Description

TECHNICAL DATA SHEET

Forged Stainless Steel Cryogenic Floating Ball Valve
Series: DQ41F/Y / DQ61F/Y
Models: Reduced Bore / Full Bore, Side-Entry (Split Body)

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1. PRODUCT OVERVIEW

This forged stainless steel cryogenic ball valve is specifically engineered for reliable shut-off and flow control of liquefied gases and cryogenic fluids down to -196°C. Designed in accordance with BS 6364, ISO 28921-1, and MSS SP-134 standards, it features a two-piece bolted body construction with extended bonnet and fully forged austenitic stainless steel components (ASTM A182 F304/F304L/F316L) to eliminate porosity and ensure structural integrity under extreme thermal cycling .

Key Features:

• 100% Forged Body Construction: ASTM A182 F304/F304L stainless steel, no cast defects, superior low-temperature impact toughness .

• Extended Bonnet (Long Neck): Minimum 250mm neck length for DN50 and above, positions stem packing at ambient temperature, prevents ice formation, and allows insulation application .

• Cryogenic Stabilization Treatment: All pressure-containing parts undergo deep cryogenic treatment (LN₂ immersion, -196°C soak for 2-6 hours, 2-3 cycles) to stabilize microstructure and relieve machining stresses .

• Blow-out Proof Stem: Integrally forged stem with anti-blowout shoulder, anti-static device (spring-loaded contact) per ISO 28921-1 .

• Low Emission Packing: Live-loaded disc spring + graphite/RPTFE packing system, meets ISO 15848-1 Class B fugitive emission requirements .

• Cavity Pressure Relief: Upstream seat is pressure-relieving design to prevent body cavity over-pressurization due to cryogenic fluid vaporization .

• Full Traceability: Positive Material Identification (PMI) and EN 10204 Type 3.1 material certification available .

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2. DESIGN STANDARDS & SPECIFICATIONS

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3. GENERAL TECHNICAL PARAMETERS

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4. MATERIALS OF CONSTRUCTION (FORGED STAINLESS STEEL)

Alternative Forged Materials (Upon Request):

• A182 F316/F316L: Enhanced pitting corrosion resistance

• A182 F321: Stabilized grade for higher intermittent temperatures

• Inconel 625 / Hastelloy C-276: For extreme low temp (< -196°C) + high corrosion

• A352 LC3 / LCB: Cast low carbon steel (not forged, for non-SS requirements)

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5. CRYOGENIC TREATMENT & TESTING

Cryogenic Stabilization Process:

1. All rough-machined forged components (body, bonnet, ball, stem) are immersed in liquid nitrogen (-196°C).

2. Soaking time: 2-6 hours depending on mass (minimum 2 hours per cycle) .

3. Components are returned to ambient temperature naturally (no forced heating).

4. Process repeated for minimum 2 cycles .

5. Final precision machining after stabilization to ensure dimensional stability at cryogenic service.

Purpose:

• Transforms retained austenite

• Relieves residual stresses from forging/welding

• Prevents dimensional changes and seal leakage during thermal cycling

Impact Testing:

• Charpy V-Notch test per ASTM A370

• Acceptance criteria: ≥ 41J (average) at -196°C for F304L

• AOKAVI standard: ≥ 50J at -196°C

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6. DIMENSIONS & CONNECTIONS (ASME CLASS 150/300 – REFERENCE)

6.1 Flanged Type (DQ41F/Y) – PN16/PN40 / Class 150/300

Unit: mm (Reference dimensions – subject to manufacturer design)

Notes:

• Flange drilling per ASME B16.5 (Class 150 / 300). For PN16/PN40, dimensions vary per EN 1092-1.

• Bonnet extension length per BS 6364: Minimum 250mm for DN50 and above; actual H dimension includes operator clearance .

• Weight shown for Class 150 carbon steel body; SS body slightly heavier.

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6.2 Socket Weld / Threaded Type (DQ61F/Y) – NPT/BSPT/SW

Unit: mm

Source: 

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7. PRESSURE-TEMPERATURE RATING

Forged A182 F304/F304L – ASME B16.34

Critical Notes:

• Floating ball design is limited to Class 300 maximum due to stem thrust loading .

• For Class 600 and above, trunnion-mounted cryogenic ball valve design is required.

• Pressure rating at -196°C is derated per ASME B16.34 and BS 6364 requirements .

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8. PERFORMANCE & LEAKAGE TESTS

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9. OPERATING TORQUE (REFERENCE @ -196°C)

Notes:

• Torque increases significantly with pressure differential and seat material (PCTFE higher than RPTFE).

• Safety factor for actuator sizing: 1.3 – 1.5 for pneumatic, 1.5 – 2.0 for electric .

• Values shown for RPTFE seats, clean media, DN50 tested per .

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10. DESIGN FEATURES & CRYOGENIC SPECIALTIES

Extended Bonnet (Long Neck):

• Mandatory for service below -50°C .

• Positions stem packing and actuator at ambient temperature zone.

• Prevents ice formation and lubrication solidification.

• Standard neck length: 250mm for DN50, scaled proportionally for other sizes.

Pressure Relief Mechanism:

• Floating ball design inherently allows upstream seat to act as pressure relief.

• Prevents body cavity overpressure due to liquid vaporization (cryogenic pumping effect) .

• For fixed ball designs, optional internal relief valve or self-relieving seat.

Anti-Static Device:

• Required per ISO 28921-1 and BS 5353 for flammable cryogenic media (LNG, ethylene, etc.).

• Spring-loaded plunger continuously grounds ball to body.

Oxygen Service Cleaning:

• Optional degreasing and cleaning per CGA G-4.1 (for liquid oxygen service).

• Chlorine-free packaging and labeling .

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11. APPLICATIONS & INDUSTRY USE

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12. QUALIFICATION & CERTIFICATION

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13. SELECTION & ORDERING INFORMATION

To ensure correct valve selection for your cryogenic application, please specify:

1. Model: DQ41F (Flanged) / DQ61F (SW/NPT) / DQ47F (Gear)

2. Size (DN/NPS): e.g., DN50 (2″)

3. Pressure Class: Class 150 / 300 / PN16 / PN40

4. Body Material: A182 F304/F304L (Forged SS) — standard for -196°C

5. Ball/Stem Material: A182 F304/F304L

6. Seat Material: RPTFE / PCTFE / PEEK (specify)

7. End Connection: RF flange, RTJ flange, NPT, BSPT, SW, BW

8. Design Temperature: -196°C / -101°C / -46°C

9. Service Media: LNG / LN₂ / LO₂ / Ethylene / Other (specify)

10. Operation: Manual Lever / Gear / Pneumatic / Electric

11. Special Requirements:

    • Cryogenic test with BS 6364 certificate

    • Oxygen cleaning (CGA G-4.1)

    • Anti-static device

    • Fire-safe design (API 607)

    • NACE MR0175

    • Extended bonnet length (custom)

    • PMI testing

    • EN 10204 3.1 material certs