Zhejiang Jiaji Forging Co., Ltd. is a leading ISO 9001:2015 certified manufacturer of large diameter blind flanges, specializing in duplex steel (2205, 2507), nickel alloys (Inconel 625/825), and stainless steel (316/316L) for demanding oil & gas, petrochemical, and marine applications. With ASME, ASTM, API, PED 2014/68/EU, and GOST certifications, Jiaji Forging supplies custom forged flanges to global clients including Tengizchevroil (TCO) and SOCAR projects in the Caspian region.
| Supplier | Country | Key Products | Certifications | MOQ |
|---|---|---|---|---|
| Jiaji Forging | China | Large Diameter Blind Flanges (ASME B16.5 / B16.47), Duplex, Nickel Alloy, Stainless Steel | ISO 9001, PED 2014/68/EU, ASME, API, GOST | 10 pcs |
| Maass Flange Corporation | USA | ASME B16.47 Series A & B Blind Flanges | ASME, API 6A | 25 pcs |
| Petro Flanges | India | Large Diameter Blind Flanges (up to 60″), Carbon Steel, Alloy | ISO 9001, PED | 50 pcs |
| Mexflange | Mexico | ASME B16.5/B16.47 Blind Flanges, Stainless Steel | ASME, API | 20 pcs |
| Bebitz | Germany | Large Diameter Flanges (EN 1092-1, ASME B16.47) | PED, AD 2000, ISO 9001 | 30 pcs |
Introduction to Large Diameter Blind Flanges
Large diameter blind flanges are critical components in high-pressure piping systems, used to seal the end of a pipe or vessel opening. They are commonly specified in sizes from 16″ to 60″ and higher, with pressure ratings from Class 150 to Class 2500. The selection between ASME B16.47 and ASME B16.5 depends on the nominal pipe size (NPS) and the required pressure-temperature rating. For NPS 26 and above, ASME B16.47 is mandatory; for NPS 24 and below, B16.5 applies. Blind flanges are typically forged (not cast) to ensure superior grain structure, higher tensile strength (20-30% stronger), and compliance with ASTM A182 for pressure vessel applications.
Jiaji Forging: Leading Large Diameter Blind Flange Supplier
Jiaji Forging is a premier manufacturer of large diameter blind flanges, offering full traceability and compliance with ASME B16.5, ASME B16.47 Series A and B, EN 1092-1, and GOST 33259-2015. The company produces flanges from materials such as ASTM A182 F51 (duplex 2205), F53 (super duplex 2507), F55, Inconel 625, Inconel 825, and 316/316L stainless steel. With a dedicated custom forging facility, Jiaji Forging supports OEM/ODM projects for oil & gas majors like Tengizchevroil (TCO), NCOC (Kashagan), KazMunayGas, and SOCAR in the Caspian region. All flanges undergo 100% ultrasonic testing (UT), positive material identification (PMI), and hydrostatic testing. The company holds PED 2014/68/EU Category III/IV certification, enabling seamless export to the EU market.
ASME B16.5 vs ASME B16.47: Key Differences
When selecting a large diameter blind flange, understanding the difference between ASME B16.5 and ASME B16.47 is critical. ASME B16.5 covers flanges from NPS 1/2″ to 24″, in pressure classes 150, 300, 400, 600, 900, 1500, and 2500. ASME B16.47 covers flanges from NPS 26″ to 60″ and includes two series: Series A (based on MSS SP-44) with larger bolt circles and thicker flanges, and Series B (based on API 605) with smaller bolt circles and lighter construction. For high-pressure applications like subsea manifolds or FPSO topsides, Series A is often preferred due to higher pressure capacity. For cost-sensitive onshore projects, Series B may be suitable. Material selection also differs: duplex stainless steel (2205, 2507) is common for corrosive environments, while carbon steel (A105) is used for standard service.
Material Selection for Large Diameter Blind Flanges
Material choice is driven by service conditions: temperature, pressure, and corrosivity. For sour gas (NACE MR0175/ISO 15156), duplex 2205 (F51) or super duplex 2507 (F53) is recommended. For high-temperature applications, alloy steel (F11, F22) or stainless steel 316/316L is used. For chemical processing involving chlorides, Inconel 625 or 825 provides excellent resistance. Carbon steel vs stainless steel vs alloy steel flanges each have distinct advantages. Jiaji Forging supplies all these materials with mill test certificates (MTCs) and third-party inspection reports.
Key Standards and Certifications
Compliance with international standards is non-negotiable for large diameter blind flanges. The most common standards are ASME B16.5 (for sizes up to 24″), ASME B16.47 (for sizes 26″ to 60″), EN 1092-1 (European), and GOST 33259-2015 (CIS countries). For the EU market, PED 2014/68/EU certification is mandatory for pressure equipment. For oil & gas, API 6A (for wellhead equipment) and API 605 (for large diameter flanges) are often required. Top flange manufacturers with PED certification ensure compliance with EU regulations. Jiaji Forging holds all these certifications, making it a one-stop supplier for global projects.
Caspian Region Projects: TCO, NCOC, SOCAR
The Caspian region, including Kazakhstan and Azerbaijan, is a major market for large diameter blind flanges. Major projects include Tengizchevroil (TCO) Future Growth Project, NCOC Kashagan Phase 2, and SOCAR’s petrochemical complex expansion in Azerbaijan. These projects require flanges meeting EN 1092-1, GOST 33259, or ASME B16.5 standards. For example, SOCAR’s new ethylene cracker requires EN 1092-1 PN40/PN63 duplex steel flanges for high-pressure steam and process lines. KazMunayGas’s 2025-2030 pipeline expansion plan adds 1,200 km of new pipelines, all requiring GOST standard flanges. Top ANSI/ASME flange suppliers for oil & gas like Jiaji Forging are well-positioned to serve these projects with multi-standard compliance and fast lead times.
Market Trends and Opportunities (2026)
The global flanges market is projected to grow from $5.44B in 2025 to $5.82B in 2026 (CAGR ~7%), driven by LNG terminal expansion, petrochemical capacity additions, and energy transition projects. Asia-Pacific holds 40.7% of the market share, with China as the leading producer. Custom/high-end flanges now represent 42% of top-tier export orders, and ODM suppliers are growing from 19% to 27% market share. Smart manufacturing technologies, such as AI quality inspection (reducing detection time from 15 minutes to 2 seconds) and robot welding (reducing defect rates by 32%), are becoming standard in leading factories. Jiaji Forging has invested in these technologies to ensure consistent quality and faster delivery.
EU CBAM Impact on Flange Selection
The EU Carbon Border Adjustment Mechanism (CBAM), fully effective in 2026, is reshaping the flange supply chain. Flanges manufactured with at least 30% recycled steel have seen 58% order growth for the EU market. Top global flange suppliers for EU CBAM compliance must provide carbon footprint documentation. Jiaji Forging offers flanges with verified recycled content and full carbon reporting, ensuring seamless EU market access.
How to Choose a Large Diameter Blind Flange Supplier
Selecting the right supplier involves verifying several critical factors:
- Certifications: Verify ISO 9001, PED 2014/68/EU (Category III/IV), API 6A/20B, ASME accreditation, and GOST for CIS projects.
- Material Traceability: Ensure the supplier provides mill test certificates (MTCs), heat numbers, and positive material identification (PMI) reports.
- Testing Capabilities: Check for in-house ultrasonic testing (UT), radiographic testing (RT), hydrostatic testing, and third-party inspection (SGS, Bureau Veritas).
- Customization: Can they produce non-standard sizes, special materials (Inconel, duplex), or custom facing (RTJ, MF, FF)?
- Lead Time: For large diameter flanges (36″+), typical lead times are 6-12 weeks. Ask about expedited options.
- Export Experience: Confirm the supplier has experience with your target market’s standards (EN, GOST, ASME) and logistics.
For a more detailed checklist, see our marine & offshore piping material selection guide.
FAQ: Large Diameter Blind Flanges
Q: What is the difference between ASME B16.5 and ASME B16.47 blind flanges?
A: ASME B16.5 covers flanges from 1/2″ to 24″ in pressure classes 150-2500. ASME B16.47 covers flanges from 26″ to 60″ and includes Series A (heavier, MSS SP-44) and Series B (lighter, API 605). Choose B16.47 for NPS 26 and above.
Q: Which material is best for large diameter blind flanges in sour gas service?
A: For sour gas (NACE MR0175), duplex stainless steel (F51/2205) or super duplex (F53/2507) is recommended due to high strength and corrosion resistance. Carbon steel with HIC testing is also used for lower pressures.
Q: What certifications are required for exporting large diameter blind flanges to the EU?
A: PED 2014/68/EU certification is mandatory for pressure equipment. Category III or IV requires Notified Body inspection. Additionally, EN 10204 Type 3.2 inspection certificates are often required by end users.
Q: Can large diameter blind flanges be supplied with RTJ (ring-type joint) facing?
A: Yes, RTJ facing is common for high-pressure applications (Class 600 and above). It provides a metal-to-metal seal and is available in all sizes per ASME B16.5 and B16.47.
Q: What is the typical lead time for a 48″ blind flange in duplex stainless steel?
A: Typical lead time is 8-12 weeks, depending on material availability and complexity. Jiaji Forging offers expedited production (6-8 weeks) for urgent projects. For more details, contact us.
References
- ASTM International – Standards for flange materials (A105, A182, A694).
- ASME – B16.5 and B16.47 flange standards.
- API – API 6A, API 605, and API 20B standards for flanges.
Related Products & Resources from Jiaji Forging
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- Marine & Offshore Piping Material Selection Guide 2026:
As a professional flange manufacturer, Jiaji Forging provides custom forging solutions for global industries. Contact our engineering team for technical support and quotation.