API 5L PSL2 Pipeline Steel Pipe

API 5L PSL2 (Product Specification Level 2) is a pipeline steel pipe (seamless and welded) standard developed by the American Petroleum Institute (API), suitable for high-pressure fluid transportation such as oil and natural gas. Compared with PSL1, PSL2 has stricter requirements in chemical composition, mechanical properties, impact toughness, non-destructive testing, etc., and is suitable for harsh environments such as high pressure, low temperature, and corrosive media.

API 5L PSL2 Core Features:

1. Stricter chemical composition control

a. Lower sulfur (S) and phosphorus (P) content (S ≤ 0.015%, P ≤ 0.025%)
b. Carbon equivalent (CEV) limit (such as X70 steel grade CEV ≤ 0.45%)
c. Alloy element (Nb, V, Ti) content limit (total ≤ 0.15%)

PSL2 has stricter chemical composition requirements to ensure the corrosion resistance and other physical properties of the pipe.

2. Higher requirements for mechanical properties

Steel grade	Yield strength (MPa)	Tensile strength (MPa)	Impact energy (0℃, J)
B	241~448	414~758	≥41 (longitudinal); ≥27J (transverse)
X42	290~496	414~758	≥41 (longitudinal); ≥27J (transverse)
X52	359~531	455~758	≥41 (longitudinal); ≥27J (transverse)
X70	483~621	565~827	≥41 (longitudinal); ≥27J (transverse)
X80	552~690	621~827	≥101 (longitudinal); ≥68J (transverse)

PSL2 has more stringent requirements in terms of tensile properties, impact energy, etc. For example, for all steel grades except X80, the average impact energy at 0℃ of PSL2 is ≥41J in the longitudinal direction and ≥27J in the transverse direction; for X80 steel grade, it is ≥101J in the longitudinal direction and ≥68J in the transverse direction. Note: PSL2 requires all steel grades to undergo impact tests (PSL1 only requires X80 to undergo testing)

3. Non-destructive testing (NDT) requirements
PSL2 requires ultrasonic (UT) testing or radiographic (RT) testing of each steel grade to ensure that there are no defects, while PSL1 does not require non-destructive testing.
Hydrostatic testing is mandatory (non-destructive substitution is not allowed).

4. Additional tests
Drop weight tear test (DWTT) (evaluation of fracture resistance).
Metallographic inspection (evaluation of structural uniformity).

Application areas of API 5L PSL2:

API 5L PSL2 is widely used in the oil and gas industry and is suitable for pipeline applications that require higher quality standards. Due to its strict inspection and performance requirements, PSL2 is usually used in situations with higher requirements for corrosion resistance, tensile strength and impact resistance.

Typical application examples:
1. High-pressure oil and gas pipelines (such as the China-Russia East Line X80 pipeline).
2. Low temperature environment (such as LNG pipelines, which must meet -20℃ impact toughness).
3. Acidic environment (containing H₂S, which must comply with NACE MR0175 standards).
4. Cross-border long-distance pipelines (such as the Central Asian natural gas pipeline).

Comparison of differences between API 5L PSL1 and PSL2:

Item	PSL1	PSL2
Steel grade range	A25~X70	B~X80
Impact test	Only X80 needs to be tested	All steel grades are mandatory
Non-destructive testing	Non-mandatory	UT/RT testing for each steel grade
Sulfur and phosphorus content	S≤0.030%, P≤0.030%	S≤0.015%, P≤0.025%
Upper limit of yield strength	Unlimited	Set maximum value (to prevent over-strength embrittlement)

API 5L PSL1 and PSL2: How to choose?

If it is used in high pressure, low temperature, corrosive environment (such as deep sea and polar pipelines), PSL2 is preferred.
If it is ordinary low pressure transmission (such as city gas), PSL1 is sufficient.

Note: When purchasing, the contract must indicate "API 5L PSL2" and steel grade (such as X70 steel)

Read more: Non-destructive Testing of Seamless Pipes or API 5L Seamless Line Pipe