Views: 0 Author: J-VALVES Publish Time: 2025-05-12 Origin: Site
ISO 14726 is an international standard that specifies the requirements for the design, manufacturing, and testing of valves, particularly for corrosive environments. It covers various types of valves, including ball valves and gate valves, and provides detailed guidelines to ensure their reliability and performance.
• Material Specifications: ISO 14726 allows for the use of duplex stainless steel, which offers excellent corrosion resistance and mechanical properties.
• Design Requirements: The standard specifies design requirements to ensure valves can withstand the demanding conditions of corrosive environments.
• Testing Protocols: Comprehensive testing, including hydrostatic and pneumatic tests, is required to verify the valve's integrity and performance.
Duplex Stainless Steel: Material Properties
• Composition: Duplex stainless steel, such as 2205 (UNS S31803) and 2507 (UNS S32750), contains a balanced mix of austenitic and ferritic phases. This composition provides high strength, good toughness, and excellent resistance to pitting and stress corrosion cracking.
• Corrosion Resistance: Duplex stainless steel exhibits superior resistance to chloride-induced stress corrosion cracking and pitting, making it ideal for corrosive environments.
• Mechanical Properties: High tensile strength and yield strength, combined with good ductility, make duplex stainless steel suitable for high-pressure applications.
Application of Duplex Stainless Steel in Ball Valves
• Floating Ball Design: Ball valves made from duplex stainless steel typically feature a floating ball design, which allows the ball to move slightly under pressure, ensuring a tight seal against the seat.
• Bidirectional Sealing: The design provides bidirectional sealing, ensuring reliable shutoff in both directions.
• Seat Material: The seat material is often made from PTFE or other corrosion-resistant materials to enhance sealing performance.
Application of Duplex Stainless Steel in Gate Valves
• Wedge Gate Design: Gate valves made from duplex stainless steel feature a wedge-shaped gate that compresses against the seat to create a tight seal.
• Unidirectional Sealing: The design provides excellent tight shutoff in one direction, making it suitable for on-off control applications.
• Seat Material: The seat material is often made from PTFE or other corrosion-resistant materials to enhance sealing performance.
| Feature | Duplex Stainless Steel Ball Valves | Duplex Stainless Steel Gate Valves |
| Valve Type | Floating ball design, bidirectional sealing | Wedge gate design, unidirectional sealing |
| Material | Duplex stainless steel (e.g., 2205, 2507) | Duplex stainless steel (e.g., 2205, 2507) |
| Sealing Performance | Excellent bidirectional sealing | Excellent tight shutoff in one direction |
| Applications | Chemical processing, oil and gas | Water treatment, marine and offshore |
| Testing Protocols | Hydrostatic and pneumatic tests | Hydrostatic and pneumatic tests |
