ASTM A29/A29M — Standard Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought
Scope
General requirements and the chemical composition tables for hot-wrought carbon and alloy steel bars designated by SAE/AISI number (10xx, 11xx, 12xx, 13xx, 15xx, 40xx, 41xx, 43xx, 46xx, 47xx, 48xx, 50xx, 51xx, 61xx, 81xx, 86xx, 87xx, 88xx, 92xx, 93xx, 94xx) and UNS number. It does not give mechanical properties — those come from the ordering condition, ASTM A108 (cold-finished), A434 (Q&T alloy bar), A322 (alloy bar) or the customer specification. Also defines H-band hardenability referencing SAE J1268.
Grades covered by ASTM A29
| Grade | No. | Type | C % | Yield MPa | Tensile MPa | Nearest equivalents |
|---|---|---|---|---|---|---|
| 1018 | G10180 | Low-carbon steel, cold-finished bar (case-hardenable) | 0.15 – 0.2 | ≈ 370 | ≈ 440 | C15 / C15E, S235JRC / C22, S15C / S17C / S20C |
| 1045 | G10450 | Medium-carbon steel, hardenable | 0.43 – 0.5 | ≈ 310 | ≈ 565 | C45, S45C, 45 |
| 1095 | G10950 | High-carbon steel (spring / knife / blade steel) | 0.9 – 1.03 | ≈ 380 | ≈ 650 | C100S, C90S / C98S, SK95 (SK4) |
| 4130 | G41300 | Chromium-molybdenum low-alloy steel, weldable (chromoly) | 0.28 – 0.33 | ≈ 360 | ≈ 560 | 25CrMo4, 30CrMo4, SCM430 |
| 4140 | G41400 | Chromium-molybdenum low-alloy steel (chromoly) | 0.38 – 0.43 | ≈ 415 | ≈ 655 | 42CrMo4, SCM440, 42CrMo |
| 4340 | G43400 | Nickel-chromium-molybdenum low-alloy steel, deep hardening | 0.38 – 0.43 | ≈ 470 | ≈ 745 | 34CrNiMo6, 36CrNiMo4, SNCM439 |
| 8620 | G86200 | Nickel-chromium-molybdenum case-hardening steel | 0.18 – 0.23 | ≈ 385 | ≈ 540 | 20NiCrMo2-2, SNCM220, 20CrNiMo |
Revision history and superseded standards
| Year | Change |
|---|---|
| 1920s | SAE numbering system established; A29 codifies chemistry for ASTM buyers |
| 2020 | A29/A29M-20 — current |
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