Steel X52-R (L360R / X52R)
Grade
ASTM API 5L X52 · GB L360
PSL2 as-rolled condition with guaranteed CVN and CE limits; economical for small-diameter welded pipe.
Values for the R condition
Other X52 tempers and conditions
X52 is listed in 7 conditions; see the grade overview at X52.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
API 5L X52 PSL1 | Lowest-cost X52 for non-critical, non-sour, moderate-temperature lines where impact testing is not required. | 400 | 520 | 26 | 170 HB | 10 % IACS |
RThis page L360R / X52R | PSL2 as-rolled condition with guaranteed CVN and CE limits; economical for small-diameter welded pipe. | 400 | 520 | 26 | 170 HB | 10 % IACS |
Normalized | Pick when uniform fine-grain structure and good low-temperature toughness are needed in seamless pipe or after hot induction bending. | 405 | 525 | 29 | 160 HB | 10 % IACS |
L360NS / X52NS | Normalized seamless pipe for sour gas gathering lines; HIC/SSC qualified with ≤250 HV10 hardness limit. | 405 | 525 | 29 | 176 HB | 10 % IACS |
MDefault Thermomechanically controlled processed | Default modern choice for welded (ERW/SAWL/SAWH) transmission line pipe: lowest carbon equivalent, best field weldability and excellent low-temperature toughness. | 415 | 530 | 30 | 165 HB | 10 % IACS |
L360QS / X52QS | Heavy-wall sour-service pipe combining Q&T toughness with HIC/SSC-qualified clean steel chemistry. | 425 | 540 | 28 | 13 HRC | 9.5 % IACS |
L360Q / X52Q | Choose for heavy-wall seamless pipe, risers and induction bends where high uniform toughness through thick sections is required. | 430 | 545 | 28 | 12 HRC | 9.5 % IACS |
What is X52-R?
X52-R is X52 in the R grade — pSL2 as-rolled condition with guaranteed CVN and CE limits; economical for small-diameter welded pipe. X52-R has a yield strength of 400 MPa (58 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 207 GPa (30 Msi). X52-R has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). M is the default condition FabDigit quotes; R is available on request or by drawing note.
Advantages
- Easy to machine — 62/100, better than 89% of steel grades
- Forms and bends easily — 72/100, better than 88% of steel grades
- Readily welded — 86/100, better than 85% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
X52-R properties
Typical room-temperature values for X52-R; 23 are specific to this condition. Other listed values are X52 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
X52-R has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
X52-R has a yield strength of 400 MPa (58 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
X52-R is rated for continuous service to 350°C (662 °F). It conducts heat at 48 W/m·K (27.7 BTU/hr·ft·°F), better than 79% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
X52-R conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of X52-R takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 20%.
Manufacturability7
X52-R's machinability is good (62/100, better than 89% of steel grades); weldability excellent (86/100); formability very good (72/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with X52-R
Is X52 easy to machine?
Machines like 1020–1025 C-Mn steel (~65 % of AISI 1212); use coated carbide, moderate speeds, ample coolant — micro-alloy carbonitrides cause slightly faster flank wear than plain carbon steel.
Can X52 be welded?
Excellent field weldability (CE_IIW ≤0.43, Pcm ≤0.25): SMAW cellulosic/low-hydrogen, GMAW/FCAW or automatic GTAW root; typically no preheat above 10 mm wall unless ambient <5 °C, avoid high heat input in TMCP material to protect HAZ toughness.
Can X52 be formed, bent or molded?
Very good cold formability — UOE/JCOE plate forming, spiral coil forming and cold field bends to 1.5 D; hot induction bending should be followed by re-normalizing or Q&T requalification to restore properties.
What surface finishes work on X52?
Standard finish is grit-blast plus FBE, 3-layer PE/PP or coal-tar coating with cathodic protection; internal flow-coat epoxy is common for gas lines. Not anodizable; phosphating or zinc metallizing for above-ground sections.
X52 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| CPSL2 L360M/N; PSL1 seamless up to 0.28 | ≤ 0.22 | 0.1 |
| Si | ≤ 0.45 | 0.25 |
| MnPSL1 up to 1.40 | ≤ 1.4 | 1.15 |
| Psour grades ≤0.020 | ≤ 0.03 | 0.01 |
| Ssour (MS/NS/QS) ≤0.003 | ≤ 0.02 | 0 |
| Nbmicro-alloying | ≤ 0.05 | 0.03 |
| Vmicro-alloying | ≤ 0.05 | 0.03 |
| TiNb+V+Ti ≤ 0.15 total | ≤ 0.04 | 0.02 |
| Cu | ≤ 0.5 | 0.1 |
| Ni | ≤ 0.5 | 0.1 |
| Cr0.50 max for some PSL2 conditions | ≤ 0.3 | 0.1 |
| Mo | ≤ 0.15 | 0.03 |
| B | ≤ 5×10⁻⁴ | 2×10⁻⁴ |
| Algrain refinement / deoxidation | ≤ 0.06 | 0.03 |
| Fe | balance | — |
X52-R — frequently asked
What is X52-R used for?
X52-R is typically used for oil pipelines, gas pipelines and welded pipe. In short: baseline transmission pipe grade; best field weldability; cold field bends to 1.5 D.
What is the yield strength of X52-R?
X52-R has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is X52-R easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines like 1020–1025 C-Mn steel (~65 % of AISI 1212); use coated carbide, moderate speeds, ample coolant — micro-alloy carbonitrides cause slightly faster flank wear than plain carbon steel.
Can X52-R be welded?
Yes — weldability is rated excellent (86/100). Excellent field weldability (CE_IIW ≤0.43, Pcm ≤0.25): SMAW cellulosic/low-hydrogen, GMAW/FCAW or automatic GTAW root; typically no preheat above 10 mm wall unless ambient <5 °C, avoid high heat input in TMCP material to protect HAZ toughness.
What surface finishes work on X52-R?
Standard finish is grit-blast plus FBE, 3-layer PE/PP or coal-tar coating with cathodic protection; internal flow-coat epoxy is common for gas lines. Not anodizable; phosphating or zinc metallizing for above-ground sections.
Can X52-R be formed, bent or molded?
Very good cold formability — UOE/JCOE plate forming, spiral coil forming and cold field bends to 1.5 D; hot induction bending should be followed by re-normalizing or Q&T requalification to restore properties.
What is the maximum service temperature of X52-R?
X52-R is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between X52-M and X52 PSL1?
M is the default condition — default modern choice for welded (ERW/SAWL/SAWH) transmission line pipe: lowest carbon equivalent, best field weldability and excellent low-temperature toughness. PSL1: lowest-cost X52 for non-critical, non-sour, moderate-temperature lines where impact testing is not required. Yield strength is 415 MPa in M versus 400 MPa in PSL1.
Sources
- API Specification 5L, Line Pipe (46th ed.) — American Petroleum Institute (2018)
- ISO 3183 Petroleum and natural gas industries — Steel pipe for pipeline transportation systems — ISO (2019)
- NACE MR0175 / ISO 15156-2 (sour service materials) — NACE/ISO (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Line pipe grade data (Tenaris, Vallourec, / ) — various producers (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.