Aluminum ZL204A
ZL204A (A242.0) is a high-strength Al-Cu sand casting alloy with a cadmium micro-addition that improves castability and ageing response, supplied in F, T4, T5 and T6.
Reference datasheet — ZL204A is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the T5 condition
ZL204A tempers and conditions
ZL204A is supplied in 4 conditions, soft to hard. T5 is the default FabDigit quotes; the values on this page are for it.
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 |
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?
ZL204A (A242.0) is a high-strength Al-Cu sand casting alloy with a cadmium micro-addition that improves castability and ageing response, supplied in F, T4, T5 and T6. Heat treated it reaches 470 MPa tensile, 330 MPa yield, 6 % elongation and 110 HB, with 130 W/m·K thermal conductivity, 32 % IACS and service to 250 °C, which is why it is used for aerospace structural castings rather than general Al-Si housings. The limits are foundry and joining related: a wide freezing range needs chills and heavy risering, fusion welds are crack-sensitive, and the copper content demands protective coating. Where castability and weldability matter more than strength, A356.0 is the usual alternative. ZL204A 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). ZL204A has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 81% of aluminum grades. Elongation at break is 6% and the elastic modulus is 70 GPa (10.2 Msi).
What is ZL204A used for?
- Aerospace structural castings
- High-load machine brackets
- Aircraft equipment and instrument mounts
- Actuator and linkage housings
- Fatigue-critical machined castings
- Load-bearing defence hardware castings
Advantages
- High service temperature — 250°C (482 °F), better than 97% of aluminum grades
- High strength — 330 MPa (47.9 ksi), better than 81% 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
- Hard to polish — 45/100, worse than 76% of aluminum grades
ZL204A properties
Typical room-temperature values for ZL204A-T5; bars are the position among aluminum grades.
Physical3
ZL204A 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 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 81% of aluminum grades. Elongation at break is 6% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
ZL204A is rated for continuous service to 250°C (482 °F). It conducts heat at 130 W/m·K (75.1 BTU/hr·ft·°F), worse than 65% of aluminum grades. Thermal expansion is 22.6 µm/m·K (12.6 µin/in·°F).
Electrical3
ZL204A conducts electricity at 32 % IACS, worse than 63% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (33/100), worse than 91% of aluminum grades.
Sustainability4
Producing a kilogram of ZL204A 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's machinability is good (68/100, better than 67% of aluminum grades); weldability poor (22/100); formability not recommended (5/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. ZL204A is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZL204A
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.
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 |
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.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum ZL204A in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Also called
- ZAlCu5MnCdA
- Similar grades
- A242.0
How much does ZL204A cost?
ZL204A is a premium-cost aluminum ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ZL204A — frequently asked
What is ZL204A used for?
ZL204A 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?
ZL204A has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 470 MPa (68.2 ksi) — stronger than 81% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is ZL204A easy to machine?
Reasonably — machinability is rated good (68/100, better than 67% 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 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?
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 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?
ZL204A 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.
How much does ZL204A cost?
ZL204A is a premium-cost aluminum ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.