PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

803-1385637-08X-08Seat,valve

Naval Ship Systems Command · NSN 4820-01-540-8802 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-01-540-8802 — this item is cataloged by the U.S. Government under National Stock Number 4820-01-540-8802. Primary manufacturer part number: 803-1385637-08X-08.
Features
  • Seat,valve — FSC 4820
  • Flange Seat to Disk End Height: 1.094 INCHES NOMINAL IN
  • Thread Quantity Per Inch: 12 SINGLE THREADED PORTION
  • Thread Series Designator: UNS SINGLE THREADED PORTION
  • Material Document and Classification: ASTM A494 GR -30C ASSN STD SINGLE MATERIAL RESPONSE OR QQ-N-281 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
  • Style Designator: THREADED FLANGED
  • Seating Surface Shape: FLAT
  • Body Inside Diameter: 7.938 INCHES NOMINAL IN
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Nickel Alloy Overall construction
General Description

The Seat,valve, cataloged under National Stock Number 4820-01-540-8802, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Naval Ship Systems Command. Government technical data includes 12 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 2 commercial cross-references from 1 manufacturer, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4820-01-540-8802
Primary Part Number803-1385637-08X-08
Item NameSeat,valve
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerNaval Ship Systems Command
StatusACTIVE
Flange Seat to Disk End Height1.094 INCHES NOMINAL IN
Thread Quantity Per Inch12 SINGLE THREADED PORTION
Thread Series DesignatorUNS SINGLE THREADED PORTION
Material Document and ClassificationASTM A494 GR -30C ASSN STD SINGLE MATERIAL RESPONSE OR QQ-N-281 FED SPEC SINGLE MATERIAL RESPONSE OVERALL
Style DesignatorTHREADED FLANGED
Seating Surface ShapeFLAT
Body Inside Diameter7.938 INCHES NOMINAL IN
MaterialNICKEL ALLOY OVERALL
Thread Class3A SINGLE THREADED PORTION A
Thread Length0.750 INCHES NOMINAL SINGLE THREADED PORTION IN
Under Flange Height0.750 INCHES NOMINAL IN
Flange Diameter9.125 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 12
4820-00-058-36301385637-052AF INTERCHANGEABLE
Valve,check
Naval Ship Systems Command
4820-00-243-6698 INTERCHANGEABLE
Seat,valve
4820-00-878-4325803-1385637-082 INTERCHANGEABLE
Valve,check
Naval Ship Systems Command
4820-01-072-1204803-1385637-04X-17 INTERCHANGEABLE
Disk,valve
Naval Ship Systems Command
4820-01-426-24601260-014K800 INTERCHANGEABLE
Valve,check
Milwaukee Valve Co, Inc Div Milwaukee Valve Company, Llc
4820-01-435-5880803-1385637-05X-20 INTERCHANGEABLE
Disk,valve
Naval Ship Systems Command
5310-01-487-7109803-1385637-06X-22 INTERCHANGEABLE
Washer,flat
Naval Ship Systems Command
5310-01-487-7137803-1385637-02X-22 INTERCHANGEABLE
Washer,flat
Naval Ship Systems Command
5310-01-487-8128803-1385637-05X-22 INTERCHANGEABLE
Washer,flat
Naval Ship Systems Command
5310-01-521-1009803-1385637-10X-11 INTERCHANGEABLE
Nut,plain,hexagon
Naval Ship Systems Command
Cross-Reference Index
Part NumberManufacturer
1385637 Naval Ship Systems Command (USA)
803-1385637-08X-08 PRIMARY Naval Ship Systems Command (USA)
Related Parts
4820-00-058-3630INTERCHANGEABLE
VALVE,CHECK
1385637-052AF
4820-00-243-6698INTERCHANGEABLE
SEAT,VALVE
4820-00-878-4325INTERCHANGEABLE
VALVE,CHECK
803-1385637-082
4820-01-072-1204INTERCHANGEABLE
DISK,VALVE
803-1385637-04X-17
4820-01-426-2460INTERCHANGEABLE
VALVE,CHECK
1260-014K800
4820-01-435-5880INTERCHANGEABLE
DISK,VALVE
803-1385637-05X-20
5310-01-487-7109INTERCHANGEABLE
WASHER,FLAT
803-1385637-06X-22
5310-01-487-7137INTERCHANGEABLE
WASHER,FLAT
803-1385637-02X-22
5310-01-487-8128INTERCHANGEABLE
WASHER,FLAT
803-1385637-05X-22
5310-01-521-1009INTERCHANGEABLE
NUT,PLAIN,HEXAGON
803-1385637-10X-11
5310-01-521-1020INTERCHANGEABLE
NUT,PLAIN,HEXAGON
803-1385637-03X-11
5310-01-521-1025INTERCHANGEABLE
NUT,PLAIN,HEXAGON
803-1385637-05X-11

Frequently Asked Questions

What is NSN 4820-01-540-8802?

NSN 4820-01-540-8802 is a Seat,valve, manufactured by Naval Ship Systems Command, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-01-540-8802?

NSN 4820-01-540-8802 has 2 cross-referenced part numbers: 1385637 (Naval Ship Systems Command), 803-1385637-08X-08 (Naval Ship Systems Command).

What NSN replaces 4820-01-540-8802?

There are 12 known substitutes for 4820-01-540-8802: 4820-00-058-3630, 4820-00-243-6698, 4820-00-878-4325 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 803-1385637-08X-08?

Key specifications for 803-1385637-08X-08: Flange Seat to Disk End Height: 1.094 INCHES NOMINAL IN; Thread Quantity Per Inch: 12 SINGLE THREADED PORTION; Thread Series Designator: UNS SINGLE THREADED PORTION; Material Document and Classification: ASTM A494 GR -30C ASSN STD SINGLE MATERIAL RESPONSE OR QQ-N-281 FED SPEC SINGLE MATERIAL RESPONSE OVERALL. 14 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
PartsTable Design LLC · partstable.com