Material specification

MIL-S-5626 (AMS-S-5626)

The military specification for chrome-molybdenum (4140) steel bars, rods and forging stock for aircraft applications. It is cancelled, but still cited on more than 13,000 DLA parts.

13,589 NSNs in DLA's catalog cite this spec. See the catalog data

What MIL-S-5626 covers

MIL-S-5626 covers 4140 chrome-molybdenum steel bars, rods and forging stock for aircraft applications.

It is cited on 13,589 NSNs in DLA's catalog, mostly shear bolts, pin-rivets, close-tolerance screws and machine bolts, and most of them are cadmium plated.

What the catalog callouts name

Composition
4140 chrome-molybdenum steel. Some catalog callouts add the composition explicitly.
Conditions
Catalog records that give a condition most often name Condition C4, followed by Conditions C, D and D1.

Status and revisions

EverySpec's record of MIL-S-5626C Notice 1, dated 27 September 1995, lists SAE AMS 6382 and AMS 6349 as its replacements.

SAE also published AMS-S-5626, issued December 1998 and cancelled January 2002.

Typical applications

  • Shear bolts, pin-rivets, close-tolerance screws and machine bolts lead DLA's catalog, followed by blind rivets, internal wrenching bolts and clevis bolts.
  • Cadmium plating with chromate is the finish most often called out with it.

What a shop needs to supply to MIL-S-5626

  • MIL-S-5626 is cancelled. Ask the buyer which current material spec they will accept before buying bar for a drawing that names it.
  • Expect cadmium plating and the hydrogen embrittlement controls that come with plating high-strength steel. See QQ-P-416.

The purchase order, drawing and the revision of the spec it invokes govern. Always work from the revision your contract names.

MIL-S-5626 in the DLA catalog

From DLA's public PUB LOG catalog, release 2026-10-27, covering 16 hardware and mechanical supply groups (fasteners, bearings, fittings, valves, power transmission, engine components and more).

13,589
NSNs whose catalog record cites MIL-S-5626
52%
coded open to new sources (7,110 NSNs): at least one managing service codes it AMC 1 or 2 with AMSC G
25%
coded for existing or approved sources (3,360 NSNs)

Most common items

Bolt, shear3,389
Pin-rivet3,028
Screw, close tolerance1,746
Bolt, machine1,066
Rivet, blind729
Bolt, close tolerance487
Bolt, internal wrenching415
Screw, cap, socket head396
Bolt, clevis342
Screw, shoulder298

Federal supply classes

5306 Bolts6,089
5320 Rivets3,763
5305 Screws2,498
3120 Bearings, plain, unmounted286
5310 Nuts and washers252
5325 Fastening devices145
5315 Nails, machine keys, and pins133
3020 Gears, pulleys, sprockets, and transmission chain96

Can a new source win these parts?

DLA codes each part with an acquisition method (AMC) and a suffix (AMSC). We count an NSN as open when at least one managing service codes it AMC 1 or 2 (competitive) with suffix G (the government has the full technical data and the rights to use it). Otherwise we count it as restricted when a service codes it AMC 3, 4 or 5 (buy from the manufacturer or prime) or uses a suffix that limits or conditions who can supply it (AMSC B, C, D, H, K, L, P, Q, R, T, U or Y): missing data or rights, source-control drawings, source or QPL approval, controlled castings, uneconomical breakout, an unstable design, or low-value screening for known sources. These are catalog codes; the solicitation always governs.

Open: AMC 1 or 2 with AMSC G7,11052%
Restricted: AMC 3, 4 or 5, or a restrictive AMSC3,36025%
Other acquisition codes4123%
No acquisition method in the catalog2,70720%

As of PUB LOG release 2026-10-27. How to read the codes: AMC and AMSC codes explained.

How catalog records call it out

Characteristic records that cite MIL-S-5626 or AMS-S-5626, grouped by the type, class or condition they name. Counted across the most common callout spellings, so the totals are a floor.

Not specified13,697
Condition C497
Condition C25
Condition D111
Condition D11

Finishes called out on these parts

  • Cadmium and chromate (overall) 7,616
  • Cadmium (overall) 3,462
  • Cadmium and chromate (nut) 175
  • Cadmium and chromate (bolt) 172
  • Passivate and cadmium (sleeve) 84
  • Cadmium and chromate (fastener) 81
  • Cadmium (threads) 74
  • Cadmium and chromate (threads) 67

Sample NSNs that cite MIL-S-5626

Steel machine shops in the directory

85 listed shops report this capability. Confirm the spec, revision and any approvals with the shop before you order.

See all steel machine shops

Frequently asked questions

Is MIL-S-5626 cancelled?

Yes. EverySpec records MIL-S-5626C Notice 1, dated 27 September 1995, with SAE AMS 6382 and AMS 6349 listed as replacements.

What material is MIL-S-5626?

Chrome-molybdenum (4140) steel bars, rods and forging stock for aircraft applications.

Is AMS-S-5626 still active?

No. SAE AMS-S-5626 was issued in December 1998 and cancelled in January 2002.

How many DLA parts cite MIL-S-5626?

13,589 NSNs in DLA's PUB LOG catalog (release 2026-10-27, 16 hardware and mechanical supply groups), led by shear bolts and pin-rivets.

Related

Sources