S690QL is a high-strength, quenched and tempered structural steel. It is renowned for its impressive tensile strength and toughness, making it suitable for heavy-duty applications. The "S" stands for structural steel, "690" represents the minimum yield strength in megapascals (MPa), and "QL" indicates the material is of high quality, with excellent low-temperature toughness.
S690QL steel plates are high-strength, quench-and-tempered structural steels for applications requiring superior mechanical properties. They have a minimum yield strength of 690MPa and exhibit good weldability and formability compared to conventional mild steel grades. The higher yield strength and excellent toughness make them well-suited for general fabrication and load-bearing components in construction sites where they can be subjected to considerable stresses. Additionally, these plates exhibit excellent corrosion resistance due to what is known as their 'weathering' grade characteristics, which allow them to withstand exposure to harsh weather conditions such as rain, snow and fog without losing their integrity or showing signs of degradation. Overall, they provide great value for money by simultaneously being incredibly strong yet cost-effective!
S690QL - Chemical Composition
| Element | Percentage % | Element | Percentage % |
| C | 0.20 | Cu | 0.50 |
| Si | 0.80 | Mo | 0.70 |
| Mn | 1.70 | Nb* | 0.06 |
| P | 0.025 | Ni | 2.0 |
| S | 0.015 | Ti* | 0.05 |
| N | 0.015 | V* | 0.12 |
| B | 0.0050 | Zr* | 0.15 |
| Cr | 1.50 |
S690QL - Mechanical Properties
| Designation | Mechanical Properties (ambient temperature) | |||||||
| Steel Name | Steel Number | Min. Yield Strength Reh MPa | Tensile Strength Rm MPa | Min. % elongation after fracture | ||||
| Nominal thickness (mm) | Nominal thickness (mm) | |||||||
| ≥3 ≤50 | ≥50 ≤100 | ≥100 ≤150 | ≥3 ≤50 | ≥50 ≤100 | ≥100 ≤150 | |||
| S690QL | 1.8931 | 690 | 650 | 630 | 770/940 | 760/930 | 710/900 | 14 |
S690QL - V Notch Impact Testing
| Grade | Sample Orientation | @ 0°C | @-20°C | @-40°C | @-60°C |
| S690QL | Longitudinal | 50 J | 40 J | 30 J | ¨C¨C |
| Traverse | 35 J | 30 J | 27 J | ¨C¨C |
Key Application Areas
Heavy Transportation
S690QL is widely used in bulldozers, dump trucks, articulated haulers, trailer frames, and special vehicles. Its high strength allows designers to reduce plate thickness while maintaining structural integrity, which in turn lowers vehicle weight, increases payload capacity, and improves fuel efficiency. This makes it especially valuable in long-haul and off-road transportation where every kilogram saved directly translates into better performance and lower operating costs.
Lifting & Construction Equipment
The steel is a preferred choice for crane booms, jibs, forklift frames, hydraulic arms, and support structures for large industrial machinery. Its combination of high yield strength and good toughness ensures reliable performance under dynamic and cyclic loads, while its reduced weight helps improve lifting capacity and maneuverability. These characteristics are essential in construction sites where equipment must operate safely and efficiently under heavy loads and harsh conditions.
Steel Structures
In civil engineering, S690QL is used for key components in bridges, high-rise buildings, stadiums, and offshore platforms. Its high strength enables engineers to design structures with fewer supports and longer spans, resulting in more open and flexible spaces. This not only reduces the overall weight of the structure but also lowers material and construction costs, making it an economical solution for large-scale projects.
Machine Building
S690QL is commonly employed in the manufacturing of frames and structural parts for industrial machinery that requires high fatigue and stress resistance. Its ability to withstand repeated loading and harsh operating environments ensures the durability and reliability of the equipment, reducing maintenance needs and extending service life. This makes it suitable for a wide range of applications, from heavy-duty production machinery to precision industrial systems.
Mining & Power
The steel is also used in mining equipment, power plant structures, and certain types of pressure vessels. Its high strength and toughness make it well-suited for withstanding the extreme conditions found in mining operations and power generation facilities, where equipment is exposed to heavy impacts, abrasive materials, and high-pressure environments. This reliability is crucial for ensuring the safety and efficiency of these critical infrastructure systems.
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.
What is equivalent to S690QL steel?
ASTM A514, EN 10149-2 Grade S700MC, AS/NZS 3579 Grade 700, AM 700, Bisalloy 80.
What grade is S690QL material?
S690QL is a high strength quenched and tempered steel grade that complies to steel specification EN 10025. The designation S690QL refers to a minimum yield strength of 690 MPa.
What grade of steel is S690?
S690 QL is a high yield structural steel grade produced in compliance with EN 10025:6:2004. The material is heat treated using the quench and temper process and has good bending and welding properties.
What is the difference between S690Q and S690QL?
S690Q: Minimum impact toughness tested at -20°C (30J average). → Typical Use: Cranes in temperate climates, quarry equipment. S690QL: Certified for -40°C and below (≥40J impact toughness). → Critical Use: Arctic pipelines, offshore platforms, mining vehicles in Siberia.
What is the price of S690ql?
₹ 130/KgS690 QL plate is a high-strength, quenched, and tempered steel plate designed for use in structural applications that require high strength and excellent toughness.
How does the cost of using S690QL compare to using thicker sections of lower-strength steel?
While S690QL has a higher material cost per unit weight, its high strength allows the use of thinner sections, which can lead to overall cost savings in fabrication, transportation, and assembly for weight-sensitive structures.
Why is preheating often required when welding S690QL?
Preheating is often required to reduce the cooling rate in the heat-affected zone (HAZ), thereby minimizing the risk of hardening and cold cracking, especially in thicker sections or when using high-hydrogen welding processes.
What are common applications of S690QL?
S690QL is commonly used in heavy lifting equipment (e.g., crane booms), offshore structures, mining machinery, hydraulic supports, and other weight-sensitive or high-load structural components.
How does S690QL compare to S690Q?
S690QL has improved low-temperature toughness compared to S690Q. The "L" designation signifies better impact properties at lower temperatures, making S690QL more suitable for cold environments.
How does S690QL compare to S355JR?
S690QL has a much higher yield strength than S355JR (690 MPa vs. around 355 MPa), allowing for significant weight reduction in structures, but it requires more careful welding and forming due to its higher strength and lower ductility.