High-Pressure Forged Flange

A high-pressure forged flange is a metal component used for connecting high-pressure pipelines. It is typically manufactured using a forging process to ensure high strength, high-pressure resistance, and good sealing performance. The following is a detailed description of high-pressure forged flanges:

1. Definition and Uses

High-pressure forged flanges are flanges produced through a forging process, used to connect pipelines, valves, pumps, or other equipment. They are widely used in high-pressure pipeline systems in industries such as petrochemicals, natural gas, power, shipbuilding, and nuclear power. Their main functions are:

Connecting Pipelines: Ensuring a tight connection of the pipeline system and maintaining good sealing performance.

Withstanding High Pressure: Suitable for working conditions with high pressure, high temperature, or corrosive media.

Facilitating Disassembly and Maintenance: Flange connections facilitate the installation, inspection, and replacement of pipeline systems.

2. Production Process

The manufacturing of high-pressure forged flanges mainly uses forging processes, including free forging, die forging, and mandrel forging. Specific characteristics are as follows:

Free Forging: Using simple tools and equipment, suitable for small-batch, diversified production, with lower costs. It can compensate for defects such as shrinkage cavities and porosity in cast blanks, improving mechanical properties.

Die Forging: High production efficiency, high dimensional accuracy, and reasonable fiber structure distribution, suitable for mass production, but equipment costs are higher.

Mandrel Forging: Suitable for flanges of specific shapes, balancing flexibility and quality.

The forging process gives the flange the following advantages:

High Strength: Forged parts have refined grains and a dense structure, capable of withstanding higher shear and tensile forces.

Corrosion Resistance: Compared to cast flanges, forged flanges have a lower carbon content and are less prone to rust.

Excellent Mechanical Properties: Forged parts have good streamline shapes, and their mechanical properties are superior to those of cast flanges.

3. Material

High-pressure forged flanges are typically manufactured using the following materials to meet the needs of different working conditions:

Carbon Steel: Such as WCB, suitable for general high-pressure environments.

Stainless Steel: Such as 304, 316, 316L, suitable for corrosive environments.

Alloy Steel: Such as chrome-molybdenum steel, chrome-molybdenum-vanadium steel, suitable for high-temperature and high-pressure environments.

Special Materials: Such as titanium alloys, fluoropolymer-lined materials, used for extreme corrosion or special working conditions.

4. Sealing Surface Form

High-pressure forged flanges have various sealing surface forms, selected according to the usage scenario:

Raised Face (RF): The most common, suitable for general high-pressure pipelines.

Male and Female (M/F): Provides better sealing effect, suitable for higher pressure environments.

Tongue and Groove (T/G): Used in applications requiring high sealing performance.

Flat Face (FF): Used in low-pressure or non-critical applications.

5. Standards and Specifications

High-pressure forged flanges follow international or national standards, such as:

PN Series (European System): PN63, PN100, PN160, PN250, PN320, PN400, etc.

Class Series (American System): Class 600, Class 900, Class 1500, Class 2500, etc.

Dimensions and thickness are usually designed according to standards (such as GB/T9119, HG20592, JB/T81), considering safety margins.

6. Advantages and Disadvantages

Advantages:

High strength and high-pressure resistance, suitable for harsh working conditions.

Dense structure, corrosion resistance, and long service life.

High dimensional accuracy, small machining allowance, and easy installation.

Disadvantages:

The forging process cost is higher than that of cast flanges.

Improper forging may lead to uneven grain size or hardening cracks.

7. Precautions

Selection: Select the appropriate material and sealing surface form according to pipeline pressure, medium, and temperature.

Installation: Ensure flange alignment and evenly tighten bolts to avoid leakage.

Inspection: Non-destructive testing (such as ultrasonic, magnetic particle testing) is required during the production process to ensure no defects such as porosity and cracks.

Maintenance: Regularly check the sealing surface and gaskets to prevent corrosion or wear.

8. Industry Applications

High-pressure forged flanges are widely used in:

Petrochemical Industry: Transporting high-temperature and high-pressure oil and gas.

Energy Industry: Such as high-pressure pipeline connections in wind power and nuclear power equipment.

Pressure Vessels: Ensuring reliable connection between vessels and pipelines.

Water Supply and Drainage Systems: Used in high-pressure pipelines in municipal engineering.