Shanxi Xinshunda Flange Manufacturing Co., Ltd. supplies high-precision API 6B reducing flanges engineered for high-pressure oilfield piping systems that require safe, reliable diameter transition. Fully compliant with API 6A / API 6B standards, our reducing flanges provide stable pressure containment, metal-to-metal sealing, and long service life in wellhead, manifold, and transmission line applications. Backed by 19 years of professional forging and machining expertise, we are a trusted supplier for global onshore and offshore oil & gas projects.
Product Description
API 6B reducing flange is a special transitional flange designed to connect pipes or equipment of different nominal sizes under high-pressure oilfield conditions. It integrates the functions of size reduction and flange connection in one piece, eliminating the need for extra reducers and fittings. Our API 6B reducing flanges feature a compact structure, precise bore transition, and standard RTJ sealing face to ensure zero leakage and high structural strength. They are widely used in wellhead assemblies, Christmas trees, manifolds, and high-pressure pipelines where diameter conversion is required.
Product Feature and Application
Key Features
- One-piece reducing design for safe pipe diameter transition
- Full compliance with API 6B dimensional and sealing standards
- RTJ metal-to-metal sealing for zero leakage under high pressure
- Smooth bore transition reduces flow resistance and turbulence
- High-strength forging and uniform heat treatment
- Excellent pressure resistance, fatigue resistance, and stability
- Compact structure saves installation space
- High interchangeability with API 6B wellhead and manifold equipment
- Full material traceability and complete quality documentation
Typical Applications
- Wellhead equipment and Christmas tree assemblies
- Manifold piping systems with diameter conversion
- High-pressure oil/gas transmission lines
- Choke & kill line connections
- Onshore & offshore drilling and production facilities
- Pipeline systems requiring size transition
- Instrument and process piping in oilfield projects
Product Parameter
| Standard | API 6A, API 6B |
| Pressure rating | 2000 psi, 3000 psi, 5000 psi |
| Size range | 1 13/16″ → 9″ (custom reduction ratios available) |
| Face type | Ring Type Joint (RTJ) – R, RX |
| Style | Weld Neck Reducing Flange |
| Material |
Carbon steel: A105, A350 LF2 Alloy steel: A182 F11, F22, 4130, 4140 Stainless steel: F304, F316, F316L |
| Working temperature | −60 °C to +345 °C |
| Certification | API 6A Certificate, EN 10204 3.1 MTC |
| Performance level | PR1, PR2 |
Production Details
Each API 6B reducing flange is manufactured under full-process quality control:
- Raw material inspection with mill certification and spectral analysis
- Closed-die forging for optimized grain structure and mechanical strength
- Controlled heat treatment to meet hardness and tensile requirements
- High-precision CNC machining for tapered bore, RTJ grooves, and bolting
- 100% dimensional inspection using CMM and precision gauges
- Full NDT: magnetic particle testing (MT), ultrasonic testing (UT)
- Hydrostatic testing to verify pressure integrity and safety
- Anti-corrosion surface treatment and permanent marking
- Full traceability from raw material to finished product
Production Display
Our factory is ISO 9001 & API Q1 certified, equipped with large-tonnage forging presses, high-rigidity CNC machining centers, automatic heat treatment lines, and professional NDT laboratories. We implement strict process control and complete documentation. Third-party inspection by SGS, BV, TÜV or customer-appointed institutions is available on request.
Packaging & Transportation
- Surface treatment: Anti-corrosion oil, varnish, black paint
- Packaging: Protective wrapping, reinforced wooden cases, steel pallets
- Labeling: Heat number, size, pressure class, material, standard, API mark, batch
- Documents: Commercial invoice, packing list, certificate of origin, API MTC
- Transportation: Sea, air, and express delivery for global oilfield projects
After-sales Service
We provide full life cycle technical support for API 6B reducing flanges:
- Professional consultation on size selection and installation
- Custom reduction sizes and material combinations
- Timely response to after-sales inquiries and quality claims
- On-site technical guidance and remote support
- Stable long-term supply for large-scale oilfield projects
Why Choose Shanxi Xinshunda?
- 19 years of professional flange manufacturing serving global oil & gas clients
- Full compliance with API 6A / 6B standards
- Advanced forging & machining capabilities for high-pressure flanges
- Strict quality control and complete testing & certification documents
- Competitive factory pricing and reliable on-time delivery
- Multilingual sales & technical support and global logistics service
Contact us today for product catalogs, quotations or customized solutions for your API 6B reducing flange requirements.
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