Direct factory supply featuring ISO 9001 and PED 2014/68/EU certified forged flanges for critical pressure containment and metering loops.
Deconstructing the operational mechanics, pressure tap geometry, and standard compliance of ASME B16.36 metering assemblies in modern fluid dynamics.
In modern process industries, accurately measuring the volumetric or mass flow rate of fluids—whether liquid, gas, or steam—is fundamental to operational safety, yield optimization, and custody transfer compliance. Among the various differential pressure (DP) flow measurement systems, the Orifice Flange Assembly remains the gold standard globally due to its mechanical simplicity, long-term reliability, zero moving parts, and rigorous standardization under ASME B16.36 and ISO 5167.
An Orifice Flange differs fundamentally from standard pipe flanges (such as ASME B16.5 weld neck or slip-on flanges). While standard flanges serve exclusively as mechanical joint connectors, orifice flanges are purpose-engineered metrology components designed to hold an orifice plate and provide integral differential pressure tapping holes. These pressure taps measure the static pressure differential created before and after the fluid passes through the constricted orifice orifice plate aperture, governed by Bernoulli's Principle and the continuity equation.
Orifice flanges feature precision-drilled radial tapping holes (typically 1/2" NPT or socket weld) positioned exactly 1 inch upstream and 1 inch downstream from the orifice plate face (Flange Taps), eliminating the need for separate pipe wall tapping sleeves.
Each pair of orifice flanges includes heavy-duty jack screws machined into the outer perimeter rim. These screws allow maintenance engineers to spread the flanges effortlessly during line shutdowns to inspect or replace worn orifice plates without damaging gasket faces.
To prevent fluid turbulence that distorts differential pressure signals, orifice flange bores are CNC-machined to match the exact internal pipe diameter (Schedule 40, 80, 160, or custom wall thickness) with stringent concentricity tolerances.
Founded in 1992 in Dingxiang County, Shanxi—China's recognized Hometown of Forging—Yuxin combines 33 years of metallurgical mastery with Industry 4.0 automation.
Analyzing energy transition requirements, high-pressure LNG expanding loops, and international engineering procurement expectations.
The global demand for Orifice Flanges is experiencing a transformation driven by two simultaneous macro-trends: the rapid expansion of traditional oil & gas infrastructure in the Middle East and Americas, and the rapid deployment of clean energy infrastructure, including Hydrogen blending, Liquefied Natural Gas (LNG) regasification networks, and Carbon Capture, Utilization, and Storage (CCUS) projects.
In high-pressure, hazardous fluid metering applications, EPC contractors (Engineering, Procurement, and Construction) and plant operators can no longer afford measurement inaccuracies or joint failures. Flow measurement inaccuracies of even 0.5% in high-volume gas custody transfer pipelines can equate to millions of dollars in unaccounted losses annually. Consequently, global buyers are seeking certified China Orifice Flange suppliers capable of delivering zero-defect forging quality, strict chemical composition controls (such as low carbon equivalents for weldability), and complete mill certification under EN 10204 3.1 / 3.2.
Extreme temperature fluctuations down to -196°C require orifice flanges forged from austenitic stainless steel (ASTM A182 F316/316L) or nickel alloys, with strict Charpy V-Notch impact testing at cryogenic thresholds.
Oilfields containing high concentrations of H2S and CO2 demand sour-service compliant carbon steel (ASTM A105N or A350 LF2) subjected to Hardness testing (HRC ≤ 22) and Hydrogen-Induced Cracking (HIC) resistance.
Supercritical power generation units rely on high-alloy chrome-moly steel orifice flanges (ASTM A182 F11, F22, F91) engineered to resist thermal creep and oxidation up to 600°C under continuous cyclic pressures.
How end-to-end integration—from raw billet heating to 5-axis CNC machining—eliminates middleman markups and guarantees total batch traceability.
The traditional global flange procurement model often involved fragmented supply chains: raw ingots purchased from one mill, forged at a job shop, heat-treated by a contractor, and machined by a third party. This fragmented chain introduced quality risks, extended lead times, and created ambiguity regarding heat-number traceability.
At Shanxi Yuxin Casting & Forging Co., Ltd., we operate a fully vertically integrated manufacturing facility spanning over 50,000 square meters in Dingxiang, Shanxi. By controlling 100% of the manufacturing lifecycle in-house, we deliver substantial economic and technical advantages to international buyers:
Spectrographic chemical analysis of incoming raw steel billets (A105, F304, F316L, A350 LF2) to verify carbon, manganese, silicon, and trace element thresholds prior to heating.
Hydraulic forging hammers and CNC radial-axial ring rolling machines align steel grain structures along flange contours, maximizing tensile strength and fatigue limit.
Normalized, quenched & tempered, or solution annealed in automated heat treatment furnaces with calibrated thermocouples to achieve uniform mechanical properties.
High-precision lathe turning of flange faces, gasket serrations (125-250 µin AARH finish), bore diameter, and radial NPT/socket tap holes to sub-millimeter tolerances.
Comprehensive engineering reference for piping designers, quality managers, and procurement officers.
| Standard / Code | Pressure Class Rating | Size Range Nominal | Facing Options | Common Material Grades | Testing & Documentation |
|---|---|---|---|---|---|
| ASME B16.36 (Orifice Flanges) |
Class 300, 600, 900, 1500, 2500 | 1" to 24" (DN25 – DN600) | Raised Face (RF), Ring Type Joint (RTJ) | ASTM A105, A350 LF2, A182 F304/304L, F316/316L, F11, F22 | EN 10204 3.1 / 3.2, UT (ASTM A388), MT/PT, PMI Spectro, Hydrotest |
| ASME B16.5 (Standard Flanges) |
Class 150 to Class 2500 | 1/2" to 24" (DN15 – DN600) | RF, FF, RTJ, Male & Female, Tongue & Groove | Carbon Steel, Low-Alloy Steel, Stainless Steel, Duplex F51/F53 | Dimensional Inspection Report, Hardness Test, Impact Test (-46°C) |
| ASME B16.47 (Large Diameter) |
Class 75 to Class 900 (Series A & B) | 26" to 60" (DN650 – DN1500) | Raised Face (RF), Flat Face (FF), RTJ | ASTM A105, A350 LF2, A182 F304/L, F316/L, Structural Carbon Q235B | EN 10204 3.1 MTC, UT Flaw Detection, Surface Roughness Metering |
| EN 1092-1 (European Standard) |
PN6, PN10, PN16, PN25, PN40, PN63, PN100 | DN15 to DN3000 (1/2" – 120") | Type A (Flat), Type B1/B2 (Raised), Type C/D (Tongue/Groove) | P245GH, P280GH, C22.8, 1.4301 (304), 1.4404 (316L), 1.4462 (Duplex) | TÜV CERT AD2000-W0, PED 2014/68/EU Module H, ISO 9001:2015 |
| Custom Drawing (Non-Standard) |
Per Client Design (up to 400 bar) | Outer Diameter up to 3,000 mm | Custom O-Ring Groove, Double Tap, Clad Overlay | Inconel 625 Clad, Monel 400, Hastelloy C276, Titanium Gr.2 | 3D CMM Coordinate Inspection, Radiographic Testing (RT) on welds |
Examining technical deployments across international refinery expansion projects, gas transmission loops, and offshore platforms.
Requirement: ASME B16.36 Class 900 RTJ Orifice Flange sets in ASTM A350 LF2 for sour gas custody metering.
Yuxin Solution: Forged with normalized heat treatment, 100% Ultrasonic Testing (UT) to ASTM A388, NACE MR0175 compliance with hardness under 22 HRC, fitted with 1/2" NPT pressure tap plugs and 316SS jack screws.
Requirement: Class 1500 Weld Neck Orifice Flanges in ASTM A182 F22 (2.25% Cr - 1% Mo) for high-temperature hydrogen service.
Yuxin Solution: Full-penetration forged neck, precision CNC bored to Schedule 160 pipe matching, complete with EN 10204 3.2 TÜV Rheinland witness inspection certificate.
Requirement: Compact duplex stainless steel (ASTM A182 F51) orifice meter runs resisting marine atmospheric corrosion.
Yuxin Solution: High Pitting Resistance Equivalent Number (PREN ≥ 34), 100% Liquid Penetrant Testing (PT) on all machined tap threads and gasket ring grooves.
Detailed answers to critical technical questions asked by piping designers, quality inspectors, and procurement managers.
ASME B16.5 covers standard pipe flanges (Weld Neck, Slip-On, Blind, Threaded, Socket Weld) designed primarily for connecting pipes, valves, and pressure vessels. They do not contain pressure tapping holes or jack screws. ASME B16.36 specifically governs Orifice Flanges (Weld Neck, Slip-On, and Threaded). ASME B16.36 flanges are thicker than B16.5 flanges in certain pressure classes to accommodate radial pressure tapping holes (1/2" NPT or socket weld) drilled directly through the flange body. They also incorporate jack screw slots to facilitate mechanical separation during orifice plate replacement.
Orifice plates are thin metallic metering discs clamped tightly between two orifice flanges. Over time, heat, pressure, and process media can cause gaskets to stick tightly to flange raised faces. Jackscrews provide mechanical leverage to push the flanges apart evenly without relying on hammers, chisels, or pry bars—tools that can scratch precision-machined flange faces or distort adjacent piping.
Per ASME B16.36 and ISO 5167, the internal bore of a weld neck orifice flange must match the internal diameter (ID) of the upstream and downstream straight pipe run within strict limits (typically ±0.5% of pipe ID). Any step, lip, or mismatch between the flange bore and pipe wall creates fluid eddies that alter the differential pressure signal, introducing measurement errors into flow computers.
Every flange lot exported by Shanxi Yuxin Casting & Forging Co., Ltd. is supplied with a comprehensive EN 10204 3.1 Mill Test Certificate (MTC) (or EN 10204 3.2 third-party witnessed certificate upon request by TÜV, SGS, or Lloyd's Register). The documentation includes heat number traceability, full ladle chemical analysis, mechanical property test results (Tensile, Yield, Elongation, Hardness, Charpy Impact), heat treatment records, NDT reports (UT/MT/PT), and dimensional check sheets.
Yuxin is located in Dingxiang County, Shanxi Province—the central hub of China's forging industry. This location gives us direct proximity to high-grade steel raw material mills, abundant clean energy for electric forging furnaces, and a highly skilled metallurgical workforce. Coupled with our in-house automated ring rolling and CNC turning equipment, we eliminate sub-contractor markups and achieve high production yields, passing significant cost savings directly to international buyers.
Standard carbon steel (ASTM A105) orifice flanges held in semi-finished blank stock can be CNC machined and shipped within 7 to 15 days. Custom forged or alloy items (A182 F11, F22, F51, A350 LF2) typically require 20 to 35 days depending on raw material billet procurement, heat treatment cycles, and witness inspection schedules.
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