Zinc Alloy ZA-8
ASTM ZA-8 · UNS Z35636
ZA-8 is a zinc-aluminum casting alloy with about 8% aluminum (Z35636, ASTM B669) that, unlike ZA-12 and ZA-27, can still be run on hot-chamber die-casting machines.
Values for the As Cast condition
ZA-8 tempers and conditions
ZA-8 is supplied in 4 conditions, soft to hard. As Cast 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-cast sand mould (ASTM B669 ZA-8) | Choose for low-volume, larger or thick-section parts; slower solidification lowers strength and especially ductility versus die cast. | 200 | 250 | 1.5 | 85 HB | 27.7 % IACS |
Permanent Mold Cast | Mid-volume gravity casting route giving finer structure and better properties than sand cast, below die-cast levels. | 207 | 255 | 2 | 88 HB | 27.7 % IACS |
As CastDefault hot-chamber die cast, as-cast (F) | Default commercial condition: thin-wall hot-chamber die castings with the highest strength and hardness of the ZA-8 forms. | 290 | 374 | 8 | 100 HB | 27.7 % IACS |
Die Cast | Hot-chamber pressure die cast ZA-8 (ASTM B86 / UNS Z35636): fine chill-cast structure giving the highest strength and hardness of the as-cast ZA-8 conditions. | 290 | 374 | 8 | 103 HB | 27.7 % IACS |
Supply forms, finishes and certifications
Ways ZA-8 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
Ingot | Remelt alloy ingot for casting | Supply form |
What is ZA-8?
ZA-8 is a zinc-aluminum casting alloy with about 8% aluminum (Z35636, ASTM B669) that, unlike ZA-12 and ZA-27, can still be run on hot-chamber die-casting machines. As-cast properties are approximately 290 MPa yield, 374 MPa tensile, 8% elongation and 100 HB, with 114.7 W/m·K thermal conductivity and 27.7% IACS electrical conductivity; forms include die, sand and permanent-mould castings, ingot and machined blanks. It is chosen over Zamak for higher strength and better bearing and wear behaviour, but service is limited to about 100 °C and it is not a weldable structural alloy. ZA-12 is the next step up in strength where cold-chamber or gravity casting is acceptable. ZA-8 has a density of 6.3 g/cm³ (0.228 lb/in³), lighter than 86% of zinc alloy grades. It melts at 375°C (707 °F). ZA-8 has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 374 MPa (54.2 ksi) — stronger than 93% of zinc alloy grades. Elongation at break is 8% and the elastic modulus is 85.5 GPa (12.4 Msi).
What is ZA-8 used for?
- Bearings
- Bushings
- Industrial gears
Advantages
- High strength — 290 MPa (42.1 ksi), better than 93% of zinc alloy grades
ZA-8 properties
Typical room-temperature values for ZA-8-As Cast; bars are the position among zinc alloy grades.
Physical3
ZA-8 has a density of 6.3 g/cm³ (0.228 lb/in³), lighter than 86% of zinc alloy grades. It melts at 375°C (707 °F).
Mechanical12
ZA-8 has a yield strength of 290 MPa (42.1 ksi) and a tensile strength of 374 MPa (54.2 ksi) — stronger than 93% of zinc alloy grades. Elongation at break is 8% and the elastic modulus is 85.5 GPa (12.4 Msi).
Thermal6
ZA-8 is rated for continuous service to 100°C (212 °F). It conducts heat at 114.7 W/m·K (66.3 BTU/hr·ft·°F), better than 71% of zinc alloy grades. Thermal expansion is 23.3 µm/m·K (12.9 µin/in·°F).
Electrical3
ZA-8 conducts electricity at 27.7 % IACS, better than 64% of zinc alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), better than 79% of zinc alloy grades.
Sustainability4
Producing a kilogram of ZA-8 takes about 57 MJ of energy and emits 4 kg of CO₂ — more than 86% of zinc alloy grades. Typical recycled content is 35%.
Manufacturability7
ZA-8's machinability is very good (80/100, better than 64% of zinc alloy grades); weldability poor (20/100).
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 zinc alloy family
Yield strength against density for every zinc alloy grade FabDigit runs. ZA-8 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZA-8
Is ZA-8 easy to machine?
Machines very easily with sharp positive-rake carbide or HSS tools, high speeds and light feeds, kerosene or light emulsion coolant; excellent surface finish and tapping behaviour.
Can ZA-8 be welded?
Not a weldable structural alloy — narrow freezing range and Zn volatility; repair only by zinc-based soldering/brazing or metal-filled epoxy, joins normally by cast-in features, screws or adhesives.
Can ZA-8 be formed, bent or molded?
Hot-chamber die castable at ~430–450 °C with thin walls (0.8 mm) and long die life; also sand, permanent-mould and graphite-mould gravity cast — avoid overheating melt and control Fe pickup.
Manufacturability
The process limits FabDigit's quote engine applies to ZA-8. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Excellent80 / 100 |
|---|---|
| Cutting speed (rough / finish) | — / — |
| Minimum wall | — |
| Minimum internal radius | — |
| Drill depth limit | |
| Best surface (machined / polished) | Ra — / — |
| Hardenable after machining | — |
ZA-8 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 | 8 – 8.8 | 8.4 |
| Cu | 0.8 – 1.3 | 1 |
| Mg | 0.02 – 0.03 | 0.02 |
| Femax; 0.035 max for ingot | ≤ 0.08 | |
| Pbimpurity max — intergranular corrosion control | ≤ 0.01 | |
| Cdimpurity max | ≤ 0.01 | |
| Snimpurity max | ≤ 0 | |
| Znbalance, 99.99% Zn base | balance |
What surface finishes work on ZA-8?
Not anodizable; chromate/trivalent passivation, Cu-Ni-Cr or electroless-Ni plating and powder/wet paint over phosphate all work well, and the surface buffs to a bright polish.
Surface treatments FabDigit runs on zinc alloy 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 Zinc Alloy ZA-8 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- Z35636
- Similar grades
- B669
How much does ZA-8 cost?
ZA-8 is a standard-cost zinc alloy ($$), cheaper than about 81% 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.
ZA-8 — frequently asked
What is ZA-8 used for?
ZA-8 is typically used for bearings, bushings and industrial gears. In short: higher-strength ZA die-cast.
What is the yield strength of ZA-8?
ZA-8 has a typical yield strength of 290 MPa (42.1 ksi) and a tensile strength of 374 MPa (54.2 ksi) — stronger than 93% of zinc alloy grades. Strength varies by condition: see the 4 listed tempers.
Is ZA-8 easy to machine?
Yes — machinability is rated very good (80/100, better than 64% of zinc alloy grades). Machines very easily with sharp positive-rake carbide or HSS tools, high speeds and light feeds, kerosene or light emulsion coolant; excellent surface finish and tapping behaviour.
Can ZA-8 be welded?
Not readily — weldability is rated poor (20/100). Not a weldable structural alloy — narrow freezing range and Zn volatility; repair only by zinc-based soldering/brazing or metal-filled epoxy, joins normally by cast-in features, screws or adhesives.
What surface finishes work on ZA-8?
Not anodizable; chromate/trivalent passivation, Cu-Ni-Cr or electroless-Ni plating and powder/wet paint over phosphate all work well, and the surface buffs to a bright polish.
Can ZA-8 be formed, bent or molded?
Hot-chamber die castable at ~430–450 °C with thin walls (0.8 mm) and long die life; also sand, permanent-mould and graphite-mould gravity cast — avoid overheating melt and control Fe pickup.
What is the maximum service temperature of ZA-8?
ZA-8 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 ZA-8 As Cast and ZA-8-DIE?
As Cast is the default condition — default commercial condition: thin-wall hot-chamber die castings with the highest strength and hardness of the ZA-8 forms. DIE: hot-chamber pressure die cast ZA-8 (ASTM B86 / UNS Z35636): fine chill-cast structure giving the highest strength and hardness of the as-cast ZA-8 conditions. Yield strength is 290 MPa in As Cast versus 290 MPa in DIE.
How much does ZA-8 cost?
ZA-8 is a standard-cost zinc alloy ($$), cheaper than about 81% 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.
Can FabDigit make parts in ZA-8?
Yes — ZA-8 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B86 — Zinc and Zinc-Aluminum (ZA) Alloy Foundry and Die Castings — ASTM International (2018)
- ASTM B669 — Zinc-Aluminum Alloys in Ingot Form for Foundry and Die Castings — ASTM International (2019)
- ASTM B240 — Zinc and Zinc-Aluminum Alloys in Ingot Form for Castings — ASTM International (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Zinc and Zinc Alloys) — ASM International (1990)
- ZA-8 Zinc Alloy Casting Data / Zinc Casting Design Guide — ILZRO / International Zinc Association (2011)
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.