Alloy Steel F91 Gate Valve
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Pressure Rating
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1. Key Features of F91 (EN 1.4903) Valves:

 

F91 (EN 1.4903) valves are alloy steel valves made of high-temperature resistant, creep-resistant chromium-molybdenum forged steel, containing approximately 9% chromium, 1% molybdenum, and 1% vanadium. These valves can withstand extreme pressures and temperatures up to 600°C to 650°C, making them ideal for high-temperature steam media, such as high-pressure, high-temperature steam pipeline systems, power plants, and long-haul fossil fuel boilers.

 

2. Key Advantages of Freeman Valve's F91 Valves:

 

2.1 Outstanding High-Temperature Creep Fracture Strength of Freeman Valve's F91 Valves: 

The addition of V, Nb, and N elements to form stable carbonitride pinned grain boundaries results in creep strength approximately twice that of F22 and significantly higher than F9. Under the same temperature and pressure, the wall thickness can be reduced, decreasing equipment weight and pipeline load;

 

2.2 Freeman Valve's F91 valves exhibit excellent high-temperature oxidation resistance: 

Containing 9% Cr, F91 valves form a dense oxide layer, providing superior oxidation resistance in pure steam environments;

 

2.3 Freeman Valve's F91 valves demonstrate excellent resistance to hydrogen corrosion: 

F91 valves outperform low-chromium molybdenum steel in high-temperature, high-pressure hydrogen-contaminated conditions, making them ideal for high-temperature hydrogen-contaminated pipelines in oil refining hydrogenation and gasification units;

 

2.4 Freeman Valve's F91 valves exhibit good resistance to thermal fatigue: 

Their excellent resistance to thermal fatigue makes F91 valves highly suitable for boilers and combined cycle units experiencing frequent start-ups and shutdowns and temperature fluctuations.

 

3. Precautions for using F91 valves:

 

3.1 The welding and heat treatment requirements for F91 valves are extremely stringent:

F91 valves must be preheated to 205–370℃, and interpass temperature must be controlled; post-weld forced PWHT: narrow window insulation of 730–780℃; the heat treatment range is narrow, too low a temperature will easily cause hardening and embrittlement, too high a temperature will result in loss of creep strength;

 

3.2 F91 valves have limited corrosion resistance:

F91 valves are only suitable for pure steam and clean hydrogen-containing media; F91 valves are not resistant to chloride ions, sulfides, and acidic media.

 

4. Key application areas for Freeman Valve's F91 valves:

 

4.1 Freeman Valve's F91 valves have been widely used in the thermal power industry. For example:

① Main steam and high-temperature reheat steam pipelines for supercritical/subcritical and combined cycle power plants;

② Boiler superheaters and reheater headers;

③ Waste incineration and biomass high-temperature boilers;

 

4.2 Freeman Valve's F91 valves have been widely used in the petroleum refining and coal chemical industries. For example:

① High-temperature heating furnace inlets and outlets and high-temperature hydrogen pipelines in hydrogenation units;

② High-temperature and high-pressure process pipelines in coal gasification and syngas units;

 

4.3 Freeman Valve's F91 valves have been widely used in energy infrastructure and industrial heating. For example:

① High-temperature and high-pressure steam networks, accumulators, and high-temperature heat exchangers in large-scale combined heat and power plants;

② Molten salt energy storage and high-temperature thermal oil systems.

 

5. Summary of F91 Valve Selection

 

5.1 Prioritize F91 valves: 

Suitable for temperatures between 540 and 620°C, where the medium is pure steam or hydrogen-containing, and where lightweight design and creep control are key performance indicators.

 

5.2 Not recommended for F91 valves: 

① Operating temperatures consistently above 620°C; 

② Chlorine-containing, acidic, or high-sulfur corrosive environments.



Design Standard of F91 Gate Valve:

Design Acc. to ASME B16.34 (ANSI Standard F91 Gate Valve);

Design Acc. to EN-12516-1/2 (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve).

 

Test Standard of F91 Gate Valve:

Test Acc. to API 598 (ANSI Standard F91 Gate Valve);

Test Acc. to EN 12266-1/2 (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve).

 

Surface Finishing of F91 Gate Valve:

All F91 Gate Valve surface is finely machined to achieve the required roughness and conforms to standard MSS SP-110.

 

Size of F91 Gate Valve:

From DN1/4’’ to 48’’ (ANSI Standard F91 Gate Valve);

From DN8 to DN1200 (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve).

 

Face to Face of F91 Gate Valve:

Face to Face Acc. to ASME B16.10 (ANSI Standard F91 Gate Valve);

Face to Face Acc. to EN 558-1 (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve).

 

Pressure Rating of F91 Gate Valve:

ANSI Class 150 F91 Gate Valve (ANSI Standard F91 Gate Valve);

ANSI Class 300 F91 Gate Valve (ANSI Standard F91 Gate Valve);

ANSI Class 600 F91 Gate Valve (ANSI Standard F91 Gate Valve);

ANSI Class 800 F91 Gate Valve (ANSI Standard F91 Gate Valve);

ANSI Class 900 F91 Gate Valve (ANSI Standard F91 Gate Valve);

ANSI Class 1500 F91 Gate Valve (ANSI Standard F91 Gate Valve);

ANSI Class 2500 F91 Gate Valve (ANSI Standard F91 Gate Valve);

EN 1092 PN 16 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 25 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 40 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 63 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 100 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 160 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 250 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 320 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve);

EN 1092 PN 400 F91 Gate Valve (EN Standard F91 Gate Valve, DIN Standard F91 Gate Valve).

 

Working Temperature of F91 Gate Valve:

Please refer to the "Temperature and Pressure Curve of F91 Gate Valve" for temperature and pressure changes.

 

Ends Connection of F91 Gate Valve:

ANSI Flange Ends F91 Gate Valve;

ANSI Integral Flange Ends F91 Gate Valve;

ANSI Welded Flange Ends F91 Gate Valve;

Butt Weld (ASME B16.25) Ends F91 Gate Valve;

Butt Weld x ANSI Flange Ends F91 Gate Valve;

EN 1092 Flange Ends F91 Gate Valve;

EN 1092 Integral Flange Ends F91 Gate Valve;

EN 1092 Welded Flange Ends F91 Gate Valve;

Butt Weld (EN 12627) Ends F91 Gate Valve;

Butt Weld (ISO 1127) Ends F91 Gate Valve;

Butt Weld x EN 1092 Flange Ends F91 Gate Valve;

Male NPT (ASME B1.20.1) Ends F91 Gate Valve;

Male BSPP (ISO 228-1) Ends F91 Gate Valve;

Male BSPT (ISO 7-1) Ends F91 Gate Valve;

Male NPT x Female NPT Ends F91 Gate Valve;

Male BSPP x Female BSPP Ends F91 Gate Valve;

Male BSPT x Female BSPT Ends F91 Gate Valve;

Male NPT x Long Butt Weld (+100 mm) Ends F91 Gate Valve;

Male BSPP x Long Butt Weld (+100 mm) Ends F91 Gate Valve;

Male BSPT x Long Butt Weld (+100 mm) Ends F91 Gate Valve;

Female NPT (ASME B1.20.1) Ends F91 Gate Valve;

Female BSPP (ISO 228-1) Ends F91 Gate Valve;

Female BSPT (ISO 7-1) Ends F91 Gate Valve;

Socket Weld (ASME B16.11) Ends F91 Gate Valve;

Socket Weld (EN 12760) Ends F91 Gate Valve;

Female NPT x Socket Weld Ends F91 Gate Valve;

Female BSPP x Socket Weld Ends F91 Gate Valve;

Female BSPT x Socket Weld Ends F91 Gate Valve;

Butt Weld (ASME B16.25) Ends F91 Gate Valve;

Butt Weld (EN 12627) Ends F91 Gate Valve;

Female NPT x Butt Weld Ends F91 Gate Valve;

Female BSPP x Butt Weld Ends F91 Gate Valve;

Female BSPT x Butt Weld Ends F91 Gate Valve;

Female NPT x Long Butt Weld (+100 mm) Ends F91 Gate Valve;

Female BSPP x Long Butt Weld (+100 mm) Ends F91 Gate Valve;

Female BSPT x Long Butt Weld (+100 mm) Ends F91 Gate Valve;

Long Butt Weld (+100 mm Weld Stub) Ends F91 Gate Valve.

 

CE Marking of F91 Gate Valve:

CE Marking is Available to F91 Gate Valve with a Diameter of DN32 or Larger.

 

Chemical Composition of F91 Gate Valve:

For the Chemical Composition of F91 Gate Valve, please refer to EN 10204 Type 3.1 certificate.

 

Mechanical Properties of F91 Gate Valve:

For the Mechanical Properties of F91 Gate Valve, please refer to EN 10204 Type 3.1 certificate.

 

Certificate of F91 Gate Valve:

All F91 Gate Valve will be delivered with EN 10204 Type 3.1 Certificate.

 

Approvals of F91 Gate Valve:

MSS SP-110 Certified of F91 Gate Valve;

NACE MR 0175 Certified of F91 Gate Valve

API 607 Fire Safe Certified of F91 Gate Valve;

ISO 9001 Certified of F91 Gate Valve;

PED Certified of F91 Gate Valve.

 

Available Upon Request of F91 Gate Valve:

NACE MR0175 is available upon request of F91 Gate Valve;

ATEX is available upon request of F91 Gate Valve;

TA-LUFT is available upon request of F91 Gate Valve;

SIL is available upon request of F91 Gate Valve;

Degreasing is available upon request of F91 Gate Valve;

Fire Safe is available upon request of F91 Gate Valve;

Stem Extension is available upon request of F91 Gate Valve;

Double Block and Bleed is available upon request of F91 Gate Valve.

 


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