Steel X80-M
Heat-treated state · default condition
ASTM API 5L X80 · GB L555
M = thermomechanically controlled processed
Standard PSL2 delivery condition for UOE/JCOE/HFW/spiral line pipe and the pipeline plate/coil it is made from — pick this for onshore high-pressure gas transmission.
Values for the M condition
Other X80 tempers and conditions
X80 is listed in 4 conditions; see the grade overview at X80.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MDefaultThis page Thermomechanically controlled processed | Standard PSL2 delivery condition for UOE/JCOE/HFW/spiral line pipe and the pipeline plate/coil it is made from — pick this for onshore high-pressure gas transmission. | 600 | 690 | 22 | 18 HRC | 8.6 % IACS |
TMCP, offshore service | Offshore/submarine line pipe: tighter dimensional, geometry and toughness (DWTT/CVN) requirements per API 5L Annex J for laying and collapse resistance. | 610 | 700 | 22 | 214 HB | 8.6 % IACS |
Induction bend, quenched and tempered after bending | Hot induction bends made from X80 pipe and re-heat-treated to restore properties per ISO 15590-1 / DNV; specify when field bends are impractical. | 610 | 700 | 20 | 21 HRC | 8.6 % IACS |
Quenched and tempered | Used for heavy-wall seamless pipe, risers and fittings where TMCP rolling cannot reach the required thickness; higher hardness, slightly lower toughness margin. | 620 | 720 | 20 | 22 HRC | 8.6 % IACS |
What is X80-M?
X80-M is X80 heat treated to M — standard PSL2 delivery condition for UOE/JCOE/HFW/spiral line pipe and the pipeline plate/coil it is made from — pick this for onshore high-pressure gas transmission. X80-M has a yield strength of 600 MPa (87 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 77% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi). X80-M has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Advantages
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 100% of steel grades
- High strength — 600 MPa (87 ksi), better than 77% of steel grades
- Readily welded — 75/100, better than 76% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
X80-M properties
Typical room-temperature values for X80-M; 24 are specific to this condition. Other listed values are X80 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
X80-M has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical17
X80-M has a yield strength of 600 MPa (87 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 77% of steel grades. Elongation at break is 22% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
X80-M is rated for continuous service to 250°C (482 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
X80-M conducts electricity at 8.6 % IACS, better than 66% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of X80-M 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
X80-M's machinability is fair (45/100, worse than 65% of steel grades); weldability very good (75/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with X80-M
Is X80 easy to machine?
Machines like a tough C-Mn steel at ~50 % of 1212 — bevelling and counterboring need rigid setups, positive-rake carbide and generous coolant to avoid work-hardened, gummy chips.
Can X80 be welded?
Excellent weldability at CEIIW ≤0.43 / Pcm ≤0.25 with low-hydrogen consumables (GMAW-P/mechanized root, FCAW/SAW fill); control heat input (typically 0.5–2.0 kJ/mm) to limit HAZ softening and keep matching or slightly overmatching weld strength.
Can X80 be formed, bent or molded?
Cold formed by UOE/JCOE or spiral rolling followed by cold expansion (~1 %); allow for pronounced Bauschinger effect and springback, and avoid re-forming or heating above ~600 °C which erases the TMCP strength.
What surface finishes work on X80?
Shot blast to Sa 2½ then FBE, 3-layer PE/PP or liquid epoxy coating; external corrosion control always combines coating with cathodic protection — no anodizing, and hot-dip galvanizing is not used on line pipe.
X80 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 welded pipe, t ≤ 25 mm; TMCP steels typically 0.04–0.08 | ≤ 0.12 | 0.06 |
| Si | ≤ 0.45 | 0.25 |
| Mn | ≤ 1.85 | 1.75 |
| P | ≤ 0.03 | 0.01 |
| S≤0.002 typical for MS sour-service | ≤ 0.02 | 0 |
| NbNb+V+Ti ≤ 0.15 total | ≤ 0.11 | 0.06 |
| V | ≤ 0.1 | 0.02 |
| Ti | ≤ 0.06 | 0.02 |
| Cu | ≤ 0.5 | 0.2 |
| Ni | ≤ 1 | 0.25 |
| Cr | ≤ 0.5 | 0.15 |
| Mo | ≤ 0.5 | 0.2 |
| B | ≤ 5×10⁻⁴ | 2×10⁻⁴ |
| AlAl/N ≥ 2:1 typical | ≤ 0.06 | 0.03 |
| N | ≤ 0.01 | 0.01 |
| FeCEIIW ≤ 0.43 %, Pcm ≤ 0.25 % | balance | — |
X80-M — frequently asked
What is X80-M used for?
X80-M is typically used for high-pressure gas transmission, west-East pipeline projects and large diameter pipe. In short: highest-strength common line pipe; thinner wall, less steel; weld-procedure sensitive.
What is the yield strength of X80-M?
X80-M has a typical yield strength of 600 MPa (87 ksi) and a tensile strength of 690 MPa (100 ksi) — stronger than 77% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is X80-M easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machines like a tough C-Mn steel at ~50 % of 1212 — bevelling and counterboring need rigid setups, positive-rake carbide and generous coolant to avoid work-hardened, gummy chips.
Can X80-M be welded?
Yes — weldability is rated very good (75/100). Excellent weldability at CEIIW ≤0.43 / Pcm ≤0.25 with low-hydrogen consumables (GMAW-P/mechanized root, FCAW/SAW fill); control heat input (typically 0.5–2.0 kJ/mm) to limit HAZ softening and keep matching or slightly overmatching weld strength.
What surface finishes work on X80-M?
Shot blast to Sa 2½ then FBE, 3-layer PE/PP or liquid epoxy coating; external corrosion control always combines coating with cathodic protection — no anodizing, and hot-dip galvanizing is not used on line pipe.
Can X80-M be formed, bent or molded?
Cold formed by UOE/JCOE or spiral rolling followed by cold expansion (~1 %); allow for pronounced Bauschinger effect and springback, and avoid re-forming or heating above ~600 °C which erases the TMCP strength.
What is the maximum service temperature of X80-M?
X80-M is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between X80-M and X80-Q?
M is the default condition — standard PSL2 delivery condition for UOE/JCOE/HFW/spiral line pipe and the pipeline plate/coil it is made from — pick this for onshore high-pressure gas transmission. Q: used for heavy-wall seamless pipe, risers and fittings where TMCP rolling cannot reach the required thickness; higher hardness, slightly lower toughness margin. Yield strength is 600 MPa in M versus 620 MPa in Q.
Sources
- API 5L Specification for Line Pipe, 46th ed. (PSL2 grade L555M/X80M) — American Petroleum Institute (2018)
- ISO 3183 Petroleum and natural gas industries — Steel pipe for pipeline transportation systems — ISO (2019)
- ISO 15156-2 / NACE MR0175 — Materials for use in H₂S-containing environments — ISO / AMPP (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (HSLA steels) — ASM International (1990)
- High-strength TMCP line pipe steel (X80) product literature — Baosteel / Nippon Steel / Europipe (2022)
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.