API 5L PSL-1
API 5L PSL-1
The American Petroleum Institute’s (API) API 5L standard covers line pipe levels. The standard has different levels that specify different requirements for the manufacture of line pipes. PSL-1 is the most basic level and covers the simplest requirements. PSL-2 has progressively stricter requirements. All levels require test to ensure that the line pipes meet the required standards. The PSL-1 level is the most basic and is therefore less strictly regulated than the other levels. However, all levels are still subject to strict quality control measures to ensure that only the highest quality line pipes are manufactured.
The API committee establishes standards for these pipes, which are required by the majority of energy firms. PSL-1 and PSL-2 are standards that have been implemented to assist with the more stringent requirements for each grade level. These two fundamental criteria are acknowledged as having differing levels of physical and technical requirements.
What is the Difference between API 5L PSL-1 and PSL-2?
The American Petroleum Institute (API) classifies oil and gas field pipelines according to their levels of quality. The two levels are PSL-1 and PSL-2. The main difference between the two levels is that PSL-2 has stricter requirements in terms of testing and properties. To be classified as PSL-2, a pipeline must meet certain standards for chemical composition, mechanical properties (tensile strength, yield strength, elongation), and weld seam quality. In addition, test frequency must be increased to ensure that the pipeline meets all requirements. As a result, PSL-2 pipelines are typical of a higher quality than PSL-1 pipelines.
Chemical Composition for API 5L PSL-1 Pipe with t ≤ 0.984”
| Steel Grade (Steel Name) |
Mass Fraction, Based on Heat and Product Analyses a,g | |||||||
|---|---|---|---|---|---|---|---|---|
| C | Mn | P | S | V | Nb | Ti | ||
| max b | max b | min | max | max | max | max | max | |
| Seamless Pipe | ||||||||
| L175 or A25 | 0.21 | 0.6 | – | 0.030 | 0.030 | – | – | – |
| L175 or A25P | 0.21 | 0.6 | 0.045 | 0.080 | 0.030 | – | – | – |
| L21O or A | 0.22 | 0.9 | – | 0.030 | 0.030 | – | – | – |
| L245 or B | 0.28 | 1.2 | – | 0.030 | 0.030 | c.d | c.d | d |
| L290 or X42 | 0.28 | 1.3 | – | 0.030 | 0.030 | d | d | d |
| L320 or X46 | 0.28 | 1.4 | – | 0.030 | 0.030 | d | d | d |
| L360 or X52 | 0.28 | 1.4 | – | 0.030 | 0.030 | d | d | d |
| L390 or X56 | 0.28 | 1.4 | – | 0.030 | 0.030 | d | d | d |
| L415 or X60 | 0.28 e | 1.4 e | – | 0.030 | 0.030 | f | f | f |
| L450 or X65 | 0.28 e | 1.4 e | – | 0.030 | 0.030 | f | f | f |
| L485 or X70 | 0.28 e | 1.4 e | – | 0.030 | 0.030 | f | f | f |
| Welded Pipe | ||||||||
| L175 or A25 | 0.21 | 0.6 | – | 0.030 | 0.030 | – | – | – |
| L175 or A25P | 0.21 | 0.6 | 0.045 | 0.080 | 0.030 | – | – | – |
| L21O or A | 0.22 | 0.9 | – | 0.030 | 0.030 | – | – | – |
| L245 or B | 0.26 | 1.2 | – | 0.030 | 0.030 | c.d | c.d | d |
| L290 or X42 | 0.26 | 1.3 | – | 0.030 | 0.030 | d | d | d |
| L320 or X46 | 0.26 | 1.4 | – | 0.030 | 0.030 | d | d | d |
| L360 or X52 | 0.26 | 1.4 | – | 0.030 | 0.030 | d | d | d |
| L390 or X56 | 0.26 | 1.4 | – | 0.030 | 0.030 | d | d | d |
| L415 or X60 | 0.26 e | 1.4 e | – | 0.030 | 0.030 | f | f | f |
| L450 or X65 | 0.26 e | 1.45 e | – | 0.030 | 0.030 | f | f | f |
| L485 or X70 | 0.26 e | 1.65 e | – | 0.030 | 0.030 | f | f | f |
| a Cu ≤ 0.50%, Ni ≤ 0.50 %, Cr ≤ 0.50 % and Mo ≤ 0.15 % | ||||||||
| b For each reduction of 0.01 % below the specified maximum concentration for carbon, an increase of 0.05 % above the specified maximum concentration for Mn is permissible, up to a maximum of 1.65 % for grades ≥ L245 or B, but ≤ L360 or X52; up to a maximum of 1.75 % for grades > L360 or X52, but < L485 or X70; and up to a maximum of 2.00 % for Grade L485 or X70. | ||||||||
| c Unless otherwise agreed, Nb + V ≤ 0.06 % | ||||||||
| d Nb + V +Ti ≤ 0.15% | ||||||||
| e Unless otherwise agreed | ||||||||
| f Unless otherwise agreed, Nb + V + Ti ≤ 0.06 % | ||||||||
| g No deliberate addition of B is permitted and the residual B ≤ 0.001 %. | ||||||||
API 5L PSL-1 Line Pipe Mechanical Properties
| Pipe Grade | Pipe Body of Seamless and Welded Pipe | Weld Seam of EW, LW, SAW, and COW Pipe | ||
|---|---|---|---|---|
| Yield Strength a Rt0.5 MPa(psi) | Tensile Strength a Rm MPa(psi) | Elongation(on 50mm or 2in.) At % | Tensile Strength b Rm MPa(psi) | |
| min | min | min | min | |
| L175 or A25 | 175(25,400) | 310(45,000) | c | 310(45,000) |
| L175 or A25P | 175(25,400) | 310(45,000) | c | 310(45,000) |
| L21O or A | 210(30,500) | 335(48,600) | c | 335(48,600) |
| L245 or B | 245(35,500) | 415(60,200) | c | 415(60,200) |
| L290 or X42 | 290(42,100) | 415(60,200) | c | 415(60,200) |
| L320 or X46 | 320(46,400) | 435(63,100) | c | 435(63,100) |
| L360 or X52 | 360(52,200) | 460(66,700) | c | 460(66,700) |
| L390 or X56 | 390(56,600) | 490(71,100) | c | 490(71,100) |
| L415 or X60 | 415(60,200) | 520(75,400) | c | 520(75,400) |
| L450 or X65 | 450(65,300) | 535(77,600) | c | 535(77,600) |
| L485 or X70 | 485(70,300) | 570(82,700) | c | 570(82,700) |
| a For intermediate grades, the difference between the specified minimum tensile strength and the specified minimum yield strength for the pipe body shall be as given in the table for the next higher grade. | ||||
| b For intermediate grades, the specified minimum tensile strength for the weld seam shall be the same value as was determined for the pipe body using footnote a). | ||||
| c The specified minimum elongation, Af, expressed in percent and rounded to the nearest percent, shall be as determined using the following equation: | ||||
| Af = C AXC0.2 U0.9 | ||||
| where | ||||
| C is 1940 for calculations using Sl units and 625,000 for calculations using USC units | ||||
| Axc is the applicable tensile test piece cross-sectional area, expressed in square millimeters (square inches), as follows: | ||||
| 1)for circular cross-section test pieces, 130 mm² (0.20 in.²) for 12.7 mm (0.500 in,) and 8.9 mm (0.350 in,) diameter test pieces; 65 mm²(0.10 in.² ) for 6.4 mm (0.250 in.) diameter test pieces | ||||
| 2）for ful-section test pieces, the lesser of a) 485 mm²(0.75 in.²) and b) the cross-sectional area of the test piece, derived using the specifed outside diameter and the specified wall thickness of the pipe, rounded to the nearest10 mm²(0.01 in.²) | ||||
| 3)for strip test pleces, the lesser of a) 485 mm²(0.75 in.²) and b) the cross-sectional area of the test plece, derived using the specified width of the test piece and the specified wall thickness of the pipe, rounded to the nearest10 mm²(0.01 in.²); | ||||
| U is the specified minimum tensile strength, expressed in megapascals (pounds per square inch) | ||||
| Pipe Grade | Pipe Body of Seamless and Eslded Pipe | Weld Seam of HFW,SAW, and COW Pipe | |||||
|---|---|---|---|---|---|---|---|
| Yield Strength a Rt0.5 MPa(psi) | Tensile Strength a Rm MPa(psi) | Ratio a,c Rt0.5/Rm | Elongation(on 50mm or 2in.) At % | Tensile Strength b Rm MPa(psi) | |||
| min | max | min | max | max | min | min | |
| L245R or BR L245N or BN L245Q or BQ L245M or BM | 245(35,500) | 450(65,300)e | 415(60,200) | 655(95,000) | 0.93 | f | 415(60,200) |
| L290R or X42R L290N or X42N L290Q or X42Q L290M or X42M | 290(42,100) | 495(71,800) | 415(60,200) | 655(95,000) | 0.93 | f | 415(60,200) |
| L320N or X46N L320Q or X46Q L320M or X46M | 320(46,400) | 525(76,100) | 435(63,100) | 655(95,000) | 0.93 | f | 435(63,100) |
| L360N or X52N L360Q or X52Q L360M or X52M | 360(52,200) | 530(76,900) | 460(66,700) | 760(110,200) | 0.93 | f | 460(66,700) |
| L390N or X56N L390Q or X56Q L390M or X56M | 390(56,600) | 545(79,000) | 490(71,100) | 760(110,200) | 0.93 | f | 490(71,100) |
| L415N or X60N L415Q or X60Q L415M or X60M | 415(60,200) | 565(81,900) | 520(75,400) | 760(110,200) | 0.93 | f | 520(75,400) |
| L450Q or X65Q L450M or X65M | 450(65,300) | 600(87,000) | 535(77,600) | 760(110,200) | 0.93 | f | 535(77,600) |
| L485Q or X70Q L485M or X70M | 485(70,300) | 635(92,100) | 570(82,700) | 760(110,200) | 0.93 | f | 570(82,700) |
| L555Q or X80Q L555M or X80M | 555(80,500) | 705(102,300) | 625(90,600) | 825(119,700) | 0.93 | f | 625(90,600) |
| L625M or X90M | 625(90,600) | 775(112,400) | 695(100,800) | 915(132,700) | 0.95 | f | 695(100,800) |
| L625Q or X90Q | 625(90,600) | 775(112,400) | 695(100,800) | 915(132,700) | 0.97g | f | – |
| L690M or X100M | 690(100,100)b | 840(121,800)b | 760(110,200) | 990(143,600) | 0.97h | f | 760(110,200) |
| L690Q or X100Q | 690(100,100)b | 840(121,800)b | 760(110,200) | 990(143,600) | 0.97h | f | – |
| L830M or X120M | 830(120,400)b | 1050(152,300)b | 915(132,700) | 1145（166,100） | 0.99h | f | 915(132.700) |
a For intermediate grades, the difference between the specified minimum tensile strength and the specified minimum yield strength for the pipe body shall be as given in the table for the next higher grade.
b For intermediate grades, the specified minimum tensile strength for the weld seam shall be the same value as was determined for the pipe body using footnote a).
c The specified minimum elongation, Af expressed in percent and rounded to the nearest percent, shall be as determined using the following equation;
where
C is 1 940 for calculations using SI units and 625 000 for calculations using USC units;
Axc is the applicable tensile test piece cross-sectional area, expressed in square millimetres (square inches), as follows:
1) for circular cross-section test pieces, 130 mm2 (0.20 in2) for 12,5 mm (0.500 in) and 8,9 mm (0.350 in) diameter test pieces; and 65 mm2(0.10 in2) for 6,4 mm (0.250 in) diameter test pieces;
2) for full-section test pieces, the lesser of a) 485 mm2 (0.75 in2) and b) the cross-sectional area of the test piece, derived using the specified outside diameter and the specified wall thickness of the pipe, rounded to the nearest 10 mm2 (0.01 in2);
3) for strip test pieces, the lesser of a) 485 mm2 (0.75 in2) and b) the cross-sectional area of the test piece, derived using the specified width of the test piece and the specified wall thickness of the pipe, rounded to the nearest 10 mm2(0.01 in2);
U is the specified minimum tensile strength, expressed in megapascals (pounds per square inch).
Dimensions and Sizes of API 5L PSL-1 Line Pipe
When specifying a line pipe for an application, it is important to check that the dimensions and masses of the pipe meet the required standards. For example, the dimensions and masses of API 5L PSL-1 line pipes are specified in ISO 4200 and ASME B36.10M. These standards provide a guide for different size pipes and specify the wall thickness of each size. Checking that a particular pipe meets the required standards can be done by referring to these tables. Doing so helps to ensure that the pipe is the right size and has the correct wall thickness. This is important because using a pipe that does not meet the required standards can lead to problems such as poor performance or even failure.
| Nominal Pipe Size | Outside Diameter | Nominal Wall Thickness | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DN | Inch | mm | SCH10 | SCH20 | SCH30 | Sth | SCH40 | SCH60 | XS | SCH80 | SCH100 | SCH120 | SCH140 | SCH160 | XXS |
| 15 | 1/2″ | 21.3 | 2.11 | – | 2.41 | 2.77 | 2.77 | – | 3.73 | 3.73 | – | – | – | 4.78 | 7.47 |
| 20 | 3/4″ | 26.7 | 2.11 | – | 2.41 | 2.87 | 2.87 | – | 3.91 | 3.91 | – | – | – | 5.56 | 7.82 |
| 25 | 1″ | 33.4 | 2.77 | – | 2.9 | 3.38 | 3.38 | – | 4.55 | 4.55 | – | – | – | 6.35 | 9.09 |
| 32 | 1 1/4″ | 42.2 | 2.77 | – | 2.97 | 3.56 | 3.56 | – | 4.85 | 4.85 | – | – | – | 6.35 | 9.7 |
| 40 | 1 1/2″ | 48.3 | 2.77 | – | 3.18 | 3.68 | 3.68 | – | 5.08 | 5.08 | – | – | – | 7.14 | 10.15 |
| 50 | 2″ | 60.3 | 2.77 | – | 3.18 | 3.91 | 3.91 | – | 5.54 | 5.54 | – | – | – | 8.74 | 11.07 |
| 65 | 2 1/2″ | 73 | 3.05 | – | 4.78 | 5.16 | 5.16 | – | 7.01 | 7.01 | – | – | – | 9.53 | 14.02 |
| 80 | 3″ | 88.9 | 3.05 | – | 4.78 | 5.49 | 5.49 | – | 7.62 | 7.62 | – | – | – | 11.13 | 15.25 |
| 90 | 3 1/2″ | 101.6 | 3.05 | – | 4.78 | 5.74 | 5.74 | – | 8.08 | 8.08 | – | – | – | – | – |
| 100 | 4″ | 114.3 | 3.05 | – | 4.78 | 6.02 | 6.02 | – | 8.56 | 8.56 | – | 11.13 | – | 13.49 | 17.12 |
| 125 | 5″ | 141.3 | 3.4 | – | – | 6.55 | 6.55 | – | 9.53 | 9.53 | – | 12.7 | – | 15.88 | 19.05 |
| 150 | 6″ | 168.3 | 3.4 | – | – | 7.11 | 7.11 | – | 10.97 | 10.97 | – | 14.27 | – | 18.26 | 21.95 |
| 200 | 8″ | 219.1 | 3.76 | 6.35 | 7.04 | 8.18 | 8.18 | 10.31 | 12.7 | 12.7 | 15.09 | 18.26 | 20.62 | 23.01 | 22.23 |
| 250 | 10″ | 273 | 4.19 | 6.35 | 7.8 | 9.27 | 9.27 | 12.7 | 12.7 | 15.09 | 18.26 | 21.44 | 25.4 | 28.58 | 25.4 |
| 300 | 12″ | 323.8 | 4.57 | 6.35 | 8.38 | 9.53 | 10.31 | 14.27 | 12.7 | 17.48 | 21.44 | 25.4 | 28.58 | 33.32 | 25.4 |
| 350 | 14″ | 355.6 | 6.35 | 7.92 | 9.53 | 9.53 | 11.13 | 15.09 | 12.7 | 19.05 | 23.83 | 27.79 | 31.75 | 35.71 | – |
| 400 | 16″ | 406.4 | 6.35 | 7.92 | 9.53 | 9.53 | 12.7 | 16.66 | 12.7 | 21.44 | 26.19 | 30.96 | 36.53 | 40.19 | – |
| 450 | 18″ | 457.2 | 6.35 | 7.92 | 11.13 | 9.53 | 14.27 | 19.05 | 12.7 | 23.83 | 39.36 | 34.93 | 39.67 | 45.24 | – |
| 500 | 20″ | 508 | 6.35 | 9.53 | 12.7 | 9.53 | 15.09 | 20.62 | 12.7 | 26.19 | 32.54 | 38.1 | 44.45 | 50.01 | – |
| 550 | 22″ | 558.8 | 6.35 | 9.53 | 12.7 | 9.53 | – | 22.23 | 12.7 | 28.58 | 34.93 | 41.28 | 47.63 | 53.98 | – |
| 600 | 24″ | 609.6 | 6.35 | 9.53 | 14.27 | 9.53 | 17.48 | 24.61 | 12.7 | 30.96 | 38.89 | 46.02 | 52.37 | 59.54 | – |
| 650 | 26″ | 660.4 | 7.92 | 12.7 | – | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 700 | 28″ | 711.2 | 7.92 | 12.7 | 15.88 | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 750 | 30″ | 762 | 7.92 | 12.7 | 15.88 | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 800 | 32″ | 812.8 | 7.92 | 12.7 | 15.88 | 9.53 | 17.48 | – | 12.7 | – | – | – | – | – | – |
| 850 | 34″ | 863.6 | 7.92 | 12.7 | 15.88 | 9.53 | 17.48 | – | 12.7 | – | – | – | – | – | – |
| 900 | 36″ | 914.4 | 7.92 | 12.7 | 15.88 | 9.53 | 19.05 | – | 12.7 | – | – | – | – | – | – |
| 950 | 38″ | 965.2 | – | – | – | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 1000 | 40″ | 1016 | – | – | – | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 1050 | 42″ | 1066.8 | – | – | – | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 1100 | 44″ | 1117.6 | – | – | – | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 1150 | 46″ | 1168.4 | – | – | – | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
| 1200 | 48″ | 1219.2 | – | – | – | 9.53 | – | – | 12.7 | – | – | – | – | – | – |
Delivery Conditions for API 5L PSL-1 Pipes
| PSL | Delivery Conditions for API 5L PSL-1 Steel Pipe | Steel Grade |
|---|---|---|
| PSL -1 | As rolled, normalizing rolled, thermomechanical rolled/formed, normalizing formed, normalized, and tempered; if agreed, quenched and tempered for SMLS pipe only | B |
| As rolled, normalizing rolled, thermomechanical rolled/formed, normalizing formed, normalized and tempered or quenched and tempered | X42, X46, X52, X56, X60, X65, X70 |
Test and inspection of API 5L PSL-1 Line pipes
- Hydrostatic Test
Hydrostatic testing is a critical quality control step in the production of pipelines. The test is conducted by filling the pipeline with water and then applying pressure to the water. This pressure stimulates the operational pressure that the pipeline will experience once it is in service. If there are any leaks in the weld seams or the pipe body, they will be revealed by the hydrostatic test. As a result, hydrostatic testing is an essential part of ensuring the safety and quality of pipelines.
- Bend Test
In pipeline production, a bend test is used to check for any cracks or defects in the metals being used. A sample of the metal is placed under stress and then bent to see if any cracks appear. If there are any cracks, they will be repaired before the metal is used in the construction of the pipeline. The bend test is an important part of quality control in pipeline production, as it ensures that the materials being used are strong and free from defects.
- Flattening Test
A flattening test is a type of crack-propagation test typically used to determine the crack-arrest performance of pipeline steels. The test involves applying a longitudinal or circumferential crack to a pre-cracked specimen and then subjecting the specimen to an increasing applied load until failure occurs. During testing, the crack is monitored for propagation and the applied stress and deformation of the specimen are recorded. The results of the flattening test can be used to evaluate the crack-arrest performance of pipeline steels under various loading conditions.
- CVN Impact Test
An impact test is a type of mechanical test that provides information about the toughness and ductility of materials. The test involves delivering a blow to a sample of the material under controlled conditions. The resulting deformation of the sample is then measured and analyzed. Impact tests are commonly used in the pipeline industry to assess the performance of pipe materials. The three main areas of focus in impact testing are the pipe body, weld seam, and heat-affected zone. By understanding how these areas respond to impact, engineers can optimize pipeline design and ensure safe and reliable operation.
- DWTT
DWTT is an impact test used to determine the ductility of a material. The test is performed by impact loading a material specimen, such as a pipeline, at a specified temperature. The resulting impact energy is then measured and used to calculate the DWTT of the material. The DWTT is an important parameter in the design of pipelines and other large diameter products, as it provides insight into the impact strength of the material. In general, materials with high DWTT values are more resistant to impact damage and are better suited for use in high-pressure applications. As such, the DWTT is an important tool in the production of pipelines and other large diameter products.
