Zamak 5 Zinc Die Casting
Zamak 5 (ZAl4Cu1) zinc die casting: the higher-strength zamak, its property envelope, when to pick it over Zamak 3, and how its cast parts coexist with CNC-machined work.
Last updated: 2026-10-29
Zamak 5 is the workhorse zinc die-casting alloy with copper in the recipe — roughly the ZAMAK 3 formulation plus about one percent copper — which raises tensile and yield strength and hardness at a modest cost in ductility. It is the grade chosen when a zinc casting needs more strength or better hardness than the standard 3-series alloy delivers: brackets and housings under load, gear components, hardware that sees torque, and parts where a harder as-cast surface resists handling and wear.
The alloy inherits everything that makes zinc die casting a manufacturing strategy: thin walls castable straight to net shape, long die life because the metal melts at low temperature, tight as-cast tolerances, and excellent surface for plating and painting. Most Zamak 5 volume work is cast to finish — but machined features, drilled and tapped details and precision flats are routinely added on CNC equipment when a casting alone cannot carry the tolerance, which is where the casting and machining processes meet on the same part.
Specifications
| Property | Value | Condition |
|---|---|---|
| Density | 6.6 g/cm³ | — |
| Tensile strength | ~330 MPa | — |
| Yield strength (0.2% offset) | ~260 MPa | — |
| Elongation | ~7% | — |
| Hardness | 91 HB | — |
| Recommended wall thickness | 0.6–3.0 mm (as-cast) | — |
Values above are rendered from the collected model-evidence layer, each carrying the heat-treatment condition it was reported under; fields without collected evidence are stated as not established rather than estimated. Requirements outside the table are confirmed for the specific geometry and batch at quotation.
Applications & Selection Points
Load-bearing housings and brackets
Automotive and industrial brackets, actuator and motor housings, gearbox covers and structural small hardware pick Zamak 5 over Zamak 3 when the load case needs the extra tensile and yield the copper addition buys. The ductility trade is real but modest for typical housing duty; drawings that specify the 5-series alloy are usually answering a strength or hardness failure seen on the 3-series.
Hard-wearing hardware and gears
The harder as-cast surface suits door and window hardware, lock components, gear and cam parts, and anything handled or cycled heavily. Plated Zamak 5 hardware is the standard finish system — chrome and nickel plating sits on the fine as-cast surface of the alloy without heavy pre-finishing, which is a large share of its consumer-hardware presence.
Thin-wall, high-volume geometry
The low casting temperature of zinc is what lets Zamak 5 fill wall sections thinner than aluminum dies can hold, with crisp detail and long tool life. High-volume consumer and automotive small parts — the classic territory — exploit exactly this: complex geometry at net shape, cycle times measured in seconds, and machining reserved for the few features tolerance-critical enough to need it.
Zamak 5 versus Zamak 3
The decision is rarely close: default to Zamak 3 for general duty (it is slightly more ductile and marginally cheaper); step up to Zamak 5 when strength, hardness or wear response needs it. Both share the same die-casting practice, so the switch is a drawing line, not a process change. Alloys further out — ZA-8, ZA-27 for much higher loads, or the magnesium side for weight — are different engineering conversations.
Where machining enters a Zamak 5 part
As-cast Zamak 5 carries its own tolerance band; features beyond it — precision bores, sealed flatness, tapped threads in load paths, datum-critical interfaces — get added by CNC machining of the casting. The alloy machines easily and quickly, and the standard flow is cast to near-net, then machine the critical features. Send drawings that separate as-cast surfaces from machined tolerances, and the process split prices correctly.
Frequently Asked Questions
When should a drawing specify Zamak 5 instead of Zamak 3?
When the duty involves meaningful mechanical load, torque or wear: strength and hardness are the whole reason the 5-series alloy exists, at the price of some ductility. General housings and cosmetic hardware stay on Zamak 3. If a previous Zamak 3 part cracked or brinelled in service, the 5-series upgrade is the standard response.
Can Zamak 5 parts be CNC machined?
Yes — it is one of the easiest metals to machine, and castings routinely receive machined bores, flats and threads. The efficient pattern is die-cast to near-net shape, then machine only the features the casting tolerance cannot hold. Fully machined Zamak 5 from bar stock is unusual; the alloy exists to be cast.
How does Zamak 5 handle temperature and creep?
Zamak alloys are room-temperature performers: elevated service temperature is their known boundary, where strength falls away faster than aluminum alloys. Under-hood-adjacent and other warm environments deserve an explicit check at design time — and sustained load at temperature raises the creep question. Outside that envelope, aluminum die casting or machined aluminum is the standard move.
What should I send for a Zamak 5 die-casting quote?
A STEP model, a 2D drawing marking as-cast surfaces against machined tolerances, quantity, alloy callout and finish (plating and painting are normal on this alloy). Tooling is a line item in die casting — the quote should separate tooling amortization from piece price so volume assumptions are visible.
Ordering & Documentation
Documents
Send a STEP or IGES model with a 2D drawing that distinguishes as-cast from machined features and states the alloy explicitly — Zamak 3 and 5 share dies but not properties.
Quotation
Pricing follows the model, drawing, quantity and finish system, with tooling as its own line. Machined features are quoted into the piece price after the casting — flag them early so the process split is engineered, not discovered.
Sample & Supply
First articles verify as-cast tolerance, plating adhesion where specified and any machined features. Production follows the approved sample; alloy certification accompanies supply on request.
Storage & Shipping
Zamak 5 castings are stable in ordinary storage; plated parts ship in standard protective packaging. Long-term storage in direct contact with some acids and moist wood/packing materials can discolor zinc — normal dry packing avoids it.