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H643-6506-31 — SEAT,VALVE

✓ Government record, cited
— · GATE VALVE
PRODUCT OVERVIEW

H643-6506-31: SEAT,VALVE.

The SEAT,VALVE is a the manufacturer industrial component. Key specifications include material: NICKEL ALLOY SEAT, thread_class: 2A FIRST THREADED PORTION A, thread_length: 0.500 INCHES NOMINAL FIRST THREADED PORTION IN, overall_height: 0.500 INCHES NOMINAL IN, special_features: NHA VALVE ASSY SN, style_designator: PLAIN THREADED. This part is cataloged in the U.S.

Government catalog under NSN 4820-01-498-4373, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
H643-6506-31
NSN: 4820-01-498-4373
FSC: 4820 — Valves, Nonpowered
CAGE: 96169 — ELECTRIC BOAT CORPORATION DIV GENERAL DYNAMICS ELECTRIC BOAT (USA)
SPECIFICATIONS
materialNICKEL ALLOY SEAT
thread_class2A FIRST THREADED PORTION A
thread_length0.500 INCHES NOMINAL FIRST THREADED PORTION IN
overall_height0.500 INCHES NOMINAL IN
special_featuresNHA VALVE ASSY SN
style_designatorPLAIN THREADED
nominal_thread_size0.375 INCHES FIRST THREADED PORTION IN
body_inside_diameter0.089 INCHES NOMINAL IN
seating_surface_shapeANGULAR
thread_series_designatorUNF FIRST THREADED PORTION
NSN4820-01-498-4373
COMPONENT DIAGRAM
GATE VALVE — FULL OPEN OR FULL CLOSE ONLY Rising STEM BONNET FLOW → → FLOW SEATS — — SIZE: — · — · — PN: H643-6506-31 · OEM ⚠ VERIFY BEFORE ORDERING Gate valves = FULL OPEN or FULL CLOSE only — never throttle. Partial opening causes seat erosion and vibration. ✓ BROKER TIP Rising stem shows valve position visually — easier maintenance. Non-rising stem saves headroom. PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
THREAD LENGTH: 0.500 INCHES NOMINAL FIRST THREADED PORTION IN
•
STYLE DESIGNATOR: PLAIN THREADED
•
BODY INSIDE DIAMETER: 0.089 INCHES NOMINAL IN
•
NOMINAL THREAD SIZE: 0.375 INCHES FIRST THREADED PORTION IN
•
THREAD CLASS: 2A FIRST THREADED PORTION A
•
MATERIAL: NICKEL ALLOY SEAT
TECHNICAL CHARACTERISTICS
OVERALL HEIGHT0.500 INCHES NOMINAL IN
THREAD LENGTH0.500 INCHES NOMINAL FIRST THREADED PORTION IN
STYLE DESIGNATORPLAIN THREADED
BODY INSIDE DIAMETER0.089 INCHES NOMINAL IN
NOMINAL THREAD SIZE0.375 INCHES FIRST THREADED PORTION IN
SPECIAL FEATURESNHA VALVE ASSY SN
THREAD CLASS2A FIRST THREADED PORTION A
MATERIALNICKEL ALLOY SEAT
THREAD SERIES DESIGNATORUNF FIRST THREADED PORTION
SEATING SURFACE SHAPEANGULAR
OTHER ITEMS IN FSC 4820 — Valves, Nonpowered
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
4820-00-000-0097 4820-00-001-0010 4820-00-001-0020 4820-00-001-0021 4820-00-001-0032 4820-00-001-0037 4820-00-001-0042 4820-00-001-1230
SUBSTITUTES & CROSS-REFERENCES 1
342-7107384Reference document
Same NSN cross-reference
Reference document — Drawing number reference only
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is H643-6506-31?
H643-6506-31 is a SEAT,VALVE.
What parts can replace H643-6506-31?
There is 1 known substitute for H643-6506-31: 342-7107384. Substitute compatibility should be verified for your specific system.
What is the NSN for H643-6506-31?
H643-6506-31 is cataloged in the U.S. Government catalog under NSN 4820-01-498-4373. This indicates validated use in U.S. government and defense supply chains.
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✓ PartsTable — the parts reference. Every fact cited to its source.
PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.