Aluminum 2A12-T42
Temper
GB 2A12
T42 = solution treated by the user and naturally aged
Used when O-temper material is formed first and then heat treated by the fabricator.
Values for the T42 condition
Other 2A12 tempers and conditions
2A12 is listed in 10 conditions; see the grade overview at 2A12.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Choose for deep forming, bending or cold heading before solution treatment. | 75 | 185 | 20 | 47 HB | 50 % IACS |
Strain hardened from hot working only | Low-cost mill-finish bar or profile for non-critical parts that will be heat treated or lightly loaded. | 150 | 260 | 12 | 70 HB | 42 % IACS |
T42This page Solution treated by the user and naturally aged | Used when O-temper material is formed first and then heat treated by the fabricator. | 260 | 425 | 19 | 105 HB | 30 % IACS |
T4Default Solution heat treated and naturally aged | Default stocked condition for 2A12 plate, bar and extrusion — best mix of strength, toughness and residual formability. | 325 | 470 | 19 | 120 HB | 30 % IACS |
T3, stress relieved by stretching | Preferred for thick plate that will be heavily machined — low residual stress means minimal distortion. | 325 | 470 | 19 | 120 HB | 30 % IACS |
Solution heat treated, cold worked and naturally aged | Standard aerospace sheet condition where the extra cold work raises yield strength. | 345 | 485 | 18 | 120 HB | 30 % IACS |
T6, heat treated by the user | Same target properties as T6 but achieved by re-heat-treating O or T-temper stock after forming. | 390 | 470 | 9 | 125 HB | 38 % IACS |
Solution heat treated and artificially aged | Pick when a higher yield strength and better stress-corrosion behaviour than T4 are needed, at the cost of ductility. | 395 | 475 | 10 | 125 HB | 38 % IACS |
Solution treated, cold worked, artificially aged | High-yield sheet condition for skins and fittings that must resist creep/exfoliation better than T3. | 450 | 485 | 6 | 128 HB | 38 % IACS |
T8, stress relieved by stretching | Best choice for machined structural plate needing high yield strength, low residual stress and improved exfoliation resistance. | 450 | 480 | 6 | 128 HB | 38 % IACS |
What is 2A12-T42?
2A12-T42 is 2A12 in the T42 temper — used when O-temper material is formed first and then heat treated by the fabricator. 2A12-T42 has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 425 MPa (61.6 ksi) — stronger than 68% of aluminum grades. Elongation at break is 19% and the elastic modulus is 73 GPa (10.6 Msi). 2A12-T42 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 502°C (936 °F). T4 is the default condition FabDigit quotes; T42 is available on request or by drawing note.
Advantages
- Tough — resists crack growth — 37 MPa·√m (33.7 ksi·√in), better than 94% of aluminum grades
- Ductile — tolerates forming and impact — 19%, better than 87% of aluminum grades
Limitations
- Needs corrosion protection — 28/100, worse than 99% of aluminum grades
- Difficult to weld — 15/100, worse than 96% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
- Poor heat conductor — 121 W/m·K (69.9 BTU/hr·ft·°F), worse than 76% of aluminum grades
2A12-T42 properties
Typical room-temperature values for 2A12-T42; 21 are specific to this condition. Other listed values are 2A12 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
2A12-T42 has a density of 2.78 g/cm³ (0.1 lb/in³), heavier than 74% of aluminum grades. It melts at 502°C (936 °F).
Mechanical15
2A12-T42 has a yield strength of 260 MPa (37.7 ksi) and a tensile strength of 425 MPa (61.6 ksi) — stronger than 68% of aluminum grades. Elongation at break is 19% and the elastic modulus is 73 GPa (10.6 Msi).
Thermal6
2A12-T42 is rated for continuous service to 120°C (248 °F). It conducts heat at 121 W/m·K (69.9 BTU/hr·ft·°F), worse than 76% of aluminum grades. Thermal expansion is 23.2 µm/m·K (12.9 µin/in·°F).
Electrical3
2A12-T42 conducts electricity at 30 % IACS, worse than 73% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (28/100), worse than 99% of aluminum grades.
Sustainability4
Producing a kilogram of 2A12-T42 takes about 210 MJ of energy and emits 13.5 kg of CO₂ — more than 88% of aluminum grades. Typical recycled content is 15%.
Manufacturability8
2A12-T42's machinability is good (68/100, better than 67% of aluminum grades); weldability poor (15/100); formability good (55/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 2A12-T42
Is 2A12 easy to machine?
Machines very well in T4/T351/T851 with sharp carbide tools, high speed and flood coolant; chips are short and surface finish is good, but annealed O temper is gummy.
Can 2A12 be welded?
Not recommended for MIG/TIG fusion welding (hot cracking and severe HAZ strength loss); join by riveting, bolting, adhesive bonding or friction-stir welding.
Can 2A12 be formed, bent or molded?
Form in O or freshly quenched (W) temper and re-age; T3/T4 sheet tolerates moderate bends at large radii, artificially aged tempers are nearly unformable.
What surface finishes work on 2A12?
Chromic or sulfuric anodize plus primer is normal; expect a yellow-brown film, and use clad sheet, Alodine conversion coating or paint for corrosion protection.
2A12 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 |
|---|---|---|
| Cuprimary strengthening element | 3.8 – 4.9 | 4.4 |
| Mg | 1.2 – 1.8 | 1.5 |
| Mn | 0.3 – 0.9 | 0.6 |
| Siimpurity | ≤ 0.5 | — |
| Feimpurity | ≤ 0.5 | — |
| Zn | ≤ 0.3 | — |
| Ni | ≤ 0.1 | — |
| Ti | ≤ 0.15 | — |
| others (each)total ≤ 0.15 | ≤ 0.05 | — |
| Al | balance | — |
2A12-T42 — frequently asked
What is 2A12-T42 used for?
2A12-T42 is typically used for aerospace tooling, precision fixtures, check gauges and jig plates. In short: 2024-equivalent tooling plate; high strength, low corrosion resistance; not fusion weldable.
What is the yield strength of 2A12-T42?
2A12-T42 has a typical yield strength of 260 MPa (37.7 ksi) and a tensile strength of 425 MPa (61.6 ksi) — stronger than 68% of aluminum grades. Strength varies by condition: see the 10 listed tempers.
Is 2A12-T42 easy to machine?
Reasonably — machinability is rated good (68/100, better than 67% of aluminum grades). Machines very well in T4/T351/T851 with sharp carbide tools, high speed and flood coolant; chips are short and surface finish is good, but annealed O temper is gummy.
Can 2A12-T42 be welded?
Not readily — weldability is rated poor (15/100). Not recommended for MIG/TIG fusion welding (hot cracking and severe HAZ strength loss); join by riveting, bolting, adhesive bonding or friction-stir welding.
What surface finishes work on 2A12-T42?
Chromic or sulfuric anodize plus primer is normal; expect a yellow-brown film, and use clad sheet, Alodine conversion coating or paint for corrosion protection.
Can 2A12-T42 be formed, bent or molded?
Form in O or freshly quenched (W) temper and re-age; T3/T4 sheet tolerates moderate bends at large radii, artificially aged tempers are nearly unformable.
What is the maximum service temperature of 2A12-T42?
2A12-T42 is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 2A12-T4 and 2A12-O?
T4 is the default condition — default stocked condition for 2A12 plate, bar and extrusion — best mix of strength, toughness and residual formability. O: choose for deep forming, bending or cold heading before solution treatment. Yield strength is 325 MPa in T4 versus 75 MPa in O.
Sources
- ASM Handbook Vol.2: Properties and Selection — Nonferrous Alloys (2024 alloy data) — ASM International (1990)
- MMPDS-17 typical/design properties for 2024 — Battelle/FAA (2022)
- Aluminum Association Teal Sheets — International Alloy Designations — The Aluminum Association (2018)
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.