GOST Flanges Suppliers

Russian Standard Steel Flanges

GOST Flanges Suppliers

GOST Standard Flanges: Dimensions | Specifications | Material Grade | Standards | About GOST 12820-80 Flange | All Product Types

GOST flanges are manufactured in accordance with Russian national standards, primarily GOST 12820, GOST 12821, and GOST 12822, covering various flange types such as flat flanges (similar to slip-on), weld neck flanges, and blind flanges. These flanges are designed to handle nominal pressures ranging from PN6 to PN250 and sizes from DN10 up to DN1600, making them suitable for high-pressure and high-temperature piping systems in industrial plants and oil & gas infrastructure.

At Nutech, we manufacture and export a complete range of GOST standard steel flanges with precision-engineered tolerances and superior surface finishes. These flanges are typically produced in carbon steel, stainless steel, and alloy steel materials to meet the performance requirements of pressure vessels, pipelines, and valve assemblies under Russian and CIS-based engineering codes.

Each GOST flange is fabricated using advanced forging and machining processes, ensuring compliance with dimensional accuracy, face type alignment (Raised Face, Flat Face, or RTJ on request), and international quality certifications. These flanges are available with drilling patterns that conform to matching GOST standards, making them interchangeable with Russian equipment.

With increasing global demand for Russian standard pipe flanges, especially in industries like chemical processing, oil refining, power generation, and shipbuilding, our GOST flange solutions are widely used across export markets in Europe, the Middle East, and South America. Custom marking, anti-corrosion coatings, and test certifications such as EN 10204 3.1 are provided on request to ensure full compliance with end-user requirements.

GOST Flanges Dimensions, Pressure Classes, Face Types, and Standards as per Russian Flange Specifications.

For complete technical details, including dimensions, pressure rating classes, weight charts, sizes, tolerances, and material specifications of our GOST 12821-80 Standard Flanges, please download the full Catalog PDF below.

Manufacturer of Forged GOST Standard Flanges from PN6 to PN250 – Designed for Russian Industrial and Pipeline Applications.

Technical Specifications of GOST Flanges

Specification Details
Standard GOST 12820-80, GOST 12821-80, GOST 12822-80, GOST 33259-2015
Type Weld Neck, Slip-On, Blind, Threaded, Loose Flanges (Lap Joint), Integral Flanges
Size Range DN10 to DN1600 (½″ to 64″)
Pressure Ratings PN6, PN10, PN16, PN25, PN40, PN63, PN100, PN160, PN250
Face Types Raised Face (RF), Flat Face (FF), Tongue & Groove, Male & Female
Drilling Standard According to GOST bolt-hole patterns and pitch circle diameters
Surface Finish Stock Finish, Smooth Finish, Serrated Finish as per Russian norms
Coating Options Black Paint, Anti-Rust Oil, Galvanized, Customized Coating (on request)
Testing & Inspection Hydrostatic Test, Visual & Dimensional Check, PMI, NDT (on request)
Certifications EN 10204 3.1 / 3.2, ISO 9001:2015, PED 2014/68/EU, EAC (TR CU) for CIS countries
Application Industries Oil & Gas, Petrochemical, Water Supply, District Heating, Power Plants, Mining, Construction
Origin Made in India (by Nutech Overseas)
Export Network USA, Europe, and Middle East

Complete Material Grade Chart - GOST 12822-80

Material Category GOST 33259-2015 Flange Grades
Stainless Steel GOST Flange ASTM A182 F304 / F304L / F304H, F316 / F316L / F316Ti, F310, F309S, F317 / F317L, F321 / F321H, F347 / F347H, F904L, ASTM A351 CF3 / CF3M / CF8 / CF8M / CF8C, DIN 1.4301, 1.4306, 1.4307, 1.4311, 1.4401, 1.4404, 1.4408, 1.4409, 1.4541, 1.4571, 1.4550, 1.4435, 1.4539
Duplex Steel GOST Flange ASTM A182 F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61, UNS S31803 / S32205
Super Duplex Steel GOST Flange ASTM A182 F53 / F55 / F57 / F59 / F60 / F61, UNS S32750 / S32760
Carbon Steel GOST Flange ASTM A105 / A105N, ASTM A350 LF2, ASTM A694 F52 / F56 / F60 / F65 / F70 / F80, ASTM A216 WCB, DIN 1.0460 / 1.0402 / 1.0619, Die Steel, Mild Steel
Alloy Steel GOST Flange ASTM A182 F5 / F9 / F11 / F12 / F22 / F91, AISI 4130 / 4140
Nickel Alloy GOST Flange Nickel 200 / 201, ASTM B564
Monel GOST Flange Monel 400 (UNS N04400), Monel K500 (UNS N05500), ASTM B564
Inconel GOST Flange Inconel 600 / 601 / 625 / 690 / 718 / 783 / X750, ASTM B564
Incoloy GOST Flange Incoloy 800 / 800H / 800HT (UNS N08800), Incoloy 825 (UNS N08825), Incoloy 925, ASTM B564
Hastelloy GOST Flange Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X, ASTM B564
Alloy 20 GOST Flange Alloy 20 / 20Cb-3, Carpenter® 20, ASTM B462
254 SMO GOST Flange SMO 254 / 6Mo, UNS S31254, DIN 1.4547, ASTM A182
Copper Nickel GOST Flange Copper Nickel 90/10 (C70600), 70/30 (C71500), UNS C71640, ASTM B61 / B62 / B151 / B152
Copper GOST Flange TP1, TP2, T1, T2, C10100–C12300, C14200–C17200, C21000–C71520, including C10930, C11000, C11400, C12000, C12200, C26000, C28000, C33000, C44300, C70600, etc.
Brass GOST Flange Grades 3602, 2604, H59, H62, etc.
Aluminium GOST Flange Aluminium Grades 5052, 6061, 6063, 2017, 7075, etc.
Titanium GOST Flange ASTM B381 Gr.1 / Gr.2 / Gr.4 / Gr.5 / Gr.7, UNS R50250 / R50400 / R50550 / R50700 / R52400 / R53400 / R56320 / R56400
Other Special Grades Al6XN, Tin Bronze, Aluminium Bronze, Lead Bronze, Nimonic 75 / 80A / 90

International Flange Standards We Manufacture & Supply

What is the significance of GOST 12820-80 and GOST 12821-80 standards in flange manufacturing?

GOST 12820-80 and GOST 12821-80 are two of the most widely followed Russian standards that define the dimensional, design, and pressure specifications for steel flanges used in pipelines and pressure vessels.

  • GOST 12820-80: Governs flat flanges (often used for welding), including their sizes, bolt circle diameters, and pressure ratings up to PN16.
  • GOST 12821-80: Covers steel welding neck flanges for higher-pressure applications, typically from PN6 to PN160, offering better strength and leak-proof connections.
  • Both standards define:
    • Bolt-hole patterns and tolerances
    • Flange face types (FF, RF, Tongue & Groove)
    • Material compatibility and dimensional tolerances

These standards are crucial for ensuring compatibility in Russian and CIS market pipelines, aligning with their engineering codes and infrastructure requirements. Exporters and manufacturers catering to these regions must strictly adhere to these GOST norms.

What are the commonly used pressure ratings and dimensions in GOST standard flanges?

GOST flanges are designed according to specific pressure classes and dimensional norms set by Russian engineering standards. The most common pressure ratings include:

  1. PN6, PN10, PN16, PN25, PN40, PN63, PN100, and PN160

Each rating corresponds to a maximum working pressure in bar. These flanges are available in a wide range of diameters, generally from:

  1. DN10 to DN2000, accommodating both low-pressure and high-pressure industrial systems.

Typical dimensions specified include:

  1. Flange outer diameter (OD)
  2. Bolt circle diameter (BCD)
  3. Number and size of bolt holes
  4. Flange thickness (C)
  5. Raised face or sealing surface details (type B, C, D, etc.)

These dimensions are crucial to ensure proper sealing, mechanical integrity, and compatibility in pressure pipeline applications. Manufacturers exporting to Eastern Europe, Russia, Kazakhstan, and CIS countries rely on accurate GOST-compliant flanges to meet regional infrastructure standards.

What do PN ratings mean in GOST flanges and how do they compare to ANSI pressure classes?

PN (Pressure Nominale) ratings in GOST flanges represent the maximum allowable pressure (in bars) at a reference temperature. These are crucial when selecting flanges for pipelines in industries like oil & gas, chemical processing, and waterworks.

Here’s how PN ratings typically align and compare with ANSI pressure classes:

  • PN 6 ≈ Class 150
  • PN 10 ≈ Class 150
  • PN 16 ≈ Class 150–300
  • PN 25 ≈ Class 300
  • PN 40 ≈ Class 600
  • PN 63, 100, 160 = Higher pressure systems (no direct ANSI equivalent; used in specialized pipelines)

Key Points to Understand:

  • PN ratings are metric-based, while ANSI uses psi-based pressure classes.
  • GOST flanges are often chosen for systems designed under Russian, CIS, and Eastern European norms.
  • Compatibility between GOST and ANSI systems requires special attention to drilling patterns, face types, and bolt holes.

This comparison helps global buyers understand the pressure compatibility when sourcing GOST flanges from manufacturers like us.

What are the different types of flanges covered under GOST standards?

GOST standards define a comprehensive range of industrial flange types, each designed for specific applications, pressure classes, and connection methods. Below are the most recognized GOST flange types used across process industries:

  1. GOST 12820-80 – Flat Welding Flanges (Type 01):

    Designed for butt welding with pipe, suitable for lower-pressure pipelines and systems requiring easy installation.

  2. GOST 12821-80 – Weld Neck Flanges (Type 11):

    Ideal for high-pressure and high-temperature environments, offering superior strength due to the long tapered hub.

  3. GOST 12822-80 – Blind Flanges (Type 05):

    Used to close off the ends of piping systems and pressure vessels, commonly applied in maintenance and testing.

  4. GOST 12815-80 – Flange Connection Standards:

    Governs bolt-hole arrangements, sealing faces (raised, flat, tongue & groove), and flange matching guidelines.

  5. GOST 12836-67 – Threaded Flanges (Type 13):

    Suitable for systems where welding is not feasible, often used in smaller diameter, low-pressure applications.

  6. GOST 12823-67 – Loose Flanges with Welded Ring (Type 21):

    Allows for rotational alignment of bolt holes, commonly used where frequent dismantling is required.

  7. GOST 28759.3-90 – Integral and Custom Machined Flanges:

    Special-purpose flanges produced as part of a forged or machined fitting, often for critical or bespoke systems.

Each type is engineered to meet specific industrial conditions as per Russian engineering standards, ensuring compatibility, pressure integrity, and durability in complex piping environments.

How does the surface finish of GOST flanges affect gasket sealing performance?

The surface finish of a flange plays a critical role in ensuring the effectiveness and longevity of the gasket seal. In GOST flange manufacturing, surface roughness is tightly controlled as per the sealing face type selected, such as flat face (FF), raised face (RF), or tongue & groove (T&G). Here’s how it impacts performance:

  • Rougher finishes (e.g., spiral serrated 3.2 to 6.3 µm Ra):

    These are preferred for soft gaskets like graphite or PTFE, as they allow the gasket to embed into the serrations, creating better sealing under lower bolt loads.

  • Smoother finishes (e.g., Less Than 1.6 µm Ra):

    Suitable for metallic gaskets such as ring-type joints or jacketed gaskets, where a tighter metal-to-metal seal is required.

  • GOST Sealing Face Standards:

    The standards define precise machining tolerances to ensure uniformity, minimize leakage risk, and improve gasket lifespan under pressure or thermal cycling.

  • Impact on Leak Prevention:

    A properly selected and machined surface finish minimizes micro-paths for fluid escape, especially in critical services like steam, gas, or corrosive fluids.

Correct gasket compatibility and surface finish selection in accordance with GOST specifications is essential for achieving a leak-proof, maintenance-free pipeline system.

Do you export GOST standard flanges internationally, and which countries are your primary export markets?

Yes, we export high-quality GOST standard flanges globally, catering to various industries that require Russian and CIS-compliant flange connections. Our manufacturing and export processes strictly adhere to GOST specifications and international shipping norms.

Primary Export Destinations:

  • Russia and CIS Countries: Kazakhstan, Belarus, Uzbekistan, Armenia, Azerbaijan
  • Middle East: UAE, Saudi Arabia, Qatar, Oman, Iraq
  • Europe: Poland, Bulgaria, Romania, Serbia, Ukraine
  • Asia & Africa: Vietnam, Indonesia, Egypt, South Africa

Why Global Clients Choose Us for GOST Flanges:

  • Strict compliance with GOST flange specifications including GOST 12815, GOST 12820, GOST 12821, and others
  • Availability in pressure ratings from PN6 to PN250 and sizes from DN10 to DN2000
  • Durable surface coatings like zinc, anti-corrosion black paint, or hot-dip galvanizing
  • Custom documentation for international projects including Certificate of Origin, Test Reports, and Inspection Certificates
  • On-time delivery and custom packaging suitable for marine or air shipments

Our capability to manufacture and export GOST flanges with precise tolerances and fast lead times makes us a preferred supplier for both EPC contractors and government utility projects.

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