St37, St52, Ck45, X5CrNi18-10 — replaced by EN, still specified. Issued by DIN. 3 grades and 1 standards are documented so far; each grade links to a full data sheet and a graded cross-reference to the other systems.
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Cold-rolled & coated sheet
Cold-rolled & coated sheet — DIN (superseded German)
DIN designations were formally replaced by EN standards across Europe, and yet St37, St52 and Ck45 appear on enquiries every week. Older drawings were never reissued, plant documentation still carries them, and in several export markets the DIN name remained the trade term long after the standard was withdrawn.
Treat a DIN designation as a pointer rather than a specification. St37 tells you the buyer wants something like S235JR; it does not tell you which impact class, and the old standard's requirements differ in detail from the EN grade that replaced it.
The common conversions
St37-2 → S235JR (1.0038), St44-2 → S275JR (1.0044), St52-3 → S355J2 or S355J0 depending on the old suffix, Ck45 → C45E (1.1191), X5CrNi18-10 → 1.4301. The old St numbers referred to tensile strength in kgf/mm² — St37 meant roughly 37 kgf/mm², about 360 MPa tensile, not yield.
That unit change is the trap. A buyer reading St52 as a 520 MPa yield steel is out by nearly half: St52-3 corresponds to S355, a 355 MPa yield grade with about 520 MPa tensile.
When to push back on a DIN specification
Where the part is code-governed, classed or fatigue-critical, an old DIN name is not enough to order against. The right response is to ask what the drawing is really asking for — the yield, the impact temperature and the delivery condition — and then quote the EN grade that satisfies it, stating the substitution on the certificate.
Supplying "St52" without that conversation means both sides are guessing at the impact requirement.
faq.h
What is St37 steel?
A superseded DIN designation for general structural steel, replaced by EN S235JR (1.0038). The 37 referred to a tensile strength of about 37 kgf/mm², roughly 360 MPa — not to yield strength.
What is the EN equivalent of St52?
S355, usually S355J2 or S355J0 depending on the old suffix. St52-3 is the version that most closely matches S355J2; St52 alone does not state an impact requirement.
Is Ck45 the same as C45?
Ck45 corresponds to C45E (1.1191) — the k marked a low-sulphur quality variant. Plain C45 in EN allows higher sulphur than the old Ck grade did.
Why do DIN designations still appear if they are withdrawn?
Older drawings were never reissued, plant documentation carries the old names, and in several export markets the DIN term stayed in trade use after the standard was replaced. They are pointers to an EN grade rather than valid specifications.
Does St37 mean 370 MPa yield?
No, and this is the common error. The number was tensile strength in kgf/mm², so St37 means roughly 360 MPa tensile and about 235 MPa yield — hence the equivalence with S235.