S355J2WP is a weathering steel, which is a low alloy structural steel, specialized in resisting atmospheric corrosion. The following are its core properties and uses:
I. Material Nature
Weathering steel
Between ordinary steel and stainless steel, made by adding small amounts of copper (Cu), phosphorus (P), chromium (Cr), nickel (Ni) and other alloying elements. The price is lower than stainless steel, but the corrosion resistance is 2-8 times of ordinary carbon steel.
Naming Meaning
S: structural steel
355: yield strength of 355MPa minimum
J2: -20 ℃ impact work value ≥ 27J
W: improved atmospheric corrosion resistance
P: specific phosphorus content.
Second, the performance characteristics
Corrosion resistance
A dense oxide layer (about 50-100μm thick) will form on the surface, preventing oxygen and moisture penetration and slowing down the rate of rusting. However, it is important to note that corrosion may be accelerated at welded joints, waterlogged areas, or salt-rich environments (e.g., coastal).
Mechanical Properties
High strength: tensile strength 470-630MPa, suitable for load-bearing structures.
Good toughness: impact and extrusion resistance, low temperature environment still maintain performance.
High processability: easy to cut, weld and bend, suitable for complex shape processing.
High temperature/fire resistant
Can maintain structural stability in high temperature or fire.
III. Typical Uses
Construction and bridge: such as steel structure plant, bridge body, reduce maintenance cost.
Transportation: ship structures, train cars, containers.
Energy equipment: petroleum storage tanks, chemical equipment (especially in hydrogen sulfide containing environment).
Public facilities: pylons, chimneys, harbor buildings.
IV. Precautions
Welding process: special welding consumables are required to ensure that the corrosion rate of the weld is consistent with that of the parent material.
Drainage design: Avoid water accumulation in grooves leading to localized rapid corrosion.
Surface treatment: Possible contamination of neighboring objects when used naked (rust transfer).
Summarize
S355J2WP is the "cost-effective version of stainless steel" for engineered structures with long-term outdoor exposure. It can save frequent painting and maintenance, but requires attention to environmental suitability and processing details. For seaside projects, it is recommended to use it with an anti-salt spray coating.
Translated with www.DeepL.com/Translator (free version)
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