Aluminum ZL203-T4
Temper · default condition
GB ZL203
T4 = solution heat treated and naturally aged
Standard supply condition: best combination of strength and ductility/toughness for general engineering castings.
Values for the T4 condition
Other ZL203 tempers and conditions
ZL203 is listed in 5 conditions; see the grade overview at ZL203.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Low-cost as-cast condition for lightly loaded, dimension-stable parts where machinability matters more than strength. | 95 | 150 | 2.5 | 45 HB | 31 % IACS |
T4DefaultThis page Solution heat treated and naturally aged | Standard supply condition: best combination of strength and ductility/toughness for general engineering castings. | 110 | 215 | 8 | 60 HB | 33 % IACS |
Solution heat treated and overaged (stabilized) | Overaged for dimensional stability and reduced residual stress on parts running warm or requiring tight machining tolerance. | 150 | 200 | 3 | 68 HB | 37 % IACS |
Cooled from hot working and artificially aged | Choose when higher strength and hardness are needed and 3 % elongation is acceptable. | 155 | 225 | 3 | 70 HB | 35 % IACS |
Solution heat treated and artificially aged | Peak-strength condition used mainly on the ANSI 295.0 equivalent when maximum hardness/wear resistance is required. | 165 | 250 | 5 | 75 HB | 35 % IACS |
What is ZL203-T4?
ZL203-T4 is ZL203 in the T4 temper — standard supply condition: best combination of strength and ductility/toughness for general engineering castings. ZL203-T4 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 215 MPa (31.2 ksi) — weaker than 81% of aluminum grades. Elongation at break is 8% and the elastic modulus is 70 GPa (10.2 Msi). ZL203-T4 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 545°C (1,013 °F).
Advantages
- Easy to machine — 80/100, better than 92% of aluminum grades
Limitations
- Needs corrosion protection — 35/100, worse than 85% of aluminum grades
- Low strength — 110 MPa (16 ksi), worse than 81% of aluminum grades
- Limited formability — 10/100, worse than 80% 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
ZL203-T4 properties
Typical room-temperature values for ZL203-T4; 10 are specific to this condition. Other listed values are ZL203 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
ZL203-T4 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 545°C (1,013 °F).
Mechanical12
ZL203-T4 has a yield strength of 110 MPa (16 ksi) and a tensile strength of 215 MPa (31.2 ksi) — weaker than 81% of aluminum grades. Elongation at break is 8% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
ZL203-T4 is rated for continuous service to 120°C (248 °F). It conducts heat at 138 W/m·K (79.7 BTU/hr·ft·°F), worse than 55% of aluminum grades. Thermal expansion is 23 µm/m·K (12.8 µin/in·°F).
Electrical3
ZL203-T4 conducts electricity at 33 % IACS, worse than 57% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 85% of aluminum grades.
Sustainability4
Producing a kilogram of ZL203-T4 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
ZL203-T4's machinability is very good (80/100, better than 92% of aluminum grades); weldability poor (25/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ZL203-T4
Is ZL203 easy to machine?
Excellent — one of the best-machining cast aluminium alloys; use polished-flute carbide or PCD, high speed, low feed, and flood coolant; T5/T6 gives cleaner surfaces than as-cast.
Can ZL203 be welded?
Poor — Al-Cu is highly hot-crack sensitive; repair-weld only with 4043/2319 filler, low heat input and preheat, and re-solution treat where properties matter.
Can ZL203 be formed, bent or molded?
Sand and permanent-mould casting only; long freezing range demands generous risers, chills and directional solidification to avoid hot tears and shrinkage porosity — not suitable for pressure-tight castings.
What surface finishes work on ZL203?
Anodizing gives grey, non-decorative films because of the copper; prefer chromate/phosphate conversion coating plus primer and paint, or hard anodize where wear resistance dominates.
ZL203 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 – 5 | 4.5 |
| Siimpurity limit (sand cast); improves fluidity | ≤ 1.2 | 0.6 |
| Feimpurity; 1.0 max for permanent-mould in some sources | ≤ 0.8 | — |
| Mgimpurity | ≤ 0.05 | — |
| Mnimpurity | ≤ 0.1 | — |
| Znimpurity | ≤ 0.25 | — |
| Niimpurity | ≤ 0.1 | — |
| Tigrain refiner residue / impurity | ≤ 0.2 | — |
| others (each)total impurities ≤ 2.1 % (sand) / ≤ 1.5 % (permanent mould) | ≤ 0.05 | — |
| Al | balance | — |
ZL203-T4 — frequently asked
What is ZL203-T4 used for?
ZL203-T4 is typically used for general machinery castings, gear housings and covers, machine tool brackets and bases, fixture and jig bodies, non-pressure instrument housings and heavily machined prototype castings. In short: best-machining cast aluminum; low-cost Al-Cu sand casting; not for pressure-tight parts.
What is the yield strength of ZL203-T4?
ZL203-T4 has a typical yield strength of 110 MPa (16 ksi) and a tensile strength of 215 MPa (31.2 ksi) — weaker than 81% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is ZL203-T4 easy to machine?
Yes — machinability is rated very good (80/100, better than 92% of aluminum grades). Excellent — one of the best-machining cast aluminium alloys; use polished-flute carbide or PCD, high speed, low feed, and flood coolant; T5/T6 gives cleaner surfaces than as-cast.
Can ZL203-T4 be welded?
Not readily — weldability is rated poor (25/100). Poor — Al-Cu is highly hot-crack sensitive; repair-weld only with 4043/2319 filler, low heat input and preheat, and re-solution treat where properties matter.
What surface finishes work on ZL203-T4?
Anodizing gives grey, non-decorative films because of the copper; prefer chromate/phosphate conversion coating plus primer and paint, or hard anodize where wear resistance dominates.
Can ZL203-T4 be formed, bent or molded?
Sand and permanent-mould casting only; long freezing range demands generous risers, chills and directional solidification to avoid hot tears and shrinkage porosity — not suitable for pressure-tight castings.
What is the maximum service temperature of ZL203-T4?
ZL203-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 ZL203-T4 and ZL203-T6?
T4 is the default condition — standard supply condition: best combination of strength and ductility/toughness for general engineering castings. T6: peak-strength condition used mainly on the ANSI 295.0 equivalent when maximum hardness/wear resistance is required. Yield strength is 110 MPa in T4 versus 165 MPa in T6.
Sources
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (295.0, 208.0 data) — ASM International (1990)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
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.