EN 10025-2:2019· Europe

S355

Europe's workhorse structural steel: 355 MPa minimum yield up to 16 mm, 470–630 MPa tensile from 3 to 100 mm.

Non-alloy structural steel for buildings, bridges, cranes and offshore structures. “S” stands for structural, 355 for the minimum yield strength in MPa at the thinnest thickness band; the suffix gives the impact quality. Yield falls as the product gets thicker, so always read the band for your thickness.

S355JR1.004527 J at +20 °CS355J01.055327 J at 0 °CS355J21.057727 J at −20 °CS355K21.059640 J at −20 °C

Nominal thicknessmm

Yield strength ReH: ≥ 345MPa
Confirmed16–40 mm
Tensile strength Rm: 470–630MPa
Confirmed3–100 mm
Elongation after fracture A: ≥ 22%
Confirmed3–40 mm · longitudinal, L₀ = 5.65√S₀
Design yield strength fy: 355MPa
Confirmed≤ 40 mm
Design ultimate strength fu: 490MPa
Corroborated≤ 40 mm

All values

Strength

Yield strength ReH

Upper yield strength guaranteed by the product standard (minimum).

Condition	Value	Evidence
	≥ 355MPa	Confirmed
	≥ 345MPa	Confirmed
	≥ 335MPa	Confirmed
	≥ 325MPa	Confirmed
	≥ 315MPa	Confirmed
	≥ 295MPa	Confirmed
	≥ 285MPa	Confirmed
	≥ 275MPa	Confirmed
	≥ 265MPa	Confirmed

Tensile strength Rm

Ultimate tensile strength. Product standards give a range or a minimum.

Condition	Value	Evidence
	510–680MPa	Confirmed
	470–630MPa	Confirmed
	450–600MPa	Confirmed
	450–600MPa	Corroborated
	450–600MPa	Corroborated

Ductility

Elongation after fracture A

Minimum elongation; depends on gauge length and test direction.

Condition	Value	Evidence
	≥ 22%	Confirmed
	≥ 21%	Confirmed
	≥ 20%	Confirmed
	≥ 18%	Single source
	≥ 17%	Single source

Toughness

Impact energy (Charpy V) KV

Minimum absorbed energy at the stated test temperature.

Condition	Value	Evidence
	≥ 27J	Confirmed
	≥ 27J	Corroborated
	≥ 27J	Confirmed1
	≥ 40J	Confirmed1

Design values (Eurocode)

Design yield strength fy

Nominal value used in design calculations (before partial factors).

Condition	Value	Evidence
	355MPa	Confirmed
	335MPa	Single source

Design ultimate strength fu

Nominal ultimate strength used in design calculations.

Condition	Value	Evidence
	490MPa	Corroborated1
	470MPa	Single source

Physical constants

Modulus of elasticity E

Young's modulus for design.

Condition	Value	Evidence
	210 000MPa	Confirmed1

Shear modulus G

G = E / 2(1 + ν).

Condition	Value	Evidence
	81 000MPa	Corroborated1

Poisson's ratio ν

In the elastic range.

Condition	Value	Evidence
	0.3	Confirmed

Coefficient of thermal expansion α

Linear, near room temperature.

Condition	Value	Evidence
	12×10⁻⁶ /K	Confirmed

Density ρ

Mass per unit volume.

Condition	Value	Evidence
	7 850kg/m³	Confirmed1

Unit weight γ

Weight per unit volume, for self-weight loads.

Condition	Value	Evidence
	78.5kN/m³	Single source

Chemical composition

Show on the periodic table

S355J2, ladle analysis, % by mass, maximum

Element	Applies to	Max %	Evidence
C	≤ 30 mm	0.20	Corroborated
C	30–100 mm	0.22	Corroborated
Si	all thicknesses	0.55	Confirmed
Mn	all thicknesses	1.60	Confirmed
P	flat products	0.025	Corroborated
S	flat products	0.025	Corroborated
Cu	all thicknesses	0.55	Confirmed
CEV	≤ 30 mm	0.45	Corroborated
CEV	30–150 mm	0.47	Single source
CEV	150–250 mm	0.49	Single source

Product (check) analysis allows slightly higher limits (C 0.23, Si 0.60, Mn 1.70, P and S 0.035, Cu 0.60 per Roymech and The World Material). JR and J0 allow more P and S. CEV = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15; for long products the CEV limit is 0.54 (Sider Ticino).

S355 in other standards

Full comparison

“Equivalent” tables online usually match grades by name. This one compares the values each standard actually guarantees, so a 30 MPa gap in yield is visible before it is in your calculation.

Grade	Standard	Min. yield at 10 mm	Tensile at 10 mm	Match	What differs
S355	EN 10025-2:2019	≥ 355MPa7	470–630MPa9	—	Reference grade.
St 52-3	DIN 17100(withdrawn)	not verified	not verified	Close match	The withdrawn German predecessor. Same strength class; designations on old drawings map to S355J2.
С355	GOST 27772-2015	≥ 355MPa1	≥ 470MPa1	Close match	Same yield steps as S355 up to 100 mm (355/345/335/325/315 MPa) per GOST 27772 Table 4; tensile 470 MPa minimum with no upper limit, and the table starts at 8 mm.
Q355	GB/T 1591-2018	≥ 355MPa3	470–630MPa2	Close match	China's direct counterpart since GB/T 1591-2018 renamed Q345 to Q355. Q355B/C/D test 34 J where S355JR/J0/J2 test 27 J; thickness bands and chemistry differ.
SM520	JIS G 3106	≥ 365MPa1	520–640MPa2	Close match	Matches S355's yield (365 MPa ≤ 16 mm, 355 MPa 16–40 mm) with a higher tensile range, 520–640 MPa.
A992	ASTM A992/A992M	≥ 345MPa2	≥ 450MPa2	Approximate	The US wide-flange grade: 345 MPa (50 ksi) yield, 450 MPa tensile, with a yield-to-tensile cap of 0.85 for ductility.
A572 Grade 50	ASTM A572/A572M	≥ 345MPa4	≥ 450MPa4	Approximate	Minimum yield 345 MPa (50 ksi), 10 MPa below S355; minimum tensile 450 MPa (65 ksi) with no upper limit. No impact test unless ordered as a supplement.
350W	CSA G40.21	≥ 350MPa2	450–655MPa2	Approximate	Yield 350 MPa (50 ksi), 5 MPa below S355, and only 46 ksi above 2½ in.; tensile 65–95 ksi. W has no guaranteed impact test; 350WT adds it.
Grade 350	AS/NZS 3678:2016	≥ 360MPa2	≥ 450MPa2	Approximate	Yield bands differ (360 MPa up to 12 mm, then 350 and 340). Minimum tensile 450 MPa, below S355's 470.
E350	IS 2062:2011	≥ 350MPa1	≥ 490MPa1	Approximate	Yield 350 MPa for the thinnest band, 5 MPa below S355; minimum tensile 490 MPa, above S355's 470.
SM490	JIS G 3106	≥ 325MPa2	490–610MPa3	Not equivalent	Usually listed as the JIS equivalent, but its guaranteed yield is 325 MPa — 30 MPa (8 %) below S355. Fine as a tensile-class match, not for yield-governed design.
09G2S (09Г2С)	GOST 19281-2014	≥ 265MPa1	≥ 430MPa1	Not equivalent	A chemistry grade, not a strength class: under GOST 19281-2014 it is supplied from strength class 265 upwards. Only a certificate stating class 345 or higher comes close.

Sources here are public pages that reproduce EN 10025-2:2019. For design and acceptance, the standard edition named in your specification and the inspection certificate (EN 10204 3.1) of the delivered product take precedence.