Aluminum AC4C-T7
Temper
JIS AC4C · ASTM 356.0
T7 = solution heat treated and overaged (stabilized)
Overaged for dimensional stability, reduced residual stress and better toughness at elevated service temperature, at some loss of peak strength.
Values for the T7 condition
Other AC4C tempers and conditions
AC4C is listed in 5 conditions; see the grade overview at AC4C.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Cheapest condition for low-stress housings and covers where dimensional stability and strength demands are modest. | 85 | 165 | 5 | 55 HB | 41 % IACS |
Cooled from hot working and artificially aged | Low-distortion route: modest strength/hardness gain and stress relief without a solution treatment quench. | 125 | 185 | 4 | 65 HB | 42 % IACS |
T6Default Solution heat treated and artificially aged | Standard structural condition: best balance of strength, ductility and fatigue life for wheels, knuckles and pressure-tight housings. | 180 | 250 | 5 | 80 HB | 39 % IACS |
T7This page Solution heat treated and overaged (stabilized) | Overaged for dimensional stability, reduced residual stress and better toughness at elevated service temperature, at some loss of peak strength. | 195 | 230 | 5 | 70 HB | 42 % IACS |
T6 variant, underaged | Choose when maximum strength/hardness matters more than elongation, e.g. highly loaded permanent-mold or squeeze castings. | 225 | 280 | 3 | 90 HB | 38 % IACS |
What is AC4C-T7?
AC4C-T7 is AC4C in the T7 temper — overaged for dimensional stability, reduced residual stress and better toughness at elevated service temperature, at some loss of peak strength. AC4C-T7 has a yield strength of 195 MPa (28.3 ksi) and a tensile strength of 230 MPa (33.4 ksi) — stronger than 51% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72.4 GPa (10.5 Msi). AC4C-T7 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 557°C (1,035 °F). T6 is the default condition FabDigit quotes; T7 is available on request or by drawing note.
Advantages
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
- High electrical conductivity — 42 % IACS, better than 81% of aluminum grades
AC4C-T7 properties
Typical room-temperature values for AC4C-T7; 20 are specific to this condition. Other listed values are AC4C reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
AC4C-T7 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 557°C (1,035 °F).
Mechanical14
AC4C-T7 has a yield strength of 195 MPa (28.3 ksi) and a tensile strength of 230 MPa (33.4 ksi) — stronger than 51% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72.4 GPa (10.5 Msi).
Thermal6
AC4C-T7 is rated for continuous service to 200°C (392 °F). It conducts heat at 156 W/m·K (90.1 BTU/hr·ft·°F), better than 73% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
AC4C-T7 conducts electricity at 42 % IACS, better than 81% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (61/100), better than 64% of aluminum grades.
Sustainability4
Producing a kilogram of AC4C-T7 takes about 175 MJ of energy and emits 11.5 kg of CO₂ — less than 92% of aluminum grades. Typical recycled content is 55%.
Manufacturability7
AC4C-T7's machinability is good (60/100, worse than 51% of aluminum grades); weldability very good (78/100); formability not recommended (14/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AC4C-T7
Is AC4C easy to machine?
Machines cleanly with sharp positive-rake carbide or PCD tooling at high speed; the eutectic Si abrades HSS, so use flood coolant and expect shorter tool life than 6061.
Can AC4C be welded?
Readily TIG/MIG welded with ER4043 or ER4047 filler; weld zone loses T6 properties, so re-solution and re-age for full strength and avoid welding heavily gas-porous castings.
Can AC4C be formed, bent or molded?
Excellent fluidity and feeding for sand, gravity, low-pressure and squeeze casting; degas, Sr-modify and grain-refine, and keep Fe low to protect ductility.
What surface finishes work on AC4C?
Takes protective and hard-coat anodize (grey, non-decorative), chromate/Ti-Zr conversion coats, powder coat and paint; impregnation is common for pressure tightness before plating.
AC4C 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 |
|---|---|---|
| SiSr or Na modified for fine eutectic | 6.5 – 7.5 | 7 |
| MgMg2Si precipitation hardening | 0.2 – 0.45 | 0.32 |
| Fe≤0.20 for premium/A356.2 quality | ≤ 0.55 | 0.15 |
| Cu | ≤ 0.25 | 0.05 |
| Mn | ≤ 0.35 | 0.05 |
| Zn | ≤ 0.35 | 0.05 |
| Tigrain refinement with Al-Ti-B | ≤ 0.2 | 0.12 |
| Ni | ≤ 0.1 | — |
| Cr | ≤ 0.1 | — |
| Pb | ≤ 0.05 | — |
| Sn | ≤ 0.05 | — |
| Al | balance | — |
AC4C-T7 — frequently asked
What is AC4C-T7 used for?
AC4C-T7 is typically used for automotive wheels, structural chassis parts, aerospace castings and gearbox housings. In short: A356 equivalent casting alloy; pressure-tight structural castings; best all-round AC grade.
What is the yield strength of AC4C-T7?
AC4C-T7 has a typical yield strength of 195 MPa (28.3 ksi) and a tensile strength of 230 MPa (33.4 ksi) — stronger than 51% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is AC4C-T7 easy to machine?
Reasonably — machinability is rated good (60/100, worse than 51% of aluminum grades). Machines cleanly with sharp positive-rake carbide or PCD tooling at high speed; the eutectic Si abrades HSS, so use flood coolant and expect shorter tool life than 6061.
Can AC4C-T7 be welded?
Yes — weldability is rated very good (78/100). Readily TIG/MIG welded with ER4043 or ER4047 filler; weld zone loses T6 properties, so re-solution and re-age for full strength and avoid welding heavily gas-porous castings.
What surface finishes work on AC4C-T7?
Takes protective and hard-coat anodize (grey, non-decorative), chromate/Ti-Zr conversion coats, powder coat and paint; impregnation is common for pressure tightness before plating.
Can AC4C-T7 be formed, bent or molded?
Excellent fluidity and feeding for sand, gravity, low-pressure and squeeze casting; degas, Sr-modify and grain-refine, and keep Fe low to protect ductility.
What is the maximum service temperature of AC4C-T7?
AC4C-T7 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AC4C-T6 and AC4C-F?
T6 is the default condition — standard structural condition: best balance of strength, ductility and fatigue life for wheels, knuckles and pressure-tight housings. F: cheapest condition for low-stress housings and covers where dimensional stability and strength demands are modest. Yield strength is 180 MPa in T6 versus 85 MPa in F.
Sources
- JIS H 5202 Aluminium Alloy Castings — JSA (2010)
- GB/T 1173 (ZL101) — SAC (2013)
- ASTM B26/B26M & B108 (A356.0) — ASTM (2018)
- EN 1706 (EN AC-42000 AlSi7Mg) — CEN (2020)
- ASM Handbook Vol.2: Properties and Selection — Nonferrous Alloys — ASM International (1990)
- Aluminum Association Teal Sheets / Alloy & Temper Registrations — The Aluminum Association (2015)
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.