| Internal Grade | SAE/AISI | IS | BS 970:1955 | BS 970:1983 | EN | JIS | DIN | GOST | ISO | AFNOR | GB/T | UNI | SS | CSA | AS/NZS |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AL5140 | 5140 | 40Cr1 | EN18 | 530A40 | 37Cr4 | SCr440 | 37Cr4 | 40Kh | 37Cr4 | 40C4 | 40Cr | 40Cr4 | 2244 | G51400 | AS 1444 5140 |
| AL4340 | 4340 | 40NiCr4Mo3 | EN24 | 817M40 | 34CrNiMo6 | SNCM439 | 34CrNiMo6 | 38KhN3MFA | 34CrNiMo6 | 35NCD6 | 34CrNiMo6 | 34NiCrMo6 | 2541 | G43400 | AS 1444 4340 |
| AL4140 | 4140 4142 | 40Cr4Mo3 | EN19 | 709M40 | 42CrMo4 | SCM440 | 42CrMo4 | 38KhMo4 | 42CrMo4 | 42CD4 | 42CrMo | 42CrMo4 | 2245 | G41400 | AS 1444 4140 |
| AL8620 | 8620 | 20NiCrMo2 | EN362 | 805M20 | 17CrNiMo6 | SNCM220 | 17CrNiMo6 | 18KhGT | — | — | 20CrNiMo | — | 2545 | G86200 | AS 1444 8620 |
| AL4320 | 4320 | 15NiVCr1Mo15 | EN354 | 820M17 | — | SNCM420 | — | — | — | — | 20CrNi2Mo | — | — | G43200 | AS 1444 4320 |
| AL20MnCr5 | 5120 | 20MnCr1 | — | — | 20MnCr5 | SCR420 | 20MnCr5 | 20KhGT | 20MnCr5 | 20MC5 | 20CrMn | 20MnCr5 | 2511 | G51200 | AS 1444 5120 |
| AL16MnCr5 | 5115 | 17Mn1Cr95 | — | — | 16MnCr5 | SCR415 | 16MnCr5 | 15KhGT | 16MnCr5 | 16MC5 | 16CrMn | 16MnCr5 | 2510 | G51150 | AS 1444 5115 |
| AL15Cr3 | 5015 | 15Cr65 | EN206 | 523A14 | 15Cr3 | SCr415 | 15Cr3 | 15Kh | 15Cr3 | 15C3 | 15Cr | 15Cr3 | — | G50150 | AS 1444 5015 |
Note: Some alloy steels like 8620 or 16MnCr5 are primarily case-hardening grades. Others like 4140, 4340 are heat-treatable and used in critical load-bearing applications. Always check mechanical properties and heat treatment compatibility when substituting across standards.