ASTM A240 SS904L Plate Fabricated Slip-On Flange with Flat Face AWWA C207 and Custom Dimensions

ASTM A240 SS904L UNS N08904 Plate Fabricated Slip-On Flange with Flat Face is manufactured from 904L stainless steel plate, with UNS N08904 / EN 1.4539 as its commonly referenced material designations.

Unlike forged flanges, this product is produced through a plate fabrication process, typically involving plate cutting, forming or fabrication, welding where required, and precision machining. This manufacturing route provides flexibility for large-diameter flanges, customized dimensions and project-specific bolt configurations.

The flange features a Slip-On configuration with Flat Face (FF) and is suitable for bolted connections in chemical, process and other corrosive-service piping systems.

The AWWA C207 flanges are intended for attachment to steel pipes, fittings, valves or other appurtenances in water utility service. The standard specifies two general types of flange: ring-type slip-on flanges (also known as ring flanges or plate flanges) and blind flanges. Both are steel flanges without hub. The standard also provides additional information for dimensions of steel-hub flanges in Appendix B.

AWWA C207 flanges are classified into four classes according to working pressure limits: Class B (86 psi), Class D (175-150 psi), Class E (275 psi), and Class F (300 psi). These pressure limits are for conditions and temperatures customary in water utility service.

The Slip-On flange is positioned over the connecting pipe before welding. The bore is manufactured according to the pipe outside diameter and specified wall configuration.

Typical dimensional parameters include:

• Nominal Size
• Flange Outside Diameter
• Bore Diameter
• Flange Thickness
• Bolt Circle Diameter
• Bolt Hole Diameter
• Number of Bolt Holes
• Hub Length
• Face Flatness
• Face Finish

Dimensions can be manufactured according to project drawings or applicable flange dimensional requirements.

• The Flat Face (FF) design provides a flat gasket seating surface across the flange face
• The FF configuration should be selected together with compatible mating flanges, gaskets and bolting systems to ensure proper joint assembly

• Chemical Process Piping
• Acid Transfer Systems
• Chemical Storage Systems
• Phosphoric Acid Processing
• Sulfuric Acid Process Equipment
• Fertilizer Processing
• Pulp and Paper Equipment
• Desalination Systems
• Marine Process Piping
• Corrosive Process Equipment
• Industrial Water Treatment

• Chemical Storage Tanks
• Process Vessels
• Acid Transfer Lines
• Large-Diameter Process Piping
• Chemical Processing Skids
• Heat Exchangers
• Pumps
• Valves
• Mixing Equipment
• Storage and Transfer Systems

SS904L should not be considered a universal replacement for 316L. Selection should be based on the actual process chemistry, temperature and corrosion mechanism.