1. The advantages and disadvantages of zinc alloy:

Strengths: Cast zinc alloy has good fluidity and corrosion resistance, suitable for die-casting instruments, automobile parts shells, etc.

Disadvantages: The most common disadvantage of zinc alloy die castings is blistering on the surface.

2. Advantages and disadvantages of aluminum alloy:

Strengths: Aluminum alloy has low density, but relatively high strength, close to or better than high-quality steel, good plasticity, can be processed into various profiles, has excellent electrical conductivity, thermal conductivity and corrosion resistance, widely used in industry, only second Yu Gang.

Disadvantages: Aluminum alloys are prone to casting defects such as shrinkage holes, blisters, pores and slag inclusions during the production process.

Casting zinc alloys are divided into pressure casting zinc alloys (condensing under the effect of applied pressure) and gravity casting zinc alloys (condensing only under the effect of gravity) according to different casting methods.

Pressure casting zinc alloy This alloy has been developed rapidly since its use in the automotive industry in 1940, and its output has increased dramatically. About 25% of the total zinc consumption is used to produce this alloy. The most commonly used alloy system is the Zn-Al-Cu-Mg system.

Aluminum can refine grains, improve the strength and impact toughness of zinc, and can significantly reduce the corrosion of molten zinc on iron containers, avoid welding or adhesion of castings and die casting molds, so that zinc alloys can be used in hot chamber die casting machines Produced to improve yield. The suitable content of aluminum is about 3.5 to 4.3%.

Copper can improve the strength, hardness and corrosion resistance of zinc alloy, but excessive addition will reduce the impact toughness and dimensional stability of the alloy after aging. The maximum content of copper in the die-cast zinc alloy is 1.25%, preferably controlled below 1%. If the casting is large or the dimensional stability is very high, an alloy with a lower copper content should be used.

Magnesium can reduce the corrosion of the material in the die-cast zinc alloy, and can also eliminate the harmful effects of impurities such as lead and tin; the content of magnesium is about 0.01 ~ 0.08%, usually not more than 0.05%. Too much content will produce hot brittleness, making casting difficult.

Certain impurities obviously affect the function of die-cast zinc alloy. Therefore, the content of iron, lead, cadmium, tin and other impurities are extremely restricted, and the upper limits are 0.005%, 0.004%, 0.003%, and 0.02%, respectively. Therefore, high-purity zinc with a purity greater than 99.99% should be used as the raw material for die-casting zinc alloys.

Gravity casting zinc alloy 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 function, cooling speed has no obvious effect on mechanical function, residual and scrap can be recycled, the gate is simple, insensitive to overheating and remelting, shorten The rate is small, the porosity is few, can be electroplated, and can be finished by conventional methods.

Deformed zinc alloy In addition to the traditional varieties, the deformed zinc alloy used in the industry presents Zn-1Cu-0.1Ti and Zn-22Al alloys. After the former alloy is rolled, the dispersed particles of TiZn15 intermetallic compound are arranged along the rolling direction, which can prevent the grain boundaries from moving, so the creep strength can be significantly improved. This kind of zinc alloy has fine grain and good low temperature plasticity. In addition to products produced by general molding methods, it can also be rolled into complex shapes. Zn-22Al alloy is superplastic under certain conditions.