API 5CT
API 5CT
API Spec 5CT, Casing and Tubing Specification, Eighth Edition, Petroleum and Natural Gas Industries- Steel pipes for use as casing or tubing for wells. This Standard includes standards for three Product Specification Levels and specifies the technical delivery conditions for steel pipes (Casing, Tubing, and Pup Joints), coupling stock, Coupling material, and accessory material (PSL-1, PSL-2, PSL-3).
The steel material used to make the pipe billet supplied must have grain refining treated, according to the API 5CT standard. This steel must contain one or more grain refining elements, such as aluminum, niobium, vanadium, or titanium, in order for the austenite grains of the steel to be refined.
OCTG PRODUCT FEATURES
Steel Grade of API 5CT Standard
- Group 1: All casing and tubing in Grades with H, J, K, N and R
- Group 2: All casing and tubing in Grades with C, L, M and T
- Group 3: All casing and tubing in Grade P
- Group 4: All casing in Grade Q
Dimensions and Sizes of API 5CT Casing and Tubing
- Specification & Size of API 5CT Tubing
DN | O. D. | Weight | W. T. | End Processing | |||||||||
Non-upset coupling-thread | Upset coupling-thread | Steel Grade | |||||||||||
in | mm | lb./ft. | lb./ft. | in | mm | H40 | J55 | L80 | N80 | C90 | T95 | P110 | |
2 3/8 | 2.375 | 60.32 | 4.00 | – | 0.167 | 4.24 | PU | PN | PN | PN | PN | PN | – |
4.60 | 4.70 | 0.190 | 4.83 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | |||
5.80 | 5.95 | 0.254 | 6.45 | – | – | PNU | PNU | PNU | PNU | PNU | |||
6.60 | – | 0.295 | 7.49 | – | – | P | – | P | P | – | |||
7.35 | 7.45 | 0.336 | 8.53 | – | – | PU | – | PU | PU | – | |||
2 7/8 | 2.875 | 73.02 | 6.40 | 6.50 | 0.217 | 5.51 | PNU | PNU | – | – | – | – | – |
7.80 | 7.90 | 0.276 | 7.01 | – | – | – | – | – | – | – | |||
8.60 | 8.70 | 0.308 | 7.82 | – | – | PLB | PLB | PLBE | – | PLB | |||
9.35 | 9.45 | 0.340 | 8.64 | – | – | PLB | PLB | PLBE | – | PLB | |||
10.50 | – | 0.392 | 9.96 | – | – | PLB | PLB | PLB | – | PLB | |||
11.50 | – | 0.440 | 11.18 | – | – | – | – | PLB | – |  | |||
3 1/2 | 3.500 | 88.90 | 7.70 | – | 0.216 | 5.49 | PN | PN | PN | PN | PN | PN | – |
9.20 | 9.30 | 0.254 | 6.45 | PNU | PNU | PNU | PNU | PNU | PNU | PNU | |||
10.20 | – | 0.289 | 7.34 | PN | PN | PN | PN | PN | PN | – | |||
12.70 | 12.95 | 0.375 | 9.52 | – | – | PNU | PNU | PNU | PNU | PNU | |||
14.30 | – | 0.430 | 10.92 | – | – | P | – | P | P | – | |||
15.50 | – | 0.476 | 12.09 | – | – | P | – | P | P | – | |||
17.00 | – | 0.530 | 13.46 | – | – | P | – | P | P | – | |||
4 | 4.000 | 101.60 | 9.50 | – | 0.226 | 5.74 | PN | PN | PN | PN | PN | PN | – |
– | 11.00 | 0.262 | 6.65 | PU | PU | PU | PU | PU | PU | – | |||
13.20 | – | 0.330 | 8.38 | – | – | P | – | P | P | – | |||
16.10 | – | 0.415 | 10.54 | – | – | P | – | P | P | – | |||
18.90 | – | 0.500 | 12.70 | – | – | P | – | P | P | – | |||
22.20 | – | 0.610 | 15.49 | – | – | P | – | P | P | – | |||
4 1/2 | 4.500 | 114.30 | 12.60 | 12.75 | 0.271 | 6.88 | PNU | PNU | PNU | PNU | PNU | PNU | – |
15.20 | – | 0.337 | 8.56 | – | – | P | – | P | P | – | |||
17.00 | – | 0.380 | 9.65 | – | – | P | – | P | P | – | |||
18.90 | – | 0.430 | 10.92 | – | – | P | – | P | P | PLB | |||
21.50 | – | 0.500 | 12.70 | – | – | P | – | P | P | PLB | |||
23.70 | – | 0.560 | 14.22 | – | – | P | – | P | P | PLB | |||
26.10 | – | 0.630 | 16.00 | – | – | P | – | P | P | PLB | |||
P——Plain；N—— Non-upset coupling-thread；U—— Upset coupling-thread； L——Integral | |||||||||||||
- Specification & Size of API 5CT Casing
DN | O. D. | Weight | W. T. | Â | End Machining Form | |||||||
| Â | Steel Grade | |||||||||||
in | mm | lb/ft | kg/m | in | mm | H40 | J55 | L80 | N80 | C90 | P110 | |
K55 | T95 | |||||||||||
4 1/2 | 4.500 | 114.3 | 9.50 | 14.14 | 0.205 | 5.21 | PS | PS | – | – | – | – |
10.50 | 15.63 | 0.224 | 5.69 | – | PSB | – | – | – | – | |||
11.60 | 17.26 | 0.250 | 6.35 | – | PSLB | PLB | PLB | PLB | PLB | |||
13.50 | 20.09 | 0.290 | 7.37 | – | – | PLB | PLB | PLB | PLB | |||
15.10 | 22.47 | 0.337 | 9.56 | – | – | – | – | – | PLB | |||
5 | 5.000 | 127 | 11.50 | 17.11 | 0.220 | 5.59 | – | PS | – | – | – | – |
13.00 | 19.35 | 0.253 | 6.43 | – | PSLB | – | – | – | – | |||
15.00 | 22.32 | 0.296 | 7.52 | – | PSLB | PLB | PLB | PLBE | PLB | |||
18.00 | 26.79 | 0.362 | 9.19 | – | – | PLB | PLB | PLBE | PLB | |||
21.40 | 31.85 | 0.437 | 11.10 | – | – | PLB | PLB | PLB | PLB | |||
23.20 | 34.53 | 0.478 | 12.14 | – | – | – | – | PLB | – | |||
24.10 | 35.86 | 0.500 | 12.70 | – | – | – | – | PLB | – | |||
5 1/2 | 5.500 | 139.7 | 14.00 | 20.83 | 0.244 | 6.20 | PS | PS | – | – | – | – |
15.50 | 23.07 | 0.275 | 6.98 | – | PSLB | – | – | – | – | |||
17.00 | 25.30 | 0.304 | 7.72 | – | PSLB | PLB | PLB | PLBE | PLB | |||
20.00 | 29.76 | 0.361 | 9.17 | – | – | PLB | PLB | PLBE | PLB | |||
23.00 | 34.23 | 0.415 | 10.54 | – | – | PLB | PLB | PLBE | PLB | |||
26.80 | 39.88 | 0.500 | 12.70 | – | – | – | – | – | – | |||
29.70 | 44.20 | 0.562 | 14.27 | – | – | – | – | – | – | |||
32.60 | 48.51 | 0.625 | 15.88 | – | – | – | – | – | – | |||
35.30 | 52.53 | 0.687 | 17.45 | – | – | – | – | – | – | |||
38.00 | 56.55 | 0.750 | 19.05 | – | – | – | – | – | – | |||
40.50 | 60.27 | 0.812 | 20.62 | – | – | – | – | – | – | |||
43.10 | 64.14 | 0.875 | 22.22 | – | – | – | – | – | – | |||
6 5/8 | 6.625 | 168.28 | 20.00 | 29.76 | 0.288 | 7.32 | PS | PSLB | – | – | – | – |
24.00 | 35.72 | 0.352 | 8.94 | – | PSLB | PLB | PLB | PLBE | PLB | |||
28.00 | 41.67 | 0.417 | 10.59 | – | – | PLB | PLB | PLBE | PLB | |||
32.00 | 47.62 | 0.475 | 12.06 | – | – | PLB | PLB | PLBE | PLB | |||
7 | 7.000 | 177.8 | 17.00 | 25.30 | 0.231 | 5.87 | PS | – | – | – | – | – |
20.00 | 29.76 | 0.272 | 6.91 | PS | PS | – | – | – | – | |||
23.00 | 34.23 | 0.317 | 8.05 | – | PSLB | PLB | PLB | PLBE | – | |||
26.00 | 38.69 | 0.362 | 9.19 | – | PSLB | PLB | PLB | PLBE | PLB | |||
29.00 | 43.16 | 0.408 | 10.36 | – | – | PLB | PLB | PLBE | PLB | |||
32.00 | 47.62 | 0.453 | 11.51 | – | – | PLB | PLB | PLBE | PLB | |||
35.00 | 52.09 | 0.498 | 12.65 | – | – | PLB | PLB | PLBE | PLB | |||
38.00 | 56.55 | 0.540 | 13.72 | – | – | PLB | PLB | PLBE | PLB | |||
42.70 | 63.54 | 0.625 | 15.88 | – | – | – | – | – | – | |||
46.40 | 69.05 | 0.687 | 17.45 | – | – | – | – | – | – | |||
50.10 | 74.56 | 0.750 | 19.05 | – | – | – | – | – | – | |||
53.60 | 79.77 | 0.812 | 20.62 | – | – | – | – | – | – | |||
57.10 | 84.97 | 0.875 | 22.22 | – | – | – | – | – | – | |||
7 5/8 | 7.625 | 193.68 | 24.00 | 35.72 | 0.300 | 7.62 | PS | – | – | – | – | – |
26.40 | 39.29 | 0.328 | 8.33 | – | PSLB | PLB | PLB | PLBE | PLB | |||
29.70 | 44.20 | 0.375 | 9.52 | – | – | PLB | PLB | PLBE | PLB | |||
33.70 | 50.15 | 0.430 | 10.92 | – | – | PLB | PLB | PLBE | PLB | |||
39.00 | 58.05 | 0.500 | 12.70 | – | – | PLB | PLB | PLBE | PLB | |||
42.80 | 63.69 | 0.562 | 14.27 | – | – | PLB | PLB | PLB | PLB | |||
45.30 | 67.41 | 0.595 | 15.11 | – | – | PLB | PLB | PLB | PLB | |||
47.10 | 70.09 | 0.625 | 15.88 | – | – | PLB | PLB | PLB | PLB | |||
51.20 | 76.19 | 0.687 | 17.45 | – | – | – | – | – | – | |||
55.30 | 80.30 | 0.750 | 19.05 | – | – | – | – | – | – | |||
8 5/8 | 8.625 | 219.08 | 24.00 | 35.72 | 0.264 | 6.71 | – | PS | – | – | – | – |
28.00 | 41.62 | 0.304 | 7.72 | PS | – | – | – | – | – | |||
32.00 | 47.62 | 0.352 | 8.94 | PS | PSLB | – | – | – | – | |||
36.00 | 53.57 | 0.400 | 10.16 | – | PSLB | PLB | PLB | PLBE | PLB | |||
40.00 | 59.53 | 0.450 | 11.43 | – | – | PLB | PLB | PLBE | PLB | |||
44.00 | 65.48 | 0.500 | 12.70 | – | – | PLB | PLB | PLBE | PLB | |||
49.00 | 72.92 | 0.557 | 14.15 | – | – | PLB | PLB | PLBE | PLB | |||
9 5/8 | 9.625 | 244.48 | 32.30 | 48.07 | 0.312 | 7.92 | PS | – | – | – | – | – |
36.00 | 53.57 | 0.352 | 8.94 | PS | PSLB | – | – | – | – | |||
40.00 | 59.53 | 0.395 | 10.03 | – | PSLB | PLB | PLB | PLBE | – | |||
43.50 | 64.73 | 0.435 | 11.05 | – | – | PLB | PLB | PLBE | PLB | |||
47.00 | 69.94 | 0.472 | 11.99 | – | – | PLB | PLB | PLBE | PLB | |||
53.50 | 79.62 | 0.545 | 13.84 | – | – | PLB | PLB | PLBE | PLB | |||
58.40 | 86.91 | 0.595 | 15.11 | – | – | PLB | PLB | PLB | PLB | |||
59.40 | 88.40 | 0.609 | 15.47 | – | – | – | – | – | – | |||
64.90 | 96.58 | 0.672 | 17.07 | – | – | – | – | – | – | |||
70.30 | 104.62 | 0.734 | 18.64 | – | – | – | – | – | – | |||
75.60 | 112.50 | 0.797 | 20.24 | – | – | – | – | – | – | |||
10 3/4 | 10.750 | 273.05 | 32.75 | 48.74 | 0.279 | 7.09 | PS | – | – | – | – | – |
40.50 | 60.27 | 0.350 | 8.89 | PS | PSB | – | – | – | – | |||
15.50 | 67.71 | 0.400 | 10.16 | – | PSB | – | – | – | – | |||
51.00 | 75.90 | 0.450 | 11.43 | – | PSB | PSB | PSB | PSBE | PSB | |||
55.50 | 82.59 | 0.495 | 12.57 | – | – | PSB | PSB | PSBE | PSB | |||
60.70 | 90.33 | 0.545 | 13.84 | – | – | – | – | PSBE | PSB | |||
65.70 | 97.77 | 0.595 | 15.11 | – | – | – | – | PSB | PSB | |||
73.20 | 108.93 | 0.672 | 17.07 | – | – | – | – | – | – | |||
79.20 | 117.86 | 0.734 | 18.64 | – | – | – | – | – | – | |||
85.30 | 126.94 | 0.797 | 20.24 | – | – | – | – | – | – | |||
11 3/4 | 11.750 |  | 42.00 | 62.50 | 0.333 | 8.46 | PS | – | – | – | – | – |
47.00 | 69.94 | 0.375 | 20.24 | – | – | – | – | – | – | |||
54.00 | 80.36 | 0.435 | 8.46 | – | – | – | – | – | – | |||
60.00 | 89.29 | 0.489 | 9.53 | – | – | – | – | – | – | |||
65.00 | 96.73 | 0.534 | 11.05 | – | – | – | – | – | – | |||
71.00 | 105.66 | 0.582 | 14.42 | – | – | – | – | – | – | |||
13 3/8 | 13.375 | 339.73 | 48.00 | 71.43 | 0.330 | 8.38 | PS | – | – | – | – | – |
54.50 | 81.10 | 0.380 | 9.65 | – | PSB | – | – | – | – | |||
61.00 | 90.78 | 0.430 | 10.92 | – | PSB | – | – | – | – | |||
68.00 | 101.19 | 0.480 | 12.19 | – | PSB | PSB | PSB | PSB | PSB | |||
72.00 | 107.15 | 0.514 | 13.06 | – | – | PSB | PSB | PSB | PSB | |||
16 | 16.000 | 406.4 | 65.00 | 96.73 | 0.375 | 9.53 | PS | – | – | – | – | – |
75.00 | 111.61 | 0.438 | 11.13 | – | PSB | – | – | – | – | |||
84.00 | 125.01 | 0.495 | 12.57 | – | PSB | – | – | – | – | |||
109.00 | 162.21 | 0.656 | 16.66 | – | P | P | P | – | P | |||
18 5/8 | 18.625 | 473.08 | 87.50 | 130.21 | 0.435 | 11.05 | PS | PSB | – | – | – | – |
20 | 20.000 | 508 | 94.00 | 139.89 | 0.438 | 11.13 | PSL | PSLB | – | – | – | – |
106.50 | 158.49 | 0.500 | 12.70 | – | PSLB | – | – | – | – | |||
133.00 | 197.93 | 0.635 | 16.13 | – | PSLB | – | – | – | – | |||
P——Plain；S——Short-thread；L——Long-thread；B——Buttress thread；E——Extreme thread | ||||||||||||
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Chemical Composition (%) of API 5CT
Chemical Composition of API 5CT，Mass Fraction（%） | |||||||||||||||
Group | Grade | Type | C | Mn | Mo | Cr | Ni | Cu | P | S | Si | ||||
min. | max. | min. | max. | min. | max. | min. | max. | max. | max. | max. | max. | max. | |||
1 | H40 | — | — | — | — | — | — | — | — | — | — | — | 0.03 | 0.030 | — |
J55 | — | — | — | — | — | — | — | — | — | — | — | 0.03 | 0.030 | — | |
K55 | — | — | — | — | — | — | — | — | — | — | — | 0.03 | 0.030 | — | |
N80 | 1.0 | — | — | — | — | — | — | — | — | — | — | 0.03 | 0.030 | — | |
N80 | Q | — | — | — | — | — | — | — | — | — | — | 0.03 | 0.030 | — | |
R95 | — | — | 0.45 | — | 1.90 | — | — | — | — | — | — | 0.03 | 0.030 | 0.45 | |
2 | M65 | — | — | — | — | — | — | — | — | — | — | — | 0.03 | 0.030 | — |
L80 | 1 | — | 0.43 | — | 1.9 | — | — | — | — | 0.25 | 0.35 | 0.03 | 0.030 | 0.45 | |
L80 | 9Cr | — | 0.15 | 0.30 | 0.60 | 0.90 | 1.10 | 8.00 | 10.00 | 0.50 | 0.25 | 0.02 | 0.010 | 1.00 | |
L81 | 13Cr | 0.15 | 0.22 | 0.25 | 1.00 | — | — | 12.00 | 14.00 | 0.50 | 0.25 | 0.02 | 0.010 | 1.00 | |
C90 | 1.0 | — | 0.35 | — | 1.20 | 0.25 | 0.85 | — | 1.50 | 0.99 | — | 0.02 | 0.010 | — | |
T95 | 1.0 | — | 0.35 | — | 1.20 | 0.25 | 0.85 | 0.40 | 1.50 | 0.99 | — | 0.02 | 0.010 | — | |
C110 | — | — | 0.35 | — | 1.20 | 0.25 | 1.00 | 0.40 | 1.50 | 0.99 | — | 0.02 | 0.005 | — | |
3 | P110 | — | — | — | — | — | — | — | — | — | — | — | 0.03 | 0.030 | — |
4 | Q125 | 1.00 | — | 0.35 | — | 1.35 | — | 0.85 | — | 1.50 | 0.99 | — | 0.02 | 0.01 | — |
a. The carbon content for L80 may be increased up to 0, 50 % maximum if the product is oil-quenched. b. The molybdenum content for Grade C90 Type 1 has no minimum tolerance if the WT is less than 17, 78 mm. c. The carbon content for R95 may be increased up to 0, 55 % maximum if the product is oil-quenched. d. The molybdenum content for T95 Type 1 may be decreased to 0, 15 % minimum if the WT is less than 17, 78 mm. e. For EW Grade P110, the phosphorus content shall be 0,020 % maximum and the sulfur content 0,010 % maximum NL = no limit. Elements shown shall be reported in product analysis. | |||||||||||||||
Mechanical Properties of API 5CT
Mechanical Properties | ||||||||
Group | Grade | Type | Total | Yield Strength (Mpa) | Tensile | Hardness max | ||
% | min. | max. | MPa | HRC | HBW | |||
1 | H40 | — | 0.5 | 276 | 552 | 414 | — | — |
J55 | — | 0.5 | 379 | 552 | 517 | — | — | |
K55 | — | 0.5 | 379 | 552 | 655 | — | — | |
N80 | 1.0 | 0.5 | 552 | 758 | 689 | — | — | |
N80 | Q | 0.5 | 552 | 758 | 689 | — | — | |
R95 | — | 0.5 | 655 | 758 | 724 | — | — | |
2 | M65 | — | 0.5 | 445 | 586 | 586 | 22 | 235 |
L80 | 1 | 0.5 | 552 | 655 | 655 | 23 | 241 | |
L80 | 9Cr | 0.5 | 552 | 655 | 655 | 23 | 241 | |
L81 | 13Cr | 0.5 | 552 | 655 | 655 | 23 | 241 | |
C90 | 1.0 | 0.5 | 621 | 724 | 689 | 25.4 | 255 | |
T95 | 1.0 | 0.5 | 655 | 758 | 724 | 25.4 | 255 | |
C110 | — | 0.7 | 758 | 828 | 793 | 30 | 286 | |
3 | P110 | — | 0.6 | 758 | 965 | 862 | — | — |
4 | Q125 | 1.00 | 0.65 | 862 | 1034 | 931.00 | — | — |
a. In case of dispute, laboratory Rockwell C hardness testing shall be used as the referee method. b. No hardness limits, but the maximum variation is controlled by manufacturer acc API 5CT. | ||||||||
API 5CT Dimensional Deviation
Items | Allowable Deviation | |
Out Diameter | D ≤ 101.60mm | ± 0.79mm |
D ≥ 114.30mm | + 1.0%, -0.5% | |
Wall Thickness | -12.5% | |
Mass (Single Lengths) | +6.5%, -3.5% | |
Length Range of API 5CT
Length | |||
Item | Scope 1 | Scope 2 | Scope 3 |
Tubing | 6.10-7.32m | 8.53-9.75m | – |
Casing | 4.88-7.62m | 7.62-10.36m | 10.36-14.63m |
API 5CT Pipe Ending Processing
- Flat End / Plain End
A flat end / plain end pipe is a pipe that has unmachined threads. It may or may not upset, but it must fulfill all of the specifications for a certain steel grade in this standard.
- Threaded End
Casings with short or long threads are available in steel grades H40, J55, K55, or M65. If the buyer wants a long-threaded case, he or she should specify it on the order.
- Rounded Nose
To replace the conventional corner breaks on the threaded ends of external upset tubing, the manufacturer or purchaser may specify a “round” or “bullet-nose” style pipe end. To enable coating application and to ensure that the inner and outer surfaces are smooth and free of sharp edges or burrs, the modified end should be rounded.
