API 5CT is a specification for casing and tubing for petroleum and natural gas industries-used for wells. This Standard specifies the technical delivery conditions for steel pipes (casing, tubing and pup joints), coupling stock, coupling material and accessory material and establishes requirements for three Product Specification Levels (PSL-1, PSL-2, PSL-3). Grade K55 Casing Tubing is an API 5CT oil casing pipe and mostly utilized for oil well with varied end connections such as non-upset ends or an external upset end.
The API J55 casing and tubing have wide applications used in the shallow wells, geothermal wells, and water wells in the oil and natural gas fields. WLD steel is a leading API 5CT casing and tubing manufacturer and supplier, we provide not only a broad range of API 5CT K55 oilfield casing and API 5CT K55 tubing but also casing coupling, perforated pipe and more.
API 5CT K55 Chemical Composition
Grade |
C≤ |
Si≤ |
Mn≤ |
P≤ |
S≤ |
Cr≤ |
Ni≤ |
Cu≤ |
Mo≤ |
V≤ |
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 |
/ |
/ |
API 5CT K55 Mechanical Property
Steel Grade |
Yield Strength (Mpa) |
Tensile Strength (Mpa) |
Total elongation under load % |
API 5CT K55 |
379-552 |
≥655 |
0.5 |
API 5CT K55 Tolerance
Item |
Allowable tolerance |
Outer diameter |
Pipe body |
D≤101.60mm±0.79mm |
D≥114.30mm+1.0% |
-0.5% |
API 5CT K55 Size Chart
Outer Diameter |
Wall Thickness |
Weight |
Grade |
Threaded |
Length |
in |
mm |
kg/m |
lb/ft |
4 1/2″ |
114.3 |
14.14-22.47 |
9.50-11.50 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
5″ |
127 |
17.11-35.86 |
11.50-24.10 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
5 1/2″ |
139.7 |
20.83-34.23 |
14.00-23.00 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
6 5/8″ |
168.28 |
29.76-35.72 |
20.00-24.00 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
7″ |
177.8 |
25.30-56.55 |
17.00-38.00 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
7 5/8″ |
193.68 |
35.72-63.69 |
24.00-42.80 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
8 5/8″ |
219.08 |
35.72-72.92 |
24.00-49.00 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
9 5/8″ |
244.48 |
48.07-86.91 |
32.30-58.40 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
10 3/4″ |
273.05 |
48.73-97.77 |
32.75-65.70 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
11 3/4″ |
298.45 |
62.50-89.29 |
42.00-60.00 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |
13 3/8″ |
339.72 |
71.43-107.15 |
48.00-72.00 |
K55 |
LTC/STC/BTC |
R1/R2/R3 |