Aluminum 6018-T6
Temper · default condition
AA 6018 · EN AlMg1SiPbMn
T6 = solution heat treated and artificially aged
Standard stock condition for free-machining bar and rod — peak strength with excellent chip breaking.
Values for the T6 condition
Other 6018 tempers and conditions
6018 is listed in 9 conditions; see the grade overview at 6018.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition, used for intermediate forming or for stock that will be solution treated and aged later. | 65 | 130 | 22 | 35 HB | 49 % IACS |
Solution heat treated and naturally aged | Choose when parts must be bent, staked or headed after machining and aged to T6 afterwards. | 130 | 235 | 18 | 65 HB | 38 % IACS |
Cooled from hot working and artificially aged | Economical press-quenched temper for smaller sections where full T6 strength is not required. | 250 | 290 | 11 | 85 HB | 44 % IACS |
T6DefaultThis page Solution heat treated and artificially aged | Standard stock condition for free-machining bar and rod — peak strength with excellent chip breaking. | 290 | 330 | 10 | 95 HB | 42 % IACS |
T6, stress relieved by stretching | Pick for drawn bar and plate that must stay dimensionally stable after heavy metal removal. | 295 | 330 | 10 | 95 HB | 42 % IACS |
Solution treated, stretched, aged; no further straightening | Extruded bar/profile with residual stress removed by stretching — lowest distortion for one-side machining. | 295 | 330 | 10 | 95 HB | 42 % IACS |
T6, stress relieved by stretching, minor straightening | Same as T6510 but with allowance for light straightening — the usual purchase spec for long screw-machine bar. | 295 | 330 | 10 | 95 HB | 42 % IACS |
Solution heat treated, cold worked and artificially aged | Cold-drawn-before-aging bar for higher strength and even better surface finish in high-speed turning. | 340 | 370 | 8 | 105 HB | 42 % IACS |
Solution heat treated, artificially aged and cold worked | Highest-strength screw-machine temper; cold drawing after aging maximises hardness and chip control. | 365 | 390 | 7 | 115 HB | 42 % IACS |
What is 6018-T6?
6018-T6 is 6018 in the T6 temper — standard stock condition for free-machining bar and rod — peak strength with excellent chip breaking. 6018-T6 has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 74% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69 GPa (10 Msi). 6018-T6 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 585°C (1,085 °F).
Advantages
- Easy to machine — 92/100, better than 98% of aluminum grades
- Conducts heat well — 170 W/m·K (98.2 BTU/hr·ft·°F), better than 82% of aluminum grades
- High electrical conductivity — 42 % IACS, better than 81% of aluminum grades
6018-T6 properties
Typical room-temperature values for 6018-T6; 17 are specific to this condition. Other listed values are 6018 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
6018-T6 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 585°C (1,085 °F).
Mechanical16
6018-T6 has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 74% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
6018-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 170 W/m·K (98.2 BTU/hr·ft·°F), better than 82% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6018-T6 conducts electricity at 42 % IACS, better than 81% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of 6018-T6 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
6018-T6's machinability is excellent (92/100, better than 98% of aluminum grades); weldability fair (35/100); formability fair (40/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6018-T6
Is 6018 easy to machine?
Excellent free-cutting behaviour — run high SFM with polished-flute carbide, light feeds and flood coolant; lead gives short chips and mirror-like bores, but collect swarf separately for lead-bearing recycling.
Can 6018 be welded?
Not recommended for fusion welding: lead segregates at grain boundaries and causes hot cracking; use mechanical joining or adhesive bonding, or switch to 6061/6082 where welding is required.
Can 6018 be formed, bent or molded?
Form only in O/T4; in T6 and above bending and thread rolling are limited by low ductility — rolled threads are usually produced before final aging.
What surface finishes work on 6018?
Clear sulfuric anodize is possible but expect grey/streaky films from lead particles; chromate conversion, chemical nickel or trivalent passivation give more uniform cosmetics, hard anodizing should be avoided.
6018 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 |
|---|---|---|
| Siwith Mg forms Mg2Si strengthening phase | 0.5 – 0.9 | 0.7 |
| Feimpurity limit | ≤ 0.35 | 0.2 |
| Cu | ≤ 0.2 | 0.05 |
| Mngrain-structure control, distinguishes 6018 from 6262 | 0.1 – 0.45 | 0.25 |
| Mg≈1 % per AlMg1SiPbMn designation | 0.6 – 1.2 | 0.9 |
| Cr | ≤ 0.1 | — |
| Zn | ≤ 0.2 | — |
| Pbfree-machining addition; restricted by RoHS/ELV exemptions | 0.4 – 0.9 | 0.6 |
| Bioptional co-addition in some producer variants | ≤ 0.2 | — |
| Tigrain refiner | ≤ 0.1 | 0.02 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
6018-T6 — frequently asked
What is 6018-T6 used for?
6018-T6 is typically used for machined fittings and adapters, turned hardware components, threaded inserts and bushings, instrument and meter bodies, pneumatic connector bodies and rolled-thread studs and pins. In short: free-cutting Al-Mg-Si bar; mirror-finish bores; poor weldability, leaded.
What is the yield strength of 6018-T6?
6018-T6 has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 74% of aluminum grades. Strength varies by condition: see the 9 listed tempers.
Is 6018-T6 easy to machine?
Yes — machinability is rated excellent (92/100, better than 98% of aluminum grades). Excellent free-cutting behaviour — run high SFM with polished-flute carbide, light feeds and flood coolant; lead gives short chips and mirror-like bores, but collect swarf separately for lead-bearing recycling.
Can 6018-T6 be welded?
With care — weldability is rated fair (35/100). Not recommended for fusion welding: lead segregates at grain boundaries and causes hot cracking; use mechanical joining or adhesive bonding, or switch to 6061/6082 where welding is required.
What surface finishes work on 6018-T6?
Clear sulfuric anodize is possible but expect grey/streaky films from lead particles; chromate conversion, chemical nickel or trivalent passivation give more uniform cosmetics, hard anodizing should be avoided.
Can 6018-T6 be formed, bent or molded?
Form only in O/T4; in T6 and above bending and thread rolling are limited by low ductility — rolled threads are usually produced before final aging.
What is the maximum service temperature of 6018-T6?
6018-T6 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 6018-T6 and 6018-O?
T6 is the default condition — standard stock condition for free-machining bar and rod — peak strength with excellent chip breaking. O: softest condition, used for intermediate forming or for stock that will be solution treated and aged later. Yield strength is 290 MPa in T6 versus 65 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- EN 573-3 / EN 755-2 — Aluminium and aluminium alloys: chemical composition and mechanical properties of extruded bar — CEN (2019)
- Free-machining Al-Mg-Si-Pb screw-machine bar datasheets — European extruders (e.g. Alcoa/Constellium/Aluminium Rheinfelden lines) (2020)
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.