Industrial Steel Flanges

Product Description

Industrial Steel Pipe Flanges are forged, cast, or plate-machined mechanical connectors used to join pipes, valves, pumps, pressure vessels, and other piping equipment to form an accessible, sealed pipeline network.

1. Primary Structural Flange Types

2. Sealing Face Configurations

• Raised Face (RF): Features a $1.6\text{ mm}$ or $6.4\text{ mm}$ raised step with concentric machine serrations ($125\text{--}250\text{ AARH}$) to concentrate seating load on spiral-wound or flat gaskets.

• Ring Type Joint (RTJ): Features a precision annular groove that houses a solid metallic ring gasket (Type R, RX, or BX); used in extreme pressure service (Class 600 to 2500, API 5K15K).

• Flat Face (FF): Full flat surface across the face; used when mating against cast iron, plastic-lined, or lower-pressure equipment to prevent flange cracking during bolt tightening.

• Tongue & Groove (T&G) / Male & Female (M&F): Interlocking mating faces designed to retain the gasket in place under elevated pressure and prevent gasket blowout.

3. Global Dimensional & Rating Standards

4. Key Material Classifications & Specifications

• Carbon Steel: ASTM A105 / A105N (Ambient/High Temp), ASTM A36 (Plate), P250GH (EN).

• Low-Temperature Carbon Steel: ASTM A350 LF2 Class 1/2 (Impact tested down to $-46^\circ\text{C}$).

• High-Yield Carbon Steel: ASTM A694 (F42, F52, F60, F65, F70) for high-pressure cross-country transmission pipelines.

• Alloy Steel (Cr-Mo): ASTM A182 F1, F5, F9, F11, F12, F22, F91 (High-temperature steam and refining).

• Stainless Steel: ASTM A182 F304/304L, F316/316L, F321, F347 (Corrosion and chemical resistance).

• Duplex & Super Duplex: ASTM A182 F51 (UNS S31803), F53 (UNS S32750), F55 (Offshore sour service).

• Nickel Alloys: Inconel 625, Incoloy 825, Hastelloy C276, Monel 400 (Severe acid gas and marine environments).

5. Protective Surface Finishes

To prevent atmospheric corrosion during shipment and field storage, steel flanges receive functional surface coatings:

• Transparent / Yellow Anti-Rust Oil & Lacquer: Short-to-medium term indoor/outdoor protection; leaves heat numbers clearly visible.

• Black Anti-Rust Paint / Bituminous Varnish: Heavy barrier coating for long-distance marine transport.

• Hot-Dip Galvanized (HDG): Thick zinc layer ($>85\ \mu\text{m}$) providing long-term atmospheric and underground corrosion resistance.