Duplex Stainless Steel Gate Valve Description
Duplex stainless steel gate valve is a special valve made of austenite-ferrite duplex stainless steel (such as S31803/F51, S32205/F60) as the main material. It has both high strength and corrosion resistance and is suitable for harsh corrosive environments. The ratio of ferrite to austenite is close to 1:1, and the structure and performance are optimized through solution treatment.
Structure
Valve body and valve cover
Integral forged valve body: ASTM A182 F51/F60 forgings are used to avoid casting porosity defects and are suitable for high-pressure conditions (PN≥40);
Connection form: flange (RF/RTJ surface) or butt welding end (WN type), self-tightening sealing valve cover is used for high-pressure conditions.
Gate system
Elastic wedge gate: middle annular groove design, compensate for high temperature deformation, prevent jamming;
Sealing surface reinforcement: surfacing Stellite or tungsten carbide layer, hardness ≥ HRC, resistant to particle erosion.
Valve stem and seal
Blowout-proof valve stem: limit step at the bottom, in line with API 600 blowout-proof standard;
Multi-layer packing: V-type PTFE + graphite combination, low friction at low temperature, stable sealing at high temperature.
Special design
Low flow resistance flow channel: full-diameter design, flow resistance coefficient (ζ) ≤ 0.8;
Welding optimization: the valve body weld end is solution treated (quenched at 1020-1100℃) to ensure that the corrosion resistance of the weld is consistent with the parent material
Duplex Stainless Steel Gate Valve specification
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Execution standards |
API, JIS, DIN, BS, ASTM, ANSI, GB, JB, NB, HG |
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Pressure range |
Class150~Class2500Lb(PN16-PN420) |
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Size range |
NPS1/2 "to NPS72" (DN15mm to DN1800mm) |
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Operate Type |
Manual, electric,pneumatic, gear |
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Valve type |
Power station valves, gate valves, globe valves, check valves |
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Application |
power plants,petrochemicals,refining, natural gas, metallurgy |
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Connection type |
Flange, welding, thread, FM, BW, SW |
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Customization |
OEM/ODM/OSM/OBM |
Duplex Stainless Steel Gate Valve
Advantages
Ultra-high strength
Yield strength ≥450MPa, which is twice that of 304 stainless steel, and can reduce wall thickness by more than 30%; Excellent corrosion resistance
The ability to resist chloride stress corrosion is better than 316L, and the PREN value (pitting resistance equivalent) reaches 32~33; Erosion and wear resistance
The carbide sealing surface can withstand medium containing particles (such as slurry), and the wear rate is reduced by 60%; Lightweight and energy-saving
The density is lower than that of high-alloy steel, which reduces the pipeline load and is convenient for installation and maintenance.
Applications
Marine engineering
Seawater desalination system, ship ballast water pipe, subsea valve (resistant to chloride ion corrosion);
Energy and chemical industry
Acidic oil and gas field pipelines (including H₂S/CO₂), chlorine-containing medium transportation in chlor-alkali industry;
Environmental protection and power
Flue gas desulfurization (FGD) system, nuclear power cooling water pipeline (resistant to halide corrosion);
Special fluids
High-salinity brine, oxidizing acid (such as nitric acid) and mixed acid medium
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