What temperature is S690Q ?

What 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.

S690Q steel is a high-yield-strength, fine-grained structural steel, standardized under European Norm (EN) 10025-6, known for its excellent strength, toughness, and weldability, achieved through a quenching and tempering (Q+T) heat treatment. The "S" denotes structural, "690" is the minimum yield strength in MPa, and "Q" signifies the Q+T condition, making it ideal for heavy machinery, bridges, cranes, and mining equipment requiring weight savings and high load capacity.

Key Characteristics

High Strength: Minimum yield strength of 690 MPa, with tensile strength typically between 770-940 MPa, enabling lighter structures.

Toughness: Excellent low-temperature impact toughness, often tested at -20°C, ensuring performance in cold conditions.

Fine-Grained: A fine-grained microstructure enhances its mechanical properties.

Weldability: Good weldability when proper procedures, including preheating for thicker plates, are followed.

Applications: Heavy construction equipment, cranes, bridges, offshore structures, mining machinery, and power shovels.

Designation Breakdown (EN 10025-6)

S: Structural Steel.

690: Minimum yield strength in Megapascals (MPa).

Q: Quenched and Tempered condition.

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 precautions should be taken when welding S690Q ?

When welding S690Q high-strength steel, key precautions include using low-hydrogen consumables, controlling heat input to prevent HAZ softening and cracking, implementing appropriate preheating (especially for thicker plates) based on thickness and carbon equivalent, ensuring thorough joint cleaning, and managing post-weld cooling to avoid hydrogen-induced cracking and maintain mechanical properties, alongside standard PPE and ventilation.

What is the difference between S690Q and S690QL?

The main difference between S690Q and S690QL steel is their specified low-temperature impact toughness, with S690QL offering superior toughness at much colder temperatures (e.g., -40°C or lower with higher energy) compared to S690Q (typically -20°C). Both are high-strength, quenched and tempered steels with a minimum yield strength of 690 MPa, but the 'L' in S690QL signifies improved low-temperature performance for demanding applications like heavy machinery or cold-climate structures.

Mechanical properties of S690Q steel

Equivalent grades of steel S690Q (1.8931)

1What 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.

2What is the machinability of S690Q?

S690Q machinability is challenging due to its high strength (690 MPa yield) and hardness, requiring slower speeds, rigid setups, and sharp, robust tooling (carbide/ceramic) with ample coolant to manage heat and tool wear, often rated lower than standard steels, but it's fabricable with careful process control for its demanding applications in heavy equipment and structures, 

3What 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.

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 are the properties of S690q material?

S690Q is a high-strength, fine-grain structural steel (EN 10025-6) known for its minimum yield strength of 690 MPa, achieved through quenching and tempering, offering excellent load-bearing capacity, good weldability (with precautions), superior toughness, and formability, making it ideal for heavy machinery, cranes, bridges, and offshore structures. Its properties include high strength-to-weight ratio, low-temperature performance, and resistance to cracking, enabling leaner, more efficient designs.

6What is the difference between s690q and hardox 400 ?

S690Q is a high-strength structural steel (minimum yield strength 690 MPa) for load-bearing structures, while Hardox 400 is a wear-resistant steel (around 400 HBW hardness) primarily for abrasion, with S690Q focusing on strength and Hardox 400 on durability against wear, though Hardox offers some strength too. The key difference is their intended application: S690Q for structural strength  and Hardox 400 for abrasion resistance 

7What is the yield strength of S690q?

S690Q steel has a nominal minimum yield strength of 690 MPa, but this value decreases as plate thickness increases, dropping to 650 MPa for thicknesses over 50mm and 630 MPa for thicknesses over 100mm, as per EN 10025-6 standards, which specifies quenched and tempered structural steel for heavy loads.

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