The Seat,valve, cataloged under National Stock Number 4820-00-028-1219, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 11 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-00-028-1219 |
| Primary Part Number | 98HM1538-1 |
| Item Name | Seat,valve |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Flange Seat to Disk End Height | 0.062 INCHES NOMINAL IN |
| Flange Diameter | 0.935 INCHES NOMINAL IN |
| FSC Application Data | VALVE,AIRCRAFT HYDRAULIC SYSTEM |
| Body Outside Diameter | 0.759 INCHES NOMINAL IN |
| Hardness Rating | 58.0 ROCKWELL C MINIMUM AND 64.0 ROCKWELL C MAXIMUM BODY |
| Style Designator | PLAIN FLANGED |
| Material Document and Classification | QQ-764 TYPE 416 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Body Inside Diameter | 0.563 INCHES NOMINAL IN |
| Surface Treatment | PASSIVATE OVERALL |
| Material | STEEL OVERALL |
| Seating Surface Shape | FLAT |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 98HM1538-1 PRIMARY | Northrop Grumman Systems Corporation (USA) |
NSN 4820-00-028-1219 is a Seat,valve, manufactured by Northrop Grumman Systems Corporation, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-00-028-1219 has 1 manufacturer part number on file: 98HM1538-1 (Northrop Grumman Systems Corporation).
Key specifications for 98HM1538-1: Flange Seat to Disk End Height: 0.062 INCHES NOMINAL IN; Flange Diameter: 0.935 INCHES NOMINAL IN; FSC Application Data: VALVE,AIRCRAFT HYDRAULIC SYSTEM; Body Outside Diameter: 0.759 INCHES NOMINAL IN. 11 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.