The Application of Flange Plates in the Industrial Field

1. Core Functions and Structural Features

The primary function of flanges is to connect pipes or equipment while maintaining pressure resistance and leakage prevention. Key structural forms include:

Welding Flanges: Flat-welded flanges are suitable for low-pressure scenarios (≤4 MPa), while butt-welded flanges (high-neck type) handle high pressure/temperature conditions.

Threaded Flanges: Used where welding is impractical, though they are unsuitable for extreme temperatures (>260°C or <-45°C).

Loose Flanges: Ideal for corrosive environments, as the flange material can differ from the pipe material.

Sealing surfaces are designed as flat, convex-concave, or tongue-and-groove types to match media characteristics (e.g., toxic or flammable substances require tongue-and-groove designs). Gaskets—made of rubber, metal, or asbestos—deform under bolt pressure to fill surface imperfections, ensuring tight seals.

2. Applications Across Industries

Flanges are ubiquitous in industries requiring reliable fluid or gas transport:

Chemical and Petroleum: High-pressure pipelines in refineries and chemical plants use butt-welded flanges with metal gaskets to withstand corrosive chemicals and pressures up to 42 MPa.

Power and Energy: Boilers, steam turbines, and cooling systems rely on flanges to connect high-temperature water/steam pipelines, often employing lens-type metal gaskets for pressures ≥100 MPa.

Water Supply and Construction: Water tanks, drainage pipes, and firefighting systems use flat-welded flanges for low-cost, easy maintenance.

Automotive and Manufacturing: Flanges connect hydraulic systems in machinery, while in automotive modification, they adjust wheel spacing to improve stability.

3. International Standards and Material Selection

Flanges are produced under three major standard systems:

European System (DIN/P Series): Pressure ratings like PN10-PN160, emphasizing dimensional precision.

American System (ANSI/Class Series): Pressure classes (e.g., Class 150-2500), widely used in oil and gas.

Chinese System (GB/HG): Integrates international standards with local requirements.

Material choices depend on operational demands:

Carbon Steel: For general water/oil pipelines.

Stainless Steel (304/316): Resists corrosion in chemical or marine environments.

Alloy Steel: Supports high-temperature power plants.

Poor-quality "non-standard" flanges—made from subpar steel—risk leakage or fractures, emphasizing the need for certified products.

4. Installation and Maintenance Challenges

Proper installation is critical to prevent failures:

Bolt Tightening Sequences: Uneven bolt torque can cause gasket misalignment. Standards like GB/T 38343-2019 specify step-by-step tightening procedures.

Leakage Risks: Factors include vibration, temperature fluctuations, or gasket aging. Regular inspections using ultrasonic or pressure tests are essential.

Corrosion Protection: Flanges in offshore or chemical environments require coatings (e.g., zinc plating) or protective covers.

5. Future Trends and Innovations

As industries prioritize efficiency and sustainability, flanges evolve in two directions:

Lightweight and High-Strength Designs: New alloys and forging techniques enhance load capacity while reducing weight.

Smart Monitoring: Sensors embedded in flanges can detect real-time leakage or stress, enabling predictive maintenance.

Conclusion

Flange plates, though simple in concept, are engineering marvels that enable safe and adaptable industrial connections. From chemical plants to energy systems, their versatility under diverse pressures, temperatures, and corrosive conditions underscores their irreplaceable role. As technology advances, flanges will continue to support infrastructure development through improved materials and intelligent designs.