K55 steel casing from Hebei K-Steel Pipe Industry is a widely used oilfield tubular product designed for drilling and well completion in the oil and gas industry. It is classified under the API Spec 5CT standard, which defines technical requirements for casing and tubing materials.
Yield Strength: 379–552 MPa (55–80 ksi)
Tensile Strength: ≥ 655 MPa (≥ 95 ksi)
Elongation: Typically ≥ 0.5% (depends on size and processing)
These properties make K55 suitable for wells that require moderate load-bearing capacity without extreme pressure or temperature conditions.
Chemical Composition (Typical Range)
Carbon (C): ~0.34% max
Manganese (Mn): 1.25–1.50%
Phosphorus (P): ≤ 0.030%
Sulfur (S): ≤ 0.030%
K55 casing is commonly used in:
Oil and gas well drilling
Water wells
Low-pressure formations
Surface and intermediate casing strings
It is especially suitable where corrosion resistance requirements are not severe.
Advantages
Good mechanical strength for standard wells
Cost-effective compared to higher grades (e.g., N80, L80)
Widely available and easy to source globally
Compatible with standard API connections
