EN 10025-2 S690Q Sheet and Plates

EN 10025-2 S690Q sheet and plates are high-strength structural steel with the composition of carbon, manganese, chromium, and molybdenum, providing excellent weldability and toughness. These plates have superior resistance to impact, fatigue, and wear. The key benefits are better durability, light construction, and less material consumption, which makes them ideal for construction, bridges, cranes, and industrial machinery under heavy loads.

S: Stands for Structural Steel, indicating that the steel plate is mainly used for structural applications.

690: Represents its yield strength grade of 690MPa, which is an important indicator of the steel plate's strength.

Q: Indicates that the steel plate has excellent impact toughness (Quenched and Tempered), meaning it can maintain good performance under impact loads.

High strength: The yield strength of S690Q high yield structural steel plate is as high as 690MPa, and some products can even reach more than 650MPa, showing extremely high load-bearing capacity. Its tensile strength is generally between 770~940MPa, ensuring stability under high-stress environments.

High toughness: S690Q alloy structural steel plate not only has high strength but also good toughness. It can effectively absorb energy when bearing heavy loads and impacts, reducing the risk of brittle fracture. Its impact toughness performs well at different temperatures: for example, at -20℃, the impact toughness value is greater than 30J (some data show greater than 34J); at -40℃ (some sources say -60℃), the impact toughness value is greater than 27J.

Low-temperature resistance: S690Q high-strength structural steel can maintain good toughness and strength in low-temperature environments, without significant degradation due to temperature drop, making it suitable for use in cold regions.

Fatigue resistance: S690Q fine grain structural steel plate has good fatigue resistance, capable of withstanding repeated stress cycles, reducing the generation of fatigue cracks, thereby extending the service life of the structure.

Corrosion resistance: After special anti-corrosion treatment, S690Q steel plate exhibits good corrosion resistance, able to resist oxidation and corrosion, further improving its service life.

Excellent weldability: S690Q alloy quality steel plate can be connected and fixed with other steels or structures through various welding methods, facilitating construction and use.

The production process of S690Q alloy special steel plate is a complex and sophisticated process, mainly including the following steps:

1. Raw Material Preparation

Raw material selection: Scrap steel, pig iron, molten iron, etc., are mainly used as raw materials. These raw materials need to undergo strict screening and proportioning to ensure their quality and chemical composition meet production requirements.

2. Smelting and Refining

Electric arc furnace smelting: Raw materials are put into an electric arc furnace for smelting to remove impurities and adjust the chemical composition. This step is crucial for producing high-quality steel plates.

Converter refining: The molten steel after electric arc furnace smelting enters a converter for further refining to remove more impurities and improve the purity of the molten steel.

LF furnace refining: The molten steel undergoes LF furnace refining to further adjust the composition and remove impurities.

VD or VOD furnace vacuum treatment: The molten steel is subjected to vacuum treatment to remove gases and inclusions, improving the quality and purity of the molten steel.

3. Continuous Casting or Ingot Casting

Continuous casting: The refined molten steel is poured into a continuous caster, forming billets of a certain shape and size through cooling and solidification. Continuous casters are usually large slab casters capable of producing large-sized billets.

Ingot casting: For billets of certain special shapes, the ingot casting process can be adopted. This process requires pouring the refined molten steel into molds, forming billets of the desired shape through cooling and solidification.

4. Heating and Rolling

Heating treatment: Billets are subjected to heating treatment to eliminate internal stress and improve rolling performance. Heating is usually carried out in continuous furnaces and soaking furnaces.

Rolling: Through multiple passes of rolling and temperature adjustment, the steel plate is gradually formed to obtain the required thickness and size. Rolling is usually performed on large rolling mills, such as 4100mm and 4200mm rolling mills.

5. Heat Treatment

Quenching: The rolled steel plate is quenched to improve its hardness and strength. During quenching, the temperature and cooling rate need to be strictly controlled to ensure the steel plate's performance meets requirements.

Tempering: The quenched steel plate is tempered to eliminate quenching stress and improve toughness. The tempering temperature and time need to be determined according to the specific performance and purpose of the steel plate.

6. Surface Treatment and Quality Inspection

Polishing: The steel plate is polished to improve its surface finish and appearance. This step is particularly important for steel plates exposed to the outside.

Coating: The steel plate is coated to enhance its corrosion resistance and service life. The selection of coating materials needs to be determined according to the steel plate's service environment and requirements.

Chemical composition testing: The chemical composition of the finished steel plate is tested to ensure it meets production requirements. This step is key to ensuring steel plate quality.

Mechanical property testing: Mechanical properties such as yield strength, tensile strength, elongation, and impact toughness of the finished steel plate are tested. These performance indicators are important for measuring steel plate quality.

Appearance inspection: The appearance of the finished steel plate is inspected to ensure no defects such as cracks or inclusions on the surface. This step helps identify potential problems during production.

Dimensional inspection: The dimensions of the finished steel plate are inspected to ensure they meet design requirements. This step is crucial for ensuring the accuracy and assembly performance of the steel plate.

Heavy-load engineering: High-rise buildings, long-span bridges, heavy machinery (cranes, excavators, mining equipment), special vehicles (heavy-duty trucks, high-speed trains).

Energy and marine engineering: Oil drilling platforms, storage tanks, oil refining equipment, offshore platform racks, ship decks/cabin walls, wind turbine towers.

Extreme environments: Polar engineering, deep-sea development, chemical reactors, power plant boiler components, adapting to high-corrosion, high-stress, and low-temperature environments.

Special fields: Military equipment, aerospace (e.g., aircraft landing gear), nuclear energy facilities, mining hydraulic supports.

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