Difference Between PSL1 And PSL2 Pipe

Learn about the difference between PSL1 and PSL2 Pipe under API 5L Standard/ISO3183 Specificaton.  More information contact with us 

by email: info@worldironsteel.com

An API 5L line pipes manufactured in two varieties PSL 1 and PSL 2. But what is PSL? PSL stands for Product Specification Levels. PSL stands for Product Specification Levels.

Pipes are used in different type of environment such as corrosive and non-corrosive.  Pipes used in severe corrosive environment required material that can withstand such process condition. On other hands for normal services, a standard quality level pipe will also serve the purpose.    

The difference between PSL1 and PSL2 pipes are as follows;

  1. Difference in Chemical Properties

  2. Difference in Mechanical Properties

  3. Difference in Manufacturing

  4. Difference in Inspection and Defect Repair

  5. Difference in Certification & Traceability

The difference between PSL1 and PSL2 Pipes - Chemical Properties


Chemistry: Max C for Seamless pipe0.28% for grades ≥ B0.0024
Chemistry: Max C for Welded pipe0.26% for grades ≥ B0.0022
Chemistry: Max P0.03% for grades ≥ A0.0003
Chemistry: Max S0.00030.0002
Carbon equivalent:Only when purchaser specifies SR18Maximum required for each grade

Three elements change when requirements change from PSL1 to PSL2.

First is Carbon.

Maximum Carbon for Seamless PSL1 pipe is 0.28% for the grade B & higher. For all grades of PSL2 pipes maximum carbon is 0.24%.

Similarly, for welded PSL1 pipe Maximum Carbon is 0.26% for the grade B & higher. For all grades of PSL2 welded pipes maximum carbon is 0.22%. 

The second element is Phosphorus.

For PSL1 pipe, Maximum Phosphorus is 0.03% for the grade A & higher. For all grades of PSL2 pipes, maximum Phosphorus is 0.03%. So, the only difference is a grade lower than A.

The third element is Sulphur.

For PSL1 pipe, Maximum Sulphur is 0.03%. For PSL2 pipes maximum Sulphur is 0.02%.

Other than these three elements, for PSL2 pipe meeting, the Carbon equivalent is mandatory whereas for PSL1 pipe it is only required if the purchaser has specified SR18. SR18 means Supplementary Requirement No.18.

The difference between PSL1 & PSL2 Pipes - Mechanical Properties 

Yield strength, maximumNoneMaximum for each grade
UTS (Ultimate Tensile Strength) maximumNoneMaximum for each grade
Fracture toughnessNone requiredRequired for all grades

For PSL2 pipe there is a limit on Maximum Yield & Ultimate Tensile Strength whereas for PSL1 pipe meeting the minimum requirements are sufficient. The second requirement that is mandatory for PSL2 pipe is Fracture toughness which is not required for the PSL1 pipe.

The difference between PSL1 & PSL2 Pipes - Manufacturing 


Grade RangeA25 through X70B through X80
Size range0.405″ through 80″4.5″ through 80″
Type of endsPlain end, Threaded end,Bevelled end special coupling pipesPlain end
Seam weldingAll methods: continuous welding limited to A25All methods: except continuous welding and laser welding
Electric welds: welder frequencyNo minimumkHz minimum 100
Heat treatment of electric weldsRequired for grades >X42Required for all grades (B through X80)

Here in this table, ou can see the differences between PSL1 & PSL2 Pipes Manufacturing. PLS1 pipes are available in grade A25 through X70 whereas PSL2 pipes are available in Grade B through X80.

PSL1 pipes are available through size 0.405” to 80” whereas smallest diameter pipe available in PSL2 is 4.5” and the largest diameter is 80”.

PSL1 pipes are available in different types of end such as Plain end, Threaded end, Bevelled end, special coupling pipes whereas PSL2 pipes are available in only Plain End.

All kinds of welding method are acceptable to manufacture PSL1; however, continuous welding is limited to Garde A25. For PSL2 welded pipes, except continuous welding and laser welding, all other welding methods are acceptable.

For electric weld welder frequency for PSL2 pipe is minimum 100kHz whereas there is no such limitation on the PLS1 pipe.  Heat treatment of electric welds is required for all Grades of PSL2 pipes whereas for PSL1 pipe, it is required for grades higher than X42.

Inspection and Defect Repair 


Non-destructive inspection of SeamlessOnly when purchaser specifies SR4SR4 mandatory
Repair by welding of pipe body plate, and skelpPermittedProhibited
Repair by welding of weld seams without filler metalPermitted by agreementProhibited

Non-destructive inspection of a seamless pipe is mandatory for PSL2 pipe whereas for PLS1 pipe it is supplementary requirements. 

Repair of pipe body plate and skelp by welding is not allowed in PSL2 pipes whereas it is allowed in PSL1 pipes. Similarly, weld repair without filler metal is not allowed in PSL2 pipes whereas it is allowed with purchaser's permission in PSL1 pipes.

Certification & Traceability

CertificationTraceable only until all tests are passedCertificates (SR15.1) mandatory
TraceabilityTraceable only until all tests are passed unless SR15 is specifiedTraceable after completion of tests (SR15.2) mandatory

For PSL1 pipes, Traceability & Certification is not required beyond the point it passes all the required test whereas, for PSL2 pipes, Traceability & Certification is mandatory.

This is all about the difference between PSL1 and PSL2 pipes.

In short PSL1 pipes are standard quality pipe for normal services and PSL2 pipes are higher quality pipe than PSL1.