Complete Guide to Stainless Steel Flanges: Types, Applications & Industry Standards 2026
Introduction to Stainless Steel Flanges
Stainless steel flanges are essential components in piping systems across multiple industries including oil & gas, chemical processing, pharmaceuticals, and food processing. As a leading stainless steel flange manufacturer in China, Songhai has been delivering precision-engineered flange solutions since 1994.
This comprehensive guide covers everything you need to know about stainless steel flanges, from material grades to international standards and selection criteria for your specific applications.
Key Types of Stainless Steel Flanges
1. Weld Neck Flanges (WN)
Weld neck flanges feature a long tapered hub that provides optimal stress distribution. Ideal for high-pressure and high-temperature applications in petrochemical and power generation industries.
- Pressure Rating: Class 150 to Class 2500
- Temperature Range: -200°C to +800°C
- Common Standards: ASME B16.5, EN 1092-1, HG/T 20592
2. Slip-On Flanges (SO)
Slip-on flanges slide over the pipe and are welded on both sides. Cost-effective solution for low to medium pressure applications.
- Advantages: Easy alignment, lower material cost
- Applications: Water treatment, HVAC systems
3. Blind Flanges (BL)
Blind flanges seal the end of piping systems, providing access points for maintenance and inspection.
- Use Cases: Pipeline isolation, pressure testing
- Pressure Capability: Highest among all flange types
4. Socket Weld Flanges (SW)
Designed for small-diameter piping with high-pressure requirements. Common in hydraulic and instrumentation systems.
5. Threaded Flanges (TH)
Threaded flanges connect without welding, ideal for explosive environments where welding is prohibited.
Stainless Steel Grades for Flanges
304/304L Stainless Steel
The most widely used austenitic stainless steel offering excellent corrosion resistance and formability. Suitable for:
- Food and beverage processing
- Pharmaceutical equipment
- Chemical processing (mild conditions)
316/316L Stainless Steel
Enhanced corrosion resistance due to molybdenum addition (2-3%). Preferred for:
- Marine and offshore applications
- Chemical processing with chlorides
- Pharmaceutical and biotech industries
321 Stainless Steel
Stabilized with titanium for improved resistance to intergranular corrosion. Excellent for high-temperature applications up to 870°C.
310S Stainless Steel
High-temperature grade with excellent oxidation resistance up to 1150°C. Used in furnace components and heat treatment equipment.
904L Super Austenitic
Superior corrosion resistance in aggressive environments including sulfuric acid and chloride-containing media.
International Flange Standards
| Standard | Region | Pressure Classes |
|---|---|---|
| ASME B16.5 | USA/International | Class 150-2500 |
| EN 1092-1 | Europe | PN6-PN100 |
| HG/T 20592-2009 | China | PN2.5-PN160 |
| JIS B2220 | Japan | 5K-63K |
| GB/T 9112-2010 | China | PN2.5-PN160 |
| GOST 33259-2015 | Russia/CIS | PN0.1-PN200 |
Quality Control & Certifications
At Songhai Flanges, every product undergoes rigorous quality control:
- Material Certification: EN 10204 3.1/3.2 MTC
- Dimensional Inspection: 100% verification per standards
- Non-Destructive Testing: PT, MT, UT, RT as required
- Pressure Testing: Hydrostatic testing per ASME B16.5
- Surface Finish: Ra 3.2-12.5 μm as specified
Our facility is ISO 9001:2008 certified with 9 professional engineers and 18 technicians ensuring consistent quality.
Custom Flange Manufacturing
Beyond standard flanges, Songhai specializes in custom solutions:
- Large diameter flanges (up to 5000mm)
- High-pressure specialty flanges
- Non-standard materials (duplex, super duplex, Inconel)
- Special coatings and treatments
Applications by Industry
Oil & Gas
High-pressure flanges for upstream, midstream, and downstream operations. Sour service compliance (NACE MR0175).
Chemical Processing
Corrosion-resistant flanges for aggressive chemical environments. PTFE-lined options available.
Power Generation
High-temperature flanges for boiler systems, steam lines, and turbine connections.
Pharmaceutical & Food
Hygienic flanges with electropolished surfaces (Ra ≤ 0.8μm) for sanitary applications.
Marine & Offshore
Superior corrosion resistance for seawater exposure and harsh marine environments.
Why Choose Songhai Flanges
- 30+ Years Experience: Founded in 1994 with proven track record
- Advanced Equipment: 5m CNC vertical lathes, 5m×5m machining centers
- Large Inventory: Standard stainless steel flanges in stock for quick delivery
- Custom Solutions: Engineering support for complex requirements
- Global Standards: Production capability for ASME, EN, JIS, GB, GOST
- Quality Assurance: ISO 9001 certified with full traceability
Свяжитесь с нами
Looking for reliable stainless steel flange suppliers? Contact Songhai Flanges for:
- Free technical consultation
- Competitive pricing with FOB/CIF options
- Fast delivery from stock or custom production
- Complete documentation and certification
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