The grades of line pipe steel based on API SPEC 5L specify a series of minimum mechanical requirements and not specific material composition, though the specification does list the maximum composition percentage for any component.
Therefore each mill will provide slightly different steel for a given grade.
Below are the minimum mechanical requirements for the different API 5L grades. The names are based on the minimum yield strengths – X values are in ksi and L values are in MPa. (e.g. X65 has a minimum yield strength of about 65 ksi, equivalent to L450 with a minimum yield strength of 450 MPa.
| Line Pipe Grade | Yield Strength | Tensile Strength | Elongation | |||
| MPa | ksi | MPa | ksi | % | ||
| L175 | A25 | 175 | 25.4 | 310 | 45 | |
| L210 | A | 210 | 30.5 | 335 | 48.6 | 28 |
| L245 | B | 245 | 35.5 | 415 | 60.2 | 23 |
| L290 | X42 | 290 | 42.1 | 415 | 60.2 | 23 |
| L320 | X46 | 320 | 46.4 | 435 | 63.1 | 22 |
| L360 | X52 | 360 | 52.2 | 460 | 66.7 | 21 |
| L390 | X56 | 390 | 56.6 | 490 | 71.1 | 19 |
| L415 | X60 | 415 | 60.2 | 520 | 75.4 | 19 |
| L450 | X65 | 450 | 65.3 | 535 | 77.6 | 18 |
| L485 | X70 | 485 | 70.3 | 570 | 82.7 | 17 |
| L555 | X80 | 555 | 80 | 621 | 90 | 16 |
| L690 | X100 | 690 | 100 | 760 | 110 | |