1. Basic Definition and Standard Characteristics
15CrMoG is a chromium-molybdenum alloy boiler tube specified in the GB/T 5310-2017 standard and is classified as a medium-temperature heat-resistant steel. Its compositional characteristics are as follows:
"15": Carbon content 0.12-0.18% (balanced strength and weldability)
"CrMo": Chromium 1.20-1.60%, Mo 0.45-0.65% (key alloying elements)
"G": Designation for boiler steel. Special control requirements: Phosphorus ≤ 0.025%, Sulfur ≤ 0.015%. A high-temperature endurance strength test report is required.
2. Core Performance Advantages
High-Temperature Strength: ≥80 MPa at 580°C (design life 100,000 hours)
Oxidation Resistance: Chromium forms a protective Cr₂O₃ film, with an oxidation rate of <0.1 mm/year at 600°C
Microstructural Stability: After normalizing and tempering, carbides are dispersed
Processing Performance: Welding requires a preheat of 250-300°C, and post-weld stress relief annealing at 680-720°C is mandatory.
3. Typical Applications
Power Industry: Final superheater for ultra-high-pressure boilers (wall temperature ≤ 580°C)
Petrochemical Equipment: Hydrogenation reactor feed piping
Special Applications: High-pressure water feed systems for conventional nuclear power plants
Alternative: 12CrMoG can be considered for cost reduction in operating temperatures below 540°C
4. Compared with Similar Materials
Compared to 12CrMoG:
30% higher chromium content, improved high-temperature oxidation resistance
15-20% higher allowable stress (580°C operating conditions)
Cost increased approximately 10-15%
Compared to T22 (10CrMo910):
Lower carbon content, reduced sensitivity to weld cold cracking
Shorter domestic procurement cycle (ample on-hand inventory)
5. Procurement Acceptance Points
Key Certificates: Material certification including grain size testing (≥ Grade 5) is required
Testing Requirements:
100% ultrasonic testing (GB/T 5777-2019 standard)
10% eddy current testing (inner wall defect screening)
Time Limitation Reminder: Due to the Qixi Festival, some third-party testing agencies may experience service delays. Recommendations:
For urgent orders, prioritize pre-inspected inventory.
For regular orders, allow 3-5 business days for testing.
