Key facts
Where to buy| Property | Value | Source |
|---|---|---|
| Composition | Carbon 0.15 %, chromium 18 %, nickel 9 %: austenitic | AC 43.13-1B CHG 1, Table 4-3 |
| The 18-8 family | 18 percent chromium, 8 percent nickel | AC 43.13-1B CHG 1, par. 4-104 |
| Specs by temper | AMS 5516 annealed, 5903 ¼ H, 5904 ½ H, 5905 ¾ H, 5906 full hard | MIL-HDBK-5J, Table 2.7.1.0(b) footnote a |
| Allowables | The 301 table applies to 302 for those specifications | MIL-HDBK-5J, Table 2.7.1.0(b) footnote a |
Design allowables — sheet and strip by temper (properties of AISI 301 table, applicable to 302)
0.187 in and under. MIL-HDBK-5J Table 2.7.1.0(b), L and LT as printed.
| Temper | Specification | Ftu L / LT, ksi | Fty L / LT, ksi | Fsu, ksi | Basis |
|---|---|---|---|---|---|
| Annealed | AMS 5516 | 73 / 75 | 26 / 30 | 50 | S |
| ¼ hard | AMS 5903 | 124 / 122 | 69 / 67 | 66 | A |
| ½ hard | AMS 5904 | 141 / 142 | 93 / 92 | 77 | A |
| ¾ hard | AMS 5905 | 157 / 163 | 118 / 113 | 88 | A |
| Full hard | AMS 5906 | 174 / 175 | 137 / 125 | 95 | A |
Properties of the 300-series alloys that the handbook ties to Table 2.7.1.0(b) by footnote. Fsu and Ftu: Table 2.7.1.0(b), p. 2-223; E 29.0 × 10³ ksi annealed (L and LT), falling to 26–28 ksi × 10³ in the hard tempers; density 0.286 lb/in³. Cold-worked tempers lose strength above 900 °F. Yield, particularly in compression, and longitudinal modulus can be raised appreciably by stress relieving at 500 to 800 °F. MIL-HDBK-5J (2003) is superseded by MMPDS.
Thicknesses and forms
Sheet and strip in annealed, ¼, ½, ¾ and full hard tempers, 0.187 in and under for the design values. Wire, bar and tube are also made; the specs for those are not in the public documents used here.
Forming
Annealed 302 is the formable condition. The harder tempers trade formability for strength. No stainless bend radii in the public FAA documents; the drawing or SRM governs.
Quick check
What does the handbook use for 302 strength values?
- A separate 302 table
Not this one. There is none.
- The 301 table, by footnote, with the 302 specifications
Best fit. Right.
- Aluminum tables
Not this one. No relation.
On a real job, the SRM decides.
Welding
AISI 300-series austenitic steels are weldable with most processes except 303 and 303Se, which carry sulfur or selenium for machinability. They are slightly harder to weld than mild steel: lower melting temperature and conductivity, but higher expansion, so distortion needs skip or back-step welding, fixtures and twice the tack welds. Clean with a non-chlorinated solvent and a stainless wire brush; shield both sides with inert gas or flux (AMT Handbook, Chapter 5, p. 5-22).
Corrosion
Austenitic steels get their corrosion resistance from an oxide film that should not be removed even if the surface is discoloured. If the film is broken by abrasion it may not restore itself without repassivation. If corrosion affects the part's structural integrity or serviceability, the part is removed (AC 43.13-1B, par. 6-164b).
Where it is used on aircraft
The 18-8 stainless of older airframes and general stainless parts; AMS 5516 and the temper specs identify the sheet. Stainless safety wire to MS20995 is 302/304 soft temper in our catalog.
Data sheet
Questions people actually ask
302 or 304?
They are close relatives: both are 18-8 austenitic, and the handbook ties both to the same property table. 304 has lower carbon (0.07 % max) than 302 (0.15 % max), ASTM A240 Table 1.
Limits — when NOT to use this
- Properties come from the 301 table by footnote, not from a 302 test table.
- Not a substitute for the alloy on the drawing.
Where to buy
Distributors coming soon.
Sources
- MIL-HDBK-5J, Metallic Materials and Elements for Aerospace Vehicle Structures (31 Jan 2003) — Table 2.7.1.0(b), footnote a, p. 2-223. Cancelled; superseded by MMPDS.
- FAA AC 43.13-1B CHG 1 — Table 4-3 and par. 4-104, par. 6-164.
- FAA-H-8083-31B, Aviation Maintenance Technician Handbook, Airframe, Volume 1 — Chapter 5, p. 5-22.
- MMPDS (formerly MIL-HDBK-5) — the current home of design allowables. A repair substantiation cites MMPDS or the SRM, not a website.