ASME B16.47 Large Diameter Flanges — Series A (MSS SP-44) & Series B (API 605) Forgings, NPS 26-60
Shivam Forge manufactures forged large-diameter flanges to ASME B16.47 (Large Diameter Steel Flanges NPS 26 Through NPS 60) — both Series A (derived from the former MSS SP-44, generally heavier) and Series B (derived from the former API 605, generally lighter) flange types — in carbon and alloy steel, for large-diameter pipeline, refinery, and power generation piping applications where standard ASME B16.5 dimensional coverage ends. EN 10204 3.1/3.2 certification. Rajkot, India. Call +91-9265772827.
ASME B16.47 governs flange dimensions for the large nominal pipe size range (NPS 26 through NPS 60) that falls outside standard ASME B16.5 coverage, which tops out at NPS 24 — a distinction that matters considerably for large-diameter pipeline, refinery, and power generation piping projects where pipe sizes routinely exceed B16.5's upper dimensional limit. The standard's defining complexity, and the aspect most likely to cause specification confusion, is its dual flange series: Series A (inherited from the former MSS SP-44 standard) and Series B (inherited from the former API 605 standard) cover the same nominal pipe sizes and pressure classes but with different, generally non-interchangeable dimensions — Series A flanges are typically heavier and thicker than Series B flanges at the equivalent size and class, meaning correctly specifying which series a project requires is a genuinely consequential decision affecting both flange interchangeability with existing piping systems and overall material cost.
Forged flanges per ASME B16.47 Series A dimensional requirements (derived from the former MSS SP-44 standard), generally the heavier of the two series at equivalent size and pressure class, commonly specified for higher-pressure or more conservative design applications.
Forged flanges per ASME B16.47 Series B dimensional requirements (derived from the former API 605 standard), generally lighter than Series A at equivalent size and class, commonly specified in refinery and process industry applications with established API 605 dimensional history.
Forged weld neck and blind flange types across both B16.47 series, in the large-diameter pressure classes and material grades large pipeline, refinery, and power generation piping projects require.
Carbon steel (A105), alloy steel (A182 grades), and stainless steel large diameter flange forgings matched to the specific process temperature, pressure, and corrosion requirements of large-diameter piping applications.
Engineering guidance supporting correct Series A versus Series B specification, since the two series are generally not dimensionally interchangeable — confirming the correct series for a given project's existing piping system compatibility and design pressure requirements is essential before manufacturing begins.
Heavy forging capability supporting the substantial size and weight large-diameter B16.47 flanges represent, drawing on our open-die and heavy forging product line rather than smaller closed-die precision forging capacity.
Full dimensional inspection verifying compliance with the specific B16.47 series, size, and pressure class dimensional tables, including bolt circle diameter, bolt hole count and size, and flange thickness.
Material test certificates per EN 10204 3.1 as standard, with 3.2 third-party witnessed certification available for large pipeline, refinery, and power generation project documentation requirements.
ASME B16.47's role in flange specification is best understood as a direct extension of ASME B16.5's coverage: where B16.5 comprehensively addresses flange dimensions for nominal pipe sizes up to NPS 24 — covering the overwhelming majority of general industrial and process piping applications — B16.47 exists specifically to extend standardized flange dimensional coverage into the large-diameter range (NPS 26 through NPS 60) that major pipeline transmission systems, large refinery process units, and power generation piping frequently require. Without B16.47's standardization, large-diameter flange specification would revert to project-specific custom dimensioning, losing the interchangeability and supply chain efficiency standardized flange dimensions provide.
The standard's dual Series A and Series B structure reflects its historical origin as a consolidation of two previously separate standards — MSS SP-44 and API 605 — into a single ASME specification, rather than a deliberate design choice to offer two options for the same application. This historical consolidation means Series A and Series B represent genuinely different dimensional lineages that happen to cover overlapping size and pressure class ranges, with Series A generally producing heavier, thicker flanges than Series B at equivalent nominal specifications — a distinction with real practical consequence for both flange interchangeability with existing installed piping (a Series A flange generally cannot substitute for a specified Series B flange without engineering review) and overall material cost, given Series A's typically greater material content.
This series distinction is precisely the area where flange specification errors most commonly occur in large-diameter piping projects: because both series share the same nominal pipe size and pressure class designation system, it's entirely possible to inadvertently specify or supply the wrong series if project documentation doesn't explicitly state which series applies — making clear series confirmation a genuinely important quality control step for both purchasers and suppliers of B16.47 large-diameter flanges, rather than an assumption that can be safely glossed over.
For large pipeline, refinery, and power generation project EPC contractors sourcing ASME B16.47 forged flanges in either Series A or Series B, Shivam Forge offers heavy forging capability with series selection guidance and full EN 10204 3.1/3.2 certification. Contact our engineering team at +91-9265772827 or sales@shivamforge.com with your size, series, and material specification for a quotation.
Series A (derived from the former MSS SP-44 standard) and Series B (derived from the former API 605 standard) cover the same nominal pipe sizes and pressure classes but with different, generally non-interchangeable dimensions. Series A flanges are typically heavier and thicker than Series B flanges at the equivalent size and class — correctly specifying which series a project requires is essential and should never be assumed.
ASME B16.5 covers flange dimensions up to NPS 24. ASME B16.47 picks up coverage from NPS 26 through NPS 60, meaning any flange specification for pipe sizes 26 inches and above requires B16.47 rather than B16.5, common in large-diameter pipeline, refinery, and power generation piping applications.
This depends on your existing piping system compatibility (matching flanges already installed or specified elsewhere in the project) and design requirements — we recommend confirming series specification with your project engineering documentation before ordering, and our engineering team can help verify series selection based on your drawing or existing system specification.
Carbon steel (A105), alloy steel (A182 grades), and stainless steel are available, matched to the specific process temperature, pressure, and corrosion requirements of your large-diameter piping application.
Yes. Forged weld neck and blind flange types across both B16.47 series, in the large-diameter pressure classes and material grades large pipeline, refinery, and power generation piping projects require.
Why Choose Shivam Forge
Shivam Forge delivers precision hot-forged components from our integrated Shapar, Rajkot facility — covering forging, CNC machining, heat treatment, and quality inspection under one roof.
