ST52-3 is a readily weldable low carbon manganese structural steel with good impact resistance, including at sub-zero service temperatures. The material is commonly supplied in the untreated or normalised condition and was standardised in DIN 17100: 1980 as St52-3 (material number 1.0570). With the introduction of the European harmonised standards the grade was carried forward into EN 10025: 1993 as S355J2G3 and then into EN 10025-2: 2004 as S355J2 (1.0577), where the designation is built from the 355 N/mm² minimum yield strength class.
Because the same steel is known under several designations, buyers frequently ask what ST52 is equivalent to. The tables below collect the composition, mechanical property and cross-standard equivalence data needed to answer that question for structural plate and long products.
What ST52-3 Steel Is and Where It Comes From
ST52 belongs to the family of general structural steels defined by a minimum yield strength and a specified impact test temperature. The suffix -3 in the old DIN 17100 system indicated normalised or controlled-rolled delivery with a guaranteed impact energy at low temperature, while the modern EN designation S355J2 states directly that the steel delivers 355 N/mm² minimum yield strength with 27 J minimum Charpy energy at -20 °C. Deoxidation is fully killed, which gives a uniform, fine-grained structure suitable for welded structures, machinery and general fabrication.
Chemical Composition According to DIN 17100 and EN 10025-2
| Country / Region | Standard | Grade | C max (%) | Si max (%) | Mn max (%) | P max (%) | S max (%) | Deoxidation |
|---|---|---|---|---|---|---|---|---|
| Germany | DIN 17100: 1980 | St52-3 (1.0570) | 0.22 | 0.60 | 1.70 | 0.045 | 0.045 | Fully killed |
| European Union | EN 10025: 1993 | S355J2G3 (1.0570) | 0.22 | 0.55 | 1.60 | 0.035 | 0.035 | Fully killed |
| European Union | EN 10025-2: 2004 | S355J2 (1.0577) | 0.22 | 0.55 | 1.60 | 0.035 | 0.035 | Fully killed |
Values are maximum product-analysis limits for plates up to 30 mm thick; the European standards also cap nitrogen and, for J2 and K2 qualities, copper additions. Successive revisions tightened phosphorus and sulphur from 0.065 % in early general-purpose grades to 0.035 % in EN 10025-2, which is one reason modern S355J2 plate is cleaner and more weldable than the original ST52 delivery.
Yield and Tensile Strength by Thickness
| Property | d ≤ 16 mm | 16 < d ≤ 40 mm | 40 < d ≤ 63 mm | 63 < d ≤ 80 mm | 80 < d ≤ 100 mm |
|---|---|---|---|---|---|
| Yield strength min (N/mm²) | 355 | 345 | 335 | 325 | 315 |
| Tensile strength (N/mm²) | 490 - 630 for 3 ≤ d ≤ 100; 515 - 680 for d < 3; by agreement above 100 | ||||
Note that 1 MPa equals 1 N/mm². Yield strength decreases stepwise with thickness because rolling reduction and cooling rate fall as sections get heavier; above 100 mm the property is subject to agreement between mill and purchaser. Elongation and impact requirements are specified for the same thickness steps, with ST52-3 and S355J2 both qualifying at 27 J minimum absorbed energy at -20 °C.
ST52 Steel Equivalent Grades Worldwide
| Germany | USA | European Union | China | Japan | India | ISO |
|---|---|---|---|---|---|---|
| DIN 17100 St52-3 (1.0570) | ASTM A572/A572M Grade 50 | EN 10025-2 S355JR / S355J0 / S355J2 (1.0577) | GB/T 1591 Q355B; Q355C | JIS G3106 SM490A / SM490B | IS 2062 E350 | ISO 630-2 S355C |
These cross-references are approximate. ASTM A572 Grade 50 reaches a 345 N/mm² minimum yield point with different chemistry ranges, Q355 grades adopt a Chinese carbon equivalent system, and the Japanese SM490 grades are impact-tested at 0 °C rather than -20 °C. Design codes may also apply their own safety factors and thickness limits, so equivalence data should never replace the ordered specification on the purchase document.
Selection and Fabrication Guidance
Service temperature drives the variant. Choose S355J2 where -20 °C impact testing is required; S355J0 (-0 °C) or S355JR (+20 °C) is sufficient for warmer, non-critical duty and costs less.
Confirm thickness-dependent properties. Design against the yield value for the actual plate thickness, not the headline 355 N/mm² figure.
Weld with low-hydrogen practice. The low carbon content allows conventional processes, but thick sections benefit from controlled heat input and preheating as defined by the qualified welding procedure.
Check traceability. Request the mill test certificate for the exact grade, heat number and impact test temperature, and confirm the delivery condition (as-rolled or normalised).
Frequently Asked Questions
Q: What is ST52 steel equivalent to in EN standards?
DIN 17100 St52-3 corresponds to EN 10025: 1993 S355J2G3 and, under the current standard, to EN 10025-2 S355J2 (1.0577), a 355 N/mm² minimum yield strength grade with 27 J impact energy at -20 °C.
Q: Is ST52 the same as S355?
They describe the same strength class but not identical specifications. S355J2 is the modern designation with tighter phosphorus and sulphur limits of 0.035 % maximum, while older ST52-3 deliveries permitted up to 0.065 % in some grades.
Q: What is the yield strength of St52-3 plate?
Minimum yield strength is 355 N/mm² up to 16 mm thickness, then 345, 335, 325 and 315 N/mm² for the 16-40 mm, 40-63 mm, 63-80 mm and 80-100 mm thickness steps respectively.
Q: Which ASTM and GB grades match ST52?
ASTM A572/A572M Grade 50 is the closest American equivalent, and GB/T 1591 Q355B or Q355C is the nearest Chinese grade. Both are low-alloy structural steels with comparable strength, though chemistry and impact requirements differ.
Q: Can ST52-3 steel be welded?
Yes. It is a fully killed, low carbon manganese steel with good weldability, including in sub-zero conditions when the correct consumables and heat input are used. Thick plates and restrained joints should follow a qualified procedure with defined preheat.
Q: What delivery condition is ST52 plate supplied in?
The steel is normally supplied untreated (as-rolled) or normalised, and both conditions are readily available in plate thicknesses from a few millimetres up to around 100 mm.
