ST52 vs S355JR Steel: Equivalent Grades Compared

If your drawings say ST52 and your supplier quotes S355JR — or the other way around — you are dealing with one of the most common grade-confusion situations in structural carbon steel. ST52 is the legacy designation from the withdrawn German standard DIN 17100, while S355JR is the current European grade under EN 10025-2. They are close cousins, but not identical on paper, and mixing them up in a contract can create acceptance disputes at the port. This guide compares ST52 and S355JR across chemistry, mechanical properties, impact requirements, weldability and supply reality, so you can specify the right grade and accept the right certificate.

Where Each Grade Comes From

ST52 (often written St 52, St52-3 or ST52-3N) was standardized in DIN 17100 as a structural steel with a minimum yield strength of roughly 355 MPa in thin sections. The “-3” suffix versions carried notch-toughness requirements, while plain ST52 did not. DIN 17100 was withdrawn and replaced by EN 10025 in the early 1990s, with the final revision EN 10025-2:2019 still in force today. S355JR is that standard’s grade 1.0045 — 355 MPa minimum yield, with 27 J impact energy at room temperature.

The practical consequence: mills in Europe, Turkey, China and Korea no longer certify to DIN 17100. When a buyer asks for ST52 today, what actually ships is S355JR or S355J2 material, sometimes dual-marked, sometimes simply relabeled on the mill test certificate. That is legitimate — but only if the substitute grade meets or exceeds what the design actually needs, which is exactly why the comparison below matters.

Chemical Composition Comparison

Element	ST52-3 (DIN 17100)	S355JR (EN 10025-2)
Carbon (C)	≤ 0.20 %	≤ 0.24 % (≤ 40 mm); ≤ 0.23 % for some products
Silicon (Si)	≤ 0.55 %	≤ 0.55 %
Manganese (Mn)	≤ 1.70 %	≤ 1.60 %
Phosphorus (P)	≤ 0.040 %	≤ 0.035 %
Sulfur (S)	≤ 0.040 %	≤ 0.035 %
Nitrogen (N)	—	≤ 0.014 % (not K2-type)
Carbon equivalent CEV	≤ 0.45 % (by agreement)	≤ 0.45 % for C ≤ 0.24 % grades; ≤ 0.47 % with higher C

Chemistry-wise the two grades overlap heavily: both are carbon-manganese steels with similar silicon and manganese ceilings. The main documented differences are sulfur and phosphorus, where EN 10025-2 JR is slightly cleaner (0.035 % versus 0.040 %). In real mill practice, modern S355 is usually killed and fine-grained with microalloying additions such as niobium or vanadium, which the old DIN grade never required. That makes today’s S355 metallurgically superior to what ST52 actually was in the 1980s.

Mechanical Properties by Thickness

Property	ST52-3 (≤ 16 mm)	S355JR (≤ 16 mm)
Minimum yield strength ReH	355 MPa	355 MPa
Tensile strength Rm	490–630 MPa	470–630 MPa
Minimum elongation A5	21–22 %	22 % (longitudinal)
Impact energy	27 J at 0 °C (St52-3)	27 J at +20 °C

Yield strength is identical at 355 MPa for the thinnest product range, and both grades taper with thickness the same way — S355JR drops to 345 MPa for 16–40 mm, 335 MPa for 40–63 mm, and down to 295 MPa at over 100 mm. Tensile ranges also overlap: ST52-3 specified 490–630 MPa while S355JR specifies 470–630 MPa, so an S355JR coil will always pass an ST52 tensile call-out.

The one place you must look carefully is impact testing temperature. S355JR is tested at +20 °C. St52-3, despite the weaker-looking paper, was traditionally tested at 0 °C. If your design code requires 0 °C or -20 °C toughness — most offshore, bridge and crane applications do — then S355JR is not an automatic substitute. The correct modern equivalents at lower temperature are:

• S355J0 (1.0553) — 27 J at 0 °C — closest match to St52-3 impact requirements
• S355J2 (1.0577) — 27 J at −20 °C — matches St52-3N and cold-climate sites
• S355K2 (1.0596) — 40 J at −20 °C — for higher toughness demand
• S235JR / St37-2 and S275JR / St44-2 follow the same substitution ladder one grade down

Weldability: ST52 vs S355JR

Both grades weld well with all conventional processes because their carbon equivalents sit at or below 0.45 %. For plates under 20 mm, no preheat is normally required with low-hydrogen consumables; from 20 to 40 mm, a preheat of 50–100 °C is a sensible precaution in humid or cold workshops, and above 50 mm most welding engineers specify 100–150 °C with controlled interpass temperature. Matching consumables are ISO 14341 G46 / ER70S-6 wire for MIG, E7018 electrodes for stick, and submerged-arc wire-flux combinations rated to S46 or better.

Because modern S355 often contains niobium or vanadium, heat input above roughly 3.5 kJ/mm can coarsen the heat-affected zone and lower toughness in thick sections. If your WPS was qualified on old ST52-3 material, it remains valid metallurgically, but re-qualifying on fine-grained S355 is cheap insurance for critical joints.

Supply Reality and Certificate Practice

Here is what actually happens in the market today. A Chinese or Korean mill produces to EN 10025-2, marks S355JR on the plate, and issues an EN 10204 3.1 certificate in that grade. When you order “ST52”, most mills will simply write S355JR on the documents and expect you to accept it, because the withdrawn standard cannot be certified. The three safe ways to handle this in procurement are:

• Specify EN 10025-2 directly. Change the drawing note from ST52 to S355JR or S355J2 and close the ambiguity at the source. This is the cleanest fix and costs nothing.
• Order “ST52 equivalent to S355J2”. Keep your legacy designation but state in the PO that material must comply with EN 10025-2 S355J2, impact tested at −20 °C, with certificate quoting the EN grade.
• Accept dual certification. Ask for the MTC to state “S355J2 (ST52-3 equivalent)” so your inspector and your classification society can trace both references.

One warning: never accept a certificate that says only “ST52” with no standard number and no heat number traceability. Without the EN reference and heat traceability you cannot verify mechanicals, and third-party inspectors will flag the shipment.

Price and Availability Differences

Because S355JR is the current, mass-produced grade, it is typically cheaper than trying to source material certified against the old DIN standard. In practice there is no price premium between “ST52” and “S355JR” quotes from the same mill — the price drivers are product form (plate versus section versus hollow section), thickness, and whether impact testing or third-party inspection is required. J0 and J2 variants add roughly 1–3 % for the additional impact testing and, for J2, often normalized or controlled-rolled delivery condition.

Quick Selection Summary

Situation	What to order
General structures, +20 °C service	S355JR (ST52 equivalent, lowest cost)
Outdoor structures, 0 °C service	S355J0 — matches St52-3
Cold climate, −20 °C service	S355J2 / S355K2
Legacy drawing says ST52 only	Confirm required impact temperature before substituting
Weldments with thick sections	S355J2 normalized, CEV ≤ 0.45 % stated on MTC

Tolerance, Marking and Delivery Condition

Both grades ship as-rolled (+AR) or normalized (+N) depending on product form and thickness, and this is another line worth checking on the quotation. Sections and hollow sections to S355JR normally come as-rolled; plates over 30 mm are often normalized or thermomechanically rolled to hold toughness. Standard delivery tolerances are governed by the product standard (EN 10029 for plate, EN 10279 for sections, EN 10219 for hollow sections), so a tolerance dispute should always be settled against the product standard rather than the grade standard. Marking on S355 material follows EN 10025-1: grade, delivery condition, melt heat number and manufacturer identification — on welded hollow sections you will typically see S355J2H, where the H suffix denotes hollow section, not a different steel. When importing, require the stencil on each piece to carry the heat number; packages without piece-level heat marking cannot be reconciled against the MTC during customs or third-party inspection and are a recurring cause of demurrage.

FAQ

Is ST52 the same as S355JR?

For most applications yes — same 355 MPa yield class, overlapping chemistry and tensile range. The exceptions are impact temperature (JR is tested at +20 °C, St52-3 at 0 °C) and sulfur/phosphorus limits. If your code demands 0 °C toughness, order S355J0 instead.

Can a supplier still certify to DIN 17100?

No. DIN 17100 is withdrawn and cannot legally appear as the certifying standard on a new mill test certificate. Any document quoting only DIN 17100 for new production is either outdated or fabricated — reject it and require EN 10025-2.

Which S355 variant replaces ST52-3N?

St52-3N (normalized) maps to S355J2G3, which in the current EN 10025-2 numbering is S355J2 with delivery condition +N or +AR with specified toughness. On certificates you will see 1.0577 (S355J2) or, for the old -G3 suffix, S355J2+N.

Is S355JR suitable for galvanizing?

Yes. Its silicon content is within the recommended range for hot-dip galvanizing, though batches with Si near the 0.55 % ceiling can show thicker, darker coatings. If coating appearance matters, ask the mill for Si ≤ 0.30 % (a Sandelin-avoiding chemistry) at the time of order.

How do I verify the material I received is really S355?

Check three things: the MTC heat number matches stencils on the material, the mechanical values meet EN 10025-2 for your thickness, and a witnessed or third-party PMI/tensile test on a sample confirms chemistry. For large structural orders, an SGS/BV/TUV witness during mill testing costs a fraction of a rejected shipment.