Aluminum 6018-T4
Temper
AA 6018 · EN AlMg1SiPbMn
T4 = solution heat treated and naturally aged
Choose when parts must be bent, staked or headed after machining and aged to T6 afterwards.
Values for the T4 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 |
T4This page 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 |
T6Default 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-T4?
6018-T4 is 6018 in the T4 temper — choose when parts must be bent, staked or headed after machining and aged to T6 afterwards. 6018-T4 has a yield strength of 130 MPa (18.9 ksi) and a tensile strength of 235 MPa (34.1 ksi) — weaker than 73% of aluminum grades. Elongation at break is 18% and the elastic modulus is 69 GPa (10 Msi). 6018-T4 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). T6 is the default condition FabDigit quotes; T4 is available on request or by drawing note.
Advantages
- Easy to machine — 82/100, better than 94% of aluminum grades
- Ductile — tolerates forming and impact — 18%, better than 86% of aluminum grades
- Forms and bends easily — 65/100, better than 80% of aluminum grades
6018-T4 properties
Typical room-temperature values for 6018-T4; 10 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-T4 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-T4 has a yield strength of 130 MPa (18.9 ksi) and a tensile strength of 235 MPa (34.1 ksi) — weaker than 73% of aluminum grades. Elongation at break is 18% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
6018-T4 is rated for continuous service to 150°C (302 °F). It conducts heat at 155 W/m·K (89.6 BTU/hr·ft·°F), better than 71% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6018-T4 conducts electricity at 38 % IACS, better than 61% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of 6018-T4 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-T4's machinability is very good (82/100, better than 94% of aluminum grades); weldability fair (35/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6018-T4
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-T4 — frequently asked
What is 6018-T4 used for?
6018-T4 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-T4?
6018-T4 has a typical yield strength of 130 MPa (18.9 ksi) and a tensile strength of 235 MPa (34.1 ksi) — weaker than 73% of aluminum grades. Strength varies by condition: see the 9 listed tempers.
Is 6018-T4 easy to machine?
Yes — machinability is rated very good (82/100, better than 94% 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-T4 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-T4?
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-T4 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-T4?
6018-T4 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.