1. Material Composition (Key Alloying Elements)
| C | <=0.12% (low carbon for weldability) | |
| 0.25–0.55% (forms protective patina) | ||
| P | <=0.070% (enhances rust layer stability) | |
| 0.30–1.25% | ||
| <=0.65% (improves low-temperature performance) | ||
| 0.20–0.50% each |
(Exact ranges may vary by manufacturer; consult mill certificates.)
2. Mechanical Properties
| Yield Strength (Rp0.2) | >=345 MPa | Comparable to GB/T 4171 |
| 470–630 MPa | (Similar to 09CuPCrNi-A) | |
| >=22% | ||
| >=27 J (-20℃) |
3. Key Advantages
:
Forms a dense, self-healing rust layer (patina) in 6–18 months, ideal for:
(freight wagons, bridges).
(resists salt spray, SO₂).
:
Low carbon and controlled phosphorus reduce cracking risks.
:
Eliminates painting needs, reducing lifecycle costs.
4. Applications
: Bogies, underframes (TBT 1979 is likely a railway-specific standard).
: Highway guardrails, transmission towers.
: Rust-colored façades (aesthetic + functional).
5. Comparison to Other Grades
| TBT 1979 | |||
| 09CuPCrNi-A | GB/T 4171 | ||
| ASTM A588 |
