Steel X65
ASTM API 5L X65 · GB L450
X65 is a micro-alloyed high-strength low-alloy line pipe steel supplied to API 5L X65 (L450), available thermomechanically rolled (M), normalized (N), quenched and tempered (Q) or as-rolled (R), with MS/MO sour-service variants.
Reference datasheet — X65 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
X65 tempers and conditions
X65 is supplied in 5 conditions, soft to hard. M is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-rolled (hot-rolled, no special heat treatment), PSL1 | Lowest-cost PSL1 option for non-critical, ambient-temperature service where no impact-energy requirement is imposed. | 480 | 565 | 25 | 178 HB | 8.6 % IACS |
Normalized | Choose for seamless or normalized-plate pipe where uniform through-thickness properties and post-forming heat treatment tolerance matter more than peak toughness. | 485 | 590 | 28 | 185 HB | — |
MDefault Thermomechanically controlled processed | Default condition for LSAW/HSAW/HFW line pipe from TMCP coil or plate — best combination of strength, low-temperature toughness and low carbon equivalent for field welding. | 495 | 570 | 32 | 180 HB | — |
TMCP, offshore service | Reel-lay / deep-water offshore pipe: narrow yield band, controlled Y/T ratio and tight ovality for strain-based design and welding productivity. | 500 | 580 | 32 | 182 HB | 8.6 % IACS |
Quenched and tempered, PSL2 | Heavy-wall seamless or thick plate pipe for deep-water/high-pressure lines — tempered martensite/bainite gives the most uniform strength and toughness in thick sections. | 515 | 615 | 26 | 195 HB | — |
Supply forms, finishes and certifications
Ways X65 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 | TMCP, sour service (H₂S) per Annex H / NACE MR0175 | Coating |
What is X65?
X65 is a micro-alloyed high-strength low-alloy line pipe steel supplied to API 5L X65 (L450), available thermomechanically rolled (M), normalized (N), quenched and tempered (Q) or as-rolled (R), with MS/MO sour-service variants. Engineers specify it for long-distance transmission pipe because 495 MPa yield and 570 MPa tensile come with good field weldability at CE_IIW ≤0.43; usual forms are UOE/JCOE longitudinal-seam and spiral welded pipe. It has no inherent corrosion resistance, so external coating plus cathodic protection is standard, and reheating TMCP material erases the rolled-in strength. X70 is the next step up when wall thickness must drop. X65 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). X65 has a yield strength of 495 MPa (71.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 62% of steel grades. Elongation at break is 32% and the elastic modulus is 207 GPa (30 Msi).
What is X65 used for?
- transmission pipelines
- offshore risers
- sour service pipe (select grades)
Advantages
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 100% of steel grades
- Ductile — tolerates forming and impact — 32%, better than 95% of steel grades
- Readily welded — 90/100, better than 90% of steel grades
- Forms and bends easily — 70/100, better than 86% 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
X65 properties
Typical room-temperature values for X65-M; bars are the position among steel grades.
Physical3
X65 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
X65 has a yield strength of 495 MPa (71.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 62% of steel grades. Elongation at break is 32% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
X65 is rated for continuous service to 250°C (482 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), better than 75% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
X65 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 X65 takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 20%.
Manufacturability7
X65's machinability is good (55/100, better than 62% of steel grades); weldability excellent (90/100); formability very good (70/100).
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. X65 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with X65
Is X65 easy to machine?
Machines like normalized C-Mn steel (~60 % of AISI 1212): carbide tooling, moderate speeds; bevel ends by machining rather than flame cutting where CVN in the HAZ matters.
Can X65 be welded?
Excellent field weldability at CE_IIW ≤0.43 / Pcm ≤0.25 — SMAW cellulosic or mechanized GMAW with E/ER 8xx-class consumables; control heat input (≈0.7–2.0 kJ/mm) to avoid HAZ softening of TMCP material, low-hydrogen practice and preheat 50–100 °C for heavy wall.
Can X65 be formed, bent or molded?
Cold formed by UOE/JCOE/spiral for welded pipe and cold bent or induction bent in the field; expect ~3–5 % strain and some Bauschinger yield drop, re-check yield after cold expansion or reeling.
X65 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 max 0.12 %; seamless up to 0.16 % | ≤ 0.12 | 0.06 |
| Si | ≤ 0.45 | 0.25 |
| Mnseamless PSL2 up to 1.75 % | ≤ 1.7 | 1.45 |
| Psour service ≤0.020 % | ≤ 0.03 | 0.01 |
| Ssour service (MS) ≤0.002 % | ≤ 0.02 | 0 |
| NbNb+V+Ti ≤ 0.15 % total | ≤ 0.06 | 0.05 |
| V | ≤ 0.1 | 0.04 |
| Ti | ≤ 0.06 | 0.02 |
| Cu | ≤ 0.5 | 0.15 |
| Ni | ≤ 0.5 | 0.18 |
| Cr | ≤ 0.5 | 0.12 |
| Mohigher in Q and heavy-wall grades | ≤ 0.5 | 0.08 |
| Alacid-soluble Al, grain refinement | 0.02 – 0.06 | 0.03 |
| N | ≤ 0.01 | 0.01 |
| Cainclusion shape control for sour service | ≤ 0.01 | 0 |
| Fe | balance |
What surface finishes work on X65?
Not anodizable — protect with shot-blast + FBE, 3LPE/3LPP or concrete weight coating, plus cathodic protection; internal flow coating or corrosion inhibitor for wet service.
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 X65 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- API 5L X65
- GB (China)
- L450
How much does X65 cost?
X65 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.
X65 — frequently asked
What is X65 used for?
X65 is typically used for transmission pipelines, offshore risers and sour service pipe (select grades). In short: workhorse line pipe grade; excellent field weldability; sour-service variants available.
What is the yield strength of X65?
X65 has a typical yield strength of 495 MPa (71.8 ksi) and a tensile strength of 570 MPa (82.7 ksi) — stronger than 62% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is X65 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like normalized C-Mn steel (~60 % of AISI 1212): carbide tooling, moderate speeds; bevel ends by machining rather than flame cutting where CVN in the HAZ matters.
Can X65 be welded?
Yes — weldability is rated excellent (90/100). Excellent field weldability at CE_IIW ≤0.43 / Pcm ≤0.25 — SMAW cellulosic or mechanized GMAW with E/ER 8xx-class consumables; control heat input (≈0.7–2.0 kJ/mm) to avoid HAZ softening of TMCP material, low-hydrogen practice and preheat 50–100 °C for heavy wall.
What surface finishes work on X65?
Not anodizable — protect with shot-blast + FBE, 3LPE/3LPP or concrete weight coating, plus cathodic protection; internal flow coating or corrosion inhibitor for wet service.
Can X65 be formed, bent or molded?
Cold formed by UOE/JCOE/spiral for welded pipe and cold bent or induction bent in the field; expect ~3–5 % strain and some Bauschinger yield drop, re-check yield after cold expansion or reeling.
What is the maximum service temperature of X65?
X65 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 X65-M and X65-Q?
M is the default condition — default condition for LSAW/HSAW/HFW line pipe from TMCP coil or plate — best combination of strength, low-temperature toughness and low carbon equivalent for field welding. Q: heavy-wall seamless or thick plate pipe for deep-water/high-pressure lines — tempered martensite/bainite gives the most uniform strength and toughness in thick sections. Yield strength is 495 MPa in M versus 515 MPa in Q.
How much does X65 cost?
X65 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 ed. — American Petroleum Institute (2018)
- ISO 3183 Petroleum and natural gas industries — Steel pipe for pipeline transportation systems — ISO (2019)
- EN 10208-2 Steel pipes for pipelines — L450MB/L450NB — CEN (2020)
- NACE MR0175 / ISO 15156-2 Materials for use in H2S-containing environments — 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 plate and coil data — Baosteel / ArcelorMittal (2022)
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.