301 at a glance
Where to buy
Designation
| Item | Value |
|---|---|
| Designation | 301 |
| Class | Steel and stainless |
| Type | austenitic stainless steel |
Composition
| Item | Limit | Source |
|---|---|---|
| Composition | Chromium 16–18 %, nickel 6–8 %, carbon up to 0.15 % | ASTM A240/A240M Table 1 (UNS S30100) |
Properties
| Property | Value | Source |
|---|---|---|
| Why it is used | The austenitic stainless used most at high strength levels in aircraft, because of its greater work-hardening | MIL-HDBK-5J, par. 2.7.1.0 |
| Strengthened by | Cold working. Cold-worked 301 held above 900 °F loses room-temperature strength | MIL-HDBK-5J, par. 2.7.1.0 |
| Do not | Hold 750–1,650 °F for long periods or cool slowly through that range | MIL-HDBK-5J, par. 2.7.1.0 |
| Specs by temper | AMS 5901 annealed, 5517 ¼ hard, 5518 ½ hard, 5902 ¾ hard, 5519 full hard | MIL-HDBK-5J, Table 2.7.1.0(b) |
| Catalog item | ½ hard 301, 0.025 in, 36 in wide, sold by the foot, listed with firewall metals | A distributor's listing |
Design allowables — sheet and strip by temper (properties of AISI 301 table, applicable to 301)
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 5901 | 73 / 75 | 26 / 30 | 50 | S |
| ¼ hard | AMS 5517 | 124 / 122 | 69 / 67 | 66 | A |
| ½ hard | AMS 5518 | 141 / 142 | 93 / 92 | 77 | A |
| ¾ hard | AMS 5902 | 157 / 163 | 118 / 113 | 88 | A |
| Full hard | AMS 5519 | 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and longitudinal modulus can be raised appreciably by stress relieving at 500 to 800 °F. MIL-HDBK-5J (2003) is superseded by MMPDS.
Forms and thicknesses in stock
| Distributor sheet | Listed | Thickness, in |
|---|---|---|
| Stainless Steel Sheet - 301 Ss 1/2 Hard .025 | 301 SS · 0.025" · 36" wide | .025 |
As distributors list them, not a statement of what a specification allows.
Notes from the guide
- Temper matters. The strength table is not interchangeable between tempers.
- Not for sustained heat in the 750–1,650 °F band.
- A weld or heat above 900 °F lowers cold-worked strength. Ask engineering.
Where to buy
AmericaDistributor coming soonOur partner for this region is on its way
EuropeDistributor coming soonOur partner for this region is on its way
OceaniaDistributor coming soonOur partner for this region is on its way
Distributors coming soon.
Sources
- MIL-HDBK-5J, Metallic Materials and Elements for Aerospace Vehicle Structures (31 Jan 2003) — par. 2.7.1.0 and Table 2.7.1.0(b), p. 2-223. Cancelled; superseded by MMPDS.
- FAA AC 43.13-1B CHG 1 — par. 4-104 and par. 6-164.
- FAA-H-8083-31B, Aviation Maintenance Technician Handbook, Airframe, Volume 1 — Chapter 5, TIG welding stainless steel, 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.
- ASTM A240/A240M, Plate, Sheet, and Strip of Chromium and Chromium-Nickel Stainless Steel — Table 1, chemical requirements (edition 10b read).
- Distributor listings — stock forms, sizes and listed facts, read 30 September 2026.
Educational reference only. not approved data. Always consult the applicable SRM, AMM, or AC 43.13-1B and your certifying authority.