Aluminum AC4D-T6
Temper · default condition
JIS AC4D · EN AC-45300
T6 = solution heat treated and artificially aged
Standard high-strength condition: best strength/ductility balance for pressure-tight, moderately loaded castings.
Values for the T6 condition
Other AC4D tempers and conditions
AC4D is listed in 5 conditions; see the grade overview at AC4D.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Lowest-cost condition for lightly loaded, dimensionally stable-enough parts where no strengthening is needed. | 100 | 170 | 2.5 | 65 HB | 43 % IACS |
Cooled from hot working and artificially aged | Choose when dimensional stability and a modest strength/hardness gain are wanted without the distortion risk of solution quenching. | 155 | 195 | 1.5 | 72 HB | 42 % IACS |
T6DefaultThis page Solution heat treated and artificially aged | Standard high-strength condition: best strength/ductility balance for pressure-tight, moderately loaded castings. | 180 | 250 | 2.5 | 88 HB | 39 % IACS |
Solution heat treated and overaged (stabilized) | Use when long-term dimensional stability at elevated temperature matters more than peak room-temperature strength. | 235 | 260 | 1 | 85 HB | 41 % IACS |
T6 variant, underaged | Pick for maximum strength and hardness / best wear and machined-surface finish where very low elongation is acceptable. | 245 | 280 | 1 | 96 HB | 37 % IACS |
What is AC4D-T6?
AC4D-T6 is AC4D in the T6 temper — standard high-strength condition: best strength/ductility balance for pressure-tight, moderately loaded castings. AC4D-T6 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 54% of aluminum grades. Elongation at break is 2.5% and the elastic modulus is 71 GPa (10.3 Msi). AC4D-T6 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 549°C (1,020 °F).
Limitations
- Limited ductility — 2.5%, worse than 83% of aluminum grades
- Limited formability — 10/100, worse than 80% of aluminum grades
- Hard to polish — 45/100, worse than 76% of aluminum grades
AC4D-T6 properties
Typical room-temperature values for AC4D-T6; 10 are specific to this condition. Other listed values are AC4D reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
AC4D-T6 has a density of 2.71 g/cm³ (0.0979 lb/in³), heavier than 51% of aluminum grades. It melts at 549°C (1,020 °F).
Mechanical12
AC4D-T6 has a yield strength of 180 MPa (26.1 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 54% of aluminum grades. Elongation at break is 2.5% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
AC4D-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 151 W/m·K (87.2 BTU/hr·ft·°F), better than 63% of aluminum grades. Thermal expansion is 22.3 µm/m·K (12.4 µin/in·°F).
Electrical3
AC4D-T6 conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.
Sustainability4
Producing a kilogram of AC4D-T6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 70%.
Manufacturability8
AC4D-T6's machinability is good (62/100, better than 55% of aluminum grades); weldability fair (40/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AC4D-T6
Is AC4D easy to machine?
Machines well in T6/T61 with sharp carbide or PCD tooling, high speed and flood coolant; eutectic Si is abrasive, so avoid HSS for production runs and expect some tool wear.
Can AC4D be welded?
Fusion welding is only fair — the 1–1.5 % Cu promotes hot cracking and reduces as-welded properties; use 4043/4145 filler for repair and re-solution + re-age if full strength is required.
Can AC4D be formed, bent or molded?
Sand and permanent-mould (gravity) casting alloy with good fluidity and pressure tightness; requires well-fed risers and controlled solidification to avoid shrinkage porosity, and Sr/Na modification plus Ti-B refinement improve ductility.
What surface finishes work on AC4D?
Hard or sulphuric anodize is functional but dark and mottled; chromate conversion, epoxy primer/paint or impregnation for pressure tightness are the usual routes, and polishing is limited by Si particles.
AC4D 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 |
|---|---|---|
| Sifluidity and strength | 4.5 – 5.5 | 5 |
| Custrength; lowers corrosion resistance | 1 – 1.5 | 1.25 |
| MgMg2Si precipitation hardening | 0.4 – 0.6 | 0.5 |
| Feimpurity max (sand/permanent mould) | ≤ 0.6 | — |
| Mn | ≤ 0.5 | — |
| Zn | ≤ 0.3 | — |
| Ni | ≤ 0.2 | — |
| Tigrain refinement | ≤ 0.2 | — |
| Cr | ≤ 0.15 | — |
| Sn | ≤ 0.05 | — |
| Pb | ≤ 0.05 | — |
| Al | balance | — |
AC4D-T6 — frequently asked
What is AC4D-T6 used for?
AC4D-T6 is typically used for cylinder heads, aircraft fittings and high-strength housings. In short: cu-Mg strengthened AC4C; higher hardness, lower ductility; pressure-tight gravity castings.
What is the yield strength of AC4D-T6?
AC4D-T6 has a typical yield strength of 180 MPa (26.1 ksi) and a tensile strength of 250 MPa (36.3 ksi) — weaker than 54% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is AC4D-T6 easy to machine?
Reasonably — machinability is rated good (62/100, better than 55% of aluminum grades). Machines well in T6/T61 with sharp carbide or PCD tooling, high speed and flood coolant; eutectic Si is abrasive, so avoid HSS for production runs and expect some tool wear.
Can AC4D-T6 be welded?
With care — weldability is rated fair (40/100). Fusion welding is only fair — the 1–1.5 % Cu promotes hot cracking and reduces as-welded properties; use 4043/4145 filler for repair and re-solution + re-age if full strength is required.
What surface finishes work on AC4D-T6?
Hard or sulphuric anodize is functional but dark and mottled; chromate conversion, epoxy primer/paint or impregnation for pressure tightness are the usual routes, and polishing is limited by Si particles.
Can AC4D-T6 be formed, bent or molded?
Sand and permanent-mould (gravity) casting alloy with good fluidity and pressure tightness; requires well-fed risers and controlled solidification to avoid shrinkage porosity, and Sr/Na modification plus Ti-B refinement improve ductility.
What is the maximum service temperature of AC4D-T6?
AC4D-T6 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 AC4D-T6 and AC4D-F?
T6 is the default condition — standard high-strength condition: best strength/ductility balance for pressure-tight, moderately loaded castings. F: lowest-cost condition for lightly loaded, dimensionally stable-enough parts where no strengthening is needed. Yield strength is 180 MPa in T6 versus 100 MPa in F.
Sources
- JIS H 5202 Aluminium alloy castings — JSA (2010)
- GB/T 1173 (ZL105 / ZAlSi5Cu1Mg) — SAC (2013)
- ASTM B26/B26M Aluminum-Alloy Sand Castings (355.0) — ASTM (2018)
- ASM Handbook Vol. 2 — Properties of Aluminum Casting Alloys — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
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.