ASME B16.47 Series B
ASME B16.47 Series B
ASME B16.47 Series B is a standard developed by the American Society of Mechanical Engineers (ASME) that provides guidelines for large-diameter steel flanges. These flanges are used in low-pressure and less demanding applications compared to Series A flanges. They are particularly common in industries like waterworks, chemical processing, and general pipeline systems.
Materials
Flanges conforming to ASME B16.47 Series B are manufactured from a range of materials based on the application, temperature, and pressure requirements:
- Carbon Steel: Common grades like ASTM A105, A350 LF2, and A36 for general pipeline applications.
- Stainless Steel: Grades like 304/304L, 316/316L for corrosion-resistant applications.
- Alloy Steel: Grades like ASTM A182 F11, F22, or F91 for high-temperature and high-pressure conditions.
- Duplex and Super Duplex Stainless Steel: For enhanced corrosion resistance in aggressive environments.
- Nickel Alloys: For use in extreme environments like offshore, chemical, and petrochemical industries.
- Low-Temperature Steels: ASTM A350 LF2 for cryogenic and low-temperature services.
Pressure-Temperature Ratings
ASME B16.47 Series B flanges are designed to handle a wide range of pressure and temperature conditions.
- Pressure Classes: 75, 150, 300, 400, 600, and 900.
- Temperature Ranges: Dependent on material selection, typically ranging from -20°F (-29°C) to over 1000°F (537°C) for high-temperature materials.
Pressure ratings decrease with temperature increases, as outlined in ASME standards. Proper material selection ensures compatibility with the operating conditions.
Flange Types
The following flange types are covered under Series B:
- Weld Neck Flanges (WN): Designed for high-pressure, high-temperature applications.
- Blind Flanges (BL): Used to close the ends of piping systems and pressure vessels.
Connection Types
Series B flanges provide reliable and flexible connection options:
- Butt-Weld Connections: Weld neck flanges are joined to the pipeline using a butt-weld. This ensures a robust and leak-proof connection.
- Bolted Connections: Blind flanges are typically bolted, allowing for easier removal for inspection and maintenance.
Coating and Surface Treatments
Coatings and surface treatments enhance durability, corrosion resistance, and sealing capabilities. Common options include:
- Anti-Corrosion Coatings: Zinc plating, epoxy coatings, or galvanizing for outdoor and corrosive environments.
- Passivation: For stainless steel flanges to improve their corrosion resistance.
- Black Oxide: Enhances resistance to moisture and mild corrosion.
- PTFE Coating: For enhanced chemical resistance and non-stick properties in aggressive environments.
- Surface Finish: Standard finish is usually a serrated or smooth finish for compatibility with gasket materials. The surface roughness is specified to ensure proper sealing.
ASME B 16.47 Series B Welding Neck Flange
