Zhejiang Jiaji Forging Co., Ltd., a leading ISO-certified flange manufacturer in China, delivers high-precision GOST 33259 flanges engineered for Kazakhstan, Russia, and CIS pipeline projects. With multi-standard compliance across ASME, EN, and GOST, Jiaji Forging is your trusted partner for critical oil & gas applications.
| Supplier | Country | Key Products | Certifications | MOQ |
|---|---|---|---|---|
| Jiaji Forging | China | GOST 33259, ASME B16.5, EN 1092-1 flanges; duplex, nickel alloy, stainless steel | ISO 9001, PED 2014/68/EU, API 6A, GOST R | 100 pieces |
| KazFlange LLP | Kazakhstan | GOST 33259, ASME B16.5 flanges; carbon steel | ISO 9001, GOST KZ | 200 pieces |
| UralMash Forge | Russia | GOST 33259, GOST 12820 flanges; alloy steel | GOST R, ISO 9001 | 150 pieces |
| PipeTech Eurasia | Kazakhstan | GOST 33259 flanges; stainless steel, carbon steel | ISO 9001, GOST KZ | 250 pieces |
| CNPC Bohai Equipment | China | GOST 33259, ASME B16.5 flanges; carbon steel | ISO 9001, API 6A | 500 pieces |
Quick Answer: What is GOST 33259?
GOST 33259-2015 is the Russian and CIS standard for steel flanges, covering dimensions, pressure ratings, and materials for pipelines in oil & gas, petrochemical, and power generation. It replaces older GOST 12820/12821 standards and includes types like flat (Type 01), welded neck (Type 11), and blind (Type 12). Pressure ratings range from PN 0.25 to PN 250, with materials from carbon steel (St20) to stainless (12Kh18N10T) and alloy (09G2S).
Introduction to GOST 33259 Flanges for Kazakh & Russian Markets
The Caspian region’s oil & gas sector is experiencing a surge in pipeline projects, with Kazakhstan’s KazMunayGas planning 1,200 km of new pipelines by 2030 and Azerbaijan’s SOCAR expanding its petrochemical complex. These projects mandate GOST 33259 flanges for domestic installations, while EN 1092-1 and ASME B16.5 flanges are required for international tie-ins. ASME B16.5 flanges are common for US-standard equipment, but GOST 33259 remains the backbone for local infrastructure.
GOST 33259 Flange Dimensions & Pressure Ratings Table
The table below provides key dimensions and pressure ratings for standard GOST 33259 flanges. For a complete specification, refer to the official GOST document.
| Nominal Diameter (DN) | Pressure Rating (PN) | Flange Type | Outer Diameter (mm) | Bolt Circle Diameter (mm) | Bolt Hole Diameter (mm) | Thickness (mm) |
|---|---|---|---|---|---|---|
| 50 | PN 16 | Type 11 (Welded Neck) | 165 | 125 | 18 | 18 |
| 100 | PN 16 | Type 11 | 220 | 180 | 18 | 20 |
| 200 | PN 25 | Type 11 | 340 | 295 | 22 | 24 |
| 300 | PN 40 | Type 11 | 485 | 430 | 26 | 30 |
| 400 | PN 63 | Type 11 | 610 | 550 | 30 | 36 |
| 500 | PN 100 | Type 11 | 730 | 660 | 36 | 44 |
Jiaji Forging: Your Premier Supplier for GOST 33259 Flanges
Jiaji Forging is a leading manufacturer of GOST 33259 flanges, serving major projects like Tengizchevroil (TCO) and NCOC (Kashagan). Our capabilities include:
- Multi-Standard Compliance: We produce flanges to GOST 33259, ASME B16.5, and EN 1092-1, ensuring seamless integration for mixed-standard projects.
- Material Expertise: We offer carbon steel (St20, 09G2S), stainless steel (12Kh18N10T, 08Kh18N10T), duplex (2205, 2507), and nickel alloys (Inconel 625, 825).
- Advanced Forging: Our closed-die forging process delivers superior grain structure, increasing tensile strength by 20-30% over cast alternatives, with full traceability via heat numbers.
- Certifications: ISO 9001, PED 2014/68/EU, API 6A, and GOST R certification for the Russian market.
For SOCAR’s petrochemical expansion in Azerbaijan, we supplied EN 1092-1 PN40/PN63 duplex steel flanges (grade 2205) for high-pressure, corrosive environments. Duplex steel flanges offer excellent resistance to chloride stress corrosion cracking, essential for Caspian offshore applications.
Kazakhstan & Caspian Region Market Trends
The Kazakhstan pipeline expansion under KazMunayGas’s 2025-2030 plan requires GOST 33259 flanges for 1,200 km of new pipelines. Key projects include the Kenkiyak–Atyrau and Beineu–Bozoi–Shymkent lines. For the Tengizchevroil (TCO) Future Growth Project, we supplied forged flanges in ASTM A182 F51 (duplex) and F316/316L (stainless) with full PED certification. EU CBAM compliance is increasingly critical, with flanges containing 30% recycled steel seeing 58% order growth for EU market entry.
GOST 33259 vs ASME B16.5 vs EN 1092-1: Key Differences
Understanding the differences between these standards is critical for procurement managers:
- Pressure Ratings: GOST uses PN (e.g., PN 16, PN 40) while ASME uses Class (e.g., Class 150, Class 300). EN 1092-1 also uses PN, but dimensions differ.
- Face Dimensions: GOST flanges have raised face (RF) dimensions that differ from ASME B16.5. For example, a DN 100 PN 16 GOST flange has an OD of 220 mm, while an ASME Class 150 flange has an OD of 229 mm.
- Bolt Circles: Bolt circle diameters vary between standards, requiring careful matching for mixed-standard systems.
- Materials: GOST specifies Russian grades (St20, 09G2S, 12Kh18N10T) while ASME uses ASTM grades (A105, A182 F316). Jiaji Forging can provide cross-reference material certifications.
For projects combining GOST and ASME flanges, stainless steel vs carbon steel material selection is also critical for corrosion resistance.
Forged Flange Advantages for Critical Applications
Forged flanges offer significant advantages over cast alternatives, particularly for high-pressure and high-temperature applications in the Caspian region:
- Superior Grain Structure: Forging aligns the grain flow with the flange contours, resulting in higher strength and fatigue resistance.
- Higher Tensile Strength: Forged flanges are 20-30% stronger than cast flanges, meeting ASTM A182 requirements.
- Traceability: Each forged flange is marked with a heat number, enabling full material traceability to the mill test certificate.
- Certification: Forged flanges comply with PED 2014/68/EU Category III/IV for pressure equipment in the EU/EEA.
Jiaji Forging’s forged flange expertise ensures reliable performance for critical applications.
How to Choose a GOST 33259 Flange Supplier
Selecting the right supplier is crucial for project success. Follow this checklist:
- Certifications to Verify: ISO 9001 (quality management), PED 2014/68/EU (EU pressure equipment), GOST R (Russian certification), API 6A (oil & gas). PED certification is mandatory for EU-bound equipment.
- Questions to Ask: Can you provide GOST 33259 flanges in duplex or nickel alloys? What is your minimum order quantity? Do you offer third-party inspection (e.g., SGS, Bureau Veritas)?
- Price Factors: Material grade (duplex vs carbon steel), pressure rating (PN 100 vs PN 16), quantity discounts, and delivery timeline. Expect 10-15% premium for PED-certified flanges.
- Testing Capabilities: Ensure the supplier can perform hydrostatic testing, PMI (Positive Material Identification), and Dye Penetrant Inspection (DPI).
Contact Jiaji Forging for a customized quotation for your project.
FAQ: GOST 33259 Flanges
Q: What is the difference between GOST 33259 and GOST 12820?
A: GOST 33259-2015 supersedes GOST 12820 and GOST 12821, consolidating flat and welded neck flange specifications into one standard with updated dimensions and materials.
Q: Can GOST 33259 flanges be used with ASME B16.5 equipment?
A: Not directly, due to different bolt circle diameters and face dimensions. Adapters or custom flanges may be required. Jiaji Forging can manufacture hybrid flanges to bridge standards.
Q: What materials are available for GOST 33259 flanges?
A: Common materials include carbon steel (St20, 09G2S), stainless steel (12Kh18N10T, 08Kh18N10T), and alloy steel (15Kh5M). For corrosive environments, duplex (2205) and nickel alloys (Inconel 625) are available.
Q: What pressure ratings are covered by GOST 33259?
A: GOST 33259 covers PN 0.25 to PN 250, with PN 16, PN 25, PN 40, PN 63, and PN 100 being most common for oil & gas applications.
Q: How do I verify GOST 33259 flange quality?
A: Request mill test certificates (MTCs) per GOST 33259, third-party inspection reports, and PMI testing. Jiaji Forging provides full traceability with heat numbers and EN 10204 3.1 certification.
References
- ASTM International – Standards for flange materials (A105, A182, A694).
- ASME – ASME B16.5 and B16.47 flange standards.
- API – API 6A and API 6D specifications for oil & gas flanges.
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As a professional flange manufacturer, Jiaji Forging provides custom forging solutions for global industries. Contact our engineering team for technical support and quotation.