PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

MIL-U-18250Union,pipe

Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M · NSN 4730-00-189-2599 · FSC 4730 · No Item Name Available
Verified by PartsTable
NSN 4730-00-189-2599 — this item is cataloged by the U.S. Government under National Stock Number 4730-00-189-2599. Primary manufacturer part number: MIL-U-18250.
Features
  • Union,pipe — FSC 4730
  • Nominal Overall Length: 2.438 INCHES IN
  • Media for Which Designed: STEAM SINGLE RESPONSE
  • Coupling Flange Shape: HEXAGON
  • Reducer Type: CONCENTRIC
  • Nominal Thread Size: 1.000 INCHES ALL ENDS IN
  • Coupling Flange Shape: HEXAGON
  • Seat Type: GROUND-JOINT
Applications
  • Fluid conveyance
  • Hydraulic system plumbing
  • Pneumatic line routing
  • Applications requiring Iron Overall construction
General Description

The Union,pipe, cataloged under National Stock Number 4730-00-189-2599, is classified within Federal Supply Class 4730 (No Item Name Available) of the Pipe, Tubing, Hose, and Fittings group. The primary manufacturer of record is Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M. Government technical data includes 26 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 4 commercial cross-references from 3 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Cancelled.

Technical Specifications
ParameterValue
NSN4730-00-189-2599
Primary Part NumberMIL-U-18250
Item NameUnion,pipe
FSC / FSG4730 / 47 — No Item Name Available
ManufacturerMilitary Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
StatusCANCELLED
Nominal Overall Length2.438 INCHES IN
Media for Which DesignedSTEAM SINGLE RESPONSE
Coupling Flange ShapeHEXAGON
Reducer TypeCONCENTRIC
Nominal Thread Size1.000 INCHES ALL ENDS IN
Coupling Flange ShapeHEXAGON
Seat TypeGROUND-JOINT
Nominal Thread Size1.000 INCHES ALL ENDS IN
Seat TypeGROUND-JOINT
Operating Pressure300.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
Connection TypeTHREADED INTERNAL PIPE ALL ENDS
Nominal Overall Length2.438 INCHES IN
MaterialIRON OVERALL
Thread Series DesignatorNPT ALL ENDS
Connection StylePLAIN (PIPE) ALL ENDS
Maximum Operating Temp218.0 CELSIUS SINGLE RESPONSE DEGC
Material Document and ClassificationASTM A197 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
Media for Which DesignedSTEAM SINGLE RESPONSE
MaterialIRON OVERALL
Style DesignatorSCREWED
Style DesignatorSCREWED
Nondefinitive Spec/std DataXA TYPE
Material Document and ClassificationASTM A197 ASSN STD SINGLE MATERIAL RESPONSE OVERALL
Nondefinitive Spec/std DataXA TYPE
Thread Series DesignatorNPT ALL ENDS
Operating Pressure300.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS
Lifecycle & Compliance
Acquisition StatusCANCELLED
HAZMATNo
Verified Substitutes 12
4730-00-189-2598 INTERCHANGEABLE
Union,pipe
4730-00-189-2600 INTERCHANGEABLE
Union,pipe
4730-00-189-26021631-400 INTERCHANGEABLE
Union,pipe
Flaton Machine Works Inc.
4730-00-189-2605 INTERCHANGEABLE
Union,pipe
4730-00-189-2606 INTERCHANGEABLE
Union,pipe
4730-00-189-2629 INTERCHANGEABLE
Union,pipe
4730-00-189-2630 INTERCHANGEABLE
Union,pipe
4730-00-189-2635 INTERCHANGEABLE
Union,pipe
4730-00-189-2638 INTERCHANGEABLE
Union,pipe
4730-00-189-2639 INTERCHANGEABLE
Union,pipe
Cross-Reference Index
Part NumberManufacturer
MIL-U-18250 Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M
B16.39 The American Society of Mechanical Engineers (USA)
198E Crane Co Div Valve Div (USA)
198E-1IN Crane Co Div Valve Div (USA)
Related Parts
4730-00-189-2598INTERCHANGEABLE
UNION,PIPE
4730-00-189-2600INTERCHANGEABLE
UNION,PIPE
4730-00-189-2602INTERCHANGEABLE
UNION,PIPE
1631-400
4730-00-189-2605INTERCHANGEABLE
UNION,PIPE
4730-00-189-2606INTERCHANGEABLE
UNION,PIPE
4730-00-189-2629INTERCHANGEABLE
UNION,PIPE
4730-00-189-2630INTERCHANGEABLE
UNION,PIPE
4730-00-189-2635INTERCHANGEABLE
UNION,PIPE
4730-00-189-2638INTERCHANGEABLE
UNION,PIPE
4730-00-189-2639INTERCHANGEABLE
UNION,PIPE
4730-00-189-2645INTERCHANGEABLE
UNION,PIPE
4730-00-189-2646INTERCHANGEABLE
UNION,PIPE

Frequently Asked Questions

What is NSN 4730-00-189-2599?

NSN 4730-00-189-2599 is a Union,pipe, manufactured by Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M, classified under FSC 4730 (No Item Name Available). Status: cancelled.

What are the part numbers for NSN 4730-00-189-2599?

NSN 4730-00-189-2599 has 4 cross-referenced part numbers: MIL-U-18250 (Military Specifications Promulgated by Military Departments/agencies Under Authority of Defense Standardization Manual 4120 3-M), B16.39 (The American Society of Mechanical Engineers), 198E (Crane Co Div Valve Div), 198E-1IN (Crane Co Div Valve Div).

What NSN replaces 4730-00-189-2599?

There are 12 known substitutes for 4730-00-189-2599: 4730-00-189-2598, 4730-00-189-2600, 4730-00-189-2602 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of MIL-U-18250?

Key specifications for MIL-U-18250: Nominal Overall Length: 2.438 INCHES IN; Media for Which Designed: STEAM SINGLE RESPONSE; Coupling Flange Shape: HEXAGON; Reducer Type: CONCENTRIC. 27 total characteristics are documented in the Federal Logistics Information System.

Is NSN 4730-00-189-2599 still in active supply?

NSN 4730-00-189-2599 is currently cancelled. Check with the Defense Logistics Agency for current availability and authorized substitutes.

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