High Fluidity Zinc-Aluminum Alloy

Thinner cell phone casings and business card holders are two applications for a new high fluidity zinc die casting alloy. This casting is now covered by a new ASTM International standard, B989, Specification for High Fluidity (HF) Zinc-Aluminum Alloy in Ingot Form for Thin Wall Die Castings.

The HF alloy was developed through a project coordinated by the Cast Metals Coalition, an industry consortium that includes the North American Die Casting Association and the International Zinc Association. Because the composition of this alloy is unique, a new standard for it was needed.

ASTM member John Malmgreen, vice president, manufacturing/quality, Eastern Alloys Inc., notes that, due to zinc's low melting point and its excellent fluidity, the alloy covered in B989 can be used to produce thinner wall sections compared to most other metal alloys or casting processes.

"Thinner walls means less weight, which translates to less material used to produce a part," says Malmgreen. Reducing the amount of material used naturally leads to reductions in both material and energy costs.

Malmgreen also notes that because the HF alloy is new to the zinc die casting industry, applications for it are still being aggressively explored.

"Casting trials have shown improvements in consistency and better fill of parts in the automotive industry, in such things as door locks," says Malmgreen. In addition, the alloy is being used in electronics as well, particularly the cell phone industry. Use of the HF alloy in the front and back casings of cell phones has significantly cut production time, energy and cost.

Producers of the HF alloy will be the primary users of B989, while it may also be used by die casters, original equipment manufacturers and commercial analytical laboratories.

B989 was developed by Subcommittee B02.04 on Zinc and Cadmium, part of ASTM International Committee B02 on Nonferrous Metals and Alloys. Future plans include developing a companion specification to cover castings that are produced with the HF alloy. All interested parties are invited to join in the standards developing activities of B02.04. B02.04 is also engaged in a long-range program to convert the standards under its jurisdiction into a uniform format. Both producers and end users are welcome.

To purchase ASTM standards, visit www.astm.org and search by the standard designation, or contact ASTM Sales (phone: 877-909-ASTM; sales@astm.org).

CONTACT Technical Information: John Malmgreen, Eastern Alloys Inc. • Maybrook, N.Y. • Phone: 845-427-2151 | ASTM Staff: Jeffrey Adkins • Phone: 610-832-9738 | Upcoming Meeting: Nov. 10-12 • November Committee Week • New Orleans, La.

Top casting – Cell phone case; Bottom casting – business card holder

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