Za 8

ZA-8 is a zinc-aluminum alloy offering high strength, excellent wear resistance, and tight dimensional control for industrial die-cast applications.

Introduction to ZA-8

ZA-8 (Zinc Aluminum Alloy 8%) is a hypoeutectic zinc-based casting alloy with approximately 8.4% aluminum content, specifically engineered for high-strength and high-precision die-cast components. It provides superior hardness, excellent dimensional stability, and improved wear resistance compared to traditional Zamak alloys.

As part of the zinc-aluminum die casting alloy group, ZA-8 is suitable for gravity and pressure die casting and can also be machined, plated, and easily polished. At Neway Die Casting, ZA-8 is utilized in components where tight tolerances, mechanical strength, and bearing properties are critical.

ZA-8 Chemical Composition

Element	Weight %	Function
Zinc (Zn)	Balance	Base metal
Aluminum (Al)	8.0–8.8	Strengthens alloy, improves wear resistance
Copper (Cu)	0.8–1.3	Increases hardness and bearing characteristics
Magnesium (Mg)	0.015–0.03	Enhances strength, reduces oxidation
Iron (Fe)	≤ 0.075	Impurity control
Tin (Sn), Nickel (Ni), Lead (Pb), Cadmium (Cd)	≤ 0.003 each	Impurities minimized per ASTM B86 standards

Physical Properties of ZA-8 Alloy

Property	Value & Unit
Density	6.3 g/cm³
Melting Range	381–390 °C
Thermal Conductivity	109 W/m·K
Electrical Conductivity	~27 % IACS
Coefficient of Thermal Expansion	~25 µm/m·°C
Specific Heat Capacity	~400 J/kg·K

High density and thermal conductivity make ZA-8 ideal for parts exposed to thermal cycling and dynamic loads.

Mechanical Properties (As-Cast & Aged)

Property	Typical Value & Unit
Ultimate Tensile Strength	350 MPa
Yield Strength	280 MPa
Elongation	1–3 %
Brinell Hardness	100 HB
Impact Strength (Notched Izod)	~3.5 J
Modulus of Elasticity	~96 GPa

These values exceed those of Zamak 3 and Zamak 5, making ZA-8 suitable for structural and load-bearing components.

Castability of ZA-8

ZA-8 is unique among zinc alloys in that it is suitable for both pressure die casting and gravity casting. It has:

Excellent dimensional control (linear shrinkage <0.006 mm/mm)
High casting fluidity, allowing for thin walls and complex geometries
Low hot tearing tendency
Improved wear resistance compared to Zamak series

At Neway’s zinc casting facility, ZA-8 is cast using thermal-balanced dies and monitored fill speeds to achieve tight dimensional tolerances without distortion.

Common Applications

ZA-8 is widely used in applications requiring strength, surface finish, and machinability:

Automotive: Transmission and drivetrain brackets, timing covers
Consumer electronics: Connector housings, lens mounts
Office equipment: Bearings, bushings, levers
Functional prototyping for zinc structural parts
Furniture and mechanical assemblies with sliding motion and wear zones

Machining Challenges and Solutions

While ZA-8 is more machinable than aluminum alloys, its high aluminum content makes it harder than Zamak, leading to increased tool wear:

Use of carbide or TiCN-coated tools is recommended
Proper lubrication prevents chip welding and edge buildup
Clamping and vibration control is essential for precision features

Neway integrates CNC post-machining and quality control (CMM + visual inspection) to guarantee surface finishes down to Ra 1.6 µm and dimensional tolerance within ±0.03 mm.