Explore certified forged blind plate flanges, weld neck components, slip-ons, and high-pressure piping items manufactured per ASME B16.5, ASME B16.47, and EN 1092-1 standards.
A Blind Plate Flange (also designated as EN 1092-1 Type 05 or DIN 2527) is a solid forged circular plate engineered without a central bore. It serves as an absolute pressure sealing boundary designed to terminate a piping system, cap pressure vessel nozzles, or isolate fluid flow during maintenance, hydrostatic testing, and system expansions.
Unlike open-bore flanges (such as Weld Neck, Slip-On, or Socket Weld flanges), which transfer axial loads through pipe walls, a blind flange absorbs the full hydrostatic end force created by internal fluid pressure across its entire surface area. This operational condition generates severe bending moments across the center disk and concentrated shear stresses along the bolt circle.
The minimum required thickness ($t$) for an unstayed flat blind flange under internal pressure is calculated using ASME Boiler and Pressure Vessel Code (BPVC) guidelines:
Where: d = effective gasket diameter; P = internal design pressure; S = maximum allowable stress value of material at design temperature; C = attachment factor (typically 0.30 for bolted covers); W = total bolt load; h_G = gasket moment arm.
Solid single-piece forging used for permanent line ends or scheduled access points. Available in Raised Face (RF), Flat Face (FF), and Ring Type Joint (RTJ) facing configurations.
Combines a solid blind disk and an open ring spacer connected by a web. Enables visual verification of positive line isolation without risk of misplacing piping components.
Independent solid handles (paddle blind) or open rings (paddle spacer) utilized in large-diameter lines where spectacle blinds exceed crane weight capabilities.
When evaluating China Blind Plate Flange Suppliers, international procurement teams must analyze the macro-economic and technical cluster dynamics of Dingxiang County, Shanxi Province—officially designated as the "Hometown of Forging in China."
Located adjacent to major steel production hubs including Taiyuan Iron and Steel (TISCO) and Baotou Steel, manufacturers such as Shanxi Yuxin Casting & Forging Co., Ltd. (Est. 1992) secure direct mill-certificated forged billets (ASTM A105, A350 LF2, F304/316). This direct link guarantees low freight overheads, precise melt-heat selection, and complete chemical composition verification prior to forging.
The Dingxiang ecosystem houses 1,000 to 6,000-ton hydraulic forging presses and automated ring-rolling mills. Closed-die forging forces internal steel grain flow structures to align along the contour of the blind flange disk. This refined grain flow eliminates porosity, increases impact resistance, and enhances structural strength compared to flame-cut plate flanges.
Selection of the appropriate material grade depends on operational design temperatures, system pressure classes, corrosion allowances, and media reactivity (such as sour H2S gas or subzero LNG lines).
| Material Category | ASTM Standard | EN / DIN Standard | Design Temperature | Yield Strength (Min) | Key Industrial Applications |
|---|---|---|---|---|---|
| Carbon Steel | ASTM A105 / A105N | EN 1092-1 P250GH / C22.8 | -29°C to 425°C | 250 MPa (36 ksi) | Oil & Gas Distribution, Steam Headers, Refining |
| Low-Temp Carbon Steel | ASTM A350 LF2 Class 1 | EN 10222-4 P280GH | -46°C to 345°C | 250 MPa (36 ksi) | Cryogenic Gas Handling, Arctic Pipelines, LPG |
| Austenitic Stainless | ASTM A182 F304L / F316L | EN 1092-1 1.4307 / 1.4404 | -196°C to 600°C | 170–205 MPa | Chemical Processing, Offshore Marine, Food & Pharma |
| Duplex Stainless | ASTM A182 F51 / F53 / F55 | EN 10222-5 1.4462 / 1.4410 | -50°C to 280°C | 450–550 MPa | Subsea Flowlines, Desalination, Sour Gas Wellheads |
| Alloy Steel | ASTM A182 F11 / F22 / F91 | 13CrMo4-5 / 10CrMo9-10 | -29°C to 650°C | 205–415 MPa | High-Pressure Steam Turbines, Hydrocrackers |
* For NACE MR0175 / ISO 15156 sour service compliance, forged carbon steel flanges require controlled hardness testing (maximum 22 HRC / 237 HBW) and specific post-weld heat treatment (PWHT) or stress relieving to prevent Hydrogen-Induced Cracking (HIC) and Sulfide Stress Corrosion Cracking (SSCC).
Blind plate flanges provide vital system safety functions across critical heavy infrastructure projects worldwide:
Class 900 to Class 2500 API 6A / ASME B16.5 Ring Type Joint (RTJ) blind flanges seal Christmas tree valves and manifold headers operating under pressures up to 10,000 PSI. High yield-strength alloy forgings prevent pressure boundary degradation under severe vibration.
Large-diameter blind flanges (ASME B16.47 Series A/B up to 60") serve as manways and inspection access covers on catalytic crackers and hydrotreating reactors, requiring precise CNC serrated gasket faces (AARH 125-250 µin) to prevent fugitive emissions.
ASTM A350 LF2 and Stainless 316L blind plates undergo Charpy V-Notch impact testing at -46°C to -196°C, ensuring high fracture toughness and preventing catastrophic brittle fractures during cryogenic boiling and transfer operations.
To adhere to Google's E-E-A-T principles and ensure industrial integrity, buyers must verify manufacturer technical capabilities through documented quality assurance steps:
Every blind plate flange produced by Shanxi Yuxin Casting & Forging Co., Ltd. features hard-stamped heat numbers matching a mill test certificate (MTC) per EN 10204 3.1 (or 3.2 third-party witnessed certification by TÜV, SGS, or Bureau Veritas). MTCs outline full chemical analysis, yield/tensile strength, elongation, hardness values, and heat treatment conditions (Normalized, Quenched & Tempered).
For critical pressure applications, blind flanges undergo Ultrasonic Testing (UT) per ASTM A388 to detect internal voids or inclusions within thick disks. Surface inspection includes Magnetic Particle Testing (MT) for carbon steels or Liquid Penetrant Testing (PT) for stainless/duplex alloys, verifying zero surface defects prior to anti-corrosion coating.
The Chinese forging industry is undergoing a structural transition toward high-precision automated manufacturing and environmental sustainability:
CNC lathes equipped with real-time laser measurement correct serration depth and flange thickness on-the-fly, ensuring facing concentricity tolerances within ±0.05 mm.
Transitioning from coal/gas furnaces to medium-frequency electric induction heaters reduces scale formation, improves forging heat uniformity, and decreases carbon intensity.
Development of specialized ultra-low-porosity forged blind plates engineered to resist hydrogen embrittlement in high-pressure green H2 transport lines up to 700 bar.
Explore additional specialized components manufactured by Shanxi Yuxin Casting & Forging Co., Ltd., including custom tube sheets, lap joint assemblies, and ASME B16.47 heavy flanges.
Common inquiries from piping engineers, project estimators, and global procurement agents answered by our senior metallurgy team.
Established in 1992 in the Zhuangli Enclave Industrial Zone, Dingxiang County, Shanxi Province, China. Operating under an integrated quality system certified by TÜV Rheinland ISO 9001:2015, PED 2014/68/EU, and AD 2000-Merkblatt W0.
Factory Address: Zhuangli Industrial Zone, Dingxiang County, Shanxi Province, China
Telephone: +86-350-6071768 | Mobile: +86 150 3443 1989
Export Desk Email: [email protected] | [email protected]
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