characteristic

1. Large relative proportion.

2. Good casting performance, can die cast precision parts with complex shape and thin wall, and the casting surface is smooth.

3. Surface treatment: electroplating, spraying, painting, polishing, grinding, etc.

4. During melting and die casting, there is no iron absorption, no corrosion, no die sticking.

5. Good mechanical properties and wear resistance at room temperature.

6. Low melting point, melting at 385 ℃, easy to die cast.

type

Traditional die-casting zinc alloys include No. 2, 3, 4, 5 and 7 alloys, and No. 3 zinc alloy is the most widely used. In the 1970s, high aluminum zinc base alloys za-8, ZA-12 and ZA-27 were developed.

Zamak 3: good fluidity and mechanical properties. It is applied to castings with low mechanical strength requirements, such as toys, lamps, decorations and some electrical parts.

Zamak 5: good fluidity and good mechanical properties. It is applied to castings with certain requirements for mechanical strength, such as auto parts, electromechanical parts, mechanical parts and electrical components.

Zamak 2: it is used for mechanical parts with special requirements for mechanical properties, high requirements for hardness, good wear resistance and general requirements for dimensional accuracy.

ZA8: it has good impact strength and dimensional stability, but poor fluidity.

Low temperature zinc alloy: it is used for die casting workpieces with small size, high precision and mechanical strength, such as electrical parts.

Superloy: with better fluidity, it is applied to die-casting workpieces with thin wall, large size, high precision and complex shape, such as electrical components and their boxes.

Different zinc alloys have different physical and mechanical properties, which provides a choice space for die casting design.

According to the manufacturing process, zinc alloy can be divided into cast zinc alloy and deformed zinc alloy. The output of cast alloy is much greater than that of deformed alloy. The composition, properties and uses of several important zinc alloys are listed in the table below.

Cast zinc alloy

According to different casting methods, it is divided into pressure casting zinc alloy (solidified under external pressure) and gravity casting zinc alloy (solidified only under gravity).

Die casting zinc alloy

Since its application in the automobile industry in 1940, the output of this alloy has increased sharply. About 25% of the total zinc consumption is used to produce this alloy. Advanced and applicable technologies are constantly adopted and developed rapidly. The number of relevant talents is also increasing, including the iron and steel talent network. The most commonly used alloy system is Zn Al Cu mg system. Some impurities obviously affect the properties of die cast zinc alloy. Therefore, the content of impurities such as iron, lead, cadmium and tin is strictly limited, and the upper limits are 0.005%, 0.004%, 0.003% and 0.02% respectively. Therefore, high-purity zinc with purity greater than 99.99% should be used as raw material for die-casting zinc alloy.

Gravity casting zinc alloy

It can be cast in sand mold, gypsum mold or hard mold. This zinc alloy not only has the characteristics of general die-casting zinc alloy, but also has high strength, good casting performance, cooling rate has no obvious impact on mechanical properties, residues and wastes can be recycled, gate is simple, insensitive to overheating and remelting, small shrinkage and few pores, can be electroplated, and can be finished by conventional methods.

Wrought zinc alloy

In addition to traditional varieties, zn-cu-0.1ti and Zn-22Al alloys appear in wrought zinc alloys used in industry. After rolling, tizn15 intermetallic compound dispersed particles are arranged in rows along the rolling direction, which can hinder the movement of grain boundary.