester components, high-power tractors, heavy-duty agricultural trailers.

✓ Higher productivity

Sectors using S690 QL

Industries where weight reduction is a critical design factor.

🏗️
Construction
🚛
Transport
⛏️
Mining
⚙️
Machinery
🌉
Infrastructure
🚜
Agriculture
🛡️
Defense

Frequently asked questions

Detailed technical answers for engineers and buyers about S690 QL plate.

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S690 QL plate is a high yield strength structural steel (690 MPa) standardized according to EN 10025-6. Its main advantages include: structural weight reduction of up to 40% compared to S355 steels, higher load capacity with smaller thicknesses, excellent toughness at low temperatures (impact energy ≥30 J at -40°C), guaranteed weldability with quenching and tempering heat treatment (QT), and certification for demanding applications such as cranes and heavy industrial vehicles.
Post-weld heat treatment (PWHT) is strictly prohibited on S690 QL steels because it destroys the optimized quenched and tempered (QT) microstructure that gives it its exceptional mechanical properties. Applying PWHT (generally 550-650°C) causes over-tempering of the material, drastically reducing the yield strength from 690 MPa to values close to 355 MPa, similar to an S355 steel. This completely invalidates the purpose of using high-strength steel and compromises structural safety.
For welding S690 QL, consumables that provide mechanical properties equivalent to or higher than the heat-affected zone (HAZ) are recommended. Covered electrodes: AWS E11018-G (yield strength ~760 MPa). MIG/MAG wires: AWS ER110S-G or equivalents with tensile strength ≥780 MPa. TIG wires: AWS ER110S-G. Recommended processes: MAG with mixed argon-CO2 gas shielding (82% Ar / 18% CO2) or pure CO2 with metal-cored wires. It is essential to keep the heat input between 0.5-2.0 kJ/mm to preserve the properties of the material.
The weight reduction depends on the type of structural loading. For elements subject to pure tension, the savings can reach 40% (going from 20 mm S355 to 12 mm S690). In bending, the typical savings is 25-30% due to the quadratic dependence of the section modulus on thickness. In compression with buckling, the savings is reduced to 15-20% because the moment of inertia depends on the cube of the thickness. Our interactive calculator allows you to determine exactly the weight savings for your specific application, taking into account the type of load and boundary conditions.
Mayor Steel maintains permanent stock of S690 QL plate in thicknesses from 4 mm to 80 mm, with standard widths of 2000 mm and 2500 mm, and lengths of 6000 mm, 8000 mm and 12000 mm. The most in-demand thicknesses (8, 10, 12, 15, 20, 25, 30, 40, 50 mm) have immediate availability with delivery in 24-48 hours. For special thicknesses or custom dimensions, the lead time is 5-10 business days via factory order. All plates are supplied with a 3.1 quality certificate according to EN 10204.
S690 QL is used in applications where the strength-to-weight ratio is critical: mobile cranes and towers (weight reduction in booms and counterweights), offshore platforms and marine structures (resistance to extreme loads with less weight), heavy industrial vehicles (dump trucks, excavator buckets, aerial work platforms), mining equipment (chassis of haul trucks, machinery components), mobile and military bridge structures, high-strength containers and tanks, and components of heavy-tonnage agricultural machinery. The ability to reduce weight maintains or increases the useful load capacity.

Need S690 QL plate?

Stock available. Certified to EN 10025-6. Delivery to destination.

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S690 QL Plate: High Yield Strength Steel for High-Performance Structures

The S690 QL plate represents the cutting edge in high-strength structural steels, offering a yield strength of 690 MPa that allows for the design of significantly lighter structures without compromising load capacity. Standardized according to the European standard EN 10025-6, this quenched and tempered (QT) steel combines exceptional mechanical strength with excellent toughness at low temperatures, making it ideal for demanding applications in sectors such as machinery construction, lifting equipment and heavy industrial vehicles.

Competitive advantages of S690 QL

The main advantage of using S690 QL over conventional structural steels such as S355 is the dramatic reduction in structural weight, which can reach up to 40% in elements subjected to pure tension. This reduction translates into multiple benefits: lower fuel consumption in vehicles, higher useful load capacity, lower foundation costs in fixed structures, and easier transport and assembly. In addition, the quenching and tempering heat treatment ensures a homogeneous microstructure with consistent mechanical properties throughout the section.

Critical welding considerations

A fundamental aspect when working with S690 QL is strict control of the welding process. The heat input must be kept between 0.5 and 2.0 kJ/mm to preserve the mechanical properties of the heat-affected zone. It is absolutely critical to remember that post-weld heat treatment (PWHT) is prohibited on this steel, as it would destroy the QT microstructure and reduce the yield strength to S355 steel levels. Welding consumables must provide equivalent properties, with AWS E11018-G electrodes or ER110S-G wires being recommended.

Stock and availability at Mayor Steel

At Mayor Steel we maintain permanent stock of S690 QL plate in thicknesses from 4 mm to 80 mm, with the standard formats most in demand by the industry. Fast-moving thicknesses (8, 10, 12, 15, 20, 25, 30, 40, 50 mm) are available for immediate delivery within 24-48 hours throughout the Iberian Peninsula. All plates are supplied with a 3.1 quality certificate according to EN 10204, guaranteeing traceability and compliance with applicable regulations.

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