Precision-machined forged steel flanges compliant with ASME B16.5, DIN 2631–2638, and EN 1092-1 Type 11 specifications. Engineered for extreme thermal and cyclical pressure integrity.
Weld Neck Raised Face (WNRF) flanges represent the premier mechanical joint category across critical hydrocarbon transportation, superheated steam channels, and cryogenic chemical facilities. Discover why dimension precision dictates piping longevity.
Unlike slip-on or socket configurations, the tapered hub dimension of a WNRF flange transfers bending stresses smoothly from the flange ring into the host pipe wall. This gradual transition prevents stress concentration at the weld toe, drastically reducing catastrophic failure risks in cyclic fatigue operations.
The standard raised face (RF) height of 2 mm (0.06 inch for Class 150/300) or 7 mm (0.25 inch for Class 600+) concentrates bolt preload over a precisely constrained annular gasket area. With a controlled serrated concentric or spiral finish (Ra 3.2 to 6.3 µm), micro-leak paths are eliminated even under rapid pressure surges.
Bore dimension (B) custom matching to the exact pipe schedule (SCH 40, SCH 80, SCH 160, or XXS) ensures a seamless internal diameter across the butt weld. This eliminates turbulent vortex formation, reduces abrasive erosion wear, and facilitates smooth in-line pipeline inspection (PIG) operations.
Essential reference data for piping designers, quality assurance auditors, and EPC engineers. Dimensions comply with ASME B16.5 and DIN EN 1092-1 standards.
| Nominal Size (NPS) | Outer Diameter (O) | Thickness (C) Min | Raised Face Dia (R) | Length Thru Hub (Y) | Standard Bore (B) SCH 40 | Bolt Circle (W) | Bolt Hole Qty & Dia |
|---|---|---|---|---|---|---|---|
| 1/2" (DN15) Cl. 150 | 88.9 mm (3.50") | 11.2 mm (0.44") | 35.0 mm (1.38") | 47.6 mm (1.88") | 15.7 mm (0.62") | 60.3 mm (2.38") | 4 × Ø15.9 mm |
| 1" (DN25) Cl. 150 | 108.0 mm (4.25") | 14.3 mm (0.56") | 50.8 mm (2.00") | 55.6 mm (2.19") | 26.7 mm (1.05") | 79.4 mm (3.12") | 4 × Ø15.9 mm |
| 2" (DN50) Cl. 150 | 152.4 mm (6.00") | 19.1 mm (0.75") | 92.1 mm (3.62") | 63.5 mm (2.50") | 52.6 mm (2.07") | 120.7 mm (4.75") | 4 × Ø19.1 mm |
| 3" (DN80) Cl. 150 | 190.5 mm (7.50") | 23.9 mm (0.94") | 127.0 mm (5.00") | 69.9 mm (2.75") | 78.0 mm (3.07") | 152.4 mm (6.00") | 4 × Ø19.1 mm |
| 4" (DN100) Cl. 150 | 228.6 mm (9.00") | 23.9 mm (0.94") | 157.2 mm (6.19") | 76.2 mm (3.00") | 102.4 mm (4.03") | 190.5 mm (7.50") | 8 × Ø19.1 mm |
| 6" (DN150) Cl. 150 | 279.4 mm (11.00") | 25.4 mm (1.00") | 215.9 mm (8.50") | 88.9 mm (3.50") | 154.2 mm (6.07") | 241.3 mm (9.50") | 8 × Ø22.2 mm |
| 8" (DN200) Cl. 150 | 342.9 mm (13.50") | 28.6 mm (1.12") | 269.9 mm (10.62") | 101.6 mm (4.00") | 202.7 mm (7.98") | 298.5 mm (11.75") | 8 × Ø22.2 mm |
| 2" (DN50) Cl. 300 | 165.1 mm (6.50") | 22.4 mm (0.88") | 92.1 mm (3.62") | 69.9 mm (2.75") | 52.6 mm (2.07") | 127.0 mm (5.00") | 8 × Ø19.1 mm |
| 4" (DN100) Cl. 300 | 254.0 mm (10.00") | 31.8 mm (1.25") | 157.2 mm (6.19") | 85.7 mm (3.38") | 102.4 mm (4.03") | 200.0 mm (7.88") | 8 × Ø22.2 mm |
* Note: Tolerance limits enforced per ASME B16.5: Outside Diameter ±1.6 mm (≤NPS 24); Bore Diameter ±0.8 mm (≤NPS 10); Hub Thickness ±0.8 mm. Strict calibration records provided in each EN 10204 3.1 Inspection Report.
Located in Dingxiang County, Shanxi Province—internationally recognised as the Flange Capital of the World—Shanxi Yuxin Casting & Forging delivers unprecedented cost-to-performance ratio, advanced closed-loop supply chains, and rapid manufacturing agility.
Continuous forging operation since 1992, retaining deep metallurgical data and forging die archives.
Fully integrated open-die hammers, hydraulic ring rollers, and multi-axis CNC horizontal lathes.
Billet sawing, hot forging, normalising furnaces, CNC turning, and destructive testing done in-house.
Fast-turnaround technical audits, drawing reviews, and custom bevel geometry quotes for global EPCs.
Precision-machined WNRF dimensions provide structural resilience and leak-tight joint sealing across the world's most demanding environments.
Utilising ASTM A350 LF2 Class 1 and duplex stainless steel (A182 F51/F53), our WNRF flanges undergo Charpy V-notch impact validation down to -46 °C and -196 °C, guaranteeing crack arrest capabilities in liquified gas transport lines.
Operating above 450 °C, superheated steam causes rapid relaxation in standard joints. Our chrome-moly A182 F11/F22 WNRF flanges provide superior creep rupture strength, controlled thermal expansion, and leak-free joint sealability.
For harsh chloride environments, Yuxin provides custom WNRF dimensions machined with RTJ (Ring Type Joint) grooves and weld overlay cladding (Inconel 625). This ensures zero pitting corrosion and total hydrostatic structural stability.
Modern international procurement managers demand far more than competitive pricing. Here are the macro shifts shaping high-spec WNRF flange sourcing today.
Counterfeit steel avoidance is critical. Enterprise procurement requires hard-stamped heat numbers directly linked to mill test reports verifying positive material identification (PMI), mechanical tensile parameters, and heat treatment charts.
With the rapid rise of green hydrogen and CCUS (Carbon Capture) infrastructure, flange hubs must possess superior grain orientation without micro-porosity, preventing high-temperature hydrogen attack (HTHA) and embrittlement failures.
Leading engineering contractors mandate PED 2014/68/EU Annex I compliance and AD-Merkblatt W0 certifications. Yuxin routinely hosts witness inspections for dimensional verifications, ultrasonic examinations (UT), and liquid penetrant tests (PT).
Authoritative answers to the most frequent metallurgical and dimensional inquiries submitted by global procurement engineers.
A Weld Neck Raised Face (WNRF) flange features a long tapered hub that is butt-welded to the adjacent pipe, transferring mechanical and cyclical thermal stress directly into the pipe wall. A Slip-On Raised Face (SORF) flange slides over the pipe end and relies on two fillet welds (internal and external). WNRF is mandated for high-pressure, severe temperature, and hazardous duty piping systems.
Matching bore dimensions prevents internal diameter offsets at the welded root pass. If the flange bore does not match the mating pipe schedule, internal steps occur, causing flow restrictions, excessive turbulence, accelerated localized cavitation, and impedance to ultrasonic or caliper pigging.
Yuxin manufactures flanges to ASME/ANSI B16.5, ASME B16.47 (Series A & B), EN 1092-1, DIN 2631–2638, JIS B2220, BS 4504, and GOST standards, across pressure ratings from Class 150 to 2500 lb, and PN6 to PN400. Custom drawing-based forgings and tube sheets are fully supported.
Every production lot ships with complete EN 10204 3.1B Inspection Certificates stating melt heat numbers, ladle chemical spectrometry analysis, tensile/yield/elongation metrics, hardness test values, and heat treatment charts. Third-party testing (PMI, UT, MT, RT) reports are available on demand.
Standard carbon steel dimensions in standard schedules ship within 7–15 days from finished billet inventory. Engineered alloy steels, custom hub lengths, or heavy forged flanges require 25–35 days. We provide flexible low-MOQ evaluation batches for qualified distributors and EPC partners.
Standard raised face finishes feature continuous spiral or concentric serrations with Ra 3.2–6.3 µm (125–250 µin AARH) for composite gaskets, or smooth 1.6 µm for spiral wound gaskets. Surface protection options include transparent rust inhibitor varnish, black immersion oil, hot-dip galvanizing, and synthetic resin primer.
Full-spectrum factory inventory including reducing flanges, expansion joints, ring forgings, tube sheets, and custom-bored fittings.
Our metallurgical and production engineers will analyze your project piping schedules, bevel geometry requirements, and custom drawings to deliver guaranteed compliant proposals within 24 hours.