What are the grades of API 5L PSL1 pipeline steel?

What are the grades of API 5L PSL1 pipeline steel?. Check the complete grade, product form, applicable edition and ordered dimensions.

State finished pipe or feedstock, manufacturing route, diameter and wall thickness for pipe, grade, edition, PSL and supplementary tests.

API Spec 5L PSL1 pipeline steel is a high-strength and low-alloy steel, which can be used to produce various pipe fittings and pipes for oil and natural gas pipeline systems. It is the pipeline steel specification defined by the American Petroleum Institute (API), where PSL1 is a part of API 5L series pipeline steel and represents the standard grade. The grades under API 5L PSL1 pipeline steel standard are:

Legacy technical note · verification required

Class I grade:
L210: carbon steel, low carbon alloy steel, carbon content ≤ 0.21, silicon content ≤ 0.03, average thickness ≤ 25mm
L245: carbon steel, low carbon alloy steel, carbon content ≤ 0.24, silicon content ≤ 0.03, average thickness ≤ 25mm
L290: carbon steel, low carbon alloy steel, carbon content ≤ 0.29, silicon content ≤ 0.03, average thickness ≤ 25mm
L320: carbon steel, low carbon alloy steel, carbon content ≤ 0.32, silicon content ≤ 0.03, average thickness ≤ 25mm
L360: carbon steel, low carbon alloy steel, carbon content ≤ 0.36, silicon content ≤ 0.03, average thickness ≤ 25mm
L390: carbon steel, low carbon alloy steel, carbon content ≤ 0.39, silicon content ≤ 0.03, average thickness ≤ 25mm
L415: carbon steel, low carbon alloy steel, carbon content ≤ 0.41, silicon content ≤ 0.03, average thickness ≤ 25mm
L450: carbon steel, low carbon alloy steel, carbon content ≤ 0.45, silicon content ≤ 0.03, average thickness ≤ 25mm
L485: carbon steel, low carbon alloy steel, carbon content ≤ 0.48, silicon content ≤ 0.03, average thickness ≤ 25mm
L555: carbon steel, low carbon alloy steel, carbon content ≤ 0.55, silicon content ≤ 0.03, average thickness ≤ 25mm

Legacy technical note · verification required

Secondary grade:
Grade B: Carbon content ≤ 0.17, silicon content ≤ 0.03, average thickness ≤ 25mm
X42: carbon content ≤ 0.28, silicon content ≤ 0.03, average thickness ≤ 25mm
X46: carbon content ≤ 0.31, silicon content ≤ 0.03, average thickness ≤ 25mm
X52: carbon content ≤ 0.37, silicon content ≤ 0.03, average thickness ≤ 25mm
X56: carbon content ≤ 0.40, silicon content ≤ 0.03, average thickness ≤ 25mm
X60: carbon content ≤ 0.43, silicon content ≤ 0.03, average thickness ≤ 25mm
X65: carbon content ≤ 0.45, silicon content ≤ 0.03, average thickness ≤ 25mm
X70: carbon content ≤ 0.50, silicon content ≤ 0.03, average thickness ≤ 25mm
X80: carbon content ≤ 0.55, silicon content ≤ 0.03, average thickness ≤ 25mm

Legacy technical table · verification required

Confirm every value against the applicable edition, thickness and material certificate.

Legacy technical table
Grade	yield strength (MPa)		Tensile strength (MPa)		Elongation A%
Grade	Lower limit value	Upper limit value	Lower limit value	Upper limit value	Upper limit value
L245/B	245	450	415	655	0.93
L290/X42	290	495	415	655	0.93
L320/X46	320	525	435	655	0.93
L360/X52	360	530	460	760	0.93
L390/X56	390	545	490	760	0.93
L415/X60	415	565	520	760	0.93
L450/X65	450	600	535	760	0.93
L485/X70	485	635	570	760	0.93
L555/X80	555	705	625	825	0.93
L625/X90	625	775	695	915	0.95
L690/X100	690	840	760	990	0.97

The grades of API 5L PSL1 pipeline steel can meet the needs of different users according to the carbon content and thickness. In addition, its low carbon content can improve the toughness and plasticity of steel, which is more conducive to pipeline processing and use. The grades under API 5L PSL1 pipeline steel standard can be applied to various industrial pipelines, such as oil, natural gas, gas, chemical industry, automobile, urban pipe network, etc. It is a good pipeline steel.

Source and scope

API Specification 5L, 47th edition publication notice · Line pipe scope and edition notice, June 2026. API identifies Spec 5L as a line pipe specification. Confirm the contract edition, PSL and pipe manufacturing route. Plate or coil feedstock needs its own agreed specification.

Apply the cited scope to the matching designation and form. Confirm any remaining technical values with the applicable edition or material certificate.

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