Eastern Alloys, Inc.

United States

• mpact Strength6 ft-lbs
• Ultimate Tensile Strength35,000 psi

Eastern Alloys manufactures mold-base alloys, also known as Kirksite alloys. Kirksite is a moderate strength zinc-base alloy that was developed primarily as a forming tool alloy. Dies cast from Kirksite provide low-cost tooling because the alloy can be accurately cast, requiring a minimum of finishing. In addition, Kirksite has been used as a general purpose casting alloy for non-stressed components. Typical uses for Kirksite alloys are: Press dies and punches for sheet metal forming. Molds for ceramics and rubber. Injection molding and compression molding dies. Tube bending dies. Mandrels for metal spinning. Low stressed non-sparking tools and repair parts. Because of the alloy's excellent fluidity and low melting temperature, casting temperatures are low, 800-850°F. Higher casting temperatures should be avoided due to possible iron contamination from the cast iron kettles normally used to melt the alloy. Iron pickup can cause poor casting surface quality and brittleness. Melting in a silicon carbide crucible is preferred as a safeguard against iron pickup. The alloy is normally cast in permanent, plaster or sand molds. Kirksite is readily machined and polished. Castings can be successfully plated following procedures used for zinc die-castings. Kirksite can also be cast in rubber tooling as a replacement for slush casting alloy (ZA-5) when higher strengths are required, with a sacrifice in fluidity.

• High Temp Yield Strength (ksi)24
• Yield Strength (ksi)57

EZAC™ is Eastern Alloys' new high strength, creep resistant, hot chamber zinc based die casting alloy. With excellent fluidity and a low casting temperature (780 - 825 F), EZAC™ is perfect for the hot chamber die casting process. In addition, because of EZAC™'s low melting temperature, it does not have the same casting difficulties (such as erosion and wear) that other similar high strength die casting alloys exhibit. Casting trials have shown neglibible component wear in EZAC™ compared to other high strength hot chamber zinc die casting alloys. Improvements of EZAC™ over traditional zinc diecasting alloys include: Creep Resistance: Creep occurs when components deform with time, being subject to elevated temperatures and stresses. Most zinc alloys are known to have lower creep resistance and are often overlooked for many applications with higher operating temperatures. Tensile Strength: With an average yield strenth of 396 MPa, EZAC™ is stronger than any other Hot Chamber Zinc die casting alloy, and is comparable in strength to ZA-27, the strongest Cold Chamber Zinc die casting alloy. High Temp Tensile Properties: EZAC™ has improved tensile strength over other the hot chamber zinc alloys. Hardness: Hardness tests comparing EZAC™ to ACuZinc5 and Zamak 2 show over a 12% improvement compared to ACuZinc5, and over 19% improvement over Zamak 2. Property ComparisonsV

• Zamak 3 (Die Cast)41.0
• Zamak 3 (Con-cast)45.6

Eastern Alloys is now offering Con-Cast Zinc Bar Stock for prototyping. Prototyping is a very important stage in product development, by helping engineers determine if parts can or cannot be made in the material being tested. There are many reasons to prototype including: Prototyping can be simple, giving quick results to the end user for fast decision making. Prototyping helps eliminate costly retooling procedures required when parts fail preliminary testing. Changes can be made to the part instead of the tool. If prototyping is not used, the end user may give up after the first round of testing because of the added time and expense of retooling the die for additional prototyping samples. There are many different ways to prototype for zinc die castings. Machining prototype parts from Con-Cast Zinc Bar Stock is a fast, simple and easy approach, producing very similar properties as actual zinc die castings. Other advantages of using Con-cast Zinc Bar stock are: The material is readily available - so there are no long lead times (unless unusual sizes are requested). There is no wait for tools to be machined. Con-Cast bar stock can be used for functional testing as well as aesthetic properties (plating, powder coating, etc.). Properties The following table gives the properties of Con-Cast parts compared to Die Casting and Sand Casting processes. As shown, the Con-cast zinc bar stock properties are very similar to the die casting component, with the exception of elongation. If elongation is a required property, than a simple heat treatment of ZA12 alloy, will produce very similar results to Zamak 3 die castings. Heat treated ZA12 bars can also be available upon request.There are many sizes and shapes of con-cast bar stock available, including round bar stock diameters ranging from ¾" to 9" and rectangular bar stock sections of 58" to 8". Hexagonal bar stock is also available upon request.

• Yield Strength - 0.2% Offset: psi x 103 (MPa)32 (221)
• Ultimate Tensile Strength: psi x 103 (MPa)41 (283)

Eastern Alloys manufactures the complete range of zinc die casting alloys. ZAMAK alloys were first developed during the 1920's by The New Jersey Zinc Company. The name ZAMAK draws upon the basic metallurgy of the alloy group: Z-Zinc, A-Aluminum, MA-Magnesium, and K-Kopper (e.g., German). In the United States, ZAMAK 3 is the most common alloy for hot chamber die casting. With a combination of superior mechanical properties and low meltingmanufacturing costs, it fulfills the needs for most die casting applications. Other ZAMAK alloys include ZAMAK 2, ZAMAK 5, and ZAMAK 7. Common to each alloy is a consistent Aluminum content range, however, the alloys differ in specification by varying amounts of copper, magnesium, and nickel - resulting in different mechanical and physical properties. Zamak 3 Ingots stacked on alloy feet Eastern Alloys is the global leader in ZA alloy manufacturing and process technology. High strength ZA alloys were originally engineered for gravity casting, but now own an increasing percentage of the die casting market. Today, there are three ZA alloys: ZA8, ZA12, ZA27. ZA8 is the only ZA alloy that can be HOT chamber die cast due to the relatively low melting temperature (708-759 F). ZA12 and ZA27 can be COLD chamber die cast at higher melting temperatures (875-1050 F). The ACuZinc is another zinc die casting alloy-, developed by General Motors Research and Development engineers. At the outset ACuZinc alloys were limited to production of GM-specific parts. More recently, however, the GM licensing agreement allows for a broader scope of applications. With the addition of high percentages of copper, ACuZinc alloys were developed to improve the wear resistance and creep properties in the zinc alloy family. Today there are two ACuZinc alloys: ACuZinc 5 (5% Copper), and ACuZinc 10 (10% Copper), and are used in a variety of automotive applications. ACuZinc 5 is HOT chamber die cast due to its lower melting temperature, whereas ACuZinc 10 is COLD chamber die cast. The process of casting these zinc die casting alloys utilize an hydraulic press that allows metal to be injected into a cavity at extremely high pressures. The term "HOT" (as in HOT chamber) refers to the fact the metal pump (gooseneck) is immersed in the hot metal. In COLD chamber die casting, the metal is ladled into a holding sleeve until a plunger forces the metal into the cavity. These processes are designed for high volume applications, and are cast at "net-shaped" precision.No. 3 alloy is usually the first choice when considering zinc die casting. Its excellent balance of desirable physical and mechanical properties, superb castability and long-term dimensional stability are the reasons why over 70% of all North American zinc die castings are in No. 3 alloy. It is, therefore, the most widely available alloy from die casting sources. ZAMAK 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. Zamak 5 No. 5 alloy castings are marginally stronger and harder than No. 3. However, these improvements are tempered with a reduction in ductility which 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. The alloy is widely die cast in Europe and does exhibit excellent castability characteristics, as well as, improved creep performance over No. 3. Because of No. 3's wide availability, material specifiers often strengthen components by design modifications instead of using No. 5. However, when an extra measure of tensile performance is needed, No. 5 alloy castings are recommended. The alloy is readily plated, finished and machined, comparable to No. 3 alloy.