API casing pipe is produced according to the API 5CT standard. It is most often used in underground construction projects to encase or protect utility lines from being damaged.
Specifications:
Standard: API 5CT.
seamless steel casing and tubing pipes: 114.3-406.4mm
welded steel casing and tubing pipes: 88.9-660.4mm
Outer Dimensions: 6.0mm-219.0mm
Wall Thickness: 1.0mm-30 mm
Length: max 12m
Material: J55, K55, N80-1, N80-Q, L80-1, P110, etc.
Thread connection: STC, LTC, BTC, XC and Premium connection
It is widely used in the cementing projects to serve as the structural retainer for the wall of oil and gas wells or wellbore. It is inserted into a well bore and cemented in place to protect both subsurface formations and the wellbore from collapsing and allow drilling fluid to circulate and extraction to take place.
The main steel grade of API 5CT: API 5CT J55, API 5CT K55, API 5CT N80, API 5CT L80, API 5CT P110.
This International Standard is applicable to the following connections in accordance with ISO 10422 or API Spec 5B:
short round thread casing (STC);
long round thread casing (LC);
buttress thread casing (BC);
extreme-line casing (XC);
non-upset tubing (NU);
external upset tubing (EU);
integral joint tubing (IJ).
For such connections, this International Standard specifies the technical delivery conditions for couplings and thread protection.For pipes covered by this International Standard, the sizes, masses, wall thicknesses, grades and applicable end finishes are defined.This International Standard may also be applied to tubulars with connections not covered by ISO/API standards.
Chemical Composition
| Grade | C≤ | Si≤ | Mn≤ | P≤ | S≤ | Cr≤ | Ni≤ | Cu≤ | Mo≤ | V≤ | Als≤ |
| API 5CT J55 | 0.34-0.39 |
0.20-0.35 |
1.25-1.50 |
0.020 |
0.015 |
0.15 |
0.20 |
0.20 |
/ |
/ |
0.020 |
| API 5CT K55 | 0.34-0.39 |
0.20-0.35 |
1.25-1.50 |
0.020 |
0.015 |
0.15 |
0.20 |
0.20 |
/ |
/ |
0.020 |
| API 5CT N80 | 0.34-0.38 |
0.20-0.35 |
1.45-1.70 |
0.020 |
0.015 |
0.15 |
/ |
/ |
/ |
0.11-0.16 |
0.020 |
| API 5CT L80 | 0.15-0.22 |
1.00 |
0.25-1.00 |
0.020 |
0.010 |
12.0-14.0 |
0.20 |
0.20 |
/ |
/ |
0.020 |
| API 5CT J P110 | 0.26-035 |
0.17-0.37 |
0.40-0.70 |
0.020 |
0.010 |
0.80-1.10 |
0.20 |
0.20 |
0.15-0.25 |
0.08 |
0.020 |
Mechanical Properties
|
Steel Grade |
Yield Strength (Mpa) |
Tensile Strength (Mpa) |
|
API 5CT J55 |
379-552 |
≥517 |
|
API 5CT K55 |
≥655 |
≥517 |
|
API 5CT N80 |
552-758 |
≥689 |
|
API 5CT L80 |
552-655 |
≥655 |
|
API 5CT P110 |
758-965 |
≥862 |
