Hot Rolled S690QL1 Steel - High Strength

S690QL1 is a type of high-strength structural steel known for its excellent combination of toughness, weldability, and load-bearing capacity. It is part of a family of quenched and tempered steels designed for demanding applications where heavy loads, dynamic forces, or harsh environmental conditions are present. The material is often used in construction machinery, mining equipment, crane structures, and large industrial components that require reliable performance under stress. Its composition and heat treatment are optimized to provide a balance of strength and ductility, making it suitable for fabrication processes such as welding, cutting, and forming.

Equivalent Grades Of S690QL1 Structural Steel Plate

Chemical Composition for S690QL1 Steel Plate

Mechanical Properties for S690QL1 Steel Plate

S690QL1 Steel Plate Notch Impact Energy

Equivalent Grades Of Grade S690QL1 (1.8988)

Key Processing Aspects

Cutting: Plasma or laser cutting are common, but waterjet cutting is also used.

Bending/Forming: Suitable for cold forming within specified limits, but hot forming may require controlled reheating and slow cooling to avoid cracking.

Welding:

Processes: Standard methods like Shielded Metal Arc (SMAW), Submerged Arc (SAW), and Gas Metal Arc (GMAW) are applicable.

Preheat: Essential to prevent hydrogen cracking; temperatures depend on thickness and joint restraint.

Filler Metals: Low-hydrogen consumables are crucial.

PWHT: Often recommended to reduce residual stresses, but must be carefully controlled (e.g., below 580°C) to avoid tempering too much and losing strength, with specific procedures developed for HSS.

Machining: Can be machined, but high strength requires appropriate tooling and speeds.

Heat Treatment (Manufacturing): The base material is already Q&T, involving heating to 870-930°C, quenching, and tempering at 550-680°C to achieve its specified strength and impact toughness.

Key Advantages

High Strength-to-Weight Ratio: With a minimum yield strength of 690 MPa, it is approximately twice as strong as standard S355 structural steel. This allows engineers to use thinner plates, reducing overall structural weight by up to 30–50% without sacrificing load capacity.

Extreme Cold Resilience: The "QL1" designation guarantees impact toughness at -60°C. This prevents brittle fracture in Arctic environments, offshore rigs, and high-altitude structures.

Cost & Efficiency Gains: Reducing material weight leads to lower transportation, handling, and foundation costs. In mobile machinery, lighter deadweight directly translates to higher payload capacity and improved fuel efficiency.

Superior Weldability & Formability: Despite its high strength, it maintains good weldability using low-hydrogen consumables. It also exhibits excellent bending properties, allowing for complex fabrications.

Primary Applications

Lifting & Heavy Machinery: Used extensively for crane booms, jibs, and lifting arms where high strength and lightness are critical for operational safety.

Offshore & Marine: Ideal for North Sea or Arctic offshore platforms, naval ships, and marine structures exposed to harsh, freezing maritime environments.

Mining & Earthmoving: Essential for high-stress components in excavators, bulldozers, dump truck bodies, and mining cars that must withstand repetitive shock and heavy loads.

Construction & Infrastructure: Applied in long-span bridges, stadiums, and high-rise buildings. Its use in skyscrapers allows for slimmer columns and more usable internal space.

Defense: Utilized in military vehicles and armored units to reduce weight for better agility while maintaining structural integrity.

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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 the minimum yield strength of S690QL1?

The minimum yield strength of S690QL1 is 690 MPa. This high yield strength makes it ideal for structures requiring high load-bearing capacity and resistance to deformation.

What is the tensile strength range of S690QL1?

The tensile strength of S690QL1 ranges from 770 MPa to 940 MPa. This range ensures sufficient strength margin for critical engineering components under various stress conditions.

What is the chemical composition main element of S690QL1?

The main chemical elements of S690QL1 include carbon (C), manganese (Mn), silicon (Si), chromium (Cr), molybdenum (Mo), and nickel (Ni), enhancing its strength and toughness.

 Is S690QL1 weldable?

Yes, S690QL1 is weldable. Proper preheating and post-weld heat treatment are recommended to avoid cold cracking, ensuring weld joint integrity and consistent mechanical performance.

What preheating temperature is needed for S690QL1 welding?

The preheating temperature for S690QL1 welding is typically 80-150°C, depending on plate thickness. Thicker plates may require higher temperatures to reduce welding stress.

What is the difference between S690QL1 and S690QL?

The main difference is impact toughness: S690QL1 has a lower minimum impact energy (30 J at -20°C) than S690QL, making it suitable for less demanding low-temperature applications.

Is S690QL1 magnetic?

Yes, S690QL1 is magnetic. As a ferritic steel, it exhibits ferromagnetic properties, which is important for applications requiring magnetic compatibility.

What is the cost comparison of S690QL1 vs. ordinary steel?

S690QL1 is more expensive than ordinary carbon steel, but its high strength reduces material usage, offsetting costs in weight-sensitive and high-performance applications.

What is the hardness of S690QL1?

The Brinell hardness of S690QL1 is usually 210-260 HBW. This hardness balances strength and machinability, suitable for components needing both durability and processability.