Aluminum 6023-T651
Temper
AA 6023 · EN AlSi1Sn1MgBi
T651 = t6, stress relieved by stretching
Choose when tight dimensional stability after heavy stock removal is required from plate or drawn bar.
Values for the T651 condition
Other 6023 tempers and conditions
6023 is listed in 8 conditions; see the grade overview at 6023.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition for heavy cold forming, deep drilling or re-heat-treatment; not a normal stock condition for this alloy. | 80 | 150 | 22 | 45 HB | 49 % IACS |
Solution heat treated and naturally aged | Intermediate strength with better ductility; used when parts are formed or staked after machining and later aged to T6. | 145 | 250 | 18 | 68 HB | 37 % IACS |
T6Default Solution heat treated and artificially aged | Standard stocked condition for automatic-lathe bar: peak strength with short, well-broken chips. | 295 | 330 | 10 | 100 HB | 40 % IACS |
T651This page T6, stress relieved by stretching | Choose when tight dimensional stability after heavy stock removal is required from plate or drawn bar. | 300 | 330 | 10 | 100 HB | 40 % IACS |
Solution treated, stretched, artificially aged, no further straightening | Extruded bar/profile with residual stress relieved by stretching and no post-stretch straightening — best distortion control for long machined parts. | 300 | 330 | 10 | 100 HB | 40 % IACS |
T6, stress relieved by stretching, minor straightening | Most common extruded free-machining bar condition: stress-relieved, straight, ready for CNC/screw-machine work. | 300 | 330 | 10 | 100 HB | 40 % IACS |
Solution heat treated, cold worked and artificially aged | Cold-drawn-then-aged bar for higher strength and even better surface finish/chip control than T6. | 350 | 375 | 8 | 110 HB | 41 % IACS |
Solution heat treated, artificially aged and cold worked | Highest-strength, close-tolerance cold-finished bar for high-volume screw-machine parts needing maximum surface quality. | 380 | 400 | 6 | 120 HB | 41 % IACS |
What is 6023-T651?
6023-T651 is 6023 in the T651 temper — choose when tight dimensional stability after heavy stock removal is required from plate or drawn bar. 6023-T651 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 77% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69.5 GPa (10.1 Msi). 6023-T651 has a density of 2.72 g/cm³ (0.0983 lb/in³), heavier than 57% of aluminum grades. It melts at 575°C (1,067 °F). T6 is the default condition FabDigit quotes; T651 is available on request or by drawing note.
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 strength — 300 MPa (43.5 ksi), better than 77% of aluminum grades
Limitations
- Difficult to weld — 25/100, worse than 76% of aluminum grades
6023-T651 properties
Typical room-temperature values for 6023-T651; 10 are specific to this condition. Other listed values are 6023 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
6023-T651 has a density of 2.72 g/cm³ (0.0983 lb/in³), heavier than 57% of aluminum grades. It melts at 575°C (1,067 °F).
Mechanical13
6023-T651 has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 77% of aluminum grades. Elongation at break is 10% and the elastic modulus is 69.5 GPa (10.1 Msi).
Thermal6
6023-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
6023-T651 conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), better than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 6023-T651 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability7
6023-T651's machinability is excellent (92/100, better than 98% of aluminum grades); weldability poor (25/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6023-T651
Is 6023 easy to machine?
Excellent — run at high spindle speed with polished-flute carbide, light lubrication; Sn/Bi phases break chips into short curls so deep drilling and Swiss-turning need no chip-breaker geometry.
Can 6023 be welded?
Poor — low-melting Sn/Bi films cause hot cracking and weak fusion zones; use mechanical joints, adhesives or friction/resistance methods instead of MIG/TIG.
Can 6023 be formed, bent or molded?
Extrude and cold-draw in the soft or T4 condition; bending in T6 requires generous radii (>3t) and heavy cold forming risks tearing at the second-phase particles.
What surface finishes work on 6023?
Takes clear and coloured sulphuric anodizing well (main advantage over 2011); bright/decorative anodizing may show slight grey speckle, and electroless-nickel or chromate conversion coatings work normally.
6023 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 the Mg2Si strengthening phase | 0.7 – 1.3 | 1 |
| Mg | 0.6 – 1.2 | 0.9 |
| Snprimary free-machining (chip-breaking) addition, lead substitute | 0.6 – 1.4 | 1 |
| Bisecondary free-machining addition | 0.2 – 0.8 | 0.5 |
| Feimpurity limit | ≤ 0.5 | 0.25 |
| Cu | ≤ 0.2 | 0.05 |
| Mn | ≤ 0.3 | 0.05 |
| Cr | ≤ 0.15 | 0.03 |
| Zn | ≤ 0.2 | 0.05 |
| Tigrain refiner | ≤ 0.1 | 0.02 |
| Pbkept low for RoHS/ELV lead-free status | ≤ 0.05 | 0 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Albalance; verify exact limits against the current AA Teal Sheets / EN 573-3 registration for EN AW-6023 | balance | — |
6023-T651 — frequently asked
What is 6023-T651 used for?
6023-T651 is typically used for precision turned parts, electrical and RF connector bodies, screw machine fittings, swiss-turned pins and spacers, deep-drilled manifold blocks and anodized instrument components. In short: lead-free free-machining alloy; anodizes better than 2011; poor fusion weldability.
What is the yield strength of 6023-T651?
6023-T651 has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 77% of aluminum grades. Strength varies by condition: see the 8 listed tempers.
Is 6023-T651 easy to machine?
Yes — machinability is rated excellent (92/100, better than 98% of aluminum grades). Excellent — run at high spindle speed with polished-flute carbide, light lubrication; Sn/Bi phases break chips into short curls so deep drilling and Swiss-turning need no chip-breaker geometry.
Can 6023-T651 be welded?
Not readily — weldability is rated poor (25/100). Poor — low-melting Sn/Bi films cause hot cracking and weak fusion zones; use mechanical joints, adhesives or friction/resistance methods instead of MIG/TIG.
What surface finishes work on 6023-T651?
Takes clear and coloured sulphuric anodizing well (main advantage over 2011); bright/decorative anodizing may show slight grey speckle, and electroless-nickel or chromate conversion coatings work normally.
Can 6023-T651 be formed, bent or molded?
Extrude and cold-draw in the soft or T4 condition; bending in T6 requires generous radii (>3t) and heavy cold forming risks tearing at the second-phase particles.
What is the maximum service temperature of 6023-T651?
6023-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 6023-T6 and 6023-O?
T6 is the default condition — standard stocked condition for automatic-lathe bar: peak strength with short, well-broken chips. O: softest condition for heavy cold forming, deep drilling or re-heat-treatment; not a normal stock condition for this alloy. Yield strength is 295 MPa in T6 versus 80 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN 573-3 Aluminium and aluminium alloys — Chemical composition (EN AW-6023 AlSi1Sn1MgBi) — CEN (2019)
- EN 755-2 Aluminium extruded rod/bar — Mechanical properties — CEN (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- Lead-free free-machining aluminium bar (Sn/Bi modified 6000 series) technical data — European extruder datasheets (2022)
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.