Q690C high-strength structural steel is a low-alloy, high-strength structural steel that complies with Chinese GB standards. It is broadly equivalent to the European S690Q/S690QL, the American ASTM A514 (Grade Q/T-1), and the international E690 standards. As a quenched and tempered low-alloy steel, it is suitable for applications subject to heavy loads, such as machinery, lifting equipment, and bridges.
What Is Q690C High-Strength Structural Steel?
Q690C high-strength structural steel is a low-alloy, high-strength structural steel plate compliant with Chinese standards, featuring a minimum yield strength of 690 MPa. Specifically engineered for heavy-duty applications, this steel plate is ideally suited for environments demanding exceptional durability, toughness, and weldability. It is currently widely utilized in heavy machinery, bridges, and crane structures, contributing to the realization of lighter-weight and more efficient designs.
Chemical Composition of Q690C High-Strength Structural Steel
| Material | C | Si | Mn | P | S | Nb | V | Ti | Cr | Ni | Cu | N | Mo | B | Al |
| Q690C | ≤ 0.18 | ≤ 0.60 | ≤ 2.00 | ≤0.030 | ≤0.030 | ≤ 0.11 | ≤ 0.12 | ≤ 0.20 | ≤ 1.00 | ≤ 0.80 | ≤ 0.80 | ≤ 0.015 | ≤ 0.30 | ≤ 0.004 | ≥ 0.015 |
Mechanical Properties of Q690C High-Strength Structural Steel
| Property | Value |
|---|---|
| Yield Strength | ≥ 690MPa (Thickness< 63mm) |
| Tensile Strength | 730–940MPa |
| Elongation | ≥ 14% |
| Impact Temperature | - 20°C |
| Impact Energy | ≥ 31 J(Typically) |
What Is Q690C High-Strength Structural Steel Equivalent to?
Q690C high-strength structural steel is a material compliant with Chinese GB standards; its properties are equivalent to those of the European S690Q/S690QL, the American ASTM A514 (specifically Grade Q or T-1), and other similar steel grades possessing a yield strength of 690 MPa.
Primary International Equivalents:
European (EN): S690Q, S690QL, S690QL1.
American (ASTM): A514 Grade Q, A709 Grade 100.
International (ISO): E690.
Swedish: Weldox 700.
Japanese: JIS SM570.
Other: Bisalloy 80, S700MC.
Primary Applications of Q690C High-Strength Structural Steel
Construction Machinery and Lifting Equipment: Used in the manufacture of structural components for heavy-duty equipment that are required to withstand immense loads,such as crane booms, mining machinery, hydraulic supports, cranes, and concrete pump trucks.
Energy and Chemical Engineering: Widely utilized in offshore engineering applications as well as in oil and natural gas transmission pipelines,including offshore drilling rigs, oil production platforms, wind turbine towers, pressure vessels, and marine storage tanks.
Building and Bridge Structures: Employed in steel structures for high-rise buildings, large-span bridges, and sports stadiums where it is necessary to reduce structural self-weight while simultaneously increasing span length or load-bearing capacity.
Specialized Transport Vehicles: Used for the skeletal frameworks and load-bearing components of lightweight logistics vehicles and specialized transport vehicles.
The Heat-Treatment of Q690C High-Strength Structural Steel
Q690C high-strength structural steel is a high-strength low-alloy (HSLA) steel with a minimum yield strength of 690 MPa; heat treatment is crucial for fully realizing its exceptional strength and toughness. This steel grade is typically produced using either the thermomechanical control process (TMCP) or the quenching and tempering (QT) process.
Key Heat Treatment Processes for Q690C High-Strength Structural Steel
Quenching and Tempering (Q&T): The standard production process involves an austenitizing treatment (typically around 900–930°C), followed by water or oil quenching to achieve a martensitic structure, and immediately succeeded by a tempering treatment aimed at enhancing the toughness of the Q690C steel.
Quenching-Partitioning-Tempering (Q-P-T) Process: An efficient, modern heat treatment technique. In this process, the Q690C steel is heated to 930°C and held at that temperature for 30 minutes, followed by oil quenching (e.g., for a duration of 60 seconds), and immediately enters a specialized tempering/partitioning stage, thereby forming a complex composite microstructure consisting of martensite and retained austenite.
Performance Optimization: Following treatment via the Q-P-T process, Q690C steel achieves a yield strength of approximately 1112.5 MPa and a tensile strength of 1285.9 MPa. Furthermore, it exhibits high surface hardness (approximately 39 HRC), with its overall performance significantly surpassing that of steel treated via the standard quenching process.
If you require further details regarding Q690C high-strength structural steel, please do not hesitate to contact us.
As a leading manufacturer of Q690C high-strength structural steel in China, GNEE boasts over 20 years of extensive industry experience. Our warehouses maintain a standing inventory of over 50,000 tons year-round, ensuring that orders can be shipped in as little as seven days. In terms of quality assurance, we are a dual-certified supplier-holding both API and ISO certifications-and we welcome inspections by third-party agencies such as SGS, BV, and Lloyd's.
By choosing our Q690C high-strength structural steel products, you will benefit from our comprehensive, customer-centric support services, as well as our extensive value-added processing capabilities. We would be delighted to provide full-scale support and assistance for your project.
Contact now to get Q690C high-strength structural steel
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Product Name |
High strength steel plate Q690C |
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Length |
4m-12m or as required |
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Width |
0.6m-3m or as required |
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Thickness |
3mm-300mm or as required |
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Standard |
AISI,ASTM,DIN,JIS,GB,JIS,SUS,EN,etc. |
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Technique |
Hot rolled |
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Surface Treatment |
Clean, blasting and painting according to customer requirement |
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Thickness tolerance |
±0.1mm |
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Material |
Q690C |
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Application |
It is mainly used to make structural parts such as car girder, beam, transmission shaft and car chassis parts, which can reduce the weight of the parts. |
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MOQ |
25tons.We also can accept sample order. |
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Shipment time |
Within 15-20 workdays after receiving deposit or L/C |
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Export packing |
Waterproof paper, and steel strip packed. |
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Capacity |
250,000 tons/year |
Can Q690C be used for wear-resistant applications?
While Q690C is harder than standard steel (approx. 220-260 HBW), it is not a dedicated wear-resistant steel. If your primary concern is abrasion, you should use dedicated wear plates like Hardox 400/450 or NM400/450. Q690C is designed for structural load-bearing.
What is the difference between Q690C and Q690D?
The only difference is the impact testing temperature:
Q690C: Tested at 0°C.
Q690D: Tested at -20°C.
Q690E: Tested at -40°C.
If your project is in a very cold environment (like Northern Europe or Canada), Q690D or E is preferred over Q690C to prevent brittle fracture.
What exactly does the name "Q690C" stand for?
The name follows the Chinese National Standard GB/T 1591:
Q: Stands for Qingfu (Yield Strength).
690: Represents the minimum yield strength of 690 MPa (for plate thickness≤16mm).
C: Indicates the quality grade based on impact toughness. Grade "C" means the steel undergoes a Charpy V-notch impact test at 0°C.