ASME/ANSI B16.47 Series A Weld Neck Flanges - Class 150 Weld Neck & Blind
Material Requirements
B16.47 dictates that Class 150 weld neck flanges be manufactured from carbon steel, alloy steel, or stainless steel compatible with a minimum temperature of -20°F. Common options include ASTM A105 and 316/316L stainless.
For blind flanges, the standard references ASTM A105 which specifies a carbon steel alloy composition suitable for temperatures to 1000°F. Blind flanges feature a solid metal face instead of a bore.
Dimensional Specifications
Stringent geometrical requirements are outlined to ensure interchangeability. Key dimensions regulated include:
- Bore diameter and thickness for each flange rating
- Bolt hole count, positions and sizes
- Face and flange face dimensions
- Welding end dimensions for weld neck flanges
Manufacturers adhere to tight tolerances defined in ASME/ANSI B16.47 Series A Weld Neck Flange to maintain dimensional consistency.
Pressure Ratings
The Class 150 designation equates to a maximum allowed pressure of 150 PSI. B16.47 provides pressure-temperature ratings taking into account materials of construction and service conditions from -20°F to 1000°F.
Markings
All flanges are required to be permanently marked with size, ratings, referenced standard, material, and manufacturer to facilitate traceability and ensure code-compliance.
Application and Uses
Class 150 weld neck flanges are well-suited for lower pressure steam, oil, gas, or air lines. Blind flanges are specified as line end closures or modular connections in these same lower temperature services.
Example industries include power, oil/gas, pulp/paper, and heating where equipment operates continuously at up to 1000°F. Compliance with B16.47 assures proper material selection, pressure capabilities, and consistent dimensions for any Class 150 high temperature flanged system.
The ASME/ANSI B16.47 Series A Weld Neck Flange standard provides essential guidelines for designers and fabricators to reliably specify and manufacture Class 150 weld neck and blind flanges suitable for temperatures to 1000°F in various industrial applications and services up to 150 PSI.
