Flange – Fixed / Integral Flange (Vulcanized/Welded as a Single Unit)

Core Structural Features

The metal fittings of flanges and rubber hoses are joined into a rigid, integral structure through vulcanization bonding (rubber-to-metal adhesion) or welding, eliminating any sliding gaps. This results in high connection strength and excellent sealing performance, making it the preferred connection method for medium- and high-pressure applications.

Material Classification

1. Carbon steel integral flanges: high strength and low cost, suitable for hydraulic systems, ordinary hydraulic fluids, low-pressure steam, and other non-corrosive media;
2. All‑stainless steel flanges (304/316): Corrosion‑ and high‑temperature resistant, suitable for chemical, petroleum, marine, food, pharmaceutical, and other applications involving acidic, alkaline, high‑temperature, or corrosive conditions.
3. Cast-iron integral flanges: Highly brittle, used only in low-pressure, ambient-temperature, non-corrosive applications (rarely employed for high-pressure hoses).

Main Features

1. Enables rigid flanged connections between rubber hoses and metal pipelines/equipment, capable of withstanding medium-to-high pressures, elevated temperatures, and vibrational loads.
2. The integrated vulcanization–welding structure eliminates joint loosening, ensuring long-term stable sealing with no risk of leakage.
3. Transmits axial forces and torque, and is suitable for industrial operating conditions involving severe impacts and vibrations, such as in hydraulic and mining applications.
4. Resistant to high-temperature, high-pressure fluid media, suitable for demanding conveying conditions such as high-temperature oil, high-pressure water, and steam.

Typical uses

1. Hydraulic transmission systems (excavators, loaders, hydraulic power units);
2. Oil drilling and mining pipeline systems (high-pressure slurry, crude oil, heavy oil);
3. High-temperature steam and high-pressure water jet cleaning equipment;
4. High-pressure chemical fluid conveyance (acidic and alkaline liquids, organic solvents; stainless steel construction);
5. High-pressure hose assemblies for ships and construction machinery.

Applicable operating conditions

Pressure: Medium to high pressure (PN16–PN100, or pressure class ≥2.5 MPa);
Temperature: High temperature / Ambient temperature (-40°C to 300°C, depending on the rubber material and metal welding process);
Media: high-pressure oil, high-temperature steam, acidic and alkaline liquids, slurry, crude oil, etc.;
Environment: Industrial settings characterized by strong vibration, high impact, and frequent reciprocating motion.

Visual description

1. Overall structure: The circular flange is rigidly connected to the metal fitting, and the fitting is tightly bonded to the rubber hose body via a vulcanized layer, with no sliding components.
2. Installation condition: The flange of the flange plate is aligned directly with the flange of the connected pipeline; after the bolts are tightened, the sealing surfaces fit tightly together, forming a gap-free, rigid seal.
3. Detail features: Flange faces are typically raised face (RF), male‑female (MFM), or ring‑type joint (RJ), paired with metal‑wound gaskets or metal‑ring gaskets. The vulcanized layer at the joint is uniform and well‑filled, with no weld cracks or vulcanization defects.

Selection Supplement

1. Advantages: high structural strength, reliable sealing, excellent vibration and shock resistance, and suitability for demanding operating conditions.
2. Limitations: Disassembly and reassembly are inconvenient; it cannot accommodate thermal expansion and contraction through sliding, and requires precise alignment during installation.
3. Matching recommendations: Pair with high-pressure rubber hose assemblies, in compliance with standards such as GB/T 10747 and HG/T 20592, and select appropriate elastomer materials—such as fluoroelastomer or nitrile rubber—based on the service medium.