Material properties
Mechanical properties: yield strength ≥355 MPa (thickness ≤16mm), tensile strength 470-630 MPa, elongation ≥22%, -20℃ impact energy ≥27J.
Chemical composition: C≤0.22%, Si≤0.55%, Mn≤1.60%, P/S≤0.035%, containing trace amounts of alloying elements such as Nb, V, Ti to improve strength.
Delivery status: usually normalized (+N mark), refines grains and improves welding performance.
Application areas
Mainly used for bridges, heavy steel structures, non-pressure-bearing parts of pressure vessels, etc.
Compared with Q345D, its standardized production control is better; better low-temperature toughness than S355J0.
National standard correspondence
Equivalent to national standard Q355ND (formerly Q345D), but there are differences in chemical composition and impact test standards.
In-depth analysis of S355J2 market (2025)
Supply and demand status
Demand side: It will still be the main material for medium and large steel structures in 2025, especially the demand for load-bearing structures in the temperature zone above -20℃ is stable.
Supply side: Domestic steel mills such as Wugang and Nangang can produce in batches, and adjustments to export tariff policies (such as during the Trump era) may affect the international market share.
Price trend
In the long run, low-carbon steel technology upgrades and new energy infrastructure demand may drive prices to rise steadily.
Competitive landscape
The international market faces competition from European local brands, but Chinese products have advantages in cost-effectiveness and customized services.
Key points of S355J2+N steel plate cutting process
Cutting method selection Thick plate (＞30mm): Flame cutting or plasma cutting 410 is recommended. Thin plate (≤20mm): Laser cutting is preferred to ensure accuracy.
Key parameter control
- Preheating: Plates with a thickness of ≥30mm need to be preheated to 80-120℃ to avoid cold cracks.
- Speed and depth: The cutting speed must match the plate thickness (e.g., plasma cutting speed is about 1-3m/min), and the depth should not exceed 2 times the plate thickness.
Post-weld treatment
- Dehydrogenation treatment: 250-350℃ insulation to reduce the risk of hydrogen-induced cracks.
- Surface treatment: Grind the burrs on the cut surface and spray an anti-corrosion coating if necessary.
Equipment and safety
When using low-hydrogen electrodes (e.g., E5015), operators must wear protective equipment
