Custom Large Diameter Flanges Manufacturer
LONGAN FLANGE, is a custom large flange factory in China. We specialize in manufacturing large diameter stainless steel flanges—custom-made to your specs, forged in-house, and machined with high precision.
- Fange diameter up to 4000 mm
- OEM & drawing-based production
- ASME / ANSI / DIN / JIS / GOST standards available
- Fast delivery & full traceability
how to order large flanges
1. Define Your Large Flange Project Requirements
LONGAN FLANGE is capable of manufacture flanges up to 4000 mm.
- Pressure class & facing type
- Pipe size & connection type
- Specifications & Standard (ASME, ANSI, DIN, JIS, API, AWWA, etc.)
- Quantity needed
2. Material Grade
LONGAN FLANGE mainly producing stainless steel large diameter flanges.
- Stainless Steel (SS304, SS316, etc.)
- Carbon Steel
- Alloy Steel
- Duplex & Super Duplex Steel
- Nickel Alloy
- Copper-Nickel
- Cast Iron / Ductile Iron
3. Applicable Standards
- ASME large flange
- ANSI large flange
- DIN large flange
- JIS large flange
- AWWA large flange
- API large flange
4. Large Flange Types
LONGAN FLANGE provides custom-forged stainless steel flanges built to your exact specs. No matter how unique or oversized, we deliver practical solutions fast. Start your custom project with us today.
- Large diameter blind flange
- Large diameter lap joint flange
- Large diameter plate flange
- Large diameter slip on flange
- Large diameter threaded flange
- Large diameter weld neck flange
- Large diameter socket neck flanges
What's Your Custom Large Flange Needs?
2. Material Grade
LONGAN FLANGE mainly producing stainless steel large diameter flanges.
- 304 Stainless Steel (SS304)
- 316 Stainless Steel (SS316)
What's Your OEM/ODM Needs?
3. Applicable Standards
- ASME large flange
- ANSI large flange
- DIN large flange
- JIS large flange
- AWWA large flange
- API large flange
- BS large flange
- GOST large flange
What's Your OEM/ODM Needs?
4. Large Flange Types
LONGAN FLANGE provides custom-forged stainless steel flanges built to your exact specs. No matter how unique or oversized, we deliver practical solutions fast. Start your custom project with us today.
- Large diameter blind flange
- Large diameter lap joint flange
- Large diameter plate flange
- Large diameter slip on flange
- Large diameter threaded flange
- Large diameter weld neck flange
- Large diameter socket neck flanges
What's Your OEM/ODM Needs?
how we deliver your custom large flange ORDERS
Custom LARGE FLANGE Design
- With over a decade of experience since 2011, we offer expert design and manufacturing of extra-large flanges tailored to your exact needs. Trust us to deliver precision, reliability, and performance.
- We also accept custom large diameter flange drawings and technical specifications for non-standard flanges.
LARGE FLANGE Manufacturing
- Forging & Rolling – Heated billet is forged, then rolled into shape under high pressure to ensure strength and durability.
- Welding & Heat Treatment – Precision welding joins components, followed by heat treatment to enhance strength, stress relief, and structural integrity.
- Surface Finishing – Painting, Spraying, Polishing
LARGE FLANGE Manufacturing
- Forging & Rolling – Heated billet is forged, then rolled into shape under high pressure to ensure strength and durability.
- Welding & Heat Treatment – Precision welding joins components, followed by heat treatment to enhance strength, stress relief, and structural integrity.
- Surface Finishing – Painting, Spraying, Polishing
Quality Control
We apply rigorous quality control at every stage to ensure your large flange meets exact standards:
- Dimensional accuracy and material compliance
- Surface integrity, flatness, and weld quality
- Verified heat treatment performance
With NDT, hardness testing, and full traceability, we guarantee zero defects and high reliability. Since 2011, our commitment to precision and quality has earned the trust of clients worldwide.
Reliable Packaging & Delivery
We ensure your custom extra-large flanges are delivered on time and in flawless, damage-free condition.
- On-time delivery with carefully planned logistics
- Heavy-duty packaging for maximum protection
- Specialized freight partners for oversized cargo handling
- Export-ready documentation for smooth global shipping
We deliver with precision, protection, and professionalism—every time.
Reliable Packaging & Delivery
We ensure your custom extra-large flanges are delivered on time and in flawless, damage-free condition.
- On-time delivery with carefully planned logistics
- Heavy-duty packaging for maximum protection
- Specialized freight partners for oversized cargo handling
- Export-ready documentation for smooth global shipping
We deliver with precision, protection, and professionalism—every time.
Request a Quote from Experienced Large Flange Manufacturer – LONGAN FLANGE
- No drawing? No problem. Just tell us the size and specs
- Fast quoting within 24 hours — even for small orders
- Stainless steel materials, custom faces, and bolt holes supported
- MOQ starts from 1 piece
ABOUT LONGAN FLNGE
Your Trusted Supplier for Custom Large Diameter Flanges – Forged, Machined, and Inspected In-House
Longan Flange is a dedicated flange factory with 25+ years of experience. We specialize in custom stainless steel flanges up to 157 inches, covering ASME, DIN, JIS, and EN standards.
All flanges are forged, machined, and inspected in-house, ensuring precision, fast delivery, and full compliance. Our products serve oil & gas, chemical, and water systems in over 50 countries.
Certifications
Our large flanges are manufactured under strict quality control and comply with major international standards. We provide full certification, including ISO 9001, CE, ASME, ANSI, DIN, JIS, etc., to support your project documentation and regulatory needs.
Exhibition
We actively participate in major industry exhibitions worldwide to connect with engineers, distributors, and project buyers face-to-face. Visit our booth to explore our custom flange solutions and discuss your project needs directly with our team.
View OUR Customization Capability
LONGAN FLANGE specializes in producing non-standard, highly customized forged stainless steel fanges tailored to your specific needs. From concept to creation, we turn unique challenges into practical solutions. Contact us to start your custom large flange project.
Where Our Flanges Are Used
Our large diameter flanges are engineered for demanding environments — from oil & gas pipelines and chemical processing plants to water treatment, mining, and power generation projects. With custom sizes and materials, we deliver solutions that meet real-world engineering challenges.
Pipeline Connections
Chemical/Petrochemical Plants
Water Treatment/Distribution
