ZA-12 Zinc Alloy - Properties & Casting Guide

ZA-12 (ZnAl11Cu1 per EN 1774) sits between ZA-8 and ZA-27 in the zinc-aluminum family: 11% aluminum for high strength and hardness, with the best combination of bearing performance and castability of the ZA grades. It is the go-to alloy when Zamak 5 or ZA-8 run out of margin on wear and load.

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ZA-12 Chemical Composition

Element	Nominal %	Range
Aluminum (Al)	11.0	10.8 to 11.5
Copper (Cu)	1.0	0.5 to 1.2
Magnesium (Mg)	0.025	0.015 to 0.03
Iron (Fe)	-	0.075 max
Lead (Pb)	-	0.006 max
Cadmium (Cd)	-	0.006 max
Zinc (Zn)	Balance	-

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Mechanical Properties vs ZA-8 and Zamak 5

Property	ZA-12	ZA-8	Zamak 5
Tensile strength	400 MPa	374 MPa	331 MPa
Yield strength	317 MPa	290 MPa	228 MPa
Elongation	4 to 7%	8%	7%
Hardness	95 to 115 HB	100 HB	91 HB
Density	6.0 g/cm3	6.30 g/cm3	6.60 g/cm3
Bearing / wear performance	Excellent	Very good	Moderate

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The One Process Limitation That Matters

ZA-12 cannot be hot-chamber die cast. Above roughly 8% aluminum, the molten alloy aggressively attacks the ferrous gooseneck and pump components submerged in hot-chamber machines. ZA-12 is therefore produced by:

• Cold-chamber die casting - the standard route for production volumes
• Gravity / permanent mold casting - for larger or lower-volume parts
• Sand casting - for prototypes and very large parts

This is the practical dividing line in the ZA family: ZA-8 is the strongest grade that still runs in fast-cycle hot-chamber machines; ZA-12 trades that cycle-time advantage for a step up in strength and wear life.

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Where ZA-12 Wins

• Bearings and bushings replacing bronze - ZA-12's hardness and embedded lubricity give excellent wear life in moderate-speed, moderate-load service
• Gears, worm wheels, and sprockets in drives and actuators
• Pulleys, sheaves, and rollers for conveyors and door systems
• Hydraulic components and valve hardware
• High-load structural hardware where Zamak 5 is marginal

The classic business case: a machined bronze bushing converted to net-shape ZA-12 typically saves 30 to 50% on piece cost while matching service life in moderate-duty applications.

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ZA-12 vs ZA-8 - Selection

Choose ZA-12	Choose ZA-8
Maximum strength and wear life	Hot-chamber cycle economics needed
Bearing / gear applications	General high-strength hardware
Cold-chamber or gravity acceptable	Small parts at very high volume
Service temperature up to ~120°C	Service up to ~110°C

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Casting ZA-12 at KastMfg

KastMfg runs ZA-12 in cold-chamber machines with shot temperatures in the 470 to 565°C range, and offers gravity casting for larger ZA-12 components. Wear-critical parts get SPC monitoring on bearing bores, and we machine critical datums in-house (CNC machining) so bearing fits ship ready to assemble.

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Frequently Asked Questions

Is ZA-12 stronger than aluminum die casting alloys?

Its 400 MPa tensile exceeds A380's 320 MPa, with far better bearing properties - but at more than double the density (6.0 vs 2.71 g/cm3). For weight-sensitive parts, aluminum wins; for compact high-load mechanisms, ZA-12 wins.

Can ZA-12 be plated or coated?

Yes - the same powder coating, plating, and chromate processes as other zinc alloys apply. Its higher aluminum content slightly changes plating pretreatment parameters, which any competent plating line handles routinely.

ZA-12 vs ZA-27 - why not just use ZA-27?

ZA-27 (27% aluminum) is stronger still, but harder to cast (wider freezing range, more shrinkage management) and more expensive. ZA-12 covers roughly 80% of applications engineers consider ZA-27 for, with better castability.

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Related Zinc Resources

• zinc die casting - KastMfg zinc capability
• ZA-8 zinc die casting - the hot-chamber-compatible ZA grade
• zinc die casting alloys - full Zamak and ZA selection guide
• Zamak 5 - when standard strength is enough

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ZA-12 inquiry: yaoqingpu1983@gmail.com | +86 138 1403 4409 | No.6, Rungu Road, Nanjing, China