1. Product Parameters
Chemical Composition (wt.%):
Carbon (C): 0.17–0.23
Manganese (Mn): 0.70–1.00 (key element for strength)
Silicon (Si): 0.17–0.37
Phosphorus (P): ≤0.025, Sulfur (S): ≤0.015
Minor Alloys: Cr, Ni, Mo ≤0.25 each13.
Mechanical Properties:
Tensile Strength: ≥450 MPa
Yield Strength: ≥275 MPa
Elongation: ≥24%, Hardness: ≤197 HB (annealed)
Standards: GB/T 5310-2017 (China), compatible with ASME SA21034.
2. Key Applications
Power Plants: Boiler tubes (superheaters, reheaters) for steam pipelines (≤580℃)
Petrochemicals: High-pressure pipelines for oil/gas transport
Mechanical Components: Shafts, gears, and high-stress fasteners
3. Advantages
High-Temperature Resistance: Excellent creep resistance under 580℃.
Processability: Good weldability and machinability with balanced ductility
Cost-Effective: Lower alloy content than Cr-Mo steels, reducing material costs
4. Supplementary Information
Heat Treatment: Normalizing (910℃ air-cooled) for optimal grain refinement
Alternatives: For higher temperatures, consider 12CrMoG or T91 alloys
Note: 20MnG is ideal for moderate-high pressure/ temperature systems, balancing performance and cost. For corrosive environments (e.g., H₂S), specialized alloys like Alloy20 may be required
