Super Duplex 5a Gate Valve
High Performance • Durable • Leak Proof
SKU: AV-GV-0241
Super Duplex 5A Gate Valve ensures reliable shut-off and superior resistance to pitting, and crevice corrosion.
Seawater, brine and chloride-bearing process lines require isolation valves that resist localised corrosion around the wedge, seat pockets and body cavity. ASTM A995 Grade 5A provides the strength and corrosion resistance needed for many severe marine and offshore duties. African Valve is a prominent Super Duplex 5A Gate Valve Manufacturer in Africa, supplying South Africa, Nigeria, Egypt, Angola, other African countries and selected export markets. ASTM A995 Grade 5A is a cast Super Duplex stainless-steel grade used for pressure-containing valve components. Its ferritic-austenitic structure combines high mechanical strength with strong resistance to chloride-induced pitting, crevice corrosion and stress-corrosion cracking. Wrought trim may use compatible F53 or F55 grades where required. The wedge moves vertically between two seats. When fully raised, it clears the flow path and leaves a nearly straight bore. This keeps pressure loss comparatively low and makes the valve suitable for full-open or full-closed isolation. The body and bonnet may be cast in ASTM A995 Grade 5A, while the stem, wedge and seat rings use compatible Super Duplex or project-approved grades. A rising-stem outside-screw-and-yoke design keeps the stem threads outside the main pressure boundary and gives visible valve position. Size Range: DN15 to DN600 The straight-through bore supports low-restriction isolation in seawater and process lines. Super Duplex strength can reduce section thickness where permitted by the design standard, but pressure-temperature ratings still follow the valve code and manufacturer calculations. Super Duplex 5A gate valves are used in desalination plants, seawater intake and injection systems, produced-water treatment, offshore firewater, brine transfer, pulp and paper processing and selected oil and gas services. They suit lines that remain fully open during operation and require positive isolation during shutdown. Casting heat-treatment records, MTCs and PMI confirm the material. Ferrite measurement, radiography, liquid penetrant examination or ultrasonic testing may be specified according to size and project class. Dimensional inspection covers body wall, wedge alignment, stem travel and end connections. Hydrostatic shell and seat tests confirm pressure integrity and shutoff. African Valve supplies Super Duplex 5A gate valves for marine, offshore, water and process projects across Africa. The enquiry should state fluid chemistry, chloride content, pressure, temperature, end connection, bonnet type, leakage requirement, actuator and inspection scope.Super Duplex 5A Gate Valve Manufacturer in Africa
What Grade 5A Means
Grade 5A still depends on correct heat treatment and phase balance. Poor casting control, welding or post-weld heat exposure can reduce corrosion performance. The service review should include temperature, oxygen level, pH, crevices and any chemical cleaning solutions used during operation.Gate Movement and Isolation
A gate valve should not be used for continuous throttling. Holding the wedge partly open can create vibration, local erosion and uneven wear at the seat edges. Solid or flexible wedges may be supplied according to valve size, pressure class and temperature.Bonnet, Stem and Seat Arrangement
Bolted bonnets allow internal access during maintenance. Welded bonnets may be used on compact forged designs, while pressure-seal bonnets are considered for higher-pressure service. Integral or renewable seats may be used, and hard-facing can reduce galling or erosion where cycling frequency is high.Technical Specifications
Pressure Ratings: ASME Class 150 to Class 1500
Design Standards: API 602 for compact forged valves; API 603 or ASME B16.34 for applicable larger designs
Testing Standard: API 598
End Connections: Flanged RF/RTJ, socket weld or butt weld
Operation: Handwheel, gearbox, pneumatic actuator or electric actuator
Body Material: ASTM A995 Grade 5A
Gate Design: Solid wedge or flexible wedge
Bonnet Design: Bolted, welded or pressure seal
Stem Design: Rising stem, OS&YPerformance in Chloride Service
For sour oil and gas service, material hardness and NACE MR0175/ISO 15156 requirements may need to be added. Warm seawater and crevice conditions should be reviewed rather than relying on the grade name alone.Industrial Applications
Manufacturing and Inspection
Isolation Valve Supply Across Africa