PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

9958Seat,valve

Northrop Grumman Systems Corporation Div Marine Systems · NSN 4810-00-218-6077 · FSC 4810 · No Item Name Available
Verified by PartsTable
NSN 4810-00-218-6077 — this item is cataloged by the U.S. Government under National Stock Number 4810-00-218-6077. Primary manufacturer part number: 9958.
Features
  • Seat,valve — FSC 4810
  • Flange Diameter: 2.125 INCHES NOMINAL IN
  • Material: COBALT ALLOY SEAT
  • Seating Surface Shape: ANGULAR
  • Nominal Thread Size: 1.750 INCHES SINGLE THREADED PORTION IN
  • Material Document and Classification: MIL-S-853,CLASS 3,TYPE A MIL SPEC SINGLE MATERIAL RESPONSE BODY
  • Style Designator: THREADED FLANGED
  • Hardness Rating: 202.0 BRINELL STANDARD MINIMUM 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 4810-00-218-6077, is classified within Federal Supply Class 4810 (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 15 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 15 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 7 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN4810-00-218-6077
Primary Part Number9958
Item NameSeat,valve
FSC / FSG4810 / 48 — No Item Name Available
ManufacturerNorthrop Grumman Systems Corporation Div Marine Systems
StatusACTIVE
Flange Diameter2.125 INCHES NOMINAL IN
MaterialCOBALT ALLOY SEAT
Seating Surface ShapeANGULAR
Nominal Thread Size1.750 INCHES SINGLE THREADED PORTION IN
Material Document and ClassificationMIL-S-853,CLASS 3,TYPE A MIL SPEC SINGLE MATERIAL RESPONSE BODY
Style DesignatorTHREADED FLANGED
Hardness Rating202.0 BRINELL STANDARD MINIMUM BODY
Thread Series DesignatorUN SINGLE THREADED PORTION
Thread Class3A SINGLE THREADED PORTION A
Thread Length0.750 INCHES NOMINAL SINGLE THREADED PORTION IN
Thread Quantity Per Inch12 SINGLE THREADED PORTION
Flange Seat to Disk End Height0.250 INCHES NOMINAL IN
Under Flange Height0.875 INCHES NOMINAL IN
MaterialSTEEL BODY
Body Inside Diameter1.313 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 7
5955-00-499-7337712731-7 INTERCHANGEABLE
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2805-00-652-9757AD41A INTERCHANGEABLE
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5950-01-081-273812272682 INTERCHANGEABLE
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U S Army Tank Automotive Command Amsta-Im-Mm
8010-01-097-5253 INTERCHANGEABLE
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6515-01-437-7535312102 INTERCHANGEABLE
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6665-01-569-3643500-0036-100 INTERCHANGEABLE
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4820-01-585-25369958 INTERCHANGEABLE
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Cross-Reference Index
Part NumberManufacturer
9958 PRIMARY Northrop Grumman Systems Corporation Div Marine Systems (USA)
D15-651PPC677 Northrop Grumman Systems Corporation Div Marine Systems (USA)
D15-651JPC677 Westinghouse Electric Corp (USA)
D15-651PPC677 Westinghouse Electric Corp Sturtevant Div (USA)
D15-651PPC677 Westinghouse Electric Corp (USA)
D15-651JPC677 Northrop Grumman Systems Corporation Div Marine Systems (USA)
D15-651BPC677 Westinghouse Electric Corp Sturtevant Div (USA)
D15-651JPC677 Westinghouse Electric Corp Sturtevant Div (USA)
D15-651QPC677 Northrop Grumman Systems Corporation Div Marine Systems (USA)
9958 Westinghouse Electric Corp Sturtevant Div (USA)
D15-651QPC677 Westinghouse Electric Corp (USA)
D15-651QPC677 Westinghouse Electric Corp Sturtevant Div (USA)
D15-651BPC677 Westinghouse Electric Corp (USA)
9958 Westinghouse Electric Corp (USA)
D15-651BPC677 Northrop Grumman Systems Corporation Div Marine Systems (USA)
Related Parts
5955-00-499-7337INTERCHANGEABLE
CRYSTAL UNIT,QUARTZ
712731-7
2805-00-652-9757INTERCHANGEABLE
GUIDE,VALVE STEM
AD41A
5950-01-081-2738INTERCHANGEABLE
TRANSFORMER,POWER
12272682
8010-01-097-5253INTERCHANGEABLE
THINNER,PAINT PRODUCTS
6515-01-437-7535INTERCHANGEABLE
MASK,ORONASAL
312102
6665-01-569-3643INTERCHANGEABLE
BATTERY CHARGER,LITHIUM ION BATT
500-0036-100
4820-01-585-2536INTERCHANGEABLE
HEAD,SAFETY,PRESSURE RELIEF
9958

Frequently Asked Questions

What is NSN 4810-00-218-6077?

NSN 4810-00-218-6077 is a Seat,valve, manufactured by Northrop Grumman Systems Corporation Div Marine Systems, classified under FSC 4810 (No Item Name Available). Status: active.

What are the part numbers for NSN 4810-00-218-6077?

NSN 4810-00-218-6077 has 15 cross-referenced part numbers: 9958 (Northrop Grumman Systems Corporation Div Marine Systems), D15-651PPC677 (Northrop Grumman Systems Corporation Div Marine Systems), D15-651JPC677 (Westinghouse Electric Corp), D15-651PPC677 (Westinghouse Electric Corp Sturtevant Div), D15-651PPC677 (Westinghouse Electric Corp) and 10 more.

What NSN replaces 4810-00-218-6077?

There are 7 known substitutes for 4810-00-218-6077: 5955-00-499-7337, 2805-00-652-9757, 5950-01-081-2738 and 4 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 9958?

Key specifications for 9958: Flange Diameter: 2.125 INCHES NOMINAL IN; Material: COBALT ALLOY SEAT; Seating Surface Shape: ANGULAR; Nominal Thread Size: 1.750 INCHES SINGLE THREADED PORTION IN. 15 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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