HT PIPE supply all different types and scales of flanges. Please feel free to contact us for further product information and pricing.
ASME B16.47 covers large-diameter steel flanges. Series A corresponds directly to the legacy MSS SP-44 standard, which specifies thicker flange profiles, larger bolt circles, and heavier bolting configurations than Series B (API 605).
Standard Coverage: Large-diameter blind flanges (NPS 26 through NPS 60).
Pressure Rating: Class 400 (intermediate high-pressure service).
Facing Standard: 0.25 in (7 mm) Raised Face (RF) comes standard for Class 400; Ring Type Joint (RTJ) or Flat Face (FF) profiles are available upon request.
Compatibility Note: Note that Series A and Series B flanges are not interchangeable in smaller sizes due to differing bolt circle and thickness dimensions. However, per ASME B16.47 specifications, Class 400 dimensions for NPS 38 and larger merge to match the Series B profile across both standards.
Material Specifications & Regional Procurement Considerations
When procuring Class 400 blind flanges, structural integrity relies on choosing forgeable materials suited to the application environment:
Carbon Steel: ASTM A105 (standard elevated temperature service) or ASTM A350 LF2 (low-temperature applications down to -45°F / -43°C).
High-Yield Line Pipe Steel: ASTM A694 (Grades F52, F60, F65, F70) commonly used in natural gas transmission and pipeline headers.
Alloy & Stainless Steel: ASTM A182 F316/316L or F304/304L for corrosive environments or process piping.
Installation & Engineering Best Practices
Handling & Rigging: Due to heavy weights (e.g., an NPS 60 blind flange weighs over 9,000 lbs), blind flanges above 30 inches should feature integrated lifting lugs or tapped eye-bolt holes to facilitate safe placement.
Gasket Selection: Use spiral wound gaskets with an inner ring or metallic RTJ gaskets rated for Class 400 service.
Torque Sequencing: Always apply star-pattern torque sequences in incremental passes (30%, 60%, 100%) using calibrated hydraulic torque wrenches to avoid flange rotation or unequal gasket compression.
ASME B16.47 Series A Class 400 Blind Flange Dimension
