PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

20256Z51MValve,relief,pressure and Temper

Anderson Greenwood Lp Dba Anderson Greenwood Crosby · NSN 4820-01-312-8198 · FSC 4820 · No Item Name Available
Verified by PartsTable
NSN 4820-01-312-8198 — this item is cataloged by the U.S. Government under National Stock Number 4820-01-312-8198. Primary manufacturer part number: 20256Z51M.
Features
  • Valve,relief,pressure and Temper — FSC 4820
  • Second Connection Face to Centerline Distance: 6.438 INCHES NOMINAL IN
  • Material Document and Classification: QQ-N-288, COMP A FED SPEC SINGLE MATERIAL RESPONSE SEAT
  • Material: NICKEL ALLOY K-500 OR NICKEL ALLOY 502 STEM
  • Temp Adjustability: NOT ADJUSTABLE
  • Material Document and Classification: QQ-N-286, CLASS A FED SPEC SINGLE MATERIAL RESPONSE OR QQ-N-286, CLASS B FED SPEC SINGLE MATERIAL RESPONSE STEM
  • Material Document and Classification: QQ-N-288, COMP A FED SPEC SINGLE MATERIAL RESPONSE BODY
  • Material: NICKEL ALLOY K-500 OR NICKEL ALLOY 502 FLOW CONTROL DEVICE
Applications
  • Flow control in piping systems
  • Pressure regulation
  • Steam and fluid isolation
  • Applications requiring Nickel Alloy K-500 or Nickel Alloy 502 Stem construction
General Description

The Valve,relief,pressure and Temper, cataloged under National Stock Number 4820-01-312-8198, is classified within Federal Supply Class 4820 (No Item Name Available) of the Valves group. The primary manufacturer of record is Anderson Greenwood Lp Dba Anderson Greenwood Crosby. Government technical data includes 15 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
NSN4820-01-312-8198
Primary Part Number20256Z51M
Item NameValve,relief,pressure and Temper
FSC / FSG4820 / 48 — No Item Name Available
ManufacturerAnderson Greenwood Lp Dba Anderson Greenwood Crosby
StatusACTIVE
Second Connection Face to Centerline Distance6.438 INCHES NOMINAL IN
Material Document and ClassificationQQ-N-288, COMP A FED SPEC SINGLE MATERIAL RESPONSE SEAT
MaterialNICKEL ALLOY K-500 OR NICKEL ALLOY 502 STEM
Temp AdjustabilityNOT ADJUSTABLE
Material Document and ClassificationQQ-N-286, CLASS A FED SPEC SINGLE MATERIAL RESPONSE OR QQ-N-286, CLASS B FED SPEC SINGLE MATERIAL RESPONSE STEM
Material Document and ClassificationQQ-N-288, COMP A FED SPEC SINGLE MATERIAL RESPONSE BODY
MaterialNICKEL ALLOY K-500 OR NICKEL ALLOY 502 FLOW CONTROL DEVICE
FSC Application DataVALVE SAFETY RELIEF
MaterialNICKEL ALLOY BODY
MaterialNICKEL ALLOY SEAT
Body StyleANGLE GIVE "ADQM" AND "ADQN" ONLY IF FLANGED ONE OR TWO ENDS
Material Document and ClassificationQQ-N-286, CLASS A FED SPEC SINGLE MATERIAL RESPONSE OR QQ-N-286, CLASS B FED SPEC SINGLE MATERIAL RESPONSE FLOW CONTROL DEVICE
Adjustable Pressure Range501.0 TO 600.0 CAMERA MOUNT
Temp Rating165.0 FAHRENHEIT DEGF
First Connection Face to Centerline Distance6.938 INCHES NOMINAL IN
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 12
3431-00-086-118013N16 INTERCHANGEABLE
Nozzle,welding
Weldcraft Customer Service
5310-00-223-3162 INTERCHANGEABLE
Washer,flat
1650-00-555-142320256 INTERCHANGEABLE
Filter,fluid
Fluid Conditioning Products, Inc.
5120-00-595-9463 INTERCHANGEABLE
Punch,tube Belling,hand
3815-00-756-147320256 INTERCHANGEABLE
Roller Assembly,cra
Tiffin Parts, L.l.c. Div Subsidiary of Pettibone Corp.
5962-01-099-9799MM54C08J INTERCHANGEABLE
Microcircuit,digital
National Semiconductor Corporation
5945-01-128-125420256 INTERCHANGEABLE
Flasher,thermal
Oeco, Llc Dba Pacific Scientific Oeco Div Fire Safety and Power Systems
4820-01-130-846820256J01S0501 INTERCHANGEABLE
Valve,safety Relief
Emerson Automation Solutions Final Control Us Lp Div Navy Product Team
6145-01-332-7457T-13447 INTERCHANGEABLE
Cable,power,electrical
Prysmian Cables and Systems Usa, Llc Div Manufacturing Plant
2910-01-343-388620256 INTERCHANGEABLE
Plunger,rotor,fuel Pump
Stanadyne Corporation Dba Stanadyne Diesel Systems
Cross-Reference Index
Part NumberManufacturer
20256Z51M Anderson Greenwood Lp Dba Anderson Greenwood Crosby (USA)
20256 Anderson Greenwood Lp Dba Anderson Greenwood Crosby (USA)
Related Parts
3431-00-086-1180INTERCHANGEABLE
NOZZLE,WELDING
13N16
5310-00-223-3162INTERCHANGEABLE
WASHER,FLAT
1650-00-555-1423INTERCHANGEABLE
FILTER,FLUID
20256
5120-00-595-9463INTERCHANGEABLE
PUNCH,TUBE BELLING,HAND
3815-00-756-1473INTERCHANGEABLE
ROLLER ASSEMBLY,CRA
20256
5962-01-099-9799INTERCHANGEABLE
MICROCIRCUIT,DIGITAL
MM54C08J
5945-01-128-1254INTERCHANGEABLE
FLASHER,THERMAL
20256
4820-01-130-8468INTERCHANGEABLE
VALVE,SAFETY RELIEF
20256J01S0501
6145-01-332-7457INTERCHANGEABLE
CABLE,POWER,ELECTRICAL
T-13447
2910-01-343-3886INTERCHANGEABLE
PLUNGER,ROTOR,FUEL PUMP
20256
4710-01-343-4433INTERCHANGEABLE
TUBE,METALLIC
20256
5330-01-461-8422INTERCHANGEABLE
PACKING ASSEMBLY
591-11500-964-3570/ASY

Frequently Asked Questions

What is NSN 4820-01-312-8198?

NSN 4820-01-312-8198 is a Valve,relief,pressure and Temper, manufactured by Anderson Greenwood Lp Dba Anderson Greenwood Crosby, classified under FSC 4820 (No Item Name Available). Status: active.

What are the part numbers for NSN 4820-01-312-8198?

NSN 4820-01-312-8198 has 2 cross-referenced part numbers: 20256Z51M (Anderson Greenwood Lp Dba Anderson Greenwood Crosby), 20256 (Anderson Greenwood Lp Dba Anderson Greenwood Crosby).

What NSN replaces 4820-01-312-8198?

There are 12 known substitutes for 4820-01-312-8198: 3431-00-086-1180, 5310-00-223-3162, 1650-00-555-1423 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 20256Z51M?

Key specifications for 20256Z51M: Second Connection Face to Centerline Distance: 6.438 INCHES NOMINAL IN; Material Document and Classification: QQ-N-288, COMP A FED SPEC SINGLE MATERIAL RESPONSE SEAT; Material: NICKEL ALLOY K-500 OR NICKEL ALLOY 502 STEM; Temp Adjustability: NOT ADJUSTABLE. 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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