A691 Gr2-1/4Cr CL22 alloy pipe is a chromium-molybdenum alloy steel welded steel pipe specially designed for high temperature and high pressure conditions. Its core material properties are as follows:
Mechanical properties
Tensile strength: 515–690 MPa
Yield strength: ≥310 MPa
Elongation: ≥20%
Heat treatment state: Normalizing + tempering (CL22 grade)
Core characteristics
- High temperature performance
The chromium-molybdenum alloy system gives excellent creep resistance (applicable temperature ≤600℃), specially designed for supercritical boilers and power equipment pipelines.
- Corrosion resistance
The chromium element forms a dense oxide film, which significantly improves the resistance to hydrogen sulfide corrosion.
- Process guarantee
The EFW process is adopted to force double-sided penetration of the weld;
100% weld non-destructive testing (RT/UT) ensures no defects
Material Equivalence and Differences
| Terms | A691 Gr2-1/4Cr CL22(welded pipe) | SA-335 P22(seamless pipe) |
|---|---|---|
| Element | 2.25% Cr + 1.0% Mo | same element |
| Production process | Welding Forming | Hot rolled/cold drawn seamless |
| Applications | Electric power, petrochemical high temperature and high pressure pipelines | Seamless pipes of the same grade |
Typical applications
- Power industry: main steam pipelines of supercritical thermal power units, boiler heating surface pipes;
- Petrochemical industry: hydrogenation reactor outlet pipelines, high-temperature cracking units;
- Quality control: must comply with ASME SA691 standards, and additional NACE MR0175 certification is required for sulfur-containing environments.
