This specification covers hot-finished or cold-finished bars, except bars for forging, suitable for machining processes. It includes rounds, squares, and hexagons in the more commonly used types of stainless free-machining steels designed especially for optimum machinability and for general corrosion and high-temperature service. Stainless steel bars other than the free-machining types are covered in a separate specification.
| UNS DesignationA | Type,B | Chemical Composition, % | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| CarbonC | ManganeseC | Phosphorus,C | SulfurC | Silicon, max | Chromium | Nickel | Molybdenum | Selenium | Other Elements | ||
| Austenitic | |||||||||||
| S20300 | XM-1D | 0.08 | 5.0–6.5 | 0.04 | 0.18–0.35 | 1.00 | 16.00–18.0 | 5.0–6.5 | . . . | . . . | Cu 1.75–2.25 |
| S30300 | 303 | 0.15 | 2.00 | 0.20 | 0.15 min | 1.00 | 17.0–19.0 | 8.0–10.0 | . . . | . . . | . . . |
| S30310 | XM-5D | 0.15 | 2.5–4.5 | 0.20 | 0.25 min | 1.00 | 17.0–19.0 | 7.0–10.0 | . . . | . . . | . . . |
| S30323 | 303Se | 0.15 | 2.00 | 0.20 | 0.06 | 1.00 | 17.0–19.0 | 8.0–10.0 | . . . | 0.15 min | . . . |
| S30345 | XM-2D | 0.15 | 2.00 | 0.05 | 0.11–0.16 | 1.00 | 17.0–19.0 | 8.0–10.0 | 0.40–0.60 | . . . | Al 0.60–1.00 |
| Martensitic | |||||||||||
| S41600 | 416 | 0.15 | 1.25 | 0.06 | 0.15 min | 1.00 | 12.0–14.0 | . . . | . . . | . . . | . . . |
| S41610 | XM-6D | 0.15 | 1.50–2.50 | 0.06 | 0.15 min | 1.00 | 12.0–14.0 | . . . | . . . | . . . | . . . |
| S41623 | 416Se | 0.15 | 1.25 | 0.06 | 0.06 | 1.00 | 12.0–14.0 | . . . | . . . | 0.15 min | . . . |
| S42020 | 420F | 0.30–0.40 | 1.25 | 0.06 | 0.15 min | 1.00 | 12.0–14.0 | 0.50E | . . . | . . . | Cu 0.60E |
| S42023 | 420FSe | 0.20–0.40 | 1.25 | 0.06 | 0.06 | 1.00 | 12.0–14.0 | 0.50E | . . . | 0.15 min | Cu 0.60E |
| S44020 | 440F | 0.95–1.20 | 1.25 | 0.06 | 0.15 min | 1.00 | 16.0–18.0 | 0.50E | . . . | . . . | Cu 0.60E |
| S44023 | 440FSe | 0.95–1.20 | 1.25 | 0.06 | 0.06 | 1.00 | 16.0–18.0 | 0.50E | . . . | 0.15 min | Cu 0.60E |
| Ferritic | |||||||||||
| S18200 | XM-34D | 0.08 | 2.50 | 0.04 | 0.15 min | 1.00 | 17.5–19.5 | . . . | 1.50–2.50 | . . . | . . . |
| S18235 | . . . | 0.025 | 0.50 | 0.030 | 0.15–0.35 | 1.00 | 17.5–18.5 | 1.00 | 2.00–2.50 | . . . | Ti 0.30–1.00 N 0.025 C+N 0.035 |
| S41603 | . . . | 0.08 | 1.25 | 0.06 | 0.15 min | 1.00 12.0- | 14.0 | . . . | . . . | . . . | . . . |
| S43020 | 430F | 0.12 | 1.25 | 0.06 | 0.15 min | 1.00 | 16.0–18.0 | . . . | . . . | . . . | . . . |
| S43023 | 430FSe | 0.12 | 1.25 | 0.06 | 0.06 | 1.00 | 16.0–18.0 | . . . | . . . | 0.15 min | . . . |
A. Designation established in accordance with Practice E527 and SAE J 1086, Recommended Practice for Numbering Metals and Alloys (UNS).
B. Unless otherwise indicated, a grade designation originally assigned by the American Iron and Steel Institute (AISI).
C. Maximum unless otherwise noted.
D. Naming system originated by ASTM.
E. At manufacturer’s option, reported only when intentionally added.
| Types | Condition | Brinell Hardness A (HBW) |
|---|---|---|
| All (except 440F, 440FSe and S18235) | A | 262 max |
| 416, 416Se, 420FSe, and XM-6 | T | 248 to 302 |
| 416, 416Se, and XM-6 | H | 293 to 352 |
| 440 F and 440FSe | A | 285 max |
| S18235 | A | 207 max |
A. Sizes below approximately 1 in. [25 mm] cross section may be tensile tested and converted to hardness per Test Methods and Definitions A370.