1. Basic Definition and Standards
12CrMoG is a chromium-molybdenum alloy boiler tube specified in the GB/T 5310 standard. "12" represents a carbon content of 0.08-0.15%, "CrMo" refers to a chromium content of 0.90-1.20% and a molybdenum content of 0.25-0.35%, and "G" designates it as boiler-grade. Compared to ordinary chromium-molybdenum steel, its sulfur and phosphorus contents are more strictly controlled (both ≤ 0.025%) and are specifically designed for the manufacture of high-temperature components in power plant boilers.
2. Core Performance Advantages
Heat Resistance: Can operate at 560°C for long periods and 600°C for short periods.
Strength: Room temperature tensile strength ≥410 MPa, 550°C high-temperature strength ≥200 MPa.
Oxidation Resistance: Chromium forms a dense oxide film, offering superior steam corrosion resistance to carbon steel.
Processability: Requires preheating to 200-250°C for welding, followed by post-weld tempering at 680-720°C.
3. Typical Applications
Main Applications:
Subcritical power plant boiler superheater tubes
Oil cracking unit furnace tubes
High-temperature and high-pressure chemical piping systems
Critical pressure-bearing components subject to cyclical heat loads.
4. Comparison with Similar Materials
Compared to 15CrMoG:
Reduced chromium content (12CrMoG: 0.9-1.2% vs. 15CrMoG: 1.2-1.6%)
Approximately 8-12% cost reduction
Approximately 20-30°C lower operating temperature Compared to T12 steel:
The addition of molybdenum improves high-temperature strength.
Impact toughness is increased by over 15%.
5. Key Points for Procurement and Acceptance
Qualification Documents: A material certificate including an intergranular corrosion test report is required.
Testing Requirements: 100% ultrasonic testing + 10% eddy current testing.
Surface Quality: No scratches exceeding 0.1mm deep on the inner and outer surfaces.
