Socket Weld Flange | Professional Non-Standard Custom Manufacturer

Socket Weld Flange (SW Flange) is a special connecting fitting for small-diameter and high-pressure pipelines. It is formed by socket insertion and circumferential fillet welding, featuring better pressure resistance and sealing performance than threaded flanges and conventional slip-on flanges. As a professional physical flange manufacturer based in Cangzhou, we specialize in producing various standard socket weld flanges compliant with Chinese, American, German and Japanese standards. We also customize non-standard socket weld flanges with thickened small diameters and special hole pitches, supporting custom processing based on drawings and samples with direct factory supply.

1. Structural Characteristics of Socket Weld Flange

The inner hole of the flange is processed into a socket with a limiting step. The pipe end is directly inserted into the socket and positioned by the step, and an annular fillet weld is made between the pipe nozzle and the outer side of the flange socket. No pipe beveling is required, ensuring simple assembly and positioning. The product is integrally forged with dense structure, no sand holes or air holes, good rigidity and small welding deformation. The weld joint boasts excellent fatigue resistance, which can resist stress changes caused by pipeline vibration and temperature alternation. Different from full penetration butt welded weld neck flanges, socket weld flanges feature compact structure and small occupation space, making them the preferred connector for small-diameter high-pressure pipelines within DN80.

2. Common Materials and Specifications

We select raw materials according to medium corrosion, temperature and pressure conditions to adapt to various working conditions such as normal temperature, high temperature, weak acid and alkali, and oil and gas:

• Carbon Steel Socket Weld Flange: 20#, Q235B, A105, 16Mn. It offers high cost performance and is mostly used for medium and small-diameter high-pressure pipelines such as steam, oil products and compressed air.
• Stainless Steel Socket Weld Flange: 304, 316L, 321, 2205 duplex steel. With excellent acid and alkali resistance and corrosion resistance, it is suitable for conveying pipelines in chemical, pharmaceutical and seawater medium environments.
• Alloy Steel Socket Weld Flange: 15CrMo, 12Cr1MoV. Featuring outstanding high-temperature resistance, it is widely used for high-temperature and high-pressure small-diameter process pipelines in boilers and power stations.

Specifications: Conventional DN15-DN80 (1/2″~3″), customized special small diameters are available; National standard pressure grades include PN16, PN25, PN40, PN63, PN100, with full-range American standard Class150~Class1500 in stock and customizable.

3. Implementation Standards and Sealing Types

All products are produced in strict accordance with domestic and international specifications, suitable for domestic engineering projects and export orders. Applicable standards include: GB/T9117, HG/T20592/HG/T20615, ASME B16.5, EN1092, JIS B2220.

A full range of customizable sealing faces are available: RF (Raised Face), FF (Full Face), MFM (Male and Female Face), TG (Tongue and Groove Face) and RJ (Ring Type Joint). RF raised face is the most commonly used type, compatible with rubber gaskets, PTFE gaskets and metal spiral wound gaskets. RJ ring type sealing is mostly applied in pipelines conveying flammable, explosive, high-pressure and highly toxic media.

4. Working Conditions and Application Scope

Socket weld flanges are suitable for small-diameter, medium and high-pressure pipelines with large temperature fluctuation and flammable, explosive or corrosive media, not applicable for large-diameter pipelines. The main application scenarios are as follows:

• Petrochemical and chemical industry: Fine chemical equipment, small-diameter process pipelines matched with reaction kettles, corrosive reagent conveying pipelines
• Boiler and power industry: Boiler instrument pipelines, high-temperature steam sampling pipelines, high-pressure small pipelines matched with power station units
• Pharmaceutical and environmental protection industry: Medical raw material conveying, high-pressure chemical dosing pipelines for sewage treatment
• Mechanical and electrical equipment: Pump and valve inlet and outlet ports, hydraulic oil circuits, high-pressure gas instrument connecting flanges
• Oil and gas industry: Small branch high-pressure pipelines for liquefied gas and natural gas, matching pipe fittings for small pressure regulating stations

5. Our Production and Customization Advantages

Equipped with complete production lines including forging, CNC machining and physical and chemical testing, we support standard bulk wholesale and customized non-standard single-piece processing:

1. Stable forging technology: Adopting integral forged blanks and precision CNC turning, the flanges feature smooth sealing surfaces and accurate bolt hole pitch tolerance, ensuring tight on-site assembly and completely eliminating leakage risks.
2. Flexible non-standard customization: We can process flanges with special wall thicknesses, non-standard aperture sizes, widened and thickened structures and special-shaped sockets without mold opening, accepting both small trial orders and large-scale engineering orders.
3. Complete quality inspection documents: Each batch of products is equipped with material quality certificates and factory dimension inspection reports. Magnetic particle testing and UT non-destructive testing reports can be provided on demand to meet the requirements of project acceptance and export customs clearance.
4. Controllable delivery efficiency: Conventional specifications are in sufficient stock and can be delivered on the same day. Customized products are arranged with refined production schedules to strictly control the production cycle and guarantee the project construction progress.
5. Common Purchasing FAQs

Q: How to select among socket weld flange, slip-on flange and weld neck flange?

A: Socket weld flanges are preferred for pipelines within DN80 with medium and high pressure and high sealing requirements; slip on neck flanges are suitable for large-diameter pipelines under normal temperature and medium-low pressure; weld neck flanges are recommended for key main pipelines above DN50 with high temperature and high pressure.

Q: Can you produce non-standard socket weld flanges with special sizes?

A: We support full-range non-standard customization. Products with unconventional pipe diameters, thickened sockets and special bolt center distances can be precisely processed and produced according to customer drawings.

Q: Can you provide complete acceptance documents?

A: We provide free complete documents including product certificates, material test reports, dimension inspection reports and NDT certificates for project inspection and export customs clearance.

Inquiry & Cooperation

Whether you need in-stock standard socket weld flanges or custom non-standard products for engineering projects, simply provide drawings, materials, calibers and pressure parameters. Our technical staff will calculate and quote for free. We welcome long-term cooperation with domestic and foreign engineering merchants, trading companies and terminal manufacturers.

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