Chemical Composition (%)
| Al | 25.5~28.0 |
|---|---|
| Cu | 2.0~2.5 |
| Mg | 0.010~0.020 |
| Fe | ≤0.075 |
| Zn | Balance |
Mechanical & Physical Properties
| Tensile strength | ≥400 MPa (sand cast) |
|---|---|
| Elongation | ≥3% (sand cast) |
| Hardness | ≈90-110 HBW |
| Density | 5.0 g/cm³ |
| Coefficient of thermal expansion | ≈26 × 10⁻⁶/K |
Typical Applications
Grade Overview
ZZnAl27Cu2Mg is a high-aluminium zinc casting alloy with 25.5-28.0% aluminium, 2.0-2.5% copper and a tightly controlled 0.010-0.020% magnesium. Sand castings reach at least 400 MPa tensile strength, 3% elongation and about 90-110 HBW, at a density of only 5.0 g/cm³. It offers good bearing properties and is used as a weight-saving substitute for tin bronze in heavy wear parts.
Selecting ZZnAl27Cu2Mg
Choose ZZnAl27Cu2Mg for thick-walled liners and liner plates, large-diameter bushings, heavy-duty slide plates and guide rails, worm wheels and racks, and metallurgical equipment wear parts. It is a cost- and weight-saving alternative to tin bronze in slow-speed, high-load duty. Where ductility or pressure tightness is critical, a bronze remains the safer choice.
Working with ZZnAl27Cu2Mg
Magnesium content is critical and must stay within 0.010-0.020%; do not widen the range. Melt clean, degas and avoid iron pickup. The alloy casts well in sand and permanent moulds and machines readily. Because elongation is only about 3%, avoid sharp section changes and shock loading. No heat treatment is required.
Frequently asked questions about ZZnAl27Cu2Mg
Is ZZnAl27Cu2Mg the same as ZA27?
Yes. ZA27 is the common shorthand for this 27% aluminium zinc alloy; ZZnAl27Cu2Mg is the GB/T 1175 designation.
Why is the magnesium range so narrow?
Magnesium controls grain refinement and dimensional stability. Outside 0.010-0.020% the alloy either becomes unstable in service or difficult to cast.
Can it replace tin bronze bushings?
In slow-speed, high-load bushings it often can, with much lower weight and cost. Check load, speed and lubrication before substituting.
Data compiled from current standards; for selection reference only. Ordering is subject to the standard and the mill certificate. Data source: Shenyang Yuheng Metal Manufacturing Co., Ltd. — yuhengmetal.com.