Material Properties of API 5L Line Pipe Steel

The grades of line pipe steel based on API SPEC 5L specify a series of minimum mechanical requirements and not specific material composition, though the specification does list the maximum composition percentage for any component.

Therefore each mill will provide slightly different steel for a given grade.

Below are the minimum mechanical requirements for the different API 5L grades. The names are based on the minimum yield strengths – X values are in ksi and L values are in MPa. (e.g. X65 has a minimum yield strength of about 65 ksi, equivalent to L450 with a minimum yield strength of 450 MPa.

Line Pipe Grade		Yield Strength		Tensile Strength		Elongation
		MPa	ksi	MPa	ksi	%
L175	A25	175	25.4	310	45
L210	A	210	30.5	335	48.6	28
L245	B	245	35.5	415	60.2	23
L290	X42	290	42.1	415	60.2	23
L320	X46	320	46.4	435	63.1	22
L360	X52	360	52.2	460	66.7	21
L390	X56	390	56.6	490	71.1	19
L415	X60	415	60.2	520	75.4	19
L450	X65	450	65.3	535	77.6	18
L485	X70	485	70.3	570	82.7	17
L555	X80	555	80	621	90	16
L690	X100	690	100	760	110