Aluminum 6018-T651
Temper
AA 6018 · EN AlMg1SiPbMn
T651 = t6, stress relieved by stretching
Pick for drawn bar and plate that must stay dimensionally stable after heavy metal removal.
Values for the T651 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 |
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 |
T651This page 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-T651?
6018-T651 is 6018 in the T651 temper — pick for drawn bar and plate that must stay dimensionally stable after heavy metal removal. 6018-T651 has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 75% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69 GPa (10 Msi). 6018-T651 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; T651 is available on request or by drawing note.
Advantages
- Easy to machine — 93/100, better than 99% 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
- High strength — 295 MPa (42.8 ksi), better than 75% of aluminum grades
6018-T651 properties
Typical room-temperature values for 6018-T651; 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-T651 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-T651 has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 75% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
6018-T651 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-T651 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-T651 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-T651's machinability is excellent (93/100, better than 99% of aluminum grades); weldability fair (35/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6018-T651
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-T651 — frequently asked
What is 6018-T651 used for?
6018-T651 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-T651?
6018-T651 has a typical yield strength of 295 MPa (42.8 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 75% of aluminum grades. Strength varies by condition: see the 9 listed tempers.
Is 6018-T651 easy to machine?
Yes — machinability is rated excellent (93/100, better than 99% 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-T651 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-T651?
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-T651 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-T651?
6018-T651 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.