A691 1 1/4Cr welded pipe is a chromium-molybdenum alloy steel welded steel pipe.
Key performance advantages
- High temperature performance
The chromium-molybdenum alloy system gives the material excellent creep resistance (working temperature ≤600℃);
Applicable to high-temperature and high-pressure pipelines such as supercritical boilers and hydrogenation units.
- Corrosion resistance
The chromium element forms a dense oxide film, which significantly improves the resistance to hydrogen sulfide corrosion (sulfur-containing medium conditions);
Need to pass the NACE MR0175 certification for use in sulfur-containing environments.
- Low-temperature toughness
CL22 grade guarantees -40℃ impact energy ≥60J, suitable for high-cold environments.
Application scenarios
- Energy and power: main steam pipelines of thermal power units, nuclear power auxiliary pipelines;
- Petrochemicals: hydrogenation reactor pipelines, high-temperature cracking units;
- Special environments: sulfur-containing oil and gas gathering and transportation, low-temperature and high-pressure service conditions (such as -29℃).
Selection considerations
- Grade distinction: Gr1-1/4Cr CL22 and Gr2-1/4Cr CL22 have different compositions and properties and cannot be directly replaced; Gr2-1/4Cr has a higher chromium content (about 2.25% Cr), corresponding to the seamless pipe SA-335 P22 grade.
- Process limitations: The distribution of welding residual stress is different from that of seamless pipes, and the applicability of supercritical conditions needs to be evaluated separately.
