Standards Guide
Common steel grade equivalents.
A practical summary of common AISI/SAE, EN and older DIN designations.
This table is for preliminary selection. Product standard, chemistry, mechanical properties, delivery condition and certificate must be checked for exact equivalence.
| Market name | Identity or conditional comparison | Group |
|---|---|---|
| 4140 / 42CrMo4 | 42CrMo4: 1.7225. SAE 4140 comparison requires chemistry, product standard and delivery-condition verification. | Engineering / Q&T steel |
| C45 / Ck45 / C45E | C45: 1.0503; C45E (historical Ck45): 1.1191. SAE 1045 is a conditional comparison, not automatic substitution. | Carbon steel |
| 16MnCr5 | 1.7131. Do not confuse with sulfur-controlled 16MnCrS5 / 1.7139. | Case-hardening steel |
| 20MnCr5 | 1.7147. Confirm product standard, hardenability requirements and delivery condition. | Case-hardening steel |
| ST37 / S235 | Historical commercial comparison; S235JR is 1.0038. Product form and impact class require verification. | Structural steel |
| ST52 / S355 | Historical commercial comparison; S355JR, J0 and J2 are distinct impact classes. S355J2 is 1.0577. | Structural steel |
Source scope
Producer references support the stated grade identities, not universal interchangeability or Erkal stock availability. Source review: 11 September 2026.
Why is certificate verification necessary?
The same commercial name can cover different standards, tolerances, impact classes or heat-treatment conditions.
Information required in an order
- Grade and standard
- Production route
- Delivery condition
- Dimensions and tolerance
- Inspection requirements
- Origin and certificate requirements