API 5L Grade A

API 5L Grade A steel pipes

API 5L Grade A

API 5L Grade A is a type of steel material that is commonly used in the oil and gas piping industry. The material is also easy to weld, making it ideal for use in fabricating pipe fittings and other pipeline components. API 5L Grade A material can be applied to both seamless and welded steel line pipes. While, API 5L Grade A is the lowest quality of steel that can be used in this application, it is not suitable for use in high-pressure pipelines. However, API 5L Grade A can be used for low-pressure applications such as water pipelines. Steel with a higher carbon content is classified as Grade B, X42, X46, X52, X56, X60, X65, X70, and X80.

The American Petroleum Institute‘s API 5L specification covers line pipes for use in pipelines that transport oil, natural gas, and water. The API 5L specification provides requirements for manufacturing line pipes, including materials, dimensions, tolerances, testing, and marking. Line pipes are manufactured from a variety of materials, including carbon steel, stainless steel, and high-strength low-alloy steel. The dimensions of line pipes are specified by the outside diameter (OD) and wall thickness. Line pipes are manufactured to meet certain strength and pressure requirements. Testing of line pipes includes hydrostatic testing, nondestructive testing, and mechanical testing. Line pipes are marked with identification information, such as the manufacturer’s name or logo, the Specification Number (API 5L), the Nominal Size (OD), the Schedule Number (wall thickness), and the Heat Number (heat treatment).

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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Specifications of API 5L Grade A

Sizes (ERW)1/2″ NB – 16″ NB
Sizes (SAW/LSAW)16″ NB – 100″ NB
Wall ThicknessSchedule 20 – Schedule XXS (heavier on request) up to 250 mm thickness
TypeSeamless / Welded/ Line Pipe / LSAW
API 5LAPI 5L Grade A PSL 1 Pipe

Dimensions and Sizes of API 5L Grade A Line Pipe

When selecting an API 5L Grade A line pipe, it is important to check the diameter and size of the pipe to ensure it meets the required standards. The dimensions and masses of different size pipes are specified in ISO 4200 and ASME B36.10M. ISO 4200 provides a guide for diameter and size, while ASME B36.10M specifies the wall thickness for each size. To check if a particular pipe meets the required standards, refer to these tables. This will ensure that the pipe selected is of the correct size and has the appropriate wall thickness. proper diameter and size are critical aspects in selecting an API 5L line pipe because it helps to ensure compatibility with existing pipelines as well as safety during installation and operation.

NPS O. D. Nominal Wall Thickness
DN Inch mm SCH5S SCH10S SCH10 SCH20 SCH30 SCH40 SCH60 SCH80 SCH100 SCH120 SCH140 SCH160 Sth XS XXS
50 2″ 60.3 1.65 2.77 3.91 5.54 8.74 3.91 5.54 11.07
65 2 1/2″ 73 2.11 3.05 5.16 7.01 9.53 5.16 7.01 14.02
80 3″ 88.9 2.11 3.05 5.49 7.62 11.13 5.49 7.52 15.24
90 3 1/2″ 101.6 2.11 3.05 5.74 8.08 5.74 8.08
100 4″ 114.3 2.11 3.05 6.02 8.58 11.13 13.49 6.02 8.56 17.12
125 5″ 141.3 2.77 3.4 6.55 9.53 12.7 15.88 6.55 9.53 18.05
150 6″ 168.3 2.77 3.4 7.11 10.97 14.27 18.26 7.11 10.97 21.95
200 8″ 219.1 2.77 3.76 6.35 7.04 8.18 10.31 12.7 15.09 18.26 20.62 23.01 8.18 12.7 22.23
250 10″ 273.1 3.4 4.19 6.35 7.8 9.27 12.7 15.09 18.26 21.44 25.4 28.58 9.27 12.7 25.4
300 12″ 323.9 3.96 4.57 6.35 8.38 10.31 14.27 17.48 21.44 25.4 28.58 33.32 9.53 12.7 25.4
350 14″ 355.5 3.96 4.78 6.35 7.92 9.53 11.13 15.09 19.05 23.83 27.79 31.75 35.71 9.53 12.7
400 16″ 406.4 4.19 4.78 6.35 7.92 9.53 12.7 16.66 21.44 26.19 30.96 36.53 40.49 9.53 12.7
450 18″ 457.2 4.19 4.78 6.35 7.92 11.13 14.27 19.05 23.83 39.36 34.93 39.67 45.24
500 20″ 508 4.78 5.54 6.35 9.53 12.7 15.09 20.62 26.19 32.54 38.1 44.45 50.01
550 22″ 558.8 4.78 5.54 6.35 9.53 12.7 22.23 28.58 34.93 41.28 47.63 53.98
600 24″ 609.6 5.54 6.35 6.35 9.53 14.27 17.48 24.61 30.96 38.89 46.02 52.37 59.54

API 5L gRADE A Pipe Chemical Composition

- Chemical Composition for API 5L GRADE A PSL 1 pipe with t ≤ 0.984”

Steel Grade Mass fraction, % based on heat and product analyses a,g
C Mn P S V Nb Ti
max b max b max max max max max
Welded Pipe
API 5L Grade A 0.22 0.9 0.3 0.3

API 5L Grade a Pipe Mechanical Properties

- Mechanical Properties for API 5L Grade A PSL-1 Pipe

Pipe Grade Tensile Properties – Pipe Body of SMLS and Welded Pipes PSL 1 Seam of Welded Pipe
Yield Strength a Tensile Strength a Elongation Tensile Strength b
Rt0,5 PSI Min Rm PSI Min (in 2in Af % min) Rm PSI Min
API 5L Grade A 30,500 48,600 c 48,600

API 5L Grade a Pipe Tolerance

O.D. Tolerance W.T. Tolerance
Grade A
D < 60.3mm +0.41/-0.40mm D < 73mm +20%/-12.5%
D ≥ 60.3m +0.75/-0.40mm D ≥ 73mm +15%/-12.5%

Test and inspection of API 5L Grade A Line pipes

- Hydrostatic Test

The hydrostatic test is one of the most important tests performed during the production of the API 5L line pipe. As its name implies, the test involves filling the pipe with water and then subjecting it to high pressure. The pressure is typically held for a while, during which any leaks will be detected. The test is important for several reasons. First, it helps to ensure that the weld seam is watertight. Second, it allows for the detection of any manufacturing defects that could lead to leaks. Finally, it ensures that the pipe can safely withstand the pressures that will be applied during service. As a result, the hydrostatic test is a critical part of quality control for API 5L line pipes.

- Bend Test

During the production of API 5L line pipes, a bending test is conducted to ensure the quality of the weld. This test involves taking a sample of the steel pipe and bending it to a specified degree. If the pipe cracks or breaks during the bending process, it is considered to be defective and must be scrapped. The bending test is an important quality control measure, as it helps to ensure that the API 5L line pipes are strong and durable.

- Flattening Test

The flattening test is a quality control measure that is carried out during the production of steel pipes. The test is used to check for cracks in the weld and to assess the deformation of the pipe under longitudinal and circumferential stress. The sampling pipe is placed on a flat surface and a weight is placed on top of it. The weight is then increased until the pipe starts to deform. The amount of deformation is then measured and recorded. The results of the flattening test can be used to assess the quality of the weld and the strength of the pipe.

- CVN Impact Test

To ensure the quality of API 5L line pipes, manufacturers subject them to a series of impact tests. There are three main test areas: the pipe body, the weld sea, and the heat-affected zone. In each of these areas, the pipes are tested for their resistance to various types of impacts. For example, the pipe body is tested for its ability to withstand blunt force trauma, while the weld sea is tested for its ability to resist stress fractures. The heat-affected zone is tested for its ability to resist thermal shock. By subjecting the pipes to these tests, manufacturers can be confident that they will be able to withstand the rigors of use in a variety of applications.

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