Aluminum EN AC-21100-T4
Temper
EN AC-21100
T4 = solution heat treated and naturally aged
Choose when maximum ductility and toughness are wanted with moderate strength, or before a straightening/machining step followed by ageing.
Values for the T4 condition
Other EN AC-21100 tempers and conditions
EN AC-21100 is listed in 5 conditions; see the grade overview at EN AC-21100.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Rarely supplied; only for non-structural parts or as the pre-heat-treatment condition, since Al-Cu gains most of its strength from ageing. | 95 | 160 | 4 | 60 HB | 38 % IACS |
T4This page Solution heat treated and naturally aged | Choose when maximum ductility and toughness are wanted with moderate strength, or before a straightening/machining step followed by ageing. | 165 | 290 | 14 | 75 HB | 30 % IACS |
Solution heat treated and under-aged | Pick when higher elongation and impact toughness are needed than T6 gives, accepting ~20–30 MPa lower proof strength. | 180 | 280 | 9 | 85 HB | 35 % IACS |
Solution heat treated and overaged (stabilized) | Non-EN-1706 shop practice used for dimensionally stable parts and elevated-temperature service, trading strength for stability and better corrosion behaviour. | 200 | 260 | 5 | 85 HB | 38 % IACS |
T6Default Solution heat treated and artificially aged | Standard condition for structural castings — highest strength and hardness of this grade, with acceptable elongation. | 210 | 320 | 6 | 95 HB | 33 % IACS |
What is EN AC-21100-T4?
EN AC-21100-T4 is EN AC-21100 in the T4 temper — choose when maximum ductility and toughness are wanted with moderate strength, or before a straightening/machining step followed by ageing. EN AC-21100-T4 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 290 MPa (42.1 ksi) — weaker than 58% of aluminum grades. Elongation at break is 14% and the elastic modulus is 72 GPa (10.4 Msi). EN AC-21100-T4 has a density of 2.75 g/cm³ (0.0994 lb/in³), heavier than 67% 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
- Low embodied carbon — 9.5 kg CO₂/kg, better than 97% of aluminum grades
- Easy to machine — 75/100, better than 86% of aluminum grades
- Ductile — tolerates forming and impact — 14%, better than 81% of aluminum grades
- Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 76% of aluminum grades
Limitations
- Needs corrosion protection — 35/100, worse than 85% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
- Difficult to weld — 25/100, worse than 76% of aluminum grades
EN AC-21100-T4 properties
Typical room-temperature values for EN AC-21100-T4; 11 are specific to this condition. Other listed values are EN AC-21100 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
EN AC-21100-T4 has a density of 2.75 g/cm³ (0.0994 lb/in³), heavier than 67% of aluminum grades. It melts at 545°C (1,013 °F).
Mechanical14
EN AC-21100-T4 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 290 MPa (42.1 ksi) — weaker than 58% of aluminum grades. Elongation at break is 14% and the elastic modulus is 72 GPa (10.4 Msi).
Thermal6
EN AC-21100-T4 is rated for continuous service to 120°C (248 °F). It conducts heat at 130 W/m·K (75.1 BTU/hr·ft·°F), worse than 65% of aluminum grades. Thermal expansion is 22.5 µm/m·K (12.5 µin/in·°F).
Electrical3
EN AC-21100-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 EN AC-21100-T4 takes about 150 MJ of energy and emits 9.5 kg of CO₂ — less than 97% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
EN AC-21100-T4's machinability is very good (75/100, better than 86% of aluminum grades); weldability poor (25/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with EN AC-21100-T4
Is EN AC-21100 easy to machine?
One of the best-machining cast aluminium alloys — sharp carbide/PCD tooling, high speeds, short chips; T6 gives the cleanest surface finish.
Can EN AC-21100 be welded?
Poor fusion weldability (hot cracking with 2000-series-type chemistry); repair welding with 2319 filler only with preheat, and re-solution + re-age afterwards.
Can EN AC-21100 be formed, bent or molded?
Sand and permanent-mould casting only; long freezing range means heavy risers, chills and controlled solidification are needed to avoid hot tears and shrinkage porosity.
What surface finishes work on EN AC-21100?
Prime and paint or chromate/chemical-conversion coat for corrosion protection; hard anodize is possible but the copper gives dark, uneven films, so decorative clear anodizing should be avoided.
EN AC-21100 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 | 4.2 – 5.2 | 4.7 |
| Tigrain refiner | 0.15 – 0.3 | 0.2 |
| Siimpurity limit | ≤ 0.18 | — |
| Feimpurity limit | ≤ 0.15 | — |
| Mg | ≤ 0.05 | — |
| Mn | ≤ 0.1 | — |
| Ni | ≤ 0.05 | — |
| Zn | ≤ 0.07 | — |
| Others (each)EN 1706 residual limit | ≤ 0.03 | — |
| Others (total)EN 1706 residual limit | ≤ 0.1 | — |
| Al | balance | — |
EN AC-21100-T4 — frequently asked
What is EN AC-21100-T4 used for?
EN AC-21100-T4 is typically used for engine components, aerospace fittings and machined structural castings. In short: best-machining cast aluminium; al-Cu without high silicon; poor castability.
What is the yield strength of EN AC-21100-T4?
EN AC-21100-T4 has a typical yield strength of 165 MPa (23.9 ksi) and a tensile strength of 290 MPa (42.1 ksi) — weaker than 58% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is EN AC-21100-T4 easy to machine?
Yes — machinability is rated very good (75/100, better than 86% of aluminum grades). One of the best-machining cast aluminium alloys — sharp carbide/PCD tooling, high speeds, short chips; T6 gives the cleanest surface finish.
Can EN AC-21100-T4 be welded?
Not readily — weldability is rated poor (25/100). Poor fusion weldability (hot cracking with 2000-series-type chemistry); repair welding with 2319 filler only with preheat, and re-solution + re-age afterwards.
What surface finishes work on EN AC-21100-T4?
Prime and paint or chromate/chemical-conversion coat for corrosion protection; hard anodize is possible but the copper gives dark, uneven films, so decorative clear anodizing should be avoided.
Can EN AC-21100-T4 be formed, bent or molded?
Sand and permanent-mould casting only; long freezing range means heavy risers, chills and controlled solidification are needed to avoid hot tears and shrinkage porosity.
What is the maximum service temperature of EN AC-21100-T4?
EN AC-21100-T4 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 EN AC-21100-T6 and EN AC-21100-F?
T6 is the default condition — standard condition for structural castings — highest strength and hardness of this grade, with acceptable elongation. F: rarely supplied; only for non-structural parts or as the pre-heat-treatment condition, since Al-Cu gains most of its strength from ageing. Yield strength is 210 MPa in T6 versus 95 MPa in F.
Sources
- EN 1706 — Aluminium and aluminium alloys: castings — chemical composition and mechanical properties — CEN (2020)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 13B / Vol. 5 — Corrosion and Surface Engineering of Aluminium — ASM International (2005)
- GB/T 1173 (ZL2xx series) — SAC (2013)
- Foundry alloy datasheets for AlCu4Ti / A201-206 type castings — various European foundries (2023)
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.