Difference between S275N and S355N steel plate

Dec 29, 2025 Leave a message

S275N and S355N are European standard (EN 10025-3) fine-grain structural steels, differentiated mainly by yield strength (S275 has ~275 MPa, S355 has ~355 MPa), with S355 offering higher strength for heavy-duty applications like bridges and cranes, while S275 serves general structures, both prized for good weldability and low-temperature toughness due to the 'N' (Normalized) designation, making them versatile for demanding projects.

S275N and S355N are both normalized fine-grain structural steel plates designed for welded constructions requiring enhanced toughness at low temperatures down to -20°C.

S275N offers a minimum yield strength of 275 MPa, while S355N provides higher strength at 355 MPa, making S355N more suitable for heavier loads than S275N.

Chemical Composition Comparison

Element	Symbol	S275N Max (%)	S355N Max (%)
Carbon	C	0.20	0.20
Silicon	Si	0.40	0.50
Manganese	Mn	0.80–1.60	0.90–1.60
Phosphorus	P	0.035	0.025
Sulfur	S	0.030	0.020
Chromium	Cr	0.30	0.30
Molybdenum	Mo	0.10	0.10
Vanadium	V	0.05	0.12
Nitrogen	N	0.012	0.015
Niobium	Nb	0.050	0.050
Titanium	Ti	0.050	0.050
Aluminum	Al	≥0.020	≥0.020
Copper	Cu	0.35	0.55
CEV	-	0.40	0.43

Mechanical Properties Comparison

Nominal Thickness (mm)	Yield ReH Min (MPa) S275N	Yield ReH Min (MPa) S355N	Tensile Rm (MPa) S275N	Tensile Rm (MPa) S355N	Elongation A Min (%) Both	Charpy KV Longitudinal Min (J) at -20°C Both
≤ 16	275	355	370–530	470–630	23	47
16 < t ≤ 40	265	345	370–530	470–630	23	47
40 < t ≤ 63	255	335	370–530	470–630	23	47
63 < t ≤ 80	245	325	370–530	470–630	22	47
80 < t ≤ 100	235	315	370–530	470–630	22	47
100 < t ≤ 150	225	295	350–510	450–600	22	47
150 < t ≤ 200	215	285	350–510	450–600	22	47
200 < t ≤ 250	195	265	350–510	450–600	22	47

Heat Treatment and Welding Comparison
Heat Treatment: Both normalized (+N: 880–920°C austenitize, air cool) for fine-grain.
Welding: Low CEV (0.40/0.43), no preheat ≤40 mm; S355N may need more care for thicker sections.
Follow EN 1011-2. Gangsteel optimizes for both.