The American Petroleum Institute specification API 5CT J55 Pipe is designed for use in the oil and gas industry. API 5CT J55 is a commonly used petroleum casing pipe material. It is produced according to the API 5CT standard and used in a variety of well types, both oil and natural gas. The main purposes of using casing or tubing are to protect the wellbore from collapse and to provide a conduit for well fluids. The casing is placed in the well first, followed by tubing, which is often smaller in diameter and thus can be nested inside the casing. Both casing and tubing must be made from strong materials that can withstand the high pressures and temperatures encountered deep underground. API 5CT J55 meets these requirements and is, therefore, an excellent choice for OCTG (oil country tubular goods) applications. It is typically produced as seamless steel pipe, but can also be procured in welded form. API 5CT J55 has a relatively high yield strength and good fatigue resistance, making it an ideal choice for high-pressure, high-load applications such as petroleum products. Thanks to its versatility and affordability, API 5CT J55 is one of the most popular steel grades used in OCTG applications today.

Why choose tuspipe?


Since 1998, Tianjin United Steel Pipe Co., Ltd (TUSPIPE) has been committed to supplying high-quality line pipes.

With over 500,000 tons annual production capacity, the company serves various fields and industries, such as oil & gas exploitation and transmission, ship & auto-building, water & electricity, environmental protection, mechanical engineering, infrastructure construction and etc.

TUSPIPE places a premium on product quality and rigorous product quality control. In order to maintain good product quality,  the company has established a Test & Inspection Center since 2004. With a series of state-of-the-art tests and inspection equipment, the test & inspection center is able to perform the tensile tests, hydro tests, impact tests, DWTT, etc.

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The applications of API 5CT J55 casing and tubing

API 5CT J55 casing and tubing are used in a variety of well applications for the petroleum industry. The J55 casing pipe is a relatively common one in oil and gas drilling. Its relatively affordable price point and its ability to protect the well make it a popular choice among well operators. The J55 tubing is similarly well suited for petroleum operations. Its steel makeup gives it greater strength and durability than some of the other options on the market, making it ideal for high-pressure applications. When used together, API 5CT J55 casing and tubing provide an economical and reliable solution for well operators.

Chemical Composition of API 5CT J55

Grade Type C Mn Mo Cr Ni max. Cu max. P max. S max. Si max.
min. max. min. max. min. max. min. max.
J55 0.03 0.03

Mechanical Analysis of API 5CT J55

API 5CT Casing Pipe Standard API 5CT Casing Pipe Type API 5CT Casing Pipe Tensile Strength API 5CT Casing Pipe Yield Strength API 5CT Casing Pipe Hardness
MPa MPa Max.
API SPEC 5CT J55 ≥517 379 ~ 552 —-

API 5CT J55 Casing & Tubing Specifications

- Specification & Size of API 5CT J55 Casing and Tubing

Code a Outer Diameter Nominal Weight Wall Thickness End Processing Type
(with thread and coupling) b, c
mm kg/m mm J55
Inch Lb/ft K55
1 2 3 4 5 7
9 5/8 32.3 244.48 48.07 7.92
9 5/8 36 244.48 53.57 8.94 SLB
9 5/8 40 244.48 59.53 10.03 SLB
9 5/8 43.5 244.48 64.73 11.05
9 5/8 47 244.48 69.94 11.99
9 5/8 53.5 244.48 79.62 13.84
9 5/8 58.4 244.48 86.91 15.11
10 3/4 32.75 273.05 48.74 7.09
10 3/4 40.5 273.05 60.27 8.89 SB
10 3/4 45.5 273.05 67.71 10.16 SB
10 3/4 51 273.05 75.9 11.43 SB
10 3/4 55.5 273.05 82.59 12.57
10 3/4 60.7 273.05 90.33 13.84
10 3/4 65.7 273.05 97.77 15.11
11 3/4 42 298.45 62.5 8.46
11 3/4 47 298.45 69.94 9.53 SB
11 3/4 54 298.45 80.36 11.05 SB
11 3/4 60 298.45 89.29 12.42 SB
13 3/8 48 339.72 71.43 8.38
13 3/8
54.5 339.72 81.1 9.65 SB
13 3/8 61 339.72 90.78 10.92 SB
13 3/8 68 339.72 101.19 12.19 SB
13 3/8 72 339.72 107.15 13.06
16 65 406.4 96.73 9.53
16 75 406.4 111.61 11.13 SB
16 84 406.4 125.01 12.57 SB
18 5/8 87.5 473.08 130.21 11.05 SB
20 94 508 139.89 11.13 SLB
20 106.5 508 158.49 12.7 SLB
20 133 508 197.93 16.13 SLB
S-Short round thread, L-Long round thread, B-Buttress thread
a. Code is used for ordering reference.
b. The nominal weight of threaded and coupled casing (column 2) is shown for reference only.

Test and inspection of API 5ct j55 pipes

- Hydrostatic Test

Hydrostatic testing is a necessary step in the pipeline production process. It is used to test the water-tightness of weld seams and the pipe body itself. The test is conducted by filling the pipe with water and applying pressure. If there are any leaks, they will be revealed by this process. Hydrostatic testing is an important quality control measure that helps to ensure the safety and integrity of pipelines.

- Bend Test

The bend test is a critical quality assurance test for welded metal pipes. The test involves taking a sample of the pipe and applying a systematic force to it until it fractures. This helps to ensure that the pipe can withstand the stress of being bent without cracking. The results of the bend test can also be used to assess the quality of the welds, as well as the overall strength of the metal. As such, it is an important test for any company that manufactures or uses welded pipes.

- Flattening Test

The flattening test is a quality control test used in the manufacture of pipelines. The test is performed to determine the resistance of the pipe material to longitudinal and circumferential cracking, as well as to assess the deformation characteristics of the pipe under stress. The flatting test is an important indicator of the overall quality of the pipe and its ability to withstand stresses during operation. The results of the test can be used to adjust the manufacturing process to ensure that the pipes produced to meet the required standards.

- CVN Impact Test

In order to ensure the mechanical properties of pipeline steels, an impact test is usually performed. The test is conducted by freezing a sample of the steel to an extreme tempureture under 0℃ (32℉). The tempureture at which the sample breaks is then used to determine the steel’s impact strength. There are three main areas that are tested: the pipe body, the weld seam, and the heat-affected zone. By testing all three areas, manufacturers can be sure that their pipelines will be able to withstand whatever conditions they may encounter.


In the production of pipelines, DWTT is an impact test that is used to determine the strength of the pipeline material. It is usually performed on large diameter pipelines, and the results are used to determine the impact strength of the material. The impact strength of the material is important for determining the impact resistance of the pipeline. DWTT is performed by impact testing the material with a weight that is dropped from a height onto the pipeline material. The impact strength of the material is determined by measuring the amount of deformation that occurs during the impact. DWTT is an important test for pipeline production because it helps to ensure that the pipeline material can withstand the impact of being dropped from a height.

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