1. What is ASTM A671 CB60 Class 22 steel pipe?
A high-performance carbon-manganese EFW pipe designed for high-pressure and low-temperature service, compliant with ASTM A671-25.
CB60: Carbon-manganese steel (0.25% max C, 1.20% Mn) with Charpy impact testing at -20°F/-29°C.
Class 22: Minimum yield strength of 22 ksi (152 MPa), ideal for demanding industrial and energy applications.
2. Key Applications in Late 2025?
Energy Sector: High-pressure steam lines (up to 800 psi), geothermal energy systems.
Oil & Gas: Flowlines and gathering lines in non-sour environments (per NACE MR0175-2025).
Hydrogen Infrastructure: Piping for blue hydrogen transport (blends <25% H₂).
3. Technical Comparison to Class 21 or Other Grades?
Strength: 4.8% higher yield strength than Class 21 (22 vs. 21 ksi), allowing thinner walls for equivalent pressure ratings.
Fabrication: Mandatory PWHT (Post-Weld Heat Treatment) for all thicknesses >0.375 in (9.5 mm) to ensure weld integrity.
Cost: 7–10% premium over Class 21 (2025 Q4 avg: 2,000–2,000–2,400/ton).
4. 2025 Testing & Compliance Updates
NDT: 100% radiography or phased-array UT for all welds (ASME B31.3-2025).
Traceability: Digital MTRs with blockchain-secured data (ISO 10474:2025 Level 4).
Sustainability: Eligible for US IRA tax credits if used in renewable energy or CCS projects.
5. Procurement & Global Standards
Primary Standard: ASTM A671-25 (Section 11 for Class 22 specifics).
Alternatives:
EN 10217-1 P355TR2 (EU, with stricter impact testing).
GB/T 5310-2025 20MnG (China, requires additional validation).
