P690Q is a high-strength quenched and tempered alloy structural steel. It has excellent mechanical properties, including high tensile strength and toughness, widely used in heavy machinery, engineering structures and other fields requiring high load-bearing capacity.
P690Q Steel Specifications
P690Q is a high yield strength structural steel primarily used in demanding industrial applications where excellent weldability and performance under pressure are required.
Standard: EN 10028-6
Application: Used for building boilers, pressure vessels, reactors, heat exchangers, separators, and storage tanks in industries like petroleum, chemical, and power generation.
Mechanical Properties: The grade designation "690Q" indicates a minimum yield strength of 690 MPa for plates up to 50mm thick.
Heat Treatment: It is produced as a quenched and tempered steel.
Related Grades: Other quality levels in the standard include P690QH, P690QL1, and P690QL2, which specify different low-temperature impact test requirements (e.g., QL2 is tested at -60°C).
Mechnical property for P690Q steel plate:
| Thickness (mm) | |||
| P690Q | ≤ 50 | > 50 ≤ 100 | > 100 |
| Yield strength (≥Mpa) | 690 | 670 | 630 |
| ≤ 100 | > 100 | ||
| Tensile strength (Mpa) | 770-940 | 720-900 | |
Chemical composition for P690Q steel plate
| Main chemical elements composition of P690Q steel plate | |||||||
| C | Si | Mn | P | S | B | N | Cr |
| 0.20 | 0.80 | 1.70 | 0.025 | 0.015 | 0.005 | 0.015 | 1.50 |
| Cu | Mo | Nb | Ni | Ti | V | Zr | |
| 0.30 | 0.70 | 0.06 | 2.50 | 0.05 | 0.12 | 0.15 | |
advantages
• High Strength:
P690Q provides excellent yield and tensile strength, allowing designers to reduce material thickness while maintaining structural integrity. This results in lighter components and lower overall weight, which is particularly beneficial for pressure vessels, boilers, and heavy machinery.
• Good Toughness at Low Temperatures:
The steel maintains high toughness even in cold environments, significantly reducing the risk of brittle fracture. This makes it suitable for applications in offshore regions, cold climates, and other low‑temperature service conditions.
• Excellent Weldability:
P690Q can be readily welded using standard industrial processes when proper procedures are followed. Its weldability simplifies fabrication, reduces production time, and ensures that welded joints retain good mechanical properties.
• Stable and Reliable Performance:
Through controlled chemical composition and quenched‑and‑tempered heat treatment, P690Q achieves a fine‑grain microstructure that delivers consistent mechanical performance. This stability is essential for critical components requiring long‑term safety and durability.
• Good Resistance to Fatigue and Wear:
The material's strength and toughness also contribute to improved fatigue resistance and wear performance, making it suitable for heavy‑load and cyclic‑stress applications such as crane booms and hydraulic cylinders.
Applications
Pressure Vessels and Boilers:
It is a preferred material for manufacturing pressure vessels, boilers, and heat exchangers used in petrochemical, thermal power, and chemical processing industries. These components often operate under high internal pressure and temperature fluctuations, and P690Q's excellent strength and toughness ensure safe and stable operation over long periods.
Offshore and Marine Engineering:
In offshore oil and gas exploration platforms, ship hulls, and marine pipelines, P690Q is used to withstand harsh marine environments such as saltwater corrosion, low temperatures, and strong wind loads. Its resistance to brittle fracture at low temperatures and good weldability make it suitable for offshore structural components that require high reliability.
Heavy Machinery and Construction:
It is applied in the manufacturing of heavy machinery parts, such as excavator arms, crane booms, and hydraulic cylinders, as well as large-scale construction structures like bridges and stadiums. The high strength of P690Q allows for the design of lighter and more compact components without compromising structural integrity, reducing overall equipment weight and improving efficiency.
Nuclear Power Industry:
Some auxiliary components in nuclear power plants, such as pressure pipelines and storage tanks, also adopt P690Q. It meets the strict safety requirements of the nuclear industry, providing stable performance under high pressure and radiation environments.
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How to store P690Q steel plates properly?
P690Q steel plates should be stored in a dry, well-ventilated warehouse to avoid moisture and rust. They should be placed on a flat surface with a certain distance from the ground, and avoid contact with corrosive substances.
What is the application of P690Q in bridge construction?
In bridge construction, P690Q is used to manufacture bridge girders, piers, and other key components. Its high strength can reduce the weight of the structure, save materials, and ensure the bridge's bearing capacity and service life.
What is the impact toughness value of P690Q at low temperatures?
At -20℃, the Charpy V-notch impact toughness of P690Q is usually not less than 30J. This ensures that it does not become brittle and can resist impact loads in low-temperature environments such as cold regions.
Can P690Q be used in high-pressure pipeline systems?
Yes, P690Q is suitable for high-pressure pipeline systems. Its high tensile strength and good toughness can withstand the high pressure of the medium (such as oil, gas), ensuring the tightness and safety of the pipeline.
What is the difference between P690Q and Q690 steel?
P690Q is a European standard steel, while Q690 is a Chinese standard (GB/T 1591) steel. They have similar tensile strength, but there are differences in chemical composition, toughness requirements, and testing standards due to different standard systems.
How to improve the weldability of P690Q?
To improve the weldability of P690Q, preheating the base metal to 80-150℃ before welding, using low-hydrogen welding electrodes or wires, controlling welding current and speed, and performing post-weld heat treatment to eliminate welding stress are effective measures.
What is the microstructure of P690Q after heat treatment?
After quenching and tempering, P690Q has a tempered martensite or bainite microstructure. This microstructure gives it high strength and good toughness, balancing the mechanical properties required for engineering applications.
What is the service life of P690Q components in general working conditions?
Under proper installation, use, and maintenance, the service life of P690Q components can reach 15-20 years or more. Its high durability and corrosion resistance reduce wear and aging, ensuring long-term stable operation.
Can P690Q be used in the manufacturing of crane booms?
Yes, P690Q is widely used to manufacture crane booms. Its high strength can bear the heavy load of the crane during hoisting, and good toughness can resist impact, ensuring the safety and reliability of the boom during operation.
What are the main quality control points in the production of P690Q?
The main quality control points include strict control of chemical composition, precise heat treatment temperature and time, thorough testing of mechanical properties and microstructure, and inspection of surface quality to avoid defects such as cracks and inclusions.