Aluminum AC4B-T6
Temper
JIS AC4B
T6 = solution heat treated and artificially aged
Highest strength condition for AC4B; choose for loaded housings and pressure parts, accepting distortion risk and heat-treat cost.
Values for the T6 condition
Other AC4B tempers and conditions
AC4B is listed in 4 conditions; see the grade overview at AC4B.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
FDefault As fabricated | Default and cheapest condition; use where moderate strength and good dimensional stability after machining are enough. | 110 | 180 | 2 | 75 HB | 27 % IACS |
Cooled from hot working and artificially aged | Low-cost ageing only (no solution treatment): raises hardness and stabilises dimensions with minimal distortion risk. | 150 | 210 | 1.5 | 82 HB | 28 % IACS |
Solution heat treated and overaged (stabilized) | Overaged for maximum dimensional stability at elevated temperature; some strength traded for stability and slightly better ductility. | 170 | 240 | 2.5 | 85 HB | 29 % IACS |
T6This page Solution heat treated and artificially aged | Highest strength condition for AC4B; choose for loaded housings and pressure parts, accepting distortion risk and heat-treat cost. | 185 | 275 | 2 | 92 HB | 25 % IACS |
What is AC4B-T6?
AC4B-T6 is AC4B in the T6 temper — highest strength condition for AC4B; choose for loaded housings and pressure parts, accepting distortion risk and heat-treat cost. AC4B-T6 has a yield strength of 185 MPa (26.8 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 53% of aluminum grades. Elongation at break is 2% and the elastic modulus is 74 GPa (10.7 Msi). AC4B-T6 has a density of 2.79 g/cm³ (0.101 lb/in³), heavier than 77% of aluminum grades. It melts at 516°C (961 °F). F is the default condition FabDigit quotes; T6 is available on request or by drawing note.
Advantages
- Easy to machine — 75/100, better than 86% of aluminum grades
Limitations
- Poor heat conductor — 104 W/m·K (60.1 BTU/hr·ft·°F), worse than 92% of aluminum grades
- Low electrical conductivity — 25 % IACS, worse than 92% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Limited ductility — 2%, worse than 87% of aluminum grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 83% of aluminum grades
AC4B-T6 properties
Typical room-temperature values for AC4B-T6; 13 are specific to this condition. Other listed values are AC4B reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
AC4B-T6 has a density of 2.79 g/cm³ (0.101 lb/in³), heavier than 77% of aluminum grades. It melts at 516°C (961 °F).
Mechanical12
AC4B-T6 has a yield strength of 185 MPa (26.8 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 53% of aluminum grades. Elongation at break is 2% and the elastic modulus is 74 GPa (10.7 Msi).
Thermal6
AC4B-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 104 W/m·K (60.1 BTU/hr·ft·°F), worse than 92% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
AC4B-T6 conducts electricity at 25 % IACS, worse than 92% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 79% of aluminum grades.
Sustainability4
Producing a kilogram of AC4B-T6 takes about 150 MJ of energy and emits 11.5 kg of CO₂ — less than 97% of aluminum grades. Typical recycled content is 85%.
Manufacturability6
AC4B-T6's machinability is very good (75/100, better than 86% of aluminum grades); weldability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AC4B-T6
Is AC4B easy to machine?
Machines well with sharp PCD or polished-carbide tools and flood coolant; Si particles are abrasive so PCD is preferred for volume work, and chips are short and easy to clear.
Can AC4B be welded?
TIG/MIG repair possible with 4043/4047 filler but the 2–4 % Cu gives real hot-cracking and porosity risk; preheat 150–200 °C and re-solution/age if T6 properties are required.
Can AC4B be formed, bent or molded?
Foundry alloy only — excellent fluidity and feeding for sand, gravity and low-pressure permanent-mold casting; use Sr/Na modification and Ti-B refinement, and degas well since Cu-Si melts pick up hydrogen readily.
What surface finishes work on AC4B?
Decorative anodizing is not viable (dark, mottled film); use chromate/trivalent conversion coating, powder coat or paint, and impregnate for pressure tightness on porous sections.
AC4B 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 |
|---|---|---|
| SiJIS H5202 AC4B | 7 – 10 | 8.5 |
| Cu | 2 – 4 | 3 |
| Mg | ≤ 0.5 | 0.2 |
| Zn | ≤ 1 | 0.3 |
| Fehigher Fe embrittles; keep low for T6 | ≤ 1 | 0.6 |
| Mn | ≤ 0.5 | 0.2 |
| Ni | ≤ 0.35 | — |
| Tigrain refiner | ≤ 0.2 | 0.1 |
| Sn | ≤ 0.1 | — |
| Pb | ≤ 0.1 | — |
| Al | balance | — |
AC4B-T6 — frequently asked
What is AC4B-T6 used for?
AC4B-T6 is typically used for cylinder heads, pump housings and compressor parts. In short: best machinability in family; cu-strengthened, lower corrosion resistance; economical gravity-cast alloy.
What is the yield strength of AC4B-T6?
AC4B-T6 has a typical yield strength of 185 MPa (26.8 ksi) and a tensile strength of 275 MPa (39.9 ksi) — weaker than 53% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is AC4B-T6 easy to machine?
Yes — machinability is rated very good (75/100, better than 86% of aluminum grades). Machines well with sharp PCD or polished-carbide tools and flood coolant; Si particles are abrasive so PCD is preferred for volume work, and chips are short and easy to clear.
Can AC4B-T6 be welded?
With care — weldability is rated fair (45/100). TIG/MIG repair possible with 4043/4047 filler but the 2–4 % Cu gives real hot-cracking and porosity risk; preheat 150–200 °C and re-solution/age if T6 properties are required.
What surface finishes work on AC4B-T6?
Decorative anodizing is not viable (dark, mottled film); use chromate/trivalent conversion coating, powder coat or paint, and impregnate for pressure tightness on porous sections.
Can AC4B-T6 be formed, bent or molded?
Foundry alloy only — excellent fluidity and feeding for sand, gravity and low-pressure permanent-mold casting; use Sr/Na modification and Ti-B refinement, and degas well since Cu-Si melts pick up hydrogen readily.
What is the maximum service temperature of AC4B-T6?
AC4B-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 AC4B-F and AC4B-T6?
F is the default condition — default and cheapest condition; use where moderate strength and good dimensional stability after machining are enough. T6: highest strength condition for AC4B; choose for loaded housings and pressure parts, accepting distortion risk and heat-treat cost. Yield strength is 110 MPa in F versus 185 MPa in T6.
Sources
- JIS H 5202 Aluminium alloy castings — JSA (2010)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (319.0/B319.0) — ASM International (1990)
- ASTM B26/B26M and Aluminum Association Pink Sheets (casting alloy registration) — ASTM / Aluminum Association (2018)
- GB/T 1173 (ZL107) — SAC (2013)
- ASM Handbook Vol.13B — Corrosion of Aluminum Alloys — 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.