Aluminum AC1B-T4
Temper
JIS AC1B
T4 = solution heat treated and naturally aged
Best ductility/toughness combination for shock-loaded structural castings.
Values for the T4 condition
Other AC1B tempers and conditions
AC1B is listed in 4 conditions; see the grade overview at AC1B.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Use for low-stress parts or as the delivery state before machining and later heat treatment. | 100 | 180 | 4 | 60 HB | 38 % IACS |
T4This page Solution heat treated and naturally aged | Best ductility/toughness combination for shock-loaded structural castings. | 190 | 320 | 12 | 85 HB | 30 % IACS |
Solution heat treated and overaged (stabilized) | Pick when dimensional stability at elevated temperature and reduced residual stress matter more than peak strength. | 230 | 300 | 5 | 90 HB | 36 % IACS |
T6Default Solution heat treated and artificially aged | Default condition — maximum strength and hardness for load-bearing aerospace/machinery castings. | 250 | 350 | 6 | 100 HB | 33 % IACS |
What is AC1B-T4?
AC1B-T4 is AC1B in the T4 temper — best ductility/toughness combination for shock-loaded structural castings. AC1B-T4 has a yield strength of 190 MPa (27.6 ksi) and a tensile strength of 320 MPa (46.4 ksi) — weaker than 52% of aluminum grades. Elongation at break is 12% and the elastic modulus is 71 GPa (10.3 Msi). AC1B-T4 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 545°C (1,013 °F). T6 is the default condition FabDigit quotes; T4 is available on request or by drawing note.
Advantages
- Easy to machine — 78/100, better than 89% of aluminum grades
Limitations
- Needs corrosion protection — 35/100, worse than 85% of aluminum grades
AC1B-T4 properties
Typical room-temperature values for AC1B-T4; 11 are specific to this condition. Other listed values are AC1B reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
AC1B-T4 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 545°C (1,013 °F).
Mechanical13
AC1B-T4 has a yield strength of 190 MPa (27.6 ksi) and a tensile strength of 320 MPa (46.4 ksi) — weaker than 52% of aluminum grades. Elongation at break is 12% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
AC1B-T4 is rated for continuous service to 150°C (302 °F). It conducts heat at 125 W/m·K (72.2 BTU/hr·ft·°F), worse than 72% of aluminum grades. Thermal expansion is 22.5 µm/m·K (12.5 µin/in·°F).
Electrical3
AC1B-T4 conducts electricity at 30 % IACS, worse than 73% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 85% of aluminum grades.
Sustainability4
Producing a kilogram of AC1B-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%.
Manufacturability7
AC1B-T4's machinability is very good (78/100, better than 89% of aluminum grades); weldability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AC1B-T4
Is AC1B easy to machine?
Machines very well in T4/T6 with sharp carbide/PCD tooling, high speeds and light feeds; chips break cleanly and surface finish is good.
Can AC1B be welded?
Poor fusion weldability — Al-Cu castings are highly hot-crack sensitive; repair only with matched 2319-type filler plus preheat and post-weld solution+age.
Can AC1B be formed, bent or molded?
Sand or permanent-mould casting only; low fluidity and wide freezing range demand generous risers, chills and directional solidification to avoid hot tears and shrinkage porosity.
What surface finishes work on AC1B?
Anodising gives dull grey, less protective films because of the copper — chromate conversion, primer + paint or Ni/Cd plating is the usual protection route.
AC1B 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 |
|---|---|---|
| Cumain strengthening element (Al2Cu) | 4.2 – 5 | 4.6 |
| Mg | 0.15 – 0.35 | 0.25 |
| Tigrain refiner | 0.05 – 0.3 | 0.2 |
| Siimpurity limit | ≤ 0.2 | — |
| Feimpurity limit | ≤ 0.2 | — |
| Mnimpurity limit | ≤ 0.1 | — |
| Znimpurity limit | ≤ 0.1 | — |
| Niimpurity limit | ≤ 0.05 | — |
| Snimpurity limit | ≤ 0.05 | — |
| Pbimpurity limit | ≤ 0.05 | — |
| Al | balance | — |
AC1B-T4 — frequently asked
What is AC1B-T4 used for?
AC1B-T4 is typically used for aerospace fittings, structural castings and high-load brackets. In short: improved castability over AC1A; high-strength Al-Cu casting; machinability rating 80.
What is the yield strength of AC1B-T4?
AC1B-T4 has a typical yield strength of 190 MPa (27.6 ksi) and a tensile strength of 320 MPa (46.4 ksi) — weaker than 52% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is AC1B-T4 easy to machine?
Yes — machinability is rated very good (78/100, better than 89% of aluminum grades). Machines very well in T4/T6 with sharp carbide/PCD tooling, high speeds and light feeds; chips break cleanly and surface finish is good.
Can AC1B-T4 be welded?
Not readily — weldability is rated poor (30/100). Poor fusion weldability — Al-Cu castings are highly hot-crack sensitive; repair only with matched 2319-type filler plus preheat and post-weld solution+age.
What surface finishes work on AC1B-T4?
Anodising gives dull grey, less protective films because of the copper — chromate conversion, primer + paint or Ni/Cd plating is the usual protection route.
Can AC1B-T4 be formed, bent or molded?
Sand or permanent-mould casting only; low fluidity and wide freezing range demand generous risers, chills and directional solidification to avoid hot tears and shrinkage porosity.
What is the maximum service temperature of AC1B-T4?
AC1B-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 AC1B-T6 and AC1B-F?
T6 is the default condition — default condition — maximum strength and hardness for load-bearing aerospace/machinery castings. F: use for low-stress parts or as the delivery state before machining and later heat treatment. Yield strength is 250 MPa in T6 versus 100 MPa in F.
Sources
- JIS H5202 Aluminium alloy castings — Japanese Standards Association (2010)
- GB/T 1173 (ZL201A) — SAC (2013)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
- ASM Handbook Vol.13B — Corrosion: Materials — ASM International (2005)
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.