Aluminum Die Casting – A Total Account About The Industrial Processes Combined With Aluminum Die Casting.
The process is performed within an automatic machine suitable to resist high pressure.
The molten metal is pushed by way of a hydraulically actuated plunger in to a two-piece steel die containing one or more cavities, each an exact inverse replica in the part or parts being produced. Because of the quick chill and rapid solidification that takes place when molten metal comes in contact with the relatively cool steel side, and since the fine metallurgical grain structure that results, the mechanical properties of pressure die castings are usually superior to castings manufactured by other methods.
Zinc pressure die castings, for instance, are stronger than sand cast CNC precision machining, SAE 40 bronze, and class 30 cast iron. Also, pressure die cast components produced while using ZA alloys are stronger than pressure die cast aluminum 380 alloy.
The name “ZAMAK” is undoubtedly an acronym from the German words that comprise the alloys primary ingredients: Z (zinc) A (aluminum) M (magnesium) and K (copper). Once the alloys were,created in the 1920s the 1st useable material was designated Zamak #1. With each subsequent iteration, the designations increased sequentially (1-2-3-4-5-6-7); only the most desirable alloys (2-3-5-7) remain in use presently.
The name ZAMAK is an acronym through the German words that define the alloys main ingredients…
Zamak 2, a predecessor of the more widely used Zamak 3, has the highest strength and hardness from the 4% zinc, aluminum (Zamak) alloy family. Due to its relatively high copper content (3%), it is actually approx. 25% stronger, as cast, than Zamak 3, and almost 10% stronger than Zamak 5, with higher hardness than both.
The top copper content, however, brings about property changes upon long-term aging. These changes include slight dimensional growth (.0014in/in after 20yrs), lower elongation and reduced impact performance (to levels comparable to aluminum alloys) for die cast products. It can do, however, provide some interesting characteristics which could assist designers. Its creep performance is rated beyond other Zamaks and #2 maintains higher tensile, strength and hardness levels after long lasting aging. Also, preliminary investigations suggest #2 is a good bearing material and might eliminate bushings and wear inserts in die designs.
But it does quit impact strength and because of this limitation Zamak 2 is merely used as soon as the strength or hardness of Zamak 3 or 5 are certainly not sufficient for very long-term end use. Zamak 2 might be termed as Kirksite which is really the only alloy employed for gravity casting – mainly for metal forming dies or plastic injection molds.
ZAMAK 3 Of the zinc casting alloys, Zamak 3 is easily the most traditionally used, comprising approx. 85% ofall zinc casting tonnage worldwide. It offers the base composition for the aluminum die casting alloys (96% zinc, 4% aluminum). Its superb physical and mechanical properties, excellent castability and long lasting dimensional stability provide you with the grounds for its broad usage. The ease it could be electroplated increases the demand for this alloy, with excellent finishing characteristics 21dexupky plating, painting, and chromate treatments. It will be the “standard” through which other zinc alloys are
rated with regards to die casting which is, therefore, by far the most widely accessible alloy for die, casting sources.
Zamak 2, has the highest strength and hardness from the 4% zinc, aluminum alloy family.
Usually through casting design procedures, a Zamak 3 pressure die casting can be done to fulfill service or functional requirements. When this is not the situation, especially where strength is concerned, CNC precision machining is the next choice. Aside from a nominal 1% copper addition, the chemistry of Zamak 5 is similar to that relating to Zamak 3. The composition modification results in higher tensile strength and increased hardness, but sacrifices elongation. Zamak 5 has significantly better creep resistance compared to other alloys within the conventional group.
Zamak 5 is not as ductile as several of the other alloys, a factor to take into consideration when post casting operations for example secondary bending, riveting, swaging or crimping are required. As a result of 3’s wide availability, material specifiers often strength components by design modification instead of Zamak 5. However, when an added measure of tensile performance is essential,
Zamak 5 castings are recommended. The alloy is easily plated, finished and machined, and is comparable to Zamak 3.