L360 / X52 equivalent grades: ASTM, EN, JIS, GB, DIN

L360 / X52 is line pipe steel, 360 MPa minimum yield specified in API 5L. Below, the grades that can replace it — 4 standard systems in all — with the deciding limit named for each one rather than left to be looked up. The full L360 / X52 data sheet carries the composition and mechanical tables.

Last updated 12 October 2026

L360 / X52 and L360, L360NB / L360MB are the same steel under different national numbers; a single mill certificate covers both. X56, X42, S355J2H sit one step away, differ in a strength minimum or in the quality class rather than in the metallurgy. A106 Grade B, A53 Grade B, Q355 serve the same purpose without being the same steel, so a substitution there needs the design re-checked rather than the certificate. Counted by system: 3 in API (line pipe), 2 in EN (European), 2 in ASTM / ASME, 1 in GB/T (China).

Cross-reference table

Identical, near and functional are defined once on the grade index; the reason column below says which limit differs in each case.

L360 / X52 in API (line pipe)

• L360 — Identical The metric designation of this same grade: 360 MPa is 52 ksi. Both names appear in API 5L and a certificate may carry either or both.
• X56 — Near L390/X56: the next grade up at 390 MPa minimum yield. One step on the same ladder — the chemistry route is the same and the choice is made by the wall thickness the Barlow formula returns at the design pressure.
• X42 — Near L290/X42: 290 MPa minimum yield, the grade below. Common in gathering lines and distribution where pressures are lower and field weldability is prized over thin walls.

L360 / X52 in EN (European)

• L360NB / L360MB — Identical EN 10208-2 L360NB (normalised) and L360MB (thermomechanically rolled): the same 360 MPa minimum yield with the same L-number logic, and a test regime broadly matching PSL2 including mandatory impact testing. EN 10208-1 class A has the lower requirements and corresponds more nearly to PSL1.
• S355J2H — Near EN 10219 S355J2H: 355 MPa minimum yield with 27 J at −20 °C — almost the same strength and toughness, but it is a **structural** hollow section specification with no pipeline requirements: no yield ceiling, no carbon equivalent cap, no fracture-arrest testing. Suitable for a structural pipe, not for a transmission line.

L360 / X52 in ASTM / ASME

• A106 Grade B — Functional ASTM A106 Grade B: 240 MPa yield, seamless process pipe with elevated-temperature allowables. Much lower strength and a different purpose — A106 is for refinery and plant piping, X52 for transporting fluid between them. No ASTM pipe specification reaches 360 MPa.
• A53 Grade B — Functional ASTM A53 Grade B: 240 MPa yield general-service pipe. Dual certification with API 5L **Grade B** is common, but there is no ASTM counterpart to X52 and no route by which A53 pipe satisfies an X52 requirement.

L360 / X52 in GB/T (China)

• Q355 — Functional GB/T 1591 Q355: 355 MPa minimum yield structural steel, and the plate from which much Chinese line pipe is rolled. The yield level matches, but Q355 is a structural specification — Chinese line pipe is properly specified to GB/T 9711, which mirrors API 5L.

Superseded names for L360 / X52

• API 5LX X52 — API 5LX (withdrawn): The former separate specification for high-strength line pipe; merged into API 5L, which previously covered only Grades A and B.
• API 5LS X52 — API 5LS (withdrawn): The former specification for spiral-welded line pipe; also absorbed into API 5L.
• ISO 3183 L360 — ISO 3183: Not superseded — API 5L and ISO 3183 are harmonised, and the same grade is specified by either designation.
• StE 360.7 / GRS 360 — DIN 17172 (withdrawn): The German line-pipe grade at the same yield level, replaced by EN 10208-2 L360NB/MB.

Key data for L360 / X52

Full composition, mechanical properties by thickness, heat treatment and applications for L360 / X52 →

Verified against API 5L / ISO 3183. Last checked: October 2026.