Flanges: A Comprehensive Guide for Buyers in 2025
Flanges are essential components in piping systems, used to connect pipes, valves, pumps, and other equipment. Whether you're in construction, oil & gas, or manufacturing, understanding flanges can help you make informed purchasing decisions. This guide will walk you through the types, features, and buying considerations for flanges in 2025.
How to Find Reliable Flanges from China in 2025
China remains a top supplier of flanges due to competitive pricing and advanced manufacturing capabilities. To find reliable suppliers:
- Check certifications like ISO 9001 and API 6A
- Review supplier history and customer feedback on platforms like Alibaba
- Request material test reports for quality assurance
- Consider manufacturers with in-house testing facilities
What Buyers Should Know Before Buying Flanges from China
When sourcing flanges from China, pay attention to:
- Material grades (carbon steel, stainless steel, alloy)
- Pressure ratings (150# to 2500#)
- Surface treatments (anti-corrosion coatings)
- Lead times and minimum order quantities
Types of Flanges
Common flange types include:
- Weld Neck Flanges: Best for high-pressure applications
- Slip-On Flanges: Easier installation for low-pressure systems
- Blind Flanges: Used to seal pipe ends
- Threaded Flanges: For small diameter, low-pressure pipes
Functions and features of Flanges
Key functions include:
- Connecting piping systems without welding
- Allowing easy maintenance and inspection access
- Providing leak-proof connections with proper gaskets
Scenarios of Flanges
Flanges are used in:
- Oil and gas pipelines
- Chemical processing plants
- Water treatment facilities
- HVAC systems
How to Choose Flanges
Selection factors:
- Determine operating pressure and temperature
- Select appropriate material for your medium
- Choose the right facing type (RF, FF, RTJ)
- Consider corrosion resistance needs
Flanges Q & A
Q: What's the difference between ANSI and DIN flanges?
A: ANSI follows US standards while DIN follows German/European standards, with different dimensions and pressure ratings.
Q: How often should flanges be inspected?
A: Annual visual inspections are recommended, with more frequent checks in high-pressure systems.
Q: Can different flange types be connected?
A: Yes, with proper adapters, but matching types is preferred for safety.
Q: What causes flange leaks?
A: Improper bolt tightening, damaged gaskets, or misalignment are common causes.
Q: How to prevent flange corrosion?
A: Use corrosion-resistant materials or apply protective coatings based on environment.
