1. Key Advantages of TB/T 1979 Weather Resistant Steel
Superior atmospheric corrosion resistance (2–8 times better than standard carbon steel)
Reduced or eliminated need for painting, lowering maintenance costs
Good weldability and formability for easy fabrication
High strength-to-weight ratio, suitable for load-bearing structures
2. Material Grades & Chemical Composition
Main Grades under TB/T 1979:
Q355NHA (equivalent to ASTM A588 Grade A)
Q355NHB (equivalent to ASTM A588 Grade B)
Typical Chemical Composition (wt%):
| Element | C | Si | Mn | P | S | Cu | Cr | Ni |
|---|---|---|---|---|---|---|---|---|
| Range | ≤0.12 | 0.25–0.75 | 0.20–0.50 | ≤0.035 | ≤0.035 | 0.25–0.55 | 0.40–0.80 | ≤0.65 |
Key Features:
Copper (Cu), Chromium (Cr), and Nickel (Ni) enhance rust resistance by forming a protective oxide layer.
Low carbon (C) and sulfur (S) improve weldability and toughness.
3. Mechanical Properties
| Property | Q355NHA | Q355NHB |
|---|---|---|
| Yield Strength (MPa) | ≥355 | ≥355 |
| Tensile Strength (MPa) | 470–630 | 470–630 |
| Elongation (%) | ≥22 | ≥22 |
| Impact Toughness (-40°C, J) | ≥34 | ≥34 |
4. Comparison with International Standards
| Standard | Equivalent Grades | Key Differences |
|---|---|---|
| ASTM A588 | A588 Grade A/B | Similar corrosion resistance, slightly different alloy ranges |
| EN 10025-5 | S355J0W, S355J2W | Europe's weathering steel standard |
| JIS G3114 | SMA490AW, SMA570W | Japanese industrial standard |
5. Typical Applications
Railway rolling stock (freight cars, passenger coaches)
Bridges & highway structures (girders, guardrails)
Transmission towers & construction equipment
Shipping containers & offshore platforms
6. Why Choose TB/T 1979 Weather Resistant Steel?
✔ Long-term durability – Resists rust in humid, salty, or polluted air.
✔ Cost-effective – Eliminates frequent repainting.
✔ Eco-friendly – Reduces VOC emissions from paint.
✔ Widely certified – Complies with ISO, ASTM, and EN standards.
For specific project requirements (thickness, dimensions, testing), consult steel suppliers with TB/T 1979 certification.
