16″-1500LB Open Die Forged F91 Pressure Self-Sealing Parallel Gate Valve
Description
Technical Data Sheet
Pressure Self-Sealing Parallel Gate Valve
(Free Forging Process, Flanged Ends)
Material: ASTM A182 F91
1. General Description
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Product Type: Parallel Gate Valve (Parallel Disc / Parallel Slide Gate Valve)
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Body Construction: Free Forging Process – Solid forged body for enhanced grain structure and strength
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Body Material: ASTM A182 F91 (9Cr-1Mo-VNb Modified Alloy Steel)
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Bonnet Design: Pressure Self-Sealing (Pressure Seal) Bonnet – Utilizes line media pressure to enhance sealing
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Disc Type: Parallel double disc / Parallel slide design
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End Connections: Flanged (ASME / EN standards)
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Operation: Handwheel / Gearbox / Electric / Pneumatic actuator
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Design Standard: API 600 / API 6D / ASME B16.34 / GB/T 12234
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Face-to-Face: ASME B16.10 / API 6D / GB/T 12221
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Test Standard: API 598 / API 6D / GB/T 13927
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Temperature Range: Up to 600°C (excellent creep resistance at elevated temperatures)
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Pressure Rating: Class 150 – Class 2500 / PN16 – PN420
2. Application
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Suitable Media: High-pressure steam, high-temperature fluids, oil & gas, supercritical steam, power generation services
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Typical Industries: Ultra-supercritical thermal power plants, nuclear power, petrochemical, oil & gas refineries, high-pressure industrial systems
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Special Features: Specifically designed for high-temperature, high-pressure steam services up to 600°C
3. Technical Parameters
| Parameter | Specification Range |
|---|---|
| Nominal Diameter (DN) | DN50 – DN600 (2″ – 24″) |
| Pressure Rating | Class 150 – Class 2500 / PN16 – PN420 |
| Shell Test Pressure | 1.5 x rated pressure (per API 598) |
| Seat Test Pressure | 1.1 x rated pressure (per API 598) |
| Leakage Rate | API 598 / ISO 5208 Rate D (metal seated) |
| Operating Temperature | Up to 600°C |
| Flow Direction | Bi-directional |
| Bonnet Type | Pressure Self-Sealing (Pressure Seal) – Seal efficiency increases with pressure |
4. Materials of Construction
| Component | Material | Standard / Notes |
|---|---|---|
| Body | ASTM A182 F91 | 9Cr-1Mo-VNb modified alloy steel. Free forging process ensures superior grain structure . Excellent creep resistance up to 600°C . |
| Bonnet | ASTM A182 F91 | Same as body material – pressure self-sealing design |
| Disc / Gate | ASTM A182 F91 + Hardfacing | Parallel double disc design; seat faces hardfaced with Stellite or equivalent cobalt-based alloy for wear resistance at high temperature |
| Seat Rings | Integral / Welded-in + Stellite hardfacing | Hardfaced to match disc facing; ensures long service life in high-temperature cycling |
| Stem | ASTM A182 F91 / Inconel 750 / 17-4PH | High-strength, oxidation-resistant alloy; rolled threads for strength; anti-blowout design |
| Stem Nut | Aluminum Bronze / Ni-Resist | High strength, low friction at elevated temperatures |
| Pressure Seal Ring | Flexible Graphite + Stainless Steel wire reinforcement | Pressure-energized seal; higher pressure creates tighter seal |
| Gland Packing | Flexible Graphite / Exfoliated Graphite | High-temperature, low-friction packing suitable for steam service |
| Bonnet Gasket | Spiral Wound (SS + Graphite) / Metal Jacketed | Secondary seal; primary seal is pressure seal ring |
| Bolting | ASTM A193 Grade B16 / B8 Class 2 | High-temperature alloy steel studs and nuts |
| Yoke / Operator Mount | Carbon Steel / Fabricated Steel | ISO 5211 mounting pad for actuator |
| Coating | High-temperature resistant aluminum paint / No coating | For service above 400°C, coatings are typically not applied |
5. F91 Material Properties
ASTM A182 F91 is a modified 9Cr-1Mo-VNb ferritic alloy steel specifically developed for high-temperature service .
| Property | Value |
|---|---|
| Chemical Composition (Typical) | C: 0.08-0.12, Mn: 0.30-0.60, Cr: 8.0-9.5, Mo: 0.85-1.05, V: 0.18-0.25, Nb: 0.06-0.10, N: 0.03-0.07 |
| Tensile Strength | 585 – 760 MPa (85 – 110 ksi) |
| Yield Strength (min) | 415 MPa (60 ksi) |
| Elongation (min) | 20% |
| Hardness | 248 – 293 HB (typical) |
| Microstructure | Tempered Martensite |
| Maximum Service Temperature | 600°C (excellent creep and oxidation resistance) |
6. Pressure Self-Sealing Bonnet Design – Working Principle
The pressure self-sealing bonnet (压力自密封阀盖) is ideal for high-pressure, high-temperature F91 valves :
| Feature | Benefit |
|---|---|
| Pressure-Energized Seal | Line media pressure pushes the bonnet upward, compressing the seal ring against the body taper. Higher pressure creates tighter seal |
| Simplified Design | Eliminates large flange connections and heavy bolting; reduces stress concentration in high-temperature service |
| Compact & Lightweight | Reduces valve weight and overall height |
| Reliable at High Pressure/Temperature | Ideal for supercritical steam applications where bolted connections may relax under thermal cycling |
| Seal Ring Materials | Flexible graphite with SS reinforcement provides excellent resilience and temperature resistance up to 650°C |
7. Free Forging Process – Advantages for F91
The use of free forging (自由锻造) for F91 valve bodies is critical due to the material’s high alloy content and service requirements :
| Advantage | Benefit |
|---|---|
| Enhanced Grain Structure | Forging aligns grain flow with part contours, increasing strength and fatigue resistance at high temperatures |
| No Porosity / Voids | Eliminates casting defects; critical for high-pressure steam integrity |
| Homogeneous Structure | Ensures uniform mechanical properties throughout the thick-walled body |
| Controlled Fiber Flow | Proper forging technique ensures fiber flow follows the pressure containment path |
| Ultrasonic Inspection Capability | Forged F91 allows full volumetric examination per ASTM A388 |
8. Parallel Gate Design – Features
The parallel disc / parallel slide gate design is particularly suitable for high-temperature F91 valves :
| Feature | Benefit |
|---|---|
| Parallel Discs | Two parallel discs expand against seats when closing, providing tight shut-off |
| Low Torque Operation | Minimal friction during opening/closing – only stem packing friction |
| No Thermal Binding | Parallel design prevents binding at high temperatures – discs remain free even under thermal expansion |
| Self-Aligning | Disc assembly self-aligns to seats, compensating for minor misalignment |
| Erosion Resistance | Flow path designed to minimize seat erosion during opening |
| Bi-directional Sealing | Seals effectively in both flow directions |
9. Dimensions & Weights (Reference Values – Class 1500)
*Note: Dimensions vary by manufacturer and pressure class. F91 valves are typically heavier due to material density and wall thickness requirements. Request certified drawing from manufacturer for exact dimensions. *
| Size (inches) | DN (mm) | L (Face-to-Face) mm – RF | L (Face-to-Face) mm – RTJ | H (Open approx.) mm | Weight approx. (kg) |
|---|---|---|---|---|---|
| 2″ | 50 | 368 | 368 | 550 | 50 |
| 3″ | 80 | 381 | 384 | 650 | 85 |
| 4″ | 100 | 457 | 460 | 750 | 125 |
| 6″ | 150 | 610 | 613 | 950 | 250 |
| 8″ | 200 | 737 | 740 | 1150 | 400 |
| 10″ | 250 | 838 | 841 | 1350 | 580 |
| 12″ | 300 | 965 | 968 | 1550 | 820 |
| 14″ | 350 | 1029 | 1038 | 1750 | 1050 |
| 16″ | 400 | 1130 | 1140 | 1950 | 1400 |
| 18″ | 450 | 1219 | 1232 | 2150 | 1750 |
| 20″ | 500 | 1321 | 1334 | 2400 | 2200 |
| 24″ | 600 | 1543 | 1562 | 2800 | 3100 |
*(Note: Face-to-face dimensions based on ASME B16.10 for Class 1500. Higher pressure classes have longer face-to-face dimensions.)*
10. Testing (Per API 598 / API 6D)
| Test | Test Pressure | Acceptance Criteria |
|---|---|---|
| Shell Hydrostatic Test | 1.5 x rated pressure | No visible leakage through pressure boundary |
| Seat Leakage Test (High Pressure) | 1.1 x rated pressure | Allowable leakage per API 598 for metal-seated valves (Rate D) |
| Seat Leakage Test (Low Pressure) | 80 PSI (5.5 bar) | Visual inspection for leakage |
| Backseat Test | Rated pressure | No visible leakage when valve fully open |
| Nondestructive Examination | Per ASME B16.34 | Ultrasonic / Magnetic Particle / Dye Penetrant as specified |
11. Options & Accessories
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Operation: Handwheel, Bevel Gearbox, Electric Actuator, Pneumatic Actuator
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Stem Extension: For buried or insulated installations
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Position Indicators: Mechanical flag, limit switches, positioners
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Hardfacing: Stellite 6 / Stellite 21 / Colmonoy (various grades)
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Special Designs: NACE MR0175 sour service, Oxygen cleaning
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Certification: Material certificates EN 10204 3.1/3.2, NACE MR0175, PED, IBR (Indian Boiler Regulations)
12. Ordering Information
To ensure correct selection, please specify:
| Item | Specification |
|---|---|
| Valve Type | Pressure Self-Sealing Parallel Gate Valve – Forged Body |
| Body Material | ASTM A182 F91 |
| Size | ______ inches / DN ______ |
| Pressure Class | Class ______ |
| Trim Material | F91 + Stellite hardfacing (specify hardfacing grade) |
| Ends | Flanged – ASME B16.5 / RTJ / Other |
| Face-to-Face | ASME B16.10 / API 6D |
| Operation | Handwheel / Gearbox / Actuator |
| Media / Temperature | ______ / ______ °C |
| Special Requirements | NACE, IBR, PED, etc. |
This data sheet is a guideline based on standard industry practice for Pressure Self-Sealing Parallel Gate Valves manufactured from ASTM A182 F91 by free forging process . F91 material is specifically selected for high-temperature steam services up to 600°C in power generation and petrochemical applications . Always refer to the manufacturer’s certified drawings for exact dimensions and ratings.
