What material is 1.4903 steel pipe
Jul 04, 2025
1.4903 steel pipe is an alloy steel pipe made of martensitic heat-resistant steel, with excellent high-temperature strength and creep resistance. Its main characteristics and composition are as follows:
1. Material type and grade
Matrix structure: martensitic structure, strengthened by quenching + tempering (Q&T) process
European standard grade: X10CrMoVNb9-1 (digital code 1.4903);
American standard corresponding: SA387 Gr.91 Cl.2 (P91)
2. Chemical composition (%)
| Element | Content | Functions |
|---|---|---|
| C | 0.08–0.12 | Balanced strength and weldability |
| Cr | 8.00–9.50 | Improve oxidation resistance and corrosion resistance |
| Mo | 0.85–1.05 | Enhanced high temperature creep resistance |
| V | 0.18–0.25 | Refine grains and inhibit high temperature softening |
| Nb | 0.06–0.10 | Formation of carbonitride strengthening phase |
| Si | ≤0.50 | Deoxidizer, improve fluidity |
| Mn | 0.30–0.60 | Improve hardenability |
| S/P | ≤0.010/0.020 | Strictly control impurities to prevent embrittlement |
3. Key performance characteristics
High temperature performance:
Long-term use temperature reaches 600–620℃, and the upper limit of instantaneous heat resistance is 650℃;
The creep strength is significantly better than ordinary chromium-molybdenum steel (such as P22).
Mechanical properties:
Tensile strength ≥585 MPa, yield strength ≥415 MPa (room temperature);
Elongation ≥18%, excellent impact toughness.
4. Typical application areas
Power station equipment: high-temperature pipelines (main steam pipes, headers) of supercritical/ultra-supercritical boilers;
Petrochemical equipment: hydrogenation reactor outlet pipelines, cracking furnace tubes;
Nuclear power system: radiation-resistant support components and connecting pipes.
