PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

9975Seat,valve

Northrop Grumman Systems Corporation Div Marine Systems · NSN 4820-00-337-1101 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-00-337-1101 — this item is cataloged by the U.S. Government under National Stock Number 4820-00-337-1101. Primary manufacturer part number: 9975.
Features
  • Seat,valve — FSC 4820
  • Body Inside Diameter: 0.688 INCHES NOMINAL IN
  • Flange Diameter: 2.000 INCHES NOMINAL IN
  • Flange Seat to Disk End Height: 0.188 INCHES NOMINAL IN
  • Seating Surface Shape: ANGULAR
  • Material: COBALT ALLOY SEAT
  • Style Designator: PLAIN FLANGED
  • Material: STEEL BODY
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Cobalt Alloy Seat construction
General Description

The Seat,valve, cataloged under National Stock Number 4820-00-337-1101, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Northrop Grumman Systems Corporation Div Marine Systems. Government technical data includes 10 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 50 commercial cross-references from 4 manufacturers, enabling identification through both NSN and commercial part number lookups. 8 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4820-00-337-1101
Primary Part Number9975
Item NameSeat,valve
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerNorthrop Grumman Systems Corporation Div Marine Systems
StatusACTIVE
Body Inside Diameter0.688 INCHES NOMINAL IN
Flange Diameter2.000 INCHES NOMINAL IN
Flange Seat to Disk End Height0.188 INCHES NOMINAL IN
Seating Surface ShapeANGULAR
MaterialCOBALT ALLOY SEAT
Style DesignatorPLAIN FLANGED
MaterialSTEEL BODY
Body Outside Diameter1.500 INCHES NOMINAL IN
Seat Angle in Deg45.000 NOMINAL
Under Flange Height0.750 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 8
3439-00-009-23347-5L INTERCHANGEABLE
Desoldering Wick
Illinois Tool Works Inc. Div Itw Chemtronics
6625-01-017-3026 INTERCHANGEABLE
Bridge,resistance
5935-01-023-2501 INTERCHANGEABLE
Connector,plug,electrical
5330-01-146-52999975 INTERCHANGEABLE
Packing,preformed
Barnes Group Inc. Dba Barnes Distribution
5985-01-149-7038P3933-007-01 INTERCHANGEABLE
Attenuator,fixed
Us Army Aviation and Missile Command
8340-01-467-9185 INTERCHANGEABLE
Connector,shelter
8340-01-484-6577 INTERCHANGEABLE
Connector,shelter
5975-01-486-64559975 INTERCHANGEABLE
Adapter,stuffing Tube
Gta Marine Dba Gta Marine
Cross-Reference Index
Part NumberManufacturer
AD14S46-019PC385 Naval Ship Systems Command (USA)
D15-621JPC342 Westinghouse Electric Corp Sturtevant Div (USA)
D15-621BPC342 Northrop Grumman Systems Corporation Div Marine Systems (USA)
D15-621PPC342 Northrop Grumman Systems Corporation Div Marine Systems (USA)
D15-439BPC385 Westinghouse Electric Corp Sturtevant Div (USA)
D15-439IPC385 Northrop Grumman Systems Corporation Div Marine Systems (USA)
AD14S46-014PC385 Naval Ship Systems Command (USA)
D15-439IPC385 Westinghouse Electric Corp Sturtevant Div (USA)
D15-621BPC342 Westinghouse Electric Corp (USA)
D15-439-J Westinghouse Electric Corp Sturtevant Div (USA)
D15-621NPC342 Westinghouse Electric Corp (USA)
D15-439-B Northrop Grumman Systems Corporation Div Marine Systems (USA)
D15-439NPC385 Westinghouse Electric Corp Sturtevant Div (USA)
D15-439-J PC 342 Westinghouse Electric Corp Sturtevant Div (USA)
D15-439NPC385 Northrop Grumman Systems Corporation Div Marine Systems (USA)
AD14-S46-015 PC 342 Naval Ship Systems Command (USA)
CM5S4601-035PC34 Naval Ship Systems Command (USA)
9975 PRIMARY Northrop Grumman Systems Corporation Div Marine Systems (USA)
D15-439PPC385 Westinghouse Electric Corp Sturtevant Div (USA)
D15-439PPC385 Northrop Grumman Systems Corporation Div Marine Systems (USA)
Related Parts
3439-00-009-2334INTERCHANGEABLE
DESOLDERING WICK
7-5L
6625-01-017-3026INTERCHANGEABLE
BRIDGE,RESISTANCE
5935-01-023-2501INTERCHANGEABLE
CONNECTOR,PLUG,ELECTRICAL
5330-01-146-5299INTERCHANGEABLE
PACKING,PREFORMED
9975
5985-01-149-7038INTERCHANGEABLE
ATTENUATOR,FIXED
P3933-007-01
8340-01-467-9185INTERCHANGEABLE
CONNECTOR,SHELTER
8340-01-484-6577INTERCHANGEABLE
CONNECTOR,SHELTER
5975-01-486-6455INTERCHANGEABLE
ADAPTER,STUFFING TUBE
9975

Frequently Asked Questions

What is NSN 4820-00-337-1101?

NSN 4820-00-337-1101 is a Seat,valve, manufactured by Northrop Grumman Systems Corporation Div Marine Systems, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-00-337-1101?

NSN 4820-00-337-1101 has 50 cross-referenced part numbers: AD14S46-019PC385 (Naval Ship Systems Command), D15-621JPC342 (Westinghouse Electric Corp Sturtevant Div), D15-621BPC342 (Northrop Grumman Systems Corporation Div Marine Systems), D15-621PPC342 (Northrop Grumman Systems Corporation Div Marine Systems), D15-439BPC385 (Westinghouse Electric Corp Sturtevant Div) and 45 more.

What NSN replaces 4820-00-337-1101?

There are 8 known substitutes for 4820-00-337-1101: 3439-00-009-2334, 6625-01-017-3026, 5935-01-023-2501 and 5 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 9975?

Key specifications for 9975: Body Inside Diameter: 0.688 INCHES NOMINAL IN; Flange Diameter: 2.000 INCHES NOMINAL IN; Flange Seat to Disk End Height: 0.188 INCHES NOMINAL IN; Seating Surface Shape: ANGULAR. 10 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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