What does S690Q mean?

What does S690Q mean?

S690Q is a designation for a high-strength structural steel (S) with a minimum yield strength of 690 Megapascals (MPa), supplied in a quenched and tempered (Q) condition, meeting European standard EN 10025-6. This steel offers excellent strength, good weldability, and toughness, making it ideal for heavy equipment, cranes, offshore structures, and bridges.

Due to its high tensile strength, S690Q is widely utilized in heavy-duty industries where structural integrity is critical. It is a preferred material for the manufacturing of crane booms, offshore structures, mining equipment, and bridges. It is also extensively used in the production of heavy vehicle chassis and pressure vessels, where the ability to withstand high stress and extreme pressure is essential for operational safety and longevity.

Key Characteristics:

S: Stands for Structural Steel.

690: Indicates a minimum yield strength of 690 MPa for thicknesses up to 50mm.

Q: Signifies it's delivered in the Quenched and Tempered state, a heat treatment process that significantly increases hardness and strength.

Properties:

High Strength: Provides superior load-bearing capacity compared to conventional steels.

Good Toughness: Retains impact resistance even at low temperatures (e.g., -20°C for S690Q).

Weldability: Generally considered reasonably weldable, though specific considerations apply.

Applications:

-Heavy construction equipment

-Bridges and trestles

-Crane components

-Offshore structures (rigs, wind turbines)

-High-rise buildings and industrial structures

Variants:

S690QL & S690QL1: Similar grades with even lower minimum impact temperatures (-40°C for QL, -60°C for QL1).

In essence, S690Q offers a fantastic strength-to-weight ratio, allowing for lighter, more efficient designs in demanding engineering applications.

Is S690Q carbon steel?

Yes, S690Q is a type of high-strength low-alloy (HSLA) steel, often described as a high-strength carbon steel or low-alloy steel, known for its exceptional yield strength (690 MPa) achieved through quenching and tempering, making it ideal for heavy engineering where strength-to-weight ratio is critical, like in bridges, cranes, and mining equipment.

What are common testing requirements for S690Q ?

Common testing for S690Q steel, governed by EN 10025-6, includes tensile testing (yield & tensile strength, elongation) and Charpy V-notch impact testing (typically at -20°C for 30 Joules minimum). Other essential tests are heat analysis, with optional ultrasonic testing (UT) and product analysis, all requiring a mill test certificate (EN 10204 3.1/3.2).

What is the hardness of S690Q ?

The hardness of S690Q steel varies slightly with thickness but generally falls within the range of 210 to 278 Brinell Hardness (HB), with thicker plates having slightly lower minimum hardness values (e.g., 228-278 HB for ≤50mm, 210-266 HB for >100mm) due to the quenching and tempering process. It's an ultra-high-strength steel known for its excellent strength-to-weight ratio, not extreme hardness, but rather its tough, fine-grained microstructure.

Equivalent grades of steel S690Q (1.8931)

Mechanical properties of S690Q steel

1What are the typical application fields of S690Q ?

S690Q is a high-strength structural steel used in heavy-duty applications requiring excellent strength-to-weight ratios, such as cranes, bridges, offshore platforms, heavy machinery, wind turbine supports, and high-rise buildings, allowing for lighter, more efficient, and durable designs in construction, mining, and transportation. Its key benefit is enabling lighter structures that can handle extreme loads and dynamic stresses, reducing material use and improving fuel efficiency in transport.

2What is the difference between S690Q and S690QL1?

The main difference is their low-temperature impact toughness requirement: S690Q is tested at -20°C, S690QL at -40°C, and S690QL1 is the most demanding, certified for impact toughness at -60°C, making it suitable for colder, more extreme applications. All are high-yield strength, quenched and tempered structural steels (EN 10025-6), sharing the same minimum 690 MPa yield strength, but the 'L' and 'L1' indicate progressively lower impact energy thresholds at colder temperatures.

3What is the difference between S690Q and S690QL?

The main difference between S690Q and S690QL steel lies in their low-temperature impact toughness requirements: S690Q is tested to 30 Joules (J) at -20°C, while S690QL is tested to higher toughness, typically ≥40J at -40°C, indicating superior performance in colder conditions, making S690QL suitable for more extreme cold environments like cranes or offshore structures. Both are high-strength, quenched & tempered (Q&T) steels with a minimum yield strength of 690 MPa (hence the '690'), but the 'L' signifies "Low Temperature" toughness.

4What is S690Q equivalent to?

S690Q is a European high-strength structural steel (EN 10025-6) with a 690 MPa yield strength, and its equivalents include ASTM A709 Grade 100, German TStE690V/DILLIMAX 690, Swedish WELDOX 700, French E690T, and ISO E690, all representing similar quenched and tempered (Q&T) steels for heavy-duty applications, though specific properties like low-temp impact testing (e.g., S690QL tested at -40°C) can vary slightly between standards.

5What is the yield strength of S690Q?

The yield strength of S690Q steel is a minimum of 690 MPa (MegaPascals) for thicknesses up to 50mm, decreasing slightly for thicker plates (e.g., 650 MPa for 50-100mm), as it's a quenched and tempered high-strength structural steel designed for applications with heavy loads, providing excellent load-bearing capacity.

6What is S690Q Steel material?

S690Q steel is a high-yield-strength, quenched, and tempered structural steel (EN 10025-6 standard) known for exceptional strength, toughness, and durability, used in heavy machinery, construction (cranes, bridges), and lifting equipment where high strength-to-weight ratio is crucial, offering superior performance and efficiency in demanding applications.

7What temperature is S690Q ?

S690Q is a high-strength, quenched and tempered (Q+T) structural steel, and its "temperature" typically refers to two critical values: it is tested for impact toughness at a minimum of -20°C (where it must maintain an energy absorption of at least 30J), and its mechanical properties are generally guaranteed for service up to approximately 580°C, beyond which it may lose significant yield strength.

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If you have project requirements for S690Q, we welcome your inquiry. GNEE maintains a large inventory of commonly used high strength steel grades for your selection.For detailed mechanical properties, chemical composition, and technical data, as well as free samples, please contact our factory immediately. We offer competitive prices, stable quality, and professional service. Email:info@gneesteels.com