- Jan 02, 2018 -
The advantages and disadvantages of zinc alloy and aluminum alloy
Only found these information, I hope the landlord will be a little help! Cast as an example
Zinc alloy hardness 65-140, tensile strength 260-440
Aluminum alloy hardness 45-90, tensile strength 120-290
The overall zinc alloy hardness than aluminum, high tensile strength. The use of the situation is different
lz You can look at the mechanical design manual, such a difference, not much use. Their difference is too big. Aluminum alloy has good plasticity but low strength, but its specific strength is higher. It is suitable for medium structural materials with heavy weight. Aluminum alloy and zinc alloy have good corrosion resistance. Zinc alloy Higher hardness than aluminum, tensile strength, but there is no absolute limit. Aluminum alloy density, hardness is also great, like 2 *** and 7 *** series of alloys, the hardness is very large, and the tensile strength is better. Their main difference is the composition of the main elements of zinc alloy is zinc, generally greater than 85%, the main aluminum alloy is aluminum, generally greater than 87%, depending on the type of alloy, grades, simple understanding is that zinc alloy is zinc Which add other alloying elements, aluminum is also based on zinc added to the other elements of the alloy. Zinc alloy with low melting point, good fluidity (can be cast thin-walled parts), fusible, brazing and plastic processing, corrosion resistance in dry air and atmosphere, residual, scrap easy to recycle and remelt; but lower creep strength , The natural aging will make the size change. Zinc alloy manufacturing process can be divided into two types of zinc alloy casting and deformation. Casting alloy production is much larger than the deformation alloy. The table below lists the composition, properties and uses of several important zinc alloys.
Casting zinc alloy according to the different casting methods are divided into pressure casting zinc alloy (under the pressure of solidification) and gravity casting zinc alloy (only under gravity solidification).
Pressure casting zinc alloy This alloy from the automotive industry in 1940 after the application of rapid development, output soared. About 25% of the total zinc consumption is used to produce this alloy. The most commonly used alloys are Zn-Al-Cu-Mg systems.
Aluminum can refine the grain, improve the strength and impact toughness of zinc, and can obviously reduce the corrosion of molten iron on the iron container to avoid the welding or adhesion of the casting and the die-casting mold, so that the zinc alloy can be used in the hot-chamber die-casting machine Production to increase productivity. Appropriate aluminum content of about 3.5 to 4.3%.
Copper can improve the strength, hardness and corrosion resistance of zinc alloy, but excessive addition will reduce the alloy's impact toughness and dimensional stability after aging. The maximum content of copper in die-cast zinc alloy is 1.25%, preferably controlled below 1%. Such as large castings or dimensional stability requirements are high, should use a lower copper content of the alloy.
Magnesium die cast zinc alloy can reduce the material corrosion, but also eliminate the harmful effects of lead, tin and other impurities; magnesium content of about 0.01 to 0.08%, usually not more than 0.05%. If the content is too much will have a hot brittle, making the casting difficult.
Some impurities significantly affect the performance of die-cast zinc alloys. Therefore, the contents of iron, lead, cadmium, tin and other impurities are extremely limited. The upper limits are 0.005%, 0.004%, 0.003% and 0.02% respectively. Therefore, the high purity zinc with the purity of more than 99.99% should be selected as the raw material for die-casting zinc alloy.
Gravity casting Zinc alloy can be cast in sand, gypsum or hard mold. The zinc alloy not only has the characteristics of the general die-cast zinc alloy, but also has the advantages of high strength, good casting performance, no obvious influence on the mechanical property of the cooling rate, the residual and waste can be recycled, the gate is simple, insensitive to overheating and remelting, Small rate, stomatal less, can be plated, can be used conventional finishing.
In addition to the traditional varieties of deformed zinc alloy used in the industrial application of deformed zinc alloy, Zn-1Cu-0.1Ti and Zn-22Al alloys appeared. The former alloy after rolling, due to the TiZn15 intermetallic compound dispersed particles along the rolling line, can hinder the grain boundary movement, which can significantly improve the creep strength. This zinc alloy fine grain, with good low temperature plastic, in addition to the general method of forming products, but also rolled into complex shapes profiles. Zn-22Al alloy has superplasticity under certain conditions.