49 CFR Part 178, Appendix A
| Designation | Chemical composition, percent-ladle analysis |
|---|---|
| Grade 1 1 | Grade 2 1 2 | Grade 3 2 4 5 |
| Carbon | 0.10/0.20 | 0.24 maximum | 0.22 maximum. |
| Manganese | 1.10/1.60 | 0.50/1.00 | 1.25 maximum. |
| Phosphorus, maximum | 0.04 | 0.04 | 0.045.6 |
| Sulfur, maximum | 0.05 | 0.05 | 0.05. |
| Silicon | 0.15/0.30 | 0.30 maximum | |
| Copper, maximum | 0.4 | | |
| Columbium | | 0.01/0.04 | |
| Heat treatment authorized | (3) | (3) | (3). |
| Maximum stress (p.s.i.) | 35,000 | 35,000 | 35,000. |
1 Addition of other elements to obtain alloying effect is not authorized.
2 Ferritic grain size 6 or finer according to ASTM E 112-96 (IBR, see § 171.7 of this subchapter).
3 Any suitable heat treatment in excess of 1,100 °F., except that liquid quenching is not permitted.
4 Other alloying elements may be added and shall be reported.
5 For compositions with a maximum carbon content of 0.15 percent of ladle analysis, the maximum limit for manganese on ladle analysis may be 1.40 percent.
6 Rephosphorized Grade 3 steels containing no more than 0.15 percent phosphorus are permitted if carbon content does not exceed 0.15 percent and manganese does not exceed 1 percent.
| Element | Limit or maximum specified (percent) | Tolerance (percent) over the maximum limit or under the minimum limit |
|---|---|---|
| Under minimum limit | Over maximum limit | |
| Carbon | To 0.15 inclusive | 0.02 | 0.03 |
| Over 0.15 to 0.40 inclusive | 0.03 | 0.04 | |
| Manganese | To 0.60 inclusive | 0.03 | 0.03 |
| Over 0.60 to 1.15 inclusive | 0.04 | 0.04 | |
| Over 1.15 to 2.50 inclusive | 0.05 | 0.05 | |
| Phosphorus 7 | All ranges | | 0.01 |
| Sulfur | All ranges | | 0.01 |
| Silicon | To 0.30 inclusive | 0.02 | 0.03 |
| Over 0.30 to 1.00 inclusive | 0.05 | 0.05 | |
| Copper | To 1.00 inclusive | 0.03 | 0.03 |
| Over 1.00 to 2.00 inclusive | 0.05 | 0.05 | |
| Nickel | To 1.00 inclusive | 0.03 | 0.03 |
| Over 1.00 to 2.00 inclusive | 0.05 | 0.05 | |
| Chromium | To 0.90 inclusive | 0.03 | 0.03 |
| Over 0.90 to 2.10 inclusive | 0.05 | 0.05 | |
| Molybdenum | To 0.20 inclusive | 0.01 | 0.01 |
| Over 0.20 to 0.40 inclusive | 0.02 | 0.02 | |
| Zirconium | All ranges | 0.01 | 0.05 |
| Columbium | To 0.04 inclusive | 0.005 | 0.01 |
| Aluminum | Over 0.10 to 0.20 inclusive | 0.04 | 0.04 |
| Over 0.20 to 0.30 inclusive | 0.05 | 0.05 |
7 Rephosphorized steels not subject to check analysis for phosphorus.
[Amdt. 178-3, 34 FR 12283, July 25, 1969; 34 FR 12593, Aug. 1, 1969, as amended by Amdt. 178-64, 45 FR 81573, Dec. 11, 1980; Amdt. 178-97, 55 FR 52728, Dec. 21, 1990; 68 FR 75758, Dec. 31, 2003]