ASTM A182 F51 weld neck RF flange is manufactured from duplex stainless steel forging material and is designed for pressure piping systems, chemical processing equipment, oil and gas facilities, and industrial applications.

The weld neck raised face flange is connected to the pipe through butt welding, providing a smooth transition between the flange and pipe system. This flange design is commonly selected for high-pressure and high-temperature piping applications where dimensional accuracy and mechanical strength are required.

Manufactured according to ASTM A182 / ASME SA182 requirements, F51 flanges are produced through forging processes with controlled material composition, mechanical properties, dimensions, and inspection procedures.

Material and Standard

F51 Duplex Stainless Steel Forged Flange

Standard: ASTM A182 / ASME SA182
Material Grade: F51
UNS Number: S31803
Material Type: Duplex Stainless Steel
Flange Type: Weld Neck Raised Face (WN RF)

ASTM A182 specifies forged alloy and stainless steel piping components for pressure systems, including flanges, fittings, valves, and related components.

Material Characteristics

Duplex Stainless Steel F51

F51 is a duplex stainless steel grade containing chromium, nickel, molybdenum, and nitrogen alloying elements.

Typical characteristics:

• Duplex ferritic-austenitic structure
• Suitable for pressure piping applications
• Commonly used in corrosion-related industrial environments

Flange Design Features

Weld Neck Design

The weld neck flange includes a tapered hub that provides a gradual connection between the flange and pipe.

Common advantages:

• Suitable for butt welding connection
• Reduced stress concentration at the flange joint
• Used in high-pressure piping systems

Raised Face (RF) Facing

The raised face design provides a defined sealing surface for gasket installation.

Common gasket types include:

• Spiral wound gasket
• Metallic gasket
• Non-metallic gasket

Manufacturing Process

Forging

F51 stainless steel billets are forged to produce flange blanks with required mechanical properties.

Heat Treatment

Heat treatment is performed according to ASTM A182 requirements.

Typical processes include:

• Solution treatment
• Cooling process control

Machining

Precision machining includes:

• Bolt hole drilling
• Raised face machining
• Welding neck machining
• Surface finishing

Inspection

Final inspection includes:

• Dimensional inspection
• Material verification
• Non-destructive testing when specified

Product Specifications

Available Specifications

Applications

Oil and Gas Industry

ASTM A182 F51 weld neck flanges are commonly used in:

• Pipeline systems
• Offshore equipment
• Process piping

Chemical Processing

Applications include:

• Chemical plants
• Corrosive media piping systems
• Process equipment

Pressure Equipment

Used for:

• Pressure vessels
• Heat exchanger piping connections
• Industrial piping systems

Marine and Offshore Equipment

Suitable for:

• Offshore platforms
• Seawater-related systems