Reliable Delivery of High-Pressure WN Flanges for Singapore Project
When it comes to demanding piping systems, reliability and performance are non-negotiable. Recently, Haihao Group successfully supplied a batch of weld neck (WN) flanges with RTJ facing for a high-pressure project in Singapore, once again demonstrating our capability to provide tailor-made piping solutions.
Meeting the Demands of Critical Applications
The project required flanges capable of withstanding extreme pressure and corrosive environments. To achieve this, Haihao Group manufactured the flanges from ASTM A182 F55 super duplex stainless steel (UNS S32750/F53)-a material well known for its superior strength and resistance to chloride stress corrosion cracking.
With a PREN value above 40, F55 material ensures durability in offshore, oil & gas, and chemical service conditions where standard stainless steels often fail. The RTJ (Ring Type Joint) sealing face was selected to guarantee a secure, leak-proof connection under high-pressure operations.

Super Duplex Stainless Steel ASTM A182 F55 WN flange RTJ
Comprehensive Testing and Certification
Every flange delivered was subjected to strict inspection and testing protocols. Haihao Group provided a complete set of documentation, including:
- PMI (Positive Material Identification) to verify alloy accuracy
- Chemical composition analysis to confirm compliance with standards
- Mechanical testing, including tensile and hardness reports
- Impact test at -46℃, ensuring performance under low-temperature conditions
- Heat treatment records to validate stability of microstructure
- Non-destructive examinations (PT, UT) for surface and internal flaw detection
These reports give customers the confidence that each flange is fully compliant with ASME B16.5 and international quality standards.
Supporting Global Projects with Proven Expertise
For decades, Haihao Group has been a trusted partner in delivering high-performance pipe fittings, flanges, and connection solutions for global clients. Our Singapore customer required fast delivery with uncompromising quality, and Haihao’s strong manufacturing capability and rigorous quality management system ensured on-time supply.
Whether for offshore platforms, petrochemical installations, or high-pressure transmission lines, our super duplex stainless steel WN flanges are engineered to perform in the most demanding service environments.