Zinc Alloy Zamak 3 Gravity Cast
Heat-treated state
ASTM Zamak 3 · UNS Z33520
Use for prototypes, low-volume parts and short-run tooling/fixtures where die casting is not justified; coarser grain gives lower strength and ductility than die cast.
Values for the Gravity Cast condition
Other Zamak 3 tempers and conditions
Zamak 3 is listed in 3 conditions; see the grade overview at Zamak 3.
- Gravity Cast
- Stabilized
- As Cast
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Gravity CastThis page sand / permanent-mould / spin cast | Use for prototypes, low-volume parts and short-run tooling/fixtures where die casting is not justified; coarser grain gives lower strength and ductility than die cast. | 150 | 200 | 3 | 75 HB | 26 % IACS |
thermally aged (e.g. 3–6 h at 95–100 °C) for dimensional stability | Choose when long-term dimensional stability matters (precision gauges, optical/mechanism housings); trades a little strength for stability and higher ductility. | 205 | 255 | 15 | 78 HB | 27 % IACS |
As CastDefault hot-chamber die cast, no heat treatment | Default condition for virtually all Zamak 3 parts: as-ejected hot-chamber die castings, trimmed and optionally plated. | 221 | 283 | 10 | 82 HB | 27 % IACS |
What is Zamak 3 Gravity Cast?
Zamak 3 Gravity Cast is Zamak 3 heat treated to Gravity Cast — use for prototypes, low-volume parts and short-run tooling/fixtures where die casting is not justified; coarser grain gives lower strength and ductility than die cast. Zamak 3 Gravity Cast has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 200 MPa (29 ksi) — stronger than 50% of zinc alloy grades. Elongation at break is 3% and the elastic modulus is 85 GPa (12.3 Msi). Zamak 3 Gravity Cast has a density of 6.6 g/cm³ (0.238 lb/in³), lighter than 64% of zinc alloy grades. It melts at 381°C (718 °F). As Cast is the default condition FabDigit quotes; Gravity Cast is available on request or by drawing note.
Advantages
- Easy to machine — 90/100, better than 100% of zinc alloy grades
- Polishes to a fine finish — 85/100, better than 89% of zinc alloy grades
Limitations
- Limited ductility — 3%, worse than 86% of zinc alloy grades
Zamak 3 Gravity Cast properties
Typical room-temperature values for Zamak 3 Gravity Cast; 19 are specific to this condition. Other listed values are Zamak 3 reference data and may not represent this condition. Bars are the position among zinc alloy grades.
Physical3
Zamak 3 Gravity Cast has a density of 6.6 g/cm³ (0.238 lb/in³), lighter than 64% of zinc alloy grades. It melts at 381°C (718 °F).
Mechanical12
Zamak 3 Gravity Cast has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 200 MPa (29 ksi) — stronger than 50% of zinc alloy grades. Elongation at break is 3% and the elastic modulus is 85 GPa (12.3 Msi).
Thermal6
Zamak 3 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 3 Gravity Cast conducts electricity at 26 % IACS, worse than 86% of zinc alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 71% of zinc alloy grades.
Sustainability4
Producing a kilogram of Zamak 3 Gravity Cast takes about 53 MJ of energy and emits 3.6 kg of CO₂ — less than 68% of zinc alloy grades. Typical recycled content is 25%.
Manufacturability8
Zamak 3 Gravity Cast's machinability is excellent (90/100, better than 100% of zinc alloy grades); weldability poor (20/100); formability poor (15/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Zamak 3 Gravity Cast
Is Zamak 3 easy to machine?
Very easy: high speeds, sharp positive-rake carbide or HSS, light feeds; long free-machining chips and excellent surface finish, minimal tool wear.
Can Zamak 3 be welded?
Fusion welding is impractical; use soft soldering with zinc-suitable flux, mechanical fasteners/heat staking or adhesives; repair by filling/plating.
Can Zamak 3 be formed, bent or molded?
Ideal hot-chamber die-casting alloy — 380–390 °C metal, thin walls down to ~0.5 mm, fine detail, long die life; keep Fe low and hold Mg to avoid hot cracking and inter-granular corrosion.
What surface finishes work on Zamak 3?
Not anodizable; standard route is Cu/Ni/Cr bright plating, or chromate/passivate plus powder coat or paint; polishes and buffs well but avoid deep grinding into porosity.
Zamak 3 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 |
|---|---|---|
| Al | 3.5 – 4.3 | 4 |
| Mg | 0.02 – 0.05 | 0.04 |
| Cutypically held below 0.10 % in Zamak 3 | ≤ 0.25 | 0.03 |
| Fe | ≤ 0.1 | — |
| Pb | ≤ 0.01 | — |
| Cd | ≤ 0 | — |
| Sn | ≤ 0 | — |
| Nimax (informational) | ≤ 0.02 | — |
| Znspecial high grade zinc (99.99 %) base | balance | — |
Zamak 3 Gravity Cast — frequently asked
What is Zamak 3 Gravity Cast used for?
Zamak 3 Gravity Cast is typically used for toys, cosmetic cases and decorative hardware. In short: workhorse die-cast zinc.
What is the yield strength of Zamak 3 Gravity Cast?
Zamak 3 Gravity Cast has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 200 MPa (29 ksi) — stronger than 50% of zinc alloy grades. Strength varies by condition: see the 3 listed tempers.
Is Zamak 3 Gravity Cast easy to machine?
Yes — machinability is rated excellent (90/100, better than 100% of zinc alloy grades). Very easy: high speeds, sharp positive-rake carbide or HSS, light feeds; long free-machining chips and excellent surface finish, minimal tool wear.
Can Zamak 3 Gravity Cast be welded?
Not readily — weldability is rated poor (20/100). Fusion welding is impractical; use soft soldering with zinc-suitable flux, mechanical fasteners/heat staking or adhesives; repair by filling/plating.
What surface finishes work on Zamak 3 Gravity Cast?
Not anodizable; standard route is Cu/Ni/Cr bright plating, or chromate/passivate plus powder coat or paint; polishes and buffs well but avoid deep grinding into porosity.
Can Zamak 3 Gravity Cast be formed, bent or molded?
Ideal hot-chamber die-casting alloy — 380–390 °C metal, thin walls down to ~0.5 mm, fine detail, long die life; keep Fe low and hold Mg to avoid hot cracking and inter-granular corrosion.
What is the maximum service temperature of Zamak 3 Gravity Cast?
Zamak 3 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.
Can FabDigit make parts in Zamak 3 Gravity Cast?
Yes — Zamak 3 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 (Alloy AG40A / UNS Z33520) — ASTM (2018)
- JIS H 5301 — Zinc alloy die castings (ZDC2) — JIS (2009)
- EN 12844 / EN 1774 — Zinc and zinc alloys, castings and alloys for casting (ZL0400) — CEN (1998)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Zinc and Zinc Alloys) — ASM International (1990)
- NADCA Product Specification Standards for Die Castings — zinc alloy property tables — NADCA (2018)
- Zinc die-casting alloy property sheets (ILZRO / Eastern Alloys Zamak 3) — ILZRO / Eastern Alloys (2020)
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.