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A1N203 — SEAT,VALVE

✓ Government record, cited
— · GATE VALVE
PRODUCT OVERVIEW

A1N203: SEAT,VALVE.

The SEAT,VALVE is a the manufacturer industrial component. Key specifications include flange_diameter: 0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN, style_designator: PLAIN FLANGED, seat_angle_in_deg: 45.000 NOMINAL, under_flange_height: 0.331 INCHES MINIMUM AND 0.349 INCHES MAXIMUM IN, body_inside_diameter: 0.150 INCHES MINIMUM AND 0.166 INCHES MAXIMUM IN, body_outside_diameter: 0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN. This part is cataloged in the U.S.

Government catalog under NSN 4820-00-986-0531, 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
A1N203
NSN: 4820-00-986-0531
FSC: 4820 — Valves, Nonpowered
CAGE: 31949 — BROOKS AUTOMATION, INC. DIV CTI CRYOGENICS (USA)
SPECIFICATIONS
flange_diameter0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN
style_designatorPLAIN FLANGED
seat_angle_in_deg45.000 NOMINAL
under_flange_height0.331 INCHES MINIMUM AND 0.349 INCHES MAXIMUM IN
body_inside_diameter0.150 INCHES MINIMUM AND 0.166 INCHES MAXIMUM IN
body_outside_diameter0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN
seating_surface_shapeANGULAR
flange_seat_to_disk_end_height0.031 INCHES MINIMUM AND 0.047 INCHES MAXIMUM IN
NSN4820-00-986-0531
COMPONENT DIAGRAM
GATE VALVE — FULL OPEN OR FULL CLOSE ONLY Rising STEM BONNET FLOW → → FLOW SEATS — — SIZE: — · — · — PN: A1N203 · 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
•
FLANGE SEAT TO DISK END HEIGHT: 0.031 INCHES MINIMUM AND 0.047 INCHES MAXIMUM IN
•
FLANGE DIAMETER: 0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN
•
BODY OUTSIDE DIAMETER: 0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN
•
STYLE DESIGNATOR: PLAIN FLANGED
•
BODY INSIDE DIAMETER: 0.150 INCHES MINIMUM AND 0.166 INCHES MAXIMUM IN
•
UNDER FLANGE HEIGHT: 0.331 INCHES MINIMUM AND 0.349 INCHES MAXIMUM IN
•
SEAT ANGLE IN DEG: 45.000 NOMINAL
•
SEATING SURFACE SHAPE: ANGULAR
TECHNICAL CHARACTERISTICS
FLANGE SEAT TO DISK END HEIGHT0.031 INCHES MINIMUM AND 0.047 INCHES MAXIMUM IN
FLANGE DIAMETER0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN
BODY OUTSIDE DIAMETER0.805 INCHES MINIMUM AND 0.809 INCHES MAXIMUM IN
STYLE DESIGNATORPLAIN FLANGED
BODY INSIDE DIAMETER0.150 INCHES MINIMUM AND 0.166 INCHES MAXIMUM IN
UNDER FLANGE HEIGHT0.331 INCHES MINIMUM AND 0.349 INCHES MAXIMUM IN
SEAT ANGLE IN DEG45.000 NOMINAL
SEATING SURFACE SHAPEANGULAR
SUBSTITUTES & CROSS-REFERENCES 1
400203Reference document
Same NSN cross-reference
Reference document — Design control — primary reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Normally procured from the manufacturer (OEM)No demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is A1N203?
A1N203 is a SEAT,VALVE.
What parts can replace A1N203?
There is 1 known substitute for A1N203: 400203. Substitute compatibility should be verified for your specific system.
What is the NSN for A1N203?
A1N203 is cataloged in the U.S. Government catalog under NSN 4820-00-986-0531. 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.