S355J2W and S355K2W are weathering (W) structural steels under the EN 10025-5 standard with a minimum yield strength of 355 MPa, differing primarily in their specified impact energy requirements, with 'K2' indicating a higher impact test energy (usually 40J) than 'J2' (usually 27J), making them suitable for atmospheric corrosion resistance and low-temperature applications, forming a protective rust layer over time.
Chemical composition of the Product analysis of grade S355J2W
|
C |
Si |
Mn |
Cu |
P |
S |
Cr |
N |
|
0.19 |
0.55 |
0.45-1.60 |
0.20-0.60 |
0.035 |
0.035 |
0.35-0.85 |
0.010 |
Chemical composition of the Product analysis of grade S355K2W
|
C |
Si |
Mn |
Cu |
P |
S |
Cr |
N |
|
0.19 |
0.55 |
0.45-1.60 |
0.20-0.60 |
0.035 |
0.035 |
0.35-0.85 |
0.010 |
Mechanical properties of grade S355J2W
|
Temperature |
-20 |
-10 |
0 |
20 |
|
Notch impact test. Min. absorbed energy J |
27 |
|
Nominal thickness (mm) |
to 16 |
16 - 40 |
40 - 63 |
63 - 80 |
80 - 100 |
100 - 150 |
|
ReH - Minimum yield strength (MPa) |
355 |
345 |
335 |
325 |
315 |
295 |
|
Nominal thickness (mm) |
to 3 |
3 - 100 |
100-150 |
|
Rm -Tensile strength (MPa) |
510-680 |
470-630 |
450-600 |
|
Nominal thickness (mm) |
≥1.5＜2 |
≥2﹤2.5 |
≥2.5＜3 |
≥3＜40 |
≥40﹤63 |
≥6﹤100 |
≥100﹤150 |
|
A - Minimum elongation Lo = 5,65 √ So (%) Longitudinal |
16 |
17 |
18 |
22 |
21 |
20 |
18 |
Mechanical properties of grade S355K2W
|
Temperature |
-20 |
-10 |
0 |
20 |
|
Notch impact test. Min. absorbed energy J |
40 |
|
|
|
|
Nominal thickness (mm) |
to 16 |
16 - 40 |
40 - 63 |
63 - 80 |
80 - 100 |
100 - 150 |
|
ReH - Minimum yield strength (MPa) |
355 |
345 |
335 |
325 |
315 |
295 |
|
Nominal thickness (mm) |
to 3 |
3 - 100 |
100-150 |
|
Rm -Tensile strength (MPa) |
510-680 |
470-630 |
450-600 |
|
Nominal thickness (mm) |
≥1.5＜2 |
≥2﹤2.5 |
≥2.5＜3 |
≥3＜40 |
≥40﹤63 |
≥6﹤100 |
≥100﹤150 |
|
A - Minimum elongation Lo = 5,65 √ So (%) Longitudinal |
16 |
17 |
18 |
22 |
21 |
20 |
18 |
Key Differences
W (Weathering): Both grades have 'W' indicating improved atmospheric corrosion resistance due to added alloying elements (like Cu, Cr, Ni, Mo) that form a stable, protective oxide layer, eliminating the need for painting in many applications.
J2 vs. K2 (Impact Energy):
S355J2W: Requires a specific impact energy level (e.g., 27 Joules at a certain temperature).
S355K2W: Requires a higher impact energy level (e.g., 40 Joules at the same temperature).
Standard: They fall under EN 10025-5:2004, which covers hot-rolled structural steels with improved atmospheric corrosion resistance.
