1. Product Parameters
API K55 is a carbon steel casing pipe under API SPEC 5CT standard, widely used in oil and gas drilling. Key technical parameters include:
| Parameter | Value/Description |
|---|---|
| Material Grade | K55 (Carbon steel) |
| Yield Strength | ≥379 MPa (55 ksi) |
| Tensile Strength | ≥655 MPa (95 ksi) |
| Chemical Composition | C ≤0.45%, Mn ≤1.20%, P ≤0.030%, S ≤0.030% |
| Outer Diameter | 139.7–244.5 mm (5.5–9.6 inches) |
| Wall Thickness | 7.72–11.05 mm (0.3–0.43 inches) |
| Length | R-1 (4.88–7.62 m), R-2 (7.62–10.36 m), R-3 (>10.36 m) |
| Thread Type | BTC (Short Round Thread), LTC (Long Thread) |
| Standards | API SPEC 5CT, SY/T6194-96 (China) |
2. Applications
Oil & Gas Wells: Supports wellbore integrity during drilling and production.
Geothermal Wells: Used in high-temperature geothermal projects.
Water Wells: Prevents collapse in hydrogeological exploration.
3. Advantages
Higher Tensile Strength: Compared to J55, K55 offers superior tensile strength (≥655 MPa vs. 552 MPa), making it suitable for deeper wells.
Corrosion Resistance: Suitable for non-sour environments (H₂S-resistant grades like L80 are preferred for corrosive conditions).
Cost-Effective: Lower cost compared to high-grade steels (e.g., P110).
Standardized: Complies with global API standards, ensuring interchangeability.
4. Comparison with J55
| Parameter | K55 (API 5CT) | J55 (API 5CT) |
|---|---|---|
| Yield Strength | ≥379 MPa (55 ksi) | ≥379 MPa (55 ksi) |
| Tensile Strength | ≥655 MPa (95 ksi) | ≥552 MPa (80 ksi) |
| Elongation | Slightly lower | Slightly higher |
| Impact Test | Meets API 5CT | Meets API 5CT |
For detailed mechanical testing (e.g., flattening, hydrostatic pressure), refer to API SPEC 5CT
