Steel X70
ASTM API 5L X70 · GB L485
X70 is a thermomechanically controlled processed (TMCP) micro-alloyed line pipe steel to API 5L X70 (L485), offered in M, Q and PSL1 conditions plus MS/MO sour-service variants.
Reference datasheet — X70 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the M condition
X70 tempers and conditions
X70 is supplied in 3 conditions, soft to hard. M is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
MDefault Thermomechanically controlled processed | Default modern condition for large-diameter gas transmission line pipe: best combination of low carbon equivalent, high low-temperature toughness and tight yield range. | 520 | 610 | 28 | 200 HB | — |
Offshore service, X70MO | For subsea/offshore risers and flowlines: tighter yield-to-tensile ratio, strain-ageing and through-thickness (Z-direction) requirements plus DWTT and CTOD testing. | 525 | 620 | 28 | 200 HB | 10 % IACS |
quenched and tempered, X70Q / L485Q | Choose for heavy-wall seamless or thick plate where TMCP through-thickness properties are hard to achieve, e.g. risers, induction bends and fittings. | 540 | 630 | 25 | 215 HB | — |
Supply forms, finishes and certifications
Ways X70 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
MS | Sour service, X70MS | Coating |
PSL1 | API 5L Product Specification Level 1, X70 | Certification |
What is X70?
X70 is a thermomechanically controlled processed (TMCP) micro-alloyed line pipe steel to API 5L X70 (L485), offered in M, Q and PSL1 conditions plus MS/MO sour-service variants. It is the common choice for modern large-diameter gas transmission because 520 MPa yield and 610 MPa tensile allow thinner walls while keeping field weldability (CE_IIW ≤0.43) and 28 % elongation; supplied mainly as UOE/JCOE and spiral (HSAW) welded pipe. Hot forming or normalizing permanently removes the TMCP strength, and coatings plus cathodic protection are required for corrosion control. X65 is the lower-cost alternative, X80 the higher-strength step. X70 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F). X70 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 610 MPa (88.5 ksi) — stronger than 67% of steel grades. Elongation at break is 28% and the elastic modulus is 207 GPa (30 Msi).
What is X70 used for?
- long-distance gas pipelines
- large-diameter welded pipe
- arctic pipelines
Advantages
- Tough — resists crack growth — 190 MPa·√m (172.9 ksi·√in), better than 99% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Readily welded — 88/100, better than 87% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Forms and bends easily — 68/100, better than 83% of steel grades
Limitations
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
X70 properties
Typical room-temperature values for X70-M; bars are the position among steel grades.
Physical3
X70 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,490°C (2,714 °F).
Mechanical16
X70 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 610 MPa (88.5 ksi) — stronger than 67% of steel grades. Elongation at break is 28% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
X70 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 µm/m·K (6.67 µin/in·°F).
Electrical3
X70 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 X70 takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 20%.
Manufacturability6
X70's machinability is good (55/100, better than 62% of steel grades); weldability excellent (88/100); formability good (68/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. X70 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with X70
Is X70 easy to machine?
Machines like a tough C-Mn steel at roughly 60 % of AISI 1212; sharp positive-rake carbide, generous feed and rigid setup avoid work-hardened glazing on bevels and counterbores.
Can X70 be welded?
Excellent weldability with CE_IIW ≤0.43 and Pcm ≤0.25 — cellulosic or low-hydrogen SMAW, GMAW/FCAW and multi-wire SAW all standard; keep heat input moderate (≈0.5–2.5 kJ/mm) so TMCP HAZ does not soften, and preheat 50–100 °C for heavy wall or damp conditions.
Can X70 be formed, bent or molded?
Cold formed by UOE/JCOE/spiral (HSAW) routes with cold expansion 0.8–1.3 %; avoid hot forming or normalizing of TMCP material, which permanently loses strength — heavy induction bends should use Q-condition or be re-quenched and tempered.
X70 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 M/Q; PSL1 allows up to 0.28 | ≤ 0.12 | 0.06 |
| Si | ≤ 0.45 | 0.25 |
| Mn | ≤ 1.7 | 1.55 |
| P | ≤ 0.03 | 0.01 |
| S≤0.002 typical for MS sour grades | ≤ 0.02 | 0 |
| Nbmicro-alloy; Nb+V+Ti ≤0.15 | ≤ 0.06 | 0.05 |
| V | ≤ 0.1 | 0.03 |
| Ti | ≤ 0.06 | 0.02 |
| Cu | ≤ 0.5 | 0.1 |
| Ni | ≤ 0.5 | 0.15 |
| Cr | ≤ 0.5 | 0.1 |
| Mo | ≤ 0.5 | 0.15 |
| Alacid-soluble Al | ≤ 0.06 | 0.03 |
| N | ≤ 0.01 | 0.01 |
| BM condition | ≤ 5×10⁻⁴ | 2×10⁻⁴ |
| Fe | balance |
What surface finishes work on X70?
Not anodizable; standard protection is grit blast plus fusion-bonded epoxy, 3-layer PE/PP or coal-tar coating with cathodic protection, and internal flow-efficiency epoxy for gas lines.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel X70 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- API 5L X70
- GB (China)
- L485
How much does X70 cost?
X70 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
X70 — frequently asked
What is X70 used for?
X70 is typically used for long-distance gas pipelines, large-diameter welded pipe and arctic pipelines. In short: standard large-diameter gas grade; TMCP strength with weldability; arctic toughness options.
What is the yield strength of X70?
X70 has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 610 MPa (88.5 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is X70 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a tough C-Mn steel at roughly 60 % of AISI 1212; sharp positive-rake carbide, generous feed and rigid setup avoid work-hardened glazing on bevels and counterbores.
Can X70 be welded?
Yes — weldability is rated excellent (88/100). Excellent weldability with CE_IIW ≤0.43 and Pcm ≤0.25 — cellulosic or low-hydrogen SMAW, GMAW/FCAW and multi-wire SAW all standard; keep heat input moderate (≈0.5–2.5 kJ/mm) so TMCP HAZ does not soften, and preheat 50–100 °C for heavy wall or damp conditions.
What surface finishes work on X70?
Not anodizable; standard protection is grit blast plus fusion-bonded epoxy, 3-layer PE/PP or coal-tar coating with cathodic protection, and internal flow-efficiency epoxy for gas lines.
Can X70 be formed, bent or molded?
Cold formed by UOE/JCOE/spiral (HSAW) routes with cold expansion 0.8–1.3 %; avoid hot forming or normalizing of TMCP material, which permanently loses strength — heavy induction bends should use Q-condition or be re-quenched and tempered.
What is the maximum service temperature of X70?
X70 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 X70-M and X70-Q?
M is the default condition — default modern condition for large-diameter gas transmission line pipe: best combination of low carbon equivalent, high low-temperature toughness and tight yield range. Q: choose for heavy-wall seamless or thick plate where TMCP through-thickness properties are hard to achieve, e.g. risers, induction bends and fittings. Yield strength is 520 MPa in M versus 540 MPa in Q.
How much does X70 cost?
X70 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- API 5L Specification for Line Pipe, 46th edition — API (2018)
- ISO 3183 Petroleum and natural gas industries — Steel pipe for pipeline transportation systems — ISO (2019)
- EN 10208-2 Steel pipes for pipelines for combustible fluids — Requirements class B (L485MB) — CEN (2020)
- ANSI/NACE MR0175 / ISO 15156-2 — Cracking-resistant carbon and low-alloy steels — NACE/ISO (2020)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Line pipe steel grades X60–X80 (TMCP hot rolled coil and plate) — major linepipe mills (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.