Products Description
API 5CT is an international standard established by the American Petroleum Institute (API) for casing and tubing used in oil and gas drilling, with the latest edition being API 5CT 10th Edition (2022). Its key requirements include:
Material Grades:
Classified into H40, J55, K55, N80, L80, C90, T95, P110, etc., with each grade corresponding to different yield strengths (e.g., J55: 55–80 ksi, P110: ≥110 ksi).
Dimensions & Specifications:
OD range: 4.5 inches to 20 inches
Wall thickness: 2.5 mm to 25 mm
Threading: must comply with API SPEC 5B standards.
Testing Requirements:
Hydrostatic testing (pressure ≥ 80% of the minimum yield strength of the steel pipe)
NDT (Non-Destructive Testing) (ultrasonic or eddy current inspection)
Chemical composition analysis
Process
1. Raw Material Preparation
Material selection: Continuous-cast round billets or hot-rolled steel billets are used, typically made of carbon steel or alloy steel (e.g., 37Mn5). API 5CT specifies that J55-grade casing must have a carbon content ≤0.34%, while N80-grade requires alloying elements such as chromium and molybdenum.
Billet dimensions: Usually 180–350 mm in diameter, with spectroscopic analysis to ensure sulfur and phosphorus content ≤0.025% (per GB/T 222).
2. Hot Rolling Forming
Heating: Billets are heated to 1,200–1,280°C in a furnace (excessive temperatures may cause coarse grain growth), then pierced into hollow tube blanks using a piercing mill.
Continuous rolling: The tube blank is elongated to target OD (e.g., Φ139.7 mm casing with 6.2–12.7 mm wall thickness) at a rolling speed of 0.8–1.5 m/s.
3. Cold Working & Heat Treatment
Cold rolling: Performed using two- or three-roll mills, with ** deformation controlled at 30–50%** for higher precision (wall thickness tolerance ±10%).
Heat treatment:
J55: Normalizing (900°C ±20°C, held for 30 min).
N80: Quenching & tempering to achieve hardness of HRC 22–32.
Products Specification
Application: Oil well casing serves as well sidewall
Pipe Standard: API SPEC 5CT
Size:OD:114.3-508mm,WT:5.21-16.13mm
Process Type: Seamless (SMLS), Electric Resistance Welded (ERW)
Grade: J55, K55, N80-1, N80-Q, L80-1, L80-9Cr, L80-13Cr,C95, P110.
Thread types: STC,LTC,BTC etc.
Dimension Tolerances
Tensile and Hardness Requirements
Products Packaging
1. Protective Materials
Inner packaging: VCI (Vapor Corrosion Inhibitor) film is used, providing 12 months of rust protection (per API 5CT Appendix H).
Outer packaging: Multi-layer kraft paper or polyethylene wrapping film, with waterproof rating IPX4 (splash-resistant).
2. Bundling Specifications
Bundling requirements:
- ≤3 tons per casing: ≥2 straps per piece.
- >3 tons: 1 additional strap per meter (per GB/T 19830-2017).
Steel strap requirements:
- Tensile strength ≥800 MPa.
- Width ≥32 mm.
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