Application description

Widely used to connect pipes, valves, pumps, and other equipment in piping systems across oil and gas, petrochemical, power generation, water treatment, shipbuilding, and construction industries. Also suitable for high-pressure steam lines, chemical processing plants, and fire protection systems. Flanges provide easy assembly, disassembly, and maintenance access.

Production description

Billet is heated, forged (or plate cut), then machined on lathes and drilling machines to finished dimensions. Forged flanges undergo heat treatment and 100% ultrasonic testing. Sealing face is machined to specified finish (serrated, smooth, or RTJ groove). Bolt holes drilled accurately. Marking stamped.

Shipping Packaging

For export, flanges are packed in wooden crates or on ISPM-15 pallets, secured with steel straps. Machined surfaces are coated with anti-rust oil and protected with plastic caps or foam padding. Labels include grade, pressure rating, size, standard, and heat number for safe sea freight.

Why Choose Us?

1.Factory Strength: Direct manufacturer with integrated forging presses, heat treatment furnaces, CNC machining centers, and drilling lines, producing forged and plate flanges in all types (WN, SO, BL, TH, SW, LJ) from 1/2" to 60" to ASME, EN, JIS, GB standards.

2.Quality Assurance: Strict control of chemical composition, mechanical properties (tensile, yield, impact for low-temp), dimensional accuracy (bolt hole circle, facing finish), and 100% ultrasonic testing (UT) for forged flanges; compliant with ASME B16.5/B16.47, EN 1092-1, GB/T 9124.

3.Certifications & Reports: Mill test certificates (MTC) for raw materials and finished flanges with each shipment; third-party inspections (SGS, BV, DNV) and NDT reports (UT, MT, PT) available upon request.

4.Customization & Service: Wide material range (carbon steel A105, A350 LF2; stainless steel 304/316L; alloy steel F11/F22/F91; duplex 2205/2507), all pressure classes (150#-2500#, PN6-PN100), all facing types (RF, FF, RTJ, M&F, T&G), and non-standard drilling with fast lead times.

5.Export Packaging: Anti-rust oil + plastic end caps for machined surfaces + foam padding + wooden crates/ISPM-15 pallets + steel strapping + clear labeling for safe sea freight and corrosion protection.

FAQ

1. How to store steel flanges to prevent rust and sealing surface damage?

Store on dry, clean wooden pallets in a covered area. Keep anti-rust oil coating intact and protect machined sealing surfaces with plastic caps or cardboard. Avoid stacking heavy flanges directly on raised or RTJ grooves to prevent deformation. For long-term storage, seal in VCI bags.

2. What is the difference between weld neck (WN) and slip-on (SO) flanges?

Weld neck flanges have a tapered hub that transfers stress and are ideal for high pressure, extreme temperature, or cyclic service. They require full penetration butt weld. Slip-on flanges slide over the pipe and are fillet welded inside and outside; they are lower cost but rated for lower pressure and fatigue service. Choose WN for critical service, SO for general utilities.

3. What pressure class and flange facing should I choose for a given application?

Pressure class (150, 300, 600, etc.) depends on design pressure and temperature; refer to ASME B16.5 pressure-temperature ratings. For most standard services, raised face (RF) is used. Ring type joint (RTJ) is required for very high pressure or for leak-proof service in gas and hydrogen. Flat face (FF) is used only when connecting to cast iron or flat-faced equipment. We can help select appropriate class and facing based on your process conditions.