Zinc Alloy Zamak 5 Gravity Cast
Heat-treated state
ASTM Zamak 5 · UNS Z35531
For prototypes, tooling aids and thick sections where die casting is not available; coarser grain gives clearly lower strength and ductility.
Values for the Gravity Cast condition
Other Zamak 5 tempers and conditions
Zamak 5 is listed in 4 conditions; see the grade overview at Zamak 5.
- Gravity Cast
- Aged
- Stabilized
- As Cast
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Gravity CastThis page sand or permanent-mould cast section | For prototypes, tooling aids and thick sections where die casting is not available; coarser grain gives clearly lower strength and ductility. | 175 | 210 | 2.5 | 70 HB | 26 % IACS |
Long-term / accelerated natural-aged design values | Use these lower strength / higher ductility numbers for long-life structural design, since Zamak naturally ages at room temperature. | 225 | 269 | 16 | 80 HB | 27 % IACS |
3–6 h at 100 °C for dimensional stability | Choose when tight dimensional stability is needed on precision castings (gauges, gears, optical mounts) before machining or plating. | 255 | 310 | 9 | 87 HB | 26.5 % IACS |
As CastDefault hot-chamber die cast, no post-treatment | Standard supplied condition for die-cast Zamak 5 parts; use for typical strength/hardness design values. | 268 | 328 | 7 | 91 HB | 26 % IACS |
What is Zamak 5 Gravity Cast?
Zamak 5 Gravity Cast is Zamak 5 heat treated to Gravity Cast — for prototypes, tooling aids and thick sections where die casting is not available; coarser grain gives clearly lower strength and ductility. Zamak 5 Gravity Cast has a yield strength of 175 MPa (25.4 ksi) and a tensile strength of 210 MPa (30.5 ksi) — stronger than 50% of zinc alloy grades. Elongation at break is 2.5% and the elastic modulus is 90 GPa (13.1 Msi). Zamak 5 Gravity Cast has a density of 6.6 g/cm³ (0.238 lb/in³), lighter than 64% of zinc alloy grades. It melts at 380°C (716 °F). As Cast is the default condition FabDigit quotes; Gravity Cast is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 85/100, better than 89% of zinc alloy grades
Limitations
- Limited ductility — 2.5%, worse than 93% of zinc alloy grades
- Limited formability — 12/100, worse than 77% of zinc alloy grades
Zamak 5 Gravity Cast properties
Typical room-temperature values for Zamak 5 Gravity Cast; 19 are specific to this condition. Other listed values are Zamak 5 reference data and may not represent this condition. Bars are the position among zinc alloy grades.
Physical3
Zamak 5 Gravity Cast has a density of 6.6 g/cm³ (0.238 lb/in³), lighter than 64% of zinc alloy grades. It melts at 380°C (716 °F).
Mechanical14
Zamak 5 Gravity Cast has a yield strength of 175 MPa (25.4 ksi) and a tensile strength of 210 MPa (30.5 ksi) — stronger than 50% of zinc alloy grades. Elongation at break is 2.5% and the elastic modulus is 90 GPa (13.1 Msi).
Thermal6
Zamak 5 Gravity Cast is rated for continuous service to 100°C (212 °F). It conducts heat at 110 W/m·K (63.6 BTU/hr·ft·°F), worse than 64% of zinc alloy grades. Thermal expansion is 27.4 µm/m·K (15.2 µin/in·°F).
Electrical3
Zamak 5 Gravity Cast conducts electricity at 26 % IACS, worse than 86% of zinc alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (36/100), worse than 71% of zinc alloy grades.
Sustainability4
Producing a kilogram of Zamak 5 Gravity Cast takes about 53 MJ of energy and emits 3.4 kg of CO₂ — less than 68% of zinc alloy grades. Typical recycled content is 25%.
Manufacturability8
Zamak 5 Gravity Cast's machinability is excellent (85/100, better than 89% of zinc alloy grades); weldability poor (15/100); formability not recommended (12/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Zamak 5 Gravity Cast
Is Zamak 5 easy to machine?
Very free-machining with sharp carbide or HSS tools, high speeds, light feeds and no coolant needed for light cuts; avoid heavy work-hardening-free but gummy chips at low speed.
Can Zamak 5 be welded?
Not practically fusion-welded; joints made by mechanical fastening, adhesives, or soft soldering with zinc-compatible flux — keep heat below ~200 °C to avoid distortion and grain growth.
Can Zamak 5 be formed, bent or molded?
Ideal hot-chamber die-casting alloy: 415–430 °C melt, thin walls to ~0.5 mm, long tool life; allow for natural aging shrinkage (~0.07%) and stabilize precision parts at 100 °C.
What surface finishes work on Zamak 5?
Excellent substrate for buffing plus Cu-Ni-Cr electroplating, chromate/trivalent passivation, e-coat or powder paint; never anodize, and keep plating baths pH-controlled to avoid substrate attack.
Zamak 5 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 |
|---|---|---|
| AlASTM B86 AC41A | 3.5 – 4.3 | 4 |
| Cu | 0.75 – 1.25 | 1 |
| Mg | 0.03 – 0.08 | 0.05 |
| Fe | ≤ 0.1 | — |
| Pbmax — impurity, causes intergranular corrosion | ≤ 0.01 | — |
| Cd | ≤ 0 | — |
| Sn | ≤ 0 | — |
| Nimax (ingot limit) | ≤ 0.02 | — |
| ZnSpecial High Grade zinc, 99.99% base | balance | — |
Zamak 5 Gravity Cast — frequently asked
What is Zamak 5 Gravity Cast used for?
Zamak 5 Gravity Cast is typically used for automotive fittings and brackets, padlock bodies, door and window hardware, plated bathroom and furniture fittings, pump and valve housings and small gear and lever components. In short: higher-strength die-cast zinc.
What is the yield strength of Zamak 5 Gravity Cast?
Zamak 5 Gravity Cast has a typical yield strength of 175 MPa (25.4 ksi) and a tensile strength of 210 MPa (30.5 ksi) — stronger than 50% of zinc alloy grades. Strength varies by condition: see the 4 listed tempers.
Is Zamak 5 Gravity Cast easy to machine?
Yes — machinability is rated excellent (85/100, better than 89% of zinc alloy grades). Very free-machining with sharp carbide or HSS tools, high speeds, light feeds and no coolant needed for light cuts; avoid heavy work-hardening-free but gummy chips at low speed.
Can Zamak 5 Gravity Cast be welded?
Not readily — weldability is rated poor (15/100). Not practically fusion-welded; joints made by mechanical fastening, adhesives, or soft soldering with zinc-compatible flux — keep heat below ~200 °C to avoid distortion and grain growth.
What surface finishes work on Zamak 5 Gravity Cast?
Excellent substrate for buffing plus Cu-Ni-Cr electroplating, chromate/trivalent passivation, e-coat or powder paint; never anodize, and keep plating baths pH-controlled to avoid substrate attack.
Can Zamak 5 Gravity Cast be formed, bent or molded?
Ideal hot-chamber die-casting alloy: 415–430 °C melt, thin walls to ~0.5 mm, long tool life; allow for natural aging shrinkage (~0.07%) and stabilize precision parts at 100 °C.
What is the maximum service temperature of Zamak 5 Gravity Cast?
Zamak 5 Gravity Cast is rated for continuous use to about 100°C (212 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between Zamak 5 As Cast and Zamak 5 Aged?
As Cast is the default condition — standard supplied condition for die-cast Zamak 5 parts; use for typical strength/hardness design values. Aged: use these lower strength / higher ductility numbers for long-life structural design, since Zamak naturally ages at room temperature. Yield strength is 268 MPa in As Cast versus 225 MPa in Aged.
Can FabDigit make parts in Zamak 5 Gravity Cast?
Yes — Zamak 5 Gravity Cast is available for CNC machining and casting & forging with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B86 — Zinc and Zinc-Aluminum Alloy Foundry and Die Castings — ASTM International (2018)
- ASTM B240 — Zinc and Zinc-Aluminum Alloys in Ingot Form for Castings — ASTM International (2016)
- JIS H 5301 (ZDC1/ZDC2 zinc die castings) — JSA (2009)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- NADCA Product Specification Standards for Die Castings — zinc alloy properties — NADCA (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.