Aluminum ZL204A-T6
Temper
T6 = solution heat treated and artificially aged
Use where peak yield strength, hardness and elevated-temperature stability matter more than ductility.
Values for the T6 condition
Other ZL204A tempers and conditions
ZL204A is listed in 4 conditions; see the grade overview at ZL204A.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Rarely supplied; only for non-structural or trial castings, since the alloy's strength comes from heat treatment. | 130 | 220 | 2 | 65 HB | 36 % IACS |
Solution heat treated and naturally aged | Pick when maximum ductility and toughness are wanted from the solution-treated condition, accepting lower yield strength. | 250 | 410 | 9 | 95 HB | 30 % IACS |
T5Default Cooled from hot working and artificially aged | The standard registered condition for ZL204A sand castings: highest usable combination of ≥440 MPa tensile strength with ≥4 % elongation. | 330 | 470 | 6 | 110 HB | 32 % IACS |
T6This page Solution heat treated and artificially aged | Use where peak yield strength, hardness and elevated-temperature stability matter more than ductility. | 390 | 480 | 3 | 125 HB | 33 % IACS |
What is ZL204A-T6?
ZL204A-T6 is ZL204A in the T6 temper — use where peak yield strength, hardness and elevated-temperature stability matter more than ductility. ZL204A-T6 has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 87% of aluminum grades. Elongation at break is 3% and the elastic modulus is 70 GPa (10.2 Msi). ZL204A-T6 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 545°C (1,013 °F). T5 is the default condition FabDigit quotes; T6 is available on request or by drawing note.
Advantages
- High service temperature — 250°C (482 °F), better than 97% of aluminum grades
- High strength — 390 MPa (56.6 ksi), better than 87% of aluminum grades
Limitations
- Limited formability — 5/100, worse than 94% of aluminum grades
- Needs corrosion protection — 33/100, worse than 91% of aluminum grades
- Difficult to weld — 22/100, worse than 83% of aluminum grades
- Limited ductility — 3%, worse than 79% of aluminum grades
- Hard to polish — 45/100, worse than 76% of aluminum grades
ZL204A-T6 properties
Typical room-temperature values for ZL204A-T6; 10 are specific to this condition. Other listed values are ZL204A reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
ZL204A-T6 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 545°C (1,013 °F).
Mechanical12
ZL204A-T6 has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 87% of aluminum grades. Elongation at break is 3% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
ZL204A-T6 is rated for continuous service to 250°C (482 °F). It conducts heat at 135 W/m·K (78 BTU/hr·ft·°F), worse than 58% of aluminum grades. Thermal expansion is 22.6 µm/m·K (12.6 µin/in·°F).
Electrical3
ZL204A-T6 conducts electricity at 33 % IACS, worse than 57% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (33/100), worse than 91% of aluminum grades.
Sustainability4
Producing a kilogram of ZL204A-T6 takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 10%.
Manufacturability8
ZL204A-T6's machinability is very good (70/100, better than 72% of aluminum grades); weldability poor (22/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZL204A-T6
Is ZL204A easy to machine?
Machines well in T5/T6 with sharp carbide tools, high speed and moderate feed; chips are less gummy than Al-Si castings, but keep coolant flowing to avoid built-up edge and watch for hard Al-Cu intermetallics.
Can ZL204A be welded?
Poor fusion weldability — highly crack-sensitive; repair only by approved TIG procedures with Al-Cu (e.g. ER2319-type) filler followed by re-solution and re-ageing, otherwise use mechanical joints or adhesives.
Can ZL204A be formed, bent or molded?
Sand/shell casting alloy with a wide freezing range: needs high-purity charge, degassing, strong chills and generous risering, controlled pouring ~700–730 °C, and thick-to-thin directional solidification to avoid hot tears and shrinkage porosity; not suitable for cold forming.
What surface finishes work on ZL204A?
Protect always — chromate conversion or (hard) anodize plus epoxy primer is normal; anodic films are dark and non-decorative due to Cu, and shot peening is often specified on fatigue-critical machined surfaces.
ZL204A 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 |
|---|---|---|
| Cuprincipal strengthening element | 4.6 – 5.3 | 5 |
| Mnraises elevated-temperature strength | 0.6 – 0.9 | 0.75 |
| Tigrain refiner | 0.15 – 0.35 | 0.25 |
| Cdmicro-addition, improves ageing response and castability | 0.15 – 0.25 | 0.2 |
| Siimpurity limit | ≤ 0.06 | — |
| Feimpurity limit | ≤ 0.15 | — |
| Mgimpurity limit | ≤ 0.05 | — |
| Znimpurity limit | ≤ 0.1 | — |
| Al | balance | — |
ZL204A-T6 — frequently asked
What is ZL204A-T6 used for?
ZL204A-T6 is typically used for aerospace structural castings, high-load machine brackets, aircraft equipment and instrument mounts, actuator and linkage housings, fatigue-critical machined castings and load-bearing defence hardware castings. In short: highest-strength cast aluminum; 250 °C service capability; crack-sensitive, always coated.
What is the yield strength of ZL204A-T6?
ZL204A-T6 has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 480 MPa (69.6 ksi) — stronger than 87% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is ZL204A-T6 easy to machine?
Yes — machinability is rated very good (70/100, better than 72% of aluminum grades). Machines well in T5/T6 with sharp carbide tools, high speed and moderate feed; chips are less gummy than Al-Si castings, but keep coolant flowing to avoid built-up edge and watch for hard Al-Cu intermetallics.
Can ZL204A-T6 be welded?
Not readily — weldability is rated poor (22/100). Poor fusion weldability — highly crack-sensitive; repair only by approved TIG procedures with Al-Cu (e.g. ER2319-type) filler followed by re-solution and re-ageing, otherwise use mechanical joints or adhesives.
What surface finishes work on ZL204A-T6?
Protect always — chromate conversion or (hard) anodize plus epoxy primer is normal; anodic films are dark and non-decorative due to Cu, and shot peening is often specified on fatigue-critical machined surfaces.
Can ZL204A-T6 be formed, bent or molded?
Sand/shell casting alloy with a wide freezing range: needs high-purity charge, degassing, strong chills and generous risering, controlled pouring ~700–730 °C, and thick-to-thin directional solidification to avoid hot tears and shrinkage porosity; not suitable for cold forming.
What is the maximum service temperature of ZL204A-T6?
ZL204A-T6 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between ZL204A-T5 and ZL204A-F?
T5 is the default condition — the standard registered condition for ZL204A sand castings: highest usable combination of ≥440 MPa tensile strength with ≥4 % elongation. F: rarely supplied; only for non-structural or trial castings, since the alloy's strength comes from heat treatment. Yield strength is 330 MPa in T5 versus 130 MPa in F.
Sources
- GB/T 1173 Casting aluminium alloys (ZAlCu5MnCdA / ZL204A) (2013)
- GB/T 8733 Aluminium alloy ingots for remelting — SAC (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- (Chinese cast aluminium alloy handbook) (2012)
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.