In modern international piping engineering, the designation PN (Pression Nominale / Nominal Pressure) serves as the fundamental metric rating system established under European Standards (EN 1092-1) and historical Deutsches Institut für Normung (DIN) frameworks. Understanding the precise relationship between PN flange sizes, pitch circle diameters (PCD), bolt hole geometries, and wall thicknesses is essential for mechanical engineers, piping designers, and procurement managers operating across chemical processing, power generation, and marine infrastructure projects.
China has consolidated its position as the world's primary manufacturing hub for forged steel PN flanges by harmonizing domestic GB standards (such as GB/T 9112 through GB/T 9124) directly with international ISO 7005-1 and European EN 1092-1 specifications. As a specialized manufacturer operating out of Shanxi's advanced forging cluster, our production facilities yield fully certified, high-yield forged PN flanges ranging from micro-bore DN 10 (3/8") up to ultra-large scale DN 3000 (120").
Flat face or raised face slip-on plate flanges utilized primarily in low-to-medium pressure utility pipelines (PN 6 to PN 40). Machine-drilled bolt circles ensure seamless alignment with low-cost structural piping.
Engineered with a long tapered hub that transfers stress directly from the flange body to the pipe wall. Essential for high-pressure severe service conditions (PN 63 up to PN 400) subject to cyclic thermal loading.
Solid forged disc designed to seal off pressure vessel nozzles or pipe ends. Manufactured to withstand full system design pressure with customized tapped gauge ports upon request.
To streamline project engineering and cross-standard cross-referencing, the matrix below details the standardized mechanical dimensions for common nominal sizes (DN) across standard pressure classes (PN 10, PN 16, PN 25, and PN 40). All data reflects forged steel tolerances according to EN 1092-1 Annex A.
| Nominal Size (DN) | Pressure Nominal (PN) | Flange Outer Dia (D, mm) | Pitch Circle Dia (K, mm) | Number of Bolt Holes (n) | Bolt Hole Dia (L, mm) | Flange Thickness (C, mm) | Approx Weight (kg) |
|---|---|---|---|---|---|---|---|
| DN 15 (1/2") | PN 10 - PN 40 | 95 | 65 | 4 | 14 | 16 | 0.81 |
| DN 25 (1") | PN 10 - PN 40 | 115 | 85 | 4 | 14 | 18 | 1.23 |
| DN 50 (2") | PN 10 / PN 16 | 165 | 125 | 4 | 18 | 18 | 2.45 |
| DN 50 (2") | PN 25 / PN 40 | 165 | 125 | 4 | 18 | 20 | 2.82 |
| DN 100 (4") | PN 16 | 220 | 180 | 8 | 18 | 20 | 4.62 |
| DN 100 (4") | PN 40 | 235 | 190 | 8 | 22 | 24 | 7.54 |
| DN 200 (8") | PN 16 | 340 | 295 | 12 | 22 | 24 | 11.50 |
| DN 200 (8") | PN 40 | 375 | 320 | 12 | 30 | 34 | 24.60 |
| DN 500 (20") | PN 16 | 715 | 650 | 20 | 33 | 44 | 72.50 |
| DN 1000 (40") | PN 25 | 1320 | 1240 | 28 | 42 | 88 | 485.00 |
* Note: Dimensional variations exist based on flange type (e.g., Type 11 Weld Neck vs. Type 01 Plate) and facing options (Raised Face Type B1/B2, Tongue & Groove Type C/D, or Ring Type Joint RTJ). Custom drilling and non-standard hub lengths are routinely manufactured based on CAD drawings.
PN pressure-rated flanges are utilized globally in critical infrastructure projects where thermal fatigue, structural vibration, and corrosive media demand absolute integrity. Based on decades of engineering field data, our PN flange products are specified across distinct industrial applications:
Large-diameter (DN 600 to DN 2400) Type 01 flat flanges and Type 11 weld necks forged in low-carbon steel (P250GH / S235JR) or Duplex stainless steel (1.4462). Coated with fusion-bonded epoxy or zinc-rich anti-corrosion finishes for subsea or reverse-osmosis service.
Heavy-wall ASTM A105 / A350 LF2 and A182 F316L forged hubbed weld neck flanges featuring Type B2 (smooth finish) or Type C (tongue) facings. Engineered for zero VOC fugitive emissions under high-pressure cracking operations.
Thermal expansion joint flanges and tube sheet assemblies supplied to municipal energy grids across Europe and Central Asia. Fine-grain heat-treated forgings rated for continuous temperature cycles from -40°C to +450°C.
China’s Shanxi province—specifically the specialized forging cluster in Dingxiang—represents the global apex of industrial flange manufacturing. Shanxi Shanxi Yuxin Casting & Forging Co., Ltd. operates directly within this ecosystem, leveraging vertically integrated production to offer global buyers unparalleled supply security, cost efficiency, and technical rigor.
From raw steel billet heating in computer-controlled gas furnaces to precision hydraulic ring rolling and 5-axis CNC machining, every production step is performed within our facility. This eliminates sub-contractor delay risks and guarantees metallurgical integrity.
We maintain a rolling inventory of over 5,000 metric tons of prime carbon steel (A105, P250GH, Q235B), alloy steel (F11, F22), and stainless grades (304L, 316L, 904L). This structural buffer insulates international buyers from global steel market volatility.
Every single flange delivered is permanently stamped with a unique heat number. We issue comprehensive Mill Test Certificates (MTC) detailing ladle chemical composition, tensile strength, yield point, impact energy at low temperatures, and hardness tests.
As heavy industry transitions toward hydrogen transportation, carbon capture utilization and storage (CCUS), and smart pipeline monitoring, flange manufacturing must evolve beyond traditional static mechanical components. Our R&D engineering division is actively deploying advanced metallurgical and digital innovations across our PN flange lines:
Embedding micro-scale piezoelectric strain gauges and fiber-optic temperature sensors directly into high-pressure PN 100+ flange hubs to provide real-time bolt load monitoring and leak detection via Industrial IoT (IIoT) architecture.
Developing ultra-clean micro-alloyed carbon steels with restricted sulfur and phosphorus content (<0.005%) alongside specialized heat-treatment cycles (Normalized & Tempered) to eliminate hydrogen-induced cracking (HIC) in green hydrogen transmission lines.
Transitioning factory reheating furnaces to hybrid electric-induction and natural gas/hydrogen burners, reducing the embedded carbon footprint of our forged steel products by 35% to align with European CBAM regulations.
Navigating international trade requirements demands compliance with regional industrial directives. Shanxi Shanxi Yuxin Casting & Forging Co., Ltd. holds comprehensive international quality certifications, enabling seamless integration into major global engineering projects:
Mandatory for pressure equipment deployed across the European Economic Area. Our plant is audited and certified by TÜV Rheinland to supply material conforming to AD 2000-Merkblatt W0.
Rigorous quality control management system governing raw material receipt, dimensional verification, non-destructive testing (NDT), and export seaworthy packaging.
Direct answers from our metallurgical and engineering technical desk addressing critical buyer inquiries:
