Engineering in zinc, today’s answer
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Engineered Zinc Die Castings for Optimal Design Freedom and Precision.
The Advantages of Zinc Casting Alloys
Zinc casting alloys are strong, durable and cost effective engineering materials. No other alloy system provides the combination of strength, toughness, rigidity, bearing performance and economical castability. Zinc’s mechanical properties compete with and often exceed those of cast aluminum, magnesium, bronze, plastics and most cast irons. These characteristics, together with their superior finishing capabilities and choice of casting processes make zinc alloys an unrivaled material choice for saving time and money.
Assembly operations are reduced. Entire assemblies can be cast as a single unit, eliminating the need for expensive manual assembly operations.
Less material is required. Zinc’s superior casting fluidity, strength and stiffness permits the design of thin wall sections for reduced weight and material cost savings.
Machining operations are reduced. Due to the superior net-shape casting capability of zinc alloys, machining can be eliminated or drastically reduced.
Faster production and extended tool life. Die cast‑
ing production rates for zinc are much faster than for aluminum or magnesium. Coupled with a tool life often exceeding 1 million parts, tooling and machine usage charges are dramatically reduced.
Eliminate bearings and bushings. Zinc’s excellent bearing and wear properties allow greater design flexibility and reduce secondary fabrication costs by eliminating small bushings and wear inserts.
Choice of low, medium, and high production. A variety of casting processes are available to economically manufacture cast parts of whatever size and quantity required.
Surface finishing. When a finish is properly selected and applied to cast zinc, almost any desired aesthetic characteristic and coating durability can be achieved.
Environmental harmony. Pollution and greenhouse gases are minimized with zinc casting alloys.
Alloy tailored to meet your needs: general purpose and specialty alloys.
There are two basic families of zinc casting alloy. The conventional or ‘ZAMAK’ alloys are commonly named based on their sequential development, preceded by the word alloy. These include Alloy 2, Alloy 3, Alloy 5, and Alloy 7. The most recent addition to the ZAMAK family is the new high-fluidity or ‘HF’ alloy. Zinc alloys with higher amounts of aluminum than the conventional alloys use the prefix ZA followed by their approximate aluminum content. These include ZA-8, ZA-12 and ZA-27. ZA alloys offer higher strength, and useful bearing properties.
Several different systems of naming the two classes of zinc alloys have evolved along with them, as indicated in parenthesis next to the main alloy names below.
锌压铸合金有两个基本家族，常规或’ZAMAK’合金通常以其发展顺序命名，前面是“合金”这个词。这些包括Alloy2, Alloy3, Alloy5,和Alloy7. 最新加入ZAMAK家族的是新的高流动性能或称HF合金。与传统合金相比，铝含量比较高的锌合金采用ZA作为前缀，后面是其近似的铝含量。这些包括ZA-8,ZA-12和ZA-27. ZA合金提供了更高的强度和有用的承载特性。
Major alloy characristics
Alloy 3: (ZAMAK 3, ZP3, ZL3, ZP0400, ZnAl4, ZDC2) Alloy 3 is the most widely used zinc alloy in North America. Its popularity is due to an excellent balance of desirable physical and mechanical properties, superb castability and long-term dimensional stability. No. 3 also offers excellent finishing characteristics for plating, painting and chromate treatments. It is the “standard” by which other zinc alloys are rated in terms of die casting
Alloy 5: (ZAMAK 5, ZP5, ZL5, ZP0410, ZnAl4Cu1, ZDC1) Alloy 5 is the most widely used zinc alloy in Europe. No. 5 has excellent castability characteristics and improved creep performance over No. 3. No. 5 castings are also marginally stronger and harder than No. 3, however, these improvements are accompanied by a reduction in ductility that can affect formability during secondary bending, riveting, swaging or crimping operations. No. 5 contains an addition of 1% copper which accounts for these property changes. When an extra measure of tensile performance is needed, No. 5 castings are recommended. The alloy is readily plated, finished and machined, comparable to No. 3 alloy.
Alloy 7: (ZAMAK 7, ZL7)
Alloy 7 is a modification of No 3 with a lower magnesium content and tighter impurities specification. This results in improved casting fluidity, ductility and surface finish, making the alloy
popular where the die caster is making thin walled components requiring a good surface finish. However, several new high fluidity alloys have recently been developed with superior thin wall characteristics (see high fluidity alloy).
Alloy 2: (ZAMAK 2, ZP2, ZL2, ZP0430, ZnAl4Cu3, Kirksite) Alloy 2 offers the highest strength and hardness of the conventional zinc alloys. The high copper content (3%) in No. 2 results in property changes upon long-term aging. These changes include slight dimensional growth, lower elongation and reduced impact performance (to levels similar to aluminum alloys) for die cast products. No. 2 alloy exhibits excellent castability and maintains higher strength and hardness levels after long term aging. No. 2 alloy is a good bearing material, and may eliminate bushings and wear inserts in die cast designs.
High Fluidity Alloy: (HF)
The HF alloy shares the good mechanical, electric and thermal conductivity property characteristics of the conventional alloys but possesses up to 40% better fluidity. Because of its optimization of composition for high fluidity, the HF alloy s best suited for casting parts with section thickness less than 0.45 mm. It can also be used for casting parts that are difficult to fill with Alloy 3, 5 or 7 or have high surface finish requirements.
Alloy3: (ZAMAK3, ZP3, ZL3, ZP0400, ZnAl4, ZDC2)
Alloy5 (ZAMAK5, ZP5, ZL5, ZP0410, ZnAl4Cu1, ZDC1)
Alloy7: (ZAMAK7, ZL7)
Alloy2: (ZAMAK2, ZP2, ZL2, ZP0430, ZnAl4Cu3, kirksite)
A good gravity casting alloy, ZA-8 can also be hot chamber die cast and is readily plated and finished using standard procedures for conventional zinc alloys. When the performance of Alloys No. 3 or No. 5 is in question, ZA-8 is often the die casting choice because of high strength and creep properties and efficient hot chamber castability.
ZA-12 is the best gravity casting alloy for sand, permanent mold and the graphite mold casting process. It is also a good (cold chamber) die casting alloy. ZA-12 often competes with ZA-27 for strength applications. An excellent bearing alloy, ZA-12 is also platable, although plating adhesion is reduced compared to the conventional zinc alloys.
This is an exceptionally strong alloy with a reported yield strength of 380 MPa (55ksi). It is light, and has excellent bearing and wear performance. Like ZA-12, this is a cold chamber die casting alloy and additional care is needed to ensure a sound casting. ZA-27 is not recommended for plating. When brute strength or wear resistance properties are needed, ZA27 has demonstrated excellent performance.
Developed by General Motors, this alloy has improved tensile strength, hardness and creep performance compared to the conventional zinc alloys. ACuZinc5’s strength and hardness properties are comparable to ZA-12. Testing has also shown ACuZinc5 to have excellent wear characteristics. Although this alloy is a hot chamber die casting alloy, it is more difficult to die cast with a higher wear rate of the shot end components in the die casting machine.
This recently developed alloy is the most creep resistant of all the zinc die casting alloys with an order of magnitude improvement over Alloy 5 and ZA-8. This is also a very strong alloy with a yield strength 393 MPa (57 ksi) and hardness (102-140 Brinell) comparable to ZA-27. Due to its low melting temperature, EZAC can be hot chamber die cast and does not exhibit the same die casting equipment wear and tear as shown with ACuZinc5.
Guss-Druck-Sonderlegierung “GDSL” is an ultra-thin zinc die casting alloy with fluidity characteristics similar to the HF alloy, but with a higher aluminum and copper content.
TM. A trademark or Eastern Alloys
Material properties that help solve today’s engineering problems.
The Ultimate Tensile Strengths (UTS) of zinc alloys can outperform Aluminum 380 and Magnesium AZ91D. Engineering Plastics struggle to deliver equivalent performance of zinc alloy’s UTS. Even glass-reinforced Nylon cannot achieve zinc alloy’s UTS. Ambient temperature Yield Strengths of zinc alloys are far superior to those of Aluminum 380, Magnesium AZ91D and the strongest plastics. Zinc alloys also display a high degree of energy absorbing ductility when subjected to abusive or destructive levels of loading.
锌合金的极限拉伸强度(UTS)可以优于铝380和镁AZ91D。 工程塑料难以实现与锌合金UTS相当的性能，甚至玻璃增强尼龙也不能达到锌合金的UTS。 锌合金的温室屈服强度要远胜于铝380，镁AZ91D和最强的塑料。锌合金在受到滥用或破坏的程度时，也显示出高度的能量吸收延展性。
Zinc alloys are rigid engineering materials. Their strength - in shear, torsion, under bending and in compression - is far superior to aluminum, magnesium and plastics. This combined with their high strength allows the volume of individual castings to be markedly reduced, saving space and weight.
Toughness and Ductility
High impact strength and good ductility are qualities of zinc alloys that are rarely found in most other casting alloys. Ductility is important for bending and crimping in post-casting assembly operations, while impact strength provides performance in rough environments. At normal ambient temperatures, zinc die castings have a much greater impact resistance than Aluminum 380 and Magnesium AZ91D, and ABS plastics. At minus 30ºC zinc alloys still remain far better. Even at minus 40ºC zinc at least matches the impact resistance of die cast aluminum. Zinc alloys fracture toughness is also superior to most aluminum alloys and engineering plastics.
Zinc alloys are significantly harder than aluminum and magnesium. Alloying additions such as copper, contribute to the good wear resistance exhibited by zinc alloys. Hence these alloys are used in moderately demanding applications where their natural bearing properties can be exploited
As zinc alloys conduct both heat and electricity, they can be used for heat dissipating devices such as heat sinks. Zinc’s excellent casting fluidity permits thinner fin and cooling pin design to better dissipate heat. Zinc’s excellent electrical conductivity also provides good EMI, RFI and ESD shielding.
Non-sparking and non-magnetic
All zinc alloys except ZA-27 are classified as “non-sparking” and are the perfect low-cost alternative to bronze in potentially explosive environments. Unlike plastics and some other materials, zinc will not normally sustain fire during processing or use. It is a relatively fire safe material. Zinc’s non-magnetic properties are ideal for use in electronics and other applications where delicate moving parts are subject to magnetic disturbances.
This measure of a material’s ability to withstand cyclic loading is an important design criterion. Fatigue is one of the most frequent failure mechanisms in components. Zinc, like other die cast metals is between 7 to 10 times more resistant to fatigue than ABS.
Design (Creep) Stress
For applications involving continuous loading at elevated temperatures, such as locks, zinc has superior creep strength to reinforced injection molded plastics. The room temperature design stress of die cast ZA-27, as defined by the ASME Boiler Code, is 69 MPa or 10,000 psi (stress required for creep of 1% in 100,000 hours). This property allows zinc alloys to be used in applications subject to significant static loading. However, permissible design stress drops with increasing temperature and a careful review of all constant load applications at temperature is required to determine the suitability of zinc alloys.
The soundness of castings is largely related to product design, tooling layout, and process control. The tight tolerance levels of zinc alloys provide reliability and consistency required for pressure tight applications.
The damping capability of zinc alloys - their ability to absorb energy and sound caused by externally induced mechanical vibration - is comparable to magnesium, and is 5 to 10 times greater
than aluminum. This property makes zinc alloys the perfect choice for housings where vibration absorption is required.
Zinc has excellent corrosion resistance under normal atmospheric condiitons, and in many aqueous, industrial and petroleum environments. Corrosion resistance can be enhanced by such treatments as plaitng, chromaitng, painitng and zinc anodizing.
Super bearing properties ensure built-in reliability
All zinc alloys, particularly ZA-12 and ZA-27, demonstrate excellent bearing and wear resistance qualities thanks to their high hardness and natural lubricity characteristics. ZA alloy bearings should be considered wherever bronze bearings are currently being specified. They generally operate best in lubricated, high-load, low-speed applications under moderate temperature conditions, however they have also been successfully used in high speed, low load applications.
ZA alloys are direct substitutes for larger bronze industrial bushings and bearings since they cost less and are up to 43% lighter. For smaller components, zinc’s natural lubricity may contribute to lower secondary fabrication costs by eliminating small bushings and wear inserts, thus allowing greater design flexibility.
Engineering characteristics that answer your most critical needs. 工程特性，即回答你们最关键的需求
Zinc alloys are castable to closer tolerances than any other metal or molded plastic. Zinc die casting can produce repeatability of less than ± 0.001” for small components, often rivaling machining tolerances. Few other processes can easily achieve the same net shape performance presenting the opportunity to reduce or eliminate machining. “Net Shape” or “Zero Machining” manufacturing is a major advantage of zinc casting
Fast, trouble-free machining characteristics of zinc materials minimize tool wear and machining costs which is a major advantage of zinc alloys over competitive materials.
Thin Wall Capability
Exceptional casting fluidity is displayed by all conventional zinc and ZA alloys, which provides superior thin-wall castability, regardless of the casting process employed. Wall thicknesses of 0.15mm for die casting and 2.3mm for permanent mold casting are being produced. This thin-wall capability results in smaller, lighter, low cost components compared to other metals.
Zero Draft Angle Castability
Draft angle is the taper on the surface of a die required to facilitate removal of the cast part from the die cavity. Zinc alloys can be die cast with less draft angle than competitive materials. In fact, zinc components can sometimes be cast with zero draft angles which is a major advantage when producing parts in moving mechanical contacts such as gears. Zero internal draft permits net shape manufacturing resulting in lower cost production.
脱模角度是模具表面上的锥度，以便于将模具从模腔中移出。 锌合金可以与竞争性材料相比具有较小的脱模角度的压铸。 事实上，锌组件有时可以以零脱模角铸造，这是在移动机械接触件如齿轮时生产零件时的主要优点。 零内部脱模允许净形状制造，从而降低成本生产。
If required, the high ductility of zinc will allow parts to be distorted in a controlled manner to achieve a final desired shape, or be inexpensively joined to an adjacent component through bending, forming, spinning or heading. Threaded fasteners, along with flaring, riveting and crimping techniques are common low cost joining methods. Zinc alloys can also be joined using adhesive bonding or MIG and TIG welding, although welding is normally not an economical joining method for zinc die castings due to the high production volumes involved.
Conventional zinc alloys, along with ZA-8 and ZA-12, have excellent dimensional stability characteristics in their ‘as cast’ condition. ZA-27, however, may require artificial aging treatment to minimize aging effects where exceptional tolerances are required. This is accomplished by heating the part to 95°C for 24 hours.
The Variety of high quality surface finishes is another major advantage.
When clever design is combined with the versatility of the zinc die casting process, it maximizes the aesthetic appeal of products.
Zinc die castings are an outstanding choice for countless decorative and functional applications. Due to its unique physical and mechanical properties, zinc can be cast into virtually limitless shapes and sizes ranging from simple toy cars to complex connector housings.
The majority of zinc die cast applications are not exposed to corrosive environments and the aesthetic requirements of the part defines which finish should be used, which in many cases means no finish at all
For applications where the service environment is aggressive, or where aesthetics dictate, an unrivaled range and quality of conversion coatings, organic paint and superb electroplated metal finishes (e.g. nickel, satin and bright chrome) can be easily and reliably applied to any selected surfaces of your component.
Excellent substrates help yield excellent finishes. Inexpensive bulk vibratory finishing can be used to improve the ‘as cast’ surface. Exceptionally smooth finishes can be obtained prior to finishing by lightly buffing or chemical polishing.
Due to the high fluidity of zinc alloys, a precisely defined surface texture can be added to part or all of the ‘as cast’ product. As a result, zinc castings can be made to look like solid gold, weathered brass, stainless steel, and even leather. Other external features such as lettering and logos can be ‘cast in’.
Zinc alloy’s density and its counter pointing ability to be very thinly cast allow the designer to influence
the user’s perception of weight, balance, solidity and inertia. For instance, coolness in hand, a premium
quality metallic feel and other perceived sensations are factors valued by many users of zinc die castings. On the other hand, ‘warm feel’ coatings and plastic over-molding are also tactile options that the designer can utilize.
For maximum impact and success, the designer is advised to consult the die caster at an early stage to agree on the best way of designing an economical and aesthetically attractive product
Casting versatility leads to further savings.
Process Flexibility: Virtually any casting process can be used with zinc alloys to satisfy any quantity and quality requirement. Precision, high-volume die casting is the most popular casting process. Zinc alloys can also be economically gravity cast for lower volumes using sand, permanent mold, graphite mold and plaster casting technologies.
This is the most efficient process for high-volume precision casting, producing the best tolerances and rapid production rates, but having high initial tooling costs.
Die casting should be considered for components requiring a production run of at least 10,000 pieces. All tolerances depend on part size and complexity; however, tolerances of ± 0.025mm (0.001”) are common. Hot chamber die casting cycle rates range from roughly 150 parts per hour for large components to over 2000 per hour for small ones.
The traditional zinc alloys and ZA-8 can be used in a “hot chamber” die casting machine, while ZA-12 and ZA-27 must be “cold chamber” die cast - like the aluminum alloys. The hot chamber process offers faster cycle times, resulting in lower production costs.
Due to the low melting temperatures of zinc alloys, dies for zinc parts last longer—often 3-4 times longer than the same dies when used for casting aluminum alloys
Permanent Mold Casting
ZA-8 and ZA-12 are generally considered for permanent mold applications. Permanent mold casting has traditionally been done using steel or cast iron molds, but is now also performed in graphite molds. Permanent mold casting often competes with sand casting by providing tighter tolerances and a smoother surface finish, which can reduce machining operations.
Ferrous permanent molds designed for aluminum alloys are generally suitable for casting zinc alloys. However, due to the superior casting fluidity of zinc, thinner sections can be cast. This process is well suited for medium production runs of 500-10,000 pieces. Ferrous permanent mold casting has great flexibility in terms of part size, ranging from ounces up to 100 lbs.
Graphite permanent mold casting offers some distinct advantages over metal tooling. Improved tolerances, lower tooling costs, and a supe‑
rior surface finish are all benefits of the graphite mold process. Drawbacks are limited component size, complexity and coring.
All the ZA alloys are suitable for sand casting; however, ZA-12 is the most popular. Sand casting offers the greatest design flexibility in terms of size, complexity and quantity requirements. Tooling costs are generally low, therefore facilitating low volume production. However, surface smoothness and tolerance capabilities are limited, usually requiring machining.
Hot chamber zinc die casting offers minimum processing cost.
Production time savings
This process combined with the relatively low casting temperature needed for zinc alloys allows exceptionally high production rates. For medium sized zinc components, 400 to 1000 shots per hour are common. Extremely small detailed zinc castings can be produced at up to 3500 shots per hour on specialized machines. By comparison, typical shot speed ranges for medium sized aluminum, magnesium and plastic components from 100 to 250, 200 to 300 and 100 to 300, respectively.
For an equal number of same size die castings, aluminum will use at least 50% more energy than zinc, while magnesium will need at least 15% more energy per casting than zinc. This is in addition to the high energy requirements needed to produce the aluminum and magnesium.
Near Net Shape castings
Clever design of product and tool, combined with zinc alloy’s inherent accuracy and excellent surface, can result in Near Net Shape zinc castings that require, if any, just the minimum of further processing stages.
Low tooling wear
For large volumes, zinc offers considerable further cost savings because its tooling typically lasts between 750,000 shots to 2 million shots. Aluminum and magnesium will struggle to achieve 250,000 and 500,000 shots respectively.
Hot Chamber Zinc Die casting is the most cost efficient production technique for 3D components due to its production speed and the low volume of scrap produced.
Pollution and greenhouse gases are minimized with zinc die casting:
Negligible emissions to air, land and water.
Much smaller energy consumption than comparable alternative mass manufacturing processes.
Any ‘scrap’ product from processing can be recycled.
Zinc alloys, as defined by international chemical composition standards, comfortably conform to the requirements of the End of Life Vehicle (ELV), Restriction of Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE) legislation.根据国际化学成分标准定义的锌合金，完全符合报废汽车标准(ELV)、关于限制在电子电器设备中使用某些有害成分的指令(RoHS)和报废的电子电气设备(WEEE)法规
Zinc die castings are premium quality low cost products that are highly resilient to many hostile conditions. They display considerable corrosion and wear resistance thus resulting in very long and reliable service, frequently measured in decades, and saving resources by not needing to be frequently replaced.
A recycling infrastructure is actively in place to treat today’s zinc processing scraps and tomorrow’s end of life cast zinc alloy products. Zinc castings can be marked with ISO recycling mark as featured in EN 12844 for easy alloy recognition and future recycling