1. Basic characteristics and naming rules
Grade analysis
S: stands for structural steel;
355: indicates that the minimum yield strength is 355MPa when the thickness is ≤16mm;
J0: indicates that the impact energy of the impact test at 0℃ is ≥27J;
W: stands for weathering resistance.
Implementation standard
Complies with the European standard EN10025-5:2004, suitable for the production and inspection of atmospheric corrosion resistant steel.
2. Chemical composition and weathering mechanism
Main element content
Basic elements: C≤0.16%, Si≤0.50%, Mn 0.50-1.50%, P≤0.03%, S≤0.025%;
Alloy elements: Cr 0.40-0.80%, Cu 0.25-0.55%, Ni≤0.65%, Mo≤0.30%235.
Special provisions: For every 0.005% decrease in phosphorus (P), nitrogen (N) is allowed to increase by 0.001%, with an upper limit of 0.012%.
Weathering resistance principle
By adding alloy elements such as Cr, Cu, and Ni, a dense oxide film is formed on the surface of the steel plate to resist atmospheric corrosion, and the corrosion resistance is 2-8 times that of ordinary carbon steel.
3. Mechanical properties
Strength and toughness
Yield strength: ≥355MPa (when the thickness is ≤16mm); slightly reduced with increasing thickness (such as ≥335MPa when 40-63mm).
Tensile strength: 470-630MPa;
Elongation: ≥22%, with good plastic deformation ability.
Impact toughness
0℃ impact energy ≥27J, still maintains good toughness in low temperature environment.
4. Production process and delivery status
Production process
Raw material smelting → refining and degassing → continuous casting → rolling → heat treatment (normalizing or normalizing rolling) → non-destructive testing (ultrasound, radiography, etc.).
Delivery status
Common status: hot rolling, normalizing, normalizing rolling or thermomechanical rolling.
5. Application areas
Construction engineering: outdoor steel structure, industrial plant, high-rise building.
Bridges and transportation: highway/railway bridges, vehicle frames.
Ocean and energy: ship structure, offshore platform, oil equipment (containing hydrogen sulfide corrosion environment).
Other fields: containers, towers, photovoltaic brackets and other structures exposed to the atmosphere for a long time.
6. Differences from ordinary steel
S355J0W vs S355J0: The former is weathering steel with added elements such as Cu and Cr; the latter is ordinary carbon structural steel, implementing standard EN10025-2.
7. Market and Trends
Development Prospects: With the increasing demand for lightweight infrastructure and environmental protection, weathering steel has great potential for application in construction, transportation and other fields69.
Technological Innovation: In the future, it may optimize strength and fatigue resistance to adapt to more complex engineering needs16.
