Zinc Alloy ZA-27
ASTM ZA-27 · UNS Z35841
ZA-27 is a zinc-aluminum casting alloy with nominally 27% Al (UNS Z35841, ASTM B669) and the highest strength of the ZA series: 425 MPa tensile, 370 MPa yield, 3% elongation and 118 HB as cast.
Values for the As Cast condition
ZA-27 tempers and conditions
ZA-27 is supplied in 5 conditions, soft to hard. As Cast is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stabilized / heat treated (≈320 °C, 3 h, air cool) | Pick when dimensional stability and higher ductility/toughness matter more than peak strength (e.g. precision bushings before final machining). | 255 | 310 | 8 | 95 HB | 30 % IACS |
slower cooling, coarser structure | Choose for large or one-off parts; slightly lower strength but better ductility than permanent mold. | 365 | 410 | 4 | 113 HB | 29.7 % IACS |
As CastDefault gravity/permanent mold, no heat treatment | Standard stocked condition for gravity, permanent-mold and centrifugal ZA-27 castings; highest strength and hardness. | 370 | 425 | 3 | 118 HB | 29.7 % IACS |
cold-chamber pressure die cast, as cast | Only for high-volume thin-wall parts run on cold-chamber machines; wide freezing range makes ZA-27 the hardest ZA alloy to die cast. | 371 | 426 | 2.5 | 119 HB | 29.7 % IACS |
Permanent (metal/graphite) mold as cast | Best strength and hardness of the ZA-27 conditions; use for bushings, gears and load-bearing housings in medium volumes. | 375 | 425 | 2 | 120 HB | 29.7 % IACS |
What is ZA-27?
ZA-27 is a zinc-aluminum casting alloy with nominally 27% Al (UNS Z35841, ASTM B669) and the highest strength of the ZA series: 425 MPa tensile, 370 MPa yield, 3% elongation and 118 HB as cast. Engineers specify it as a bronze or cast-iron substitute for bearings, bushings and wear parts because it carries load at low density and machines freely (machinability 78). Limits are a 100 °C maximum service temperature, low ductility, no practical weldability, and a wide freezing range that demands generous feeding. ZA-12 or ZA-8 are the alternatives when more ductility or hot-chamber die casting is required. ZA-27 has a density of 5 g/cm³ (0.181 lb/in³), lighter than 100% of zinc alloy grades. It melts at 375°C (707 °F). ZA-27 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 425 MPa (61.6 ksi) — stronger than 100% of zinc alloy grades. Elongation at break is 3% and the elastic modulus is 78 GPa (11.3 Msi).
What is ZA-27 used for?
- Gears
- Industrial bushings
- Bearings
Advantages
- High strength — 370 MPa (53.7 ksi), better than 100% of zinc alloy grades
- Lightweight — 5 g/cm³ (0.181 lb/in³), better than 100% of zinc alloy grades
Limitations
- Low stiffness — 78 GPa (11.3 Msi), worse than 100% of zinc alloy grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 100% of zinc alloy grades
- Limited formability — 10/100, worse than 92% of zinc alloy grades
- Limited ductility — 3%, worse than 86% of zinc alloy grades
ZA-27 properties
Typical room-temperature values for ZA-27-As Cast; bars are the position among zinc alloy grades.
Physical3
ZA-27 has a density of 5 g/cm³ (0.181 lb/in³), lighter than 100% of zinc alloy grades. It melts at 375°C (707 °F).
Mechanical14
ZA-27 has a yield strength of 370 MPa (53.7 ksi) and a tensile strength of 425 MPa (61.6 ksi) — stronger than 100% of zinc alloy grades. Elongation at break is 3% and the elastic modulus is 78 GPa (11.3 Msi).
Thermal6
ZA-27 is rated for continuous service to 100°C (212 °F). It conducts heat at 125.5 W/m·K (72.5 BTU/hr·ft·°F), better than 100% of zinc alloy grades. Thermal expansion is 26 µm/m·K (14.4 µin/in·°F).
Electrical3
ZA-27 conducts electricity at 29.7 % IACS, better than 100% 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-27 takes about 90 MJ of energy and emits 5.5 kg of CO₂ — more than 100% of zinc alloy grades. Typical recycled content is 30%.
Manufacturability8
ZA-27's machinability is very good (78/100, worse than 61% of zinc alloy grades); weldability poor (20/100); formability not recommended (10/100).
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-27 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZA-27
Is ZA-27 easy to machine?
Machines very freely with sharp carbide or HSS tools, high speeds, light feeds and no coolant needed for many operations; avoid built-up edge by using polished rake faces.
Can ZA-27 be welded?
Not practically weldable — the wide freezing range and Zn vapour cause cracking and porosity; repair by mechanical fastening, adhesive or zinc-base solder-braze only on non-critical parts.
Can ZA-27 be formed, bent or molded?
Foundry alloy: pour at ~600–650 °C into sand, graphite or permanent molds with generous feeders (high shrinkage, hot-tear prone); cold-chamber die casting only, hot-chamber machines are unsuitable.
Manufacturability
The process limits FabDigit's quote engine applies to ZA-27. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Excellent78 / 100 |
|---|---|
| ISO material group | P.3 |
| Cutting speed (rough / finish) | 140 / 170 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
ZA-27 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 | 25 – 28 | 27 |
| Cu | 2 – 2.5 | 2.25 |
| Mg | 0.01 – 0.02 | 0.02 |
| Fe | ≤ 0.08 | |
| Pb | ≤ 0.01 | |
| Cd | ≤ 0.01 | |
| Sn | ≤ 0 | |
| Simax, where specified | ≤ 0.02 | |
| Znspecial high grade base | balance |
What surface finishes work on ZA-27?
Take chromate/phosphate conversion coats, e-coat, powder paint and electroless/electroplated Ni or Cr well after proper etch; do not anodize, and allow for natural aging dimensional change before precision finishing.
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-27 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- Z35841
- Similar grades
- B669
How much does ZA-27 cost?
ZA-27 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-27 — frequently asked
What is ZA-27 used for?
ZA-27 is typically used for gears, industrial bushings and bearings. In short: premium ZA bearing alloy.
What is the yield strength of ZA-27?
ZA-27 has a typical yield strength of 370 MPa (53.7 ksi) and a tensile strength of 425 MPa (61.6 ksi) — stronger than 100% of zinc alloy grades. Strength varies by condition: see the 5 listed tempers.
Is ZA-27 easy to machine?
Yes — machinability is rated very good (78/100, worse than 61% of zinc alloy grades). Machines very freely with sharp carbide or HSS tools, high speeds, light feeds and no coolant needed for many operations; avoid built-up edge by using polished rake faces.
Can ZA-27 be welded?
Not readily — weldability is rated poor (20/100). Not practically weldable — the wide freezing range and Zn vapour cause cracking and porosity; repair by mechanical fastening, adhesive or zinc-base solder-braze only on non-critical parts.
What surface finishes work on ZA-27?
Take chromate/phosphate conversion coats, e-coat, powder paint and electroless/electroplated Ni or Cr well after proper etch; do not anodize, and allow for natural aging dimensional change before precision finishing.
Can ZA-27 be formed, bent or molded?
Foundry alloy: pour at ~600–650 °C into sand, graphite or permanent molds with generous feeders (high shrinkage, hot-tear prone); cold-chamber die casting only, hot-chamber machines are unsuitable.
What is the maximum service temperature of ZA-27?
ZA-27 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-27 As Cast and ZA-27-PM?
As Cast is the default condition — standard stocked condition for gravity, permanent-mold and centrifugal ZA-27 castings; highest strength and hardness. PM: best strength and hardness of the ZA-27 conditions; use for bushings, gears and load-bearing housings in medium volumes. Yield strength is 370 MPa in As Cast versus 375 MPa in PM.
How much does ZA-27 cost?
ZA-27 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-27?
Yes — ZA-27 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B669 — Zinc-Aluminum (ZA) Alloys in Ingot Form for Foundry and Die Castings — ASTM International (2020)
- ASTM B791 — Zinc-Aluminum (ZA) Alloy Foundry and Die Castings — ASTM International (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Zinc and Zinc Alloys) — ASM International (1990)
- ZA-27 Zinc Alloy Datasheet — Eastern Alloys Inc. (2022)
- ZA Alloy Design and Engineering Guides — ILZRO / International Zinc Association (1995)
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.