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Graphicast ZA-12 zinc alloy offers an excellent combination of mechanical properties,
surface finish, and low cost. ZA-12's strength, hardness, and wear properties are
better than any other general-purpose nonferrous casting alloy. Because ZA-12
is spark proof, it can be used in hazardous environments, including those
underground.
With excellent castability, ZA-12 has a distinctive lustrous appearance, and its
low casting temperature promotes long mold life. Zinc metal and alloys are
also readily available at relatively stable prices, ensuring the long-term viability
of products designed with Graphicast components.
ZA-12 has approximately the same density as cast iron, but is stronger. It machines
three times faster with greatly improved tool life. It also offers much better
corrosion resistance.
ZA-12 is harder, stronger, and has better wearing qualities than aluminum, yet
it does not require heat treating. ZA-12 machines more easily than aluminum, is
more dimensionally stable, and will not warp.
ZA-12 machines as easily as either brass or bronze, yet has superior strength,
hardness, and wearing qualities. It can also be coated for corrosive
applications/environments.
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Materials
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ZA-12
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Other Casting Materials
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Properties
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Zn/11 Al/.75 Cu
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Aluminum 356-T6
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Bronze 85-5-5-5
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Class 30 Iron
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Graphicast Process
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Sand Cast
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Permanent Mold
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Sand Cast
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Tensile Strength (psi x 103)
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50
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33
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38
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37
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34
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Yield Strength (0.2% offset, psi x 103)
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31
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24
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27
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17
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-
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% Elongation (in 2 inches)
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2-3
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3.5
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5
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30
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-
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Brinell Hardness (500 kg load)
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110-125
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70
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80
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65
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180-225
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Density (lb/in3)
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.22
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.10
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.10
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.32
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.26
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Young's Modulus (psi x 106)
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12
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10.5
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10.5
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13.5
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13 to 16
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Fatigue Strength (psi x 103 @ 5 x 108 cycles)
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15
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8.5
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13
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11
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14
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Thermal Expansion (µinch/inch/°F @ 68°-212°F)
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13.4
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11.9
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11.9
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10.1
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6
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Thermal Conductivity (BTU/ft/hr/ft2/°F @ 68°F)
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67
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87
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92
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40
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26
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Electrical Conductivity (% Cu)
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28
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39
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41
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15
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-
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NOTE: Figures are correct, but are not warranted in any way by Graphicast, Inc.
For structural applications above 200°F, or for detailed fatigue, impact, or
creep strength properties, contact Graphicast.
Through a national network of experienced sales engineers, Graphicast will review
your requirements and provide an expert evaluation of the advantages of
its ZA-12 casting process for your specific part.
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Using Pro/Engineer and SolidWorks® parametric and associative 3D solid modeling
CAD software, Graphicast's experienced design engineers can work with you to
design and refine your castings. Through early involvement in the design process
and concurrent engineering, Graphicast can help you improve the quality of
your castings while dramatically shortening the design process and the time
required to get your products to market.
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Using advanced 3D printing technology, Graphicast can produce a plaster model
of your part with indications of draft and radii for the casting process.
Important design-for-manufacturing tools, these plaster models are invaluable in
identifying and correcting part problems before molds are produced.
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Design changes that result from review of the plaster or CAD model are made
quickly and easily on the CAD system. Another plaster or CAD model will
be produced to verify that all changes have been made and the part is ready
for casting.
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Graphicast has complete in-house capabilities for the production of exceptional
quality graphite tooling. Pro/Manufacturing™ CAM software automatically generates
machine tool "G" code for the mold, allowing part revisions or
modifications to be made quickly and easily.
A one-time charge covers the cost of producing the original mold as well
as ongoing mold maintenance. If the design of the part changes, Graphicast can
quickly and easily modify the mold at minimal cost.
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Using casting machines designed and built around its proprietary LTA (low
turbulence automatic-fill) technology, Graphicast produces ZA-12 castings of exceptional quality
and consistency. This rate- and temperature-controlled bottom-filling LTA process yields
castings of increased density, lower porosity, better surface finish, and
more consistent dimensions.
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With complete high-speed CNC machining capabilities in-house, Graphicast can perform any
required secondary operations quickly and economically.
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Graphicast also has the capability in-house to perform light assembly involving
bearings, bushings, dowel pins, springs, etc.
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Typically, graphite mold castings can be produced in volume with tolerances of
± .005" per inch or less. Some dimensions will be affected by draft
requirements, which are nominally 2° for any surface perpendicular to
the parting plane.
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The finish of Graphicast parts is typically better than 125 microinches-as good
or better than that of either investment cast or die cast parts.
Parts from the mold have a bright metallic finish which, in most applications,
requires no additional preparation or coating. With handling or age, this
finish takes on a matte pewter-like appearance.
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With an attractive, naturally lustrous finish, Graphicast parts are usable straight
from the mold. However, if desired, parts can be finished using the same processes
and materials as those recommended for zinc die castings.
Coating options include any commercial paint or powder coating system. A
zinc phosphate treatment or wash-primer is used under wet paints. For corrosion
resistance, zinc chromate can be used, with or without a decorative topcoat.
Acrylic or epoxy electrocoating can be used to simulate black anodized aluminum.
Painting and finishing are performed by certified subcontractors. Graphicast assumes
single-source responsibility for all parts it produces.
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