API 5L L245N Seamless Line Pipe
API 5L L245N seamless line pipe is the normalized PSL2 version of Grade B: the "245" is its specified minimum yield of 245 MPa (35,500 psi), and "N" means normalized delivery. It carries a 415 MPa (60,200 psi) minimum tensile, a base Charpy requirement of 27 J average at 0 °C, and a carbon equivalent CEIIW ≤ 0.43%. The decision that actually changes your wall thickness is not the grade name but the delivery condition - and the number you design to is 245 MPa, never the 450 MPa PSL2 ceiling.
API 5L Grade B PSL2 line pipe and L245N are the same steel under two naming systems. API 5L lets you write the grade as "L245" (SI, yield in MPa) or "Grade B" (traditional); in PSL2 a delivery-condition letter is added, so the normalized form is L245N or BN. Both names appear on the same certificate and describe identical material.
The same chemistry is supplied three ways in PSL2 - normalized (N), thermomechanically rolled (M) and quenched and tempered (Q) - and the route moves the yield by roughly 200 MPa and the elongation by double digits. L245N PSL2 line pipe is the most common of the three because normalizing gives dependable low-temperature toughness at the lowest cost. Across the family, API 5L PSL2 seamless line pipe covers every grade from L245N up to L485M/X70M, all sharing the same PSL2 test regime. We supply seamless route from 10.3 mm to 965 mm (0.405–38 in) OD; send your OD × wall and quantity for a quote.
Specifications
L245N dimensions span the full line-pipe range below; the production table lists the routine capability we quote against.
| Parameter | Capability |
|---|---|
| Standard | API SPEC 5L PSL2 (L245N / BN); ISO 3183; GB/T 9711 |
| Outside diameter | 10.3–965 mm (0.405–38 in); routine to NPS 24 (610 mm) |
| Wall thickness | 1.0–60 mm (0.039–2.36 in) |
| Length | Random or fixed; double-random available |
| Ends | Plain, beveled, or threaded + protected per order |
| Delivery condition | Normalized (N); M and Q available |
| Surface / coating | Mill varnish or bare; 3LPE/FBE/coal-tar by agreement (separate spec) |
| Certification | EN 10204 3.1 standard, 3.2 on request; third-party inspection available |
API 5L L245N chemical composition
| Element | L245N / BN (max) | Note |
|---|---|---|
| Carbon (C) | ≤ 0.24 | 0.22% for the TMCP (L245M) variant |
| Silicon (Si) | ≤ 0.40 | - |
| Manganese (Mn) | ≤ 1.20 | 1.40% belongs to L290, not L245 |
| Phosphorus (P) | ≤ 0.025 | PSL2 tighter than PSL1 (0.030) |
| Sulfur (S) | ≤ 0.015 | PSL2 tighter than PSL1 (0.030) |
| Nb + V + Ti | ≤ 0.06 | unless otherwise agreed |
| Titanium (Ti) | ≤ 0.04 | - |
| Cu / Ni / Cr | ≤ 0.50 / 0.30 / 0.30 | - |
| Mo / B | ≤ 0.15 / ≤ 0.004 | residual B ≤ 0.001 unless added |
| CEIIW / CEPcm | ≤ 0.43 / ≤ 0.25 | carbon equivalent control |
Low sulfur and phosphorus improve toughness and resist brittle fracture; manganese and trace microalloys raise strength without pushing carbon up. The PSL2 impurity ceilings are half the PSL1 values - that is what earns the mandatory impact test.
API 5L L245N mechanical properties
| Property | Value |
|---|---|
| Yield strength (Rp0.2) | 245–450 MPa (35,500–65,300 psi), double-bounded |
| Tensile strength (Rm) | 415–760 MPa (60,200–110,200 psi), double-bounded |
| Yield-to-tensile ratio | ≤ 0.93 |
| Elongation | per API 5L Annex B formula; minimum rises as wall thickness falls (Grade B ~23–26% for normal wall) |
| Charpy V-notch (PSL2 base) | 0 °C, ≥ 27 J avg (20 ft·lbf) / ≥ 20 J single (15 ft·lbf) |
| Test standards | Tensile & CVN per ASTM A370; UT per API 5L SR4 |
The double-bounded yield and tensile are the PSL2 signature: the lower number is your design floor, the upper is a mill-consistency ceiling. Elongation is formula-based, so do not quote one fixed percentage across all walls.
Tolerances
| Tolerance | Value |
|---|---|
| Outside diameter | ±0.75% to ±1.25% by diameter band |
| Wall thickness (pipe body) | +12.5% / −10% (PSL2 common figure; exact band per Table 9/10) |
| Straightness | ≤ 0.2% of length |
Confirm the exact tolerance band against the edition stated in the purchase order - the value shifts with diameter and wall.
API 5L Grade B and L245 Are the Same Steel
The question API 5L Grade B vs L245 has a short answer: they are the same steel. If a drawing says "Grade B" and the certificate says "L245", they are asking for the same 245 MPa material - the names belong to different naming generations (traditional API vs SI-style), not to different steels. Quote the legacy name when matching an old print, and write API 5L L245N PSL2 on new orders so the certificate and the current standard line up. Do not treat Grade B and L245 as two grades to "choose between".
API 5L L245N Oil line pipes
Choosing the Delivery Condition
| Delivery condition | Route | Carbon (max) | When to choose |
|---|---|---|---|
| L245N / BN | Normalized | 0.24% | Default PSL2; balanced toughness and cost for most transmission |
| L245M / BM | Thermomechanical rolled (TMCP) | 0.22% | Heavy wall, lower CE, HIC/SSC-sensitive service |
| L245Q / BQ | Quenched and tempered | 0.24% | When reserve strength or tighter property bands are needed |
All three meet the 245 MPa minimum; they differ in carbon equivalent, toughness route and cost. For the overwhelming majority of Grade B transmission lines, L245N normalized is the right call.
Quality Control and Testing
Full-body ultrasonic testing (SR4) - mandatory in PSL2; verifies the seamless pipe body without weld-related exclusion zones.
Hydrostatic test - every length, pressure from yield/wall/OD formula, no leakage; 47th edition adds pressure-gauge calibration discipline.
Charpy V-notch - 0 °C, 27 J average minimum; lower temperature/energy by SR6 agreement.
Tensile & flattening per ASTM A370 / API 5L; EN 10204 3.1 certificate with heat and batch traceability.
Third-party inspection (SGS, BV, TÜV, etc.) available on request with witness and release notes.
Why Source API 5L L245N Seamless Line Pipe from GNEE
API 5L PSL2 capability across N/M/Q routes, with coating and end-facing handled in-house or via qualified partners.
Third-party inspection (SGS/BV/TÜV) and mill-test documentation supplied on request; export packing with end protectors and VCI protection.
Technical quotation returned within 24 hours against your OD × wall, PSL level and supplements.
Test and inspection
Packaging and shipping
Send your OD × wall, PSL level and quantity - our technical team will confirm the specification (including delivery condition and any SR6/sour-service supplements) and return a quotation with lead time within 24 hours.
Request an API 5L L245N Seamless Line Pipe Quote
FAQ
What does the N in L245N mean?
N means the pipe is delivered in the normalized condition. Normalizing gives a fine, uniform ferrite-pearlite structure that improves low-temperature toughness and keeps properties consistent through the wall, compared with as-rolled material.
Is L245N the same as API 5L Grade B?
Yes - L245 and Grade B are the same 245 MPa (35,500 psi) strength tier. L245 is the SI-style name and Grade B is the traditional API name. L245N additionally specifies normalization as the delivery condition within PSL2.
Is L245N the same as X42?
No. X42 is L290 with a 290 MPa (42 ksi) minimum yield. L245N / Grade B has a 245 MPa minimum yield. They are 45 MPa apart and are not interchangeable; a spec calling for X42 cannot be met by L245N.
What is the yield strength of L245N?
For PSL2 the yield strength is double-bounded: 245–450 MPa (35,500–65,300 psi). Design to the 245 MPa minimum, not the 450 MPa PSL2 maximum. The upper bound is a quality-control ceiling, not a usable design value.
What Charpy impact requirement applies to L245N PSL2?
The base PSL2 requirement is 0 °C with full-size Charpy V-notch energy of at least 27 J average (20 ft·lbf) and 20 J single (15 ft·lbf). Lower temperatures or higher energy, such as −20 °C / 40 J, are project supplementary requirements written into the purchase order, not the standard default.
Which standards cover L245N?
API SPEC 5L (current 46th edition; 47th edition published 2026-06-02) covers L245N directly. The identical joint standard is ISO 3183, and the Chinese national equivalent is GB/T 9711. Dual-certified material is commonly supplied.
How does L245N differ from L245M and L245Q?
All three are Grade B / L245 at 245 MPa minimum yield but reach it by a different route: L245N is normalized, L245M is thermomechanically rolled (TMCP, lower carbon equivalent, better for heavy wall and HIC control), and L245Q is quenched and tempered. Choose the route from your toughness, wall-thickness and sour-service needs.
Can L245N replace ASTM A106 Grade B or A53 Grade B?
Not by default. A106 Grade B is a high-temperature seamless pipe specification, A53 Grade B is a general-purpose pipe specification, and API 5L Grade B is a line-pipe specification. Similar strength names do not make the scopes, manufacturing controls, tests or markings equivalent. Any substitution must be reviewed and approved by the project design authority.
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