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Frequently Asked Questions

FAQ Category: Alloy Selection

What is the best source of information on the physical and mechanical properties of die casting alloys?

Updated Physical and Mechanical Properties Data for the most widely used die casting alloys is presented in Technical Bulletin (No. 020), and the NADCA Product Design for Die Casting Sourcebook. This alloy properties information, plus Detailed Alloy Chemistry and Alloy Die Casting and Post-Casting Characteristics, can also be found in the NADCA Product Specification Standards Manual. All materials are available from CWM.  E-mail sales@cwmtl.com or call 630-595-4424 for more information.  We also provide electronic copies of the alloy data within our DC2 Library at the following links:  Aluminum Alloy Data, Magnesium Alloy Data, and Zinc Alloy Data.  

When is zinc the best alloy to use for a die cast part?

Zinc (Zn), or the Zamak class, of die casting alloys offer a broad range of excellent physical and mechanical properties and finishing characteristics, and are the easiest to cast. Thinner sections and smaller parts can be die cast in zinc than in other commonly used die casting alloys. Zinc alloy generally allows for greater variation in section design and for the maintenance of closer dimensional tolerances. Zinc alloy produces the best chrome plating results. The impact strength of zinc components is higher than other die casting alloys, with the exception of brass. Due to the lower pressures and temperatures required for zinc, die life is significantly lengthened and die maintenance is minimized. Zamak No. 3 offers the best combination of mechanical properties, castability and economics and is the most widely used Zn alloy in North America. For detailed information on Zinc Alloy Properties, die casting, and post-casting characteristics, consult the NADCA Product Design Sourcebook or the NADCA Product Standards Manual. Both are available from CWM. E-mail sales@cwmtl.com or call 630-595-4424 for more information.

When is aluminum the optimum choice for a die cast part?

Selecting aluminum for a die cast alloy is a common occurrence.  This image shows a furnace tender loading up a cart with both recycled A380 and new ingots, to be loaded into the aluminum furnace.  Aluminum (Al) die casting alloys have a specific gravity of approximately 2.7 g/cc, placing them among the lightweight structural metals. The majority of die castings produced worldwide are made from aluminum alloys, with good corrosion resistance and good mechanical properties. Aluminum die castings offer high dimensional stability, thermal and electrical conductivity, and strength at high temperatures. Aluminum 380 alloy is the most widely used of the Al die casting alloys, offering the best combination of properties and ease of production. For detailed information on Aluminum Alloy Properties, die casting, and post-casting characteristics, consult the NADCA Product Design Sourcebook or NADCA Product Standards Manual. Both are available from CWM. E-mail sales@cwmtl.com or call 630-595-4424 for more information.

When is magnesium the best alloy to use for a die cast part?

Magnesium ingots are placed in a melting furnace prior to pouring into the magnesium die casting machinery. Magnesium (Mg) has a specific gravity of 1.74 g/cc, making it the lightest commonly used structural metal. Mg alloys have the highest strength-to-weight ratio and excellent damping characteristics. They are the easiest alloys to machine. High-purity Mg AZ91D, the most widely-used Mg die casting alloy, has excellent corrosion resistance, strength and castability. Its use in die cast parts has grown dramatically, often replacing plastic parts for greater strength and rigidity at no weight penalty. Utilizing the faster-cycling hot-chamber process for its Mg production, CWM operates three of the world's largest hot-chamber Mg die casting machines in one of the largest custom facilities in North America. For detailed information on Magnesium Alloy Properties, die casting, and post-casting characteristics, consult the NADCA Product Design Sourcebook or NADCA Product Standards Manual. Both are available from CWM.  E-mail sales@cwmtl.com or call 630-595-4424 for more information.

When are ZA alloys the optimum choice for a die cast part?

The high aluminum content zinc alloys in the ZA group contain substantially more Al than the Zamak alloys, with the ZA numerical designation representing their approximate percent aluminum content. The higher aluminum and copper content of the ZA alloys give them several distinct advantages over the traditional zinc alloys, including far higher strength, superior wear resistance, superior creep resistance and lower densities. ZA-8, with a nominal Al content of 8.4%, is the only ZA alloy that can be cast by the faster-cycling hot-chamber process. It has the highest strength of any hot-chamber zinc alloy, and the highest creep strength of any zinc alloy. ZA-8 offers excellent bearing properties, with lighter weight and greater strength than iron and bronze. It is used to produce net- and near-net-shape parts with extremely thin walls, replacing heavily machined part designs or iron, bronze or steel. For detailed information on ZA Alloy properties, die casting, and post-casting characteristics, consult the NADCA Product Design Sourcebook or NADCA Product Standards Manual. Both are available from CWM. E-mail sales@cwmtl.com or call 630-595-4424 for more information.

When is copper the best alloy to use for a die cast part?

Copper alloy (Cu) die castings (brass and bronze) have the highest mechanical properties and corrosion resistance of all die cast materials. While shorter die life compared to the other nonferrous alloys will result in higher die replacement costs for brass castings, total product cost can be lower compared to brass machined parts or brass investment castings. Where added strength, corrosion resistance, wear resistance and greater hardness are required for a product, the possible economies of brass die castings over other production processes can be considered. The number of custom producers of copper die castings is very limited. For detailed information on copper alloy properties, die casting, and post-casting operations, consult the NADCA Product Standards Manual which is available from CWM. E-mail sales@cwmtl.com or call 630-595-4424 for more information.

When is lead the best alloy to use for a die cast part?

Lead alloy (Pb) die castings offer high part density and are generally used for special forms of corrosion resistance. While extremely close dimensions can be cast, strength is low. Lead alloy castings are offered by a limited number of custom die casters for special applications.

Can die castings be produced in iron and steel?

The extremely high temperatures required to melt ferrous metals for die casting works against their wide use, with even the highest quality dies subject to short life. While ferrous die casting is not in widespread commercial practice, stainless steel and other high temperature metals, for example, are being regularly used to produce die cast parts.



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