ASME B16.47 Large Diameter Forged Flanges

Reliable ASME B16.47 Series A & Series B Flanges Solutions Since 1983

ASME B16.47 is the industry standard for large diameter steel pipe flanges ranging from NPS 26 through NPS 60. At JS Fittings, we manufacture high-performance forged flanges that bridge the gap between heavy-duty structural integrity and precise sealing requirements for oil, gas, and water infrastructure.

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ASME B16.47 Large Diameter Flanges are the industry standard for steel pipe flanges in sizes NPS 26 through NPS 60. As a professional flange manufacturer in China since 1983, JS FITTINGS provides high-performance forged solutions for large-scale piping infrastructure, oil & gas, and water treatment systems.

Technical Specifications

Standard	ASME B16.47 Series A (MSS SP-44) & Series B (API 605)
Size Range	26″ – 60″ (NPS 26 to NPS 60)
Pressure Rating	Class 75 (Series B), Class 150, 300, 600, 900
Material Grades	Carbon Steel (ASTM A105, A105N, A350 LF2), Stainless Steel (304L, 316L, 321), Alloy Steel (F11, F22)
Flange Facing	Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ)
Surface Treatment	Anti-rust Oil, Yellow/Black Paint, Galvanized, or Varnished

Understanding Series A vs. Series B

This standard covers two distinct series of flanges: Series A (formerly MSS SP-44) and Series B (formerly API 605). While both series cover large diameters, they are not interchangeable due to differences in bolt circle diameters and dimensions.

Series A vs. Series B: Key Differences Explained

Feature	Series A (Formerly MSS SP-44)	Series B (Formerly API 605)
Design Intent	Heavier, thicker, and physically larger.	Compact, lighter, and more economical.
Bolting	Fewer but larger diameter bolts.	More numerous but smaller diameter bolts.
Applications	New pipeline projects with high external loads.	Refining and replacement where space is limited.
Gasket Pressure	Higher bolt tension for extreme sealing.	Designed for lower bolt load requirements.

Note:

Dimensions and bolt hole patterns differ significantly between Series A and Series B. They cannot be bolted together.

JS Fittings recommends Series A for high-pressure industrial pipelines and Series B for commercial refinery retrofits.

Manufacturing Specifications

Flange Types

Weld Neck Flange (WN)
Blind Flange (BL)
Slip-On Flange (SO) – Custom
Ring Type Joint (RTJ) Flange

Pressure Ratings

Class 75 (Series B Only)
Class 150, 300
Class 600, 900
PN10, PN16, PN25, PN40

Materials (Forged)

Carbon: ASTM A105, A105N, LF2
Stainless: SS304L, SS316L, 321
Alloy: F11, F22, F5, F9
High Yield: ASTM A694 F52, F60

Why Choose JS FITTINGS Forged Flanges?

At JS FITTINGS, we utilize advanced closed-die forging and heat treatment processes to ensure the integrity of our large diameter flanges:

Precision Machining: CNC turned faces for perfect gasket sealing (RF or RTJ).
Material Traceability: 100% PMI and UT testing to ensure zero internal defects.
Certification: All products are supplied with EN 10204 3.1 MTC (Mill Test Certificate).
Legacy: Over 40 years of manufacturing experience since 1983.

Applications

Our ASME B16.47 flanges are widely utilized in:

Oil and Gas Transmission Pipelines
Petrochemical Refineries & Power Plants
Municipal Water Distribution Systems
Marine & Offshore Platforms

Industrial Applications & Reliability

Large diameter flanges are the backbone of critical infrastructure. Since 1983, JS Fittings has supplied ASME B16.47 flanges to municipal water distribution, natural gas transmission, and petrochemical refineries. Our forged process ensures that every flange can withstand significant thermal expansion and internal pressure surges.