Cast Arnokrome III0 pages

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Cast Arnokrome™

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Product Information

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Arnokrome™ III, developed by The Arnold

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Engineering Company, is a ductile permanent

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magnet alloy based on the iron-chromium-cobalt

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alloy system. Since the cobalt content is lower

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than in alternative magnetic alloys, Arnokrome

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may offer a significant advantage in replacement

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situations in terms of price stability.

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The alloy has both good castability and ductility

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which permits the manufacture of a wide variety

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of product sizes and shapes. Arnokrome III may

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be sand cast into a variety of shapes, then

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machined and formed prior to magnetic heat

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treating. By adjusting the heat treatment, the

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alloy's magnetic properties can be tailored to

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specific permanent magnet requirements.

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Arnokrome III is isotropic. By controlled heat

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treatment, coercive force is varied to specific

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levels between 50 and 300 oersteds to optimize

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the performance of the material for the

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customer's application. Arnold Engineering's

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applications personnel are available to provide

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technical assistance in the user's evaluation of

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Arnokrome. Arnokrome III can be supplied in

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most shapes available in Alnico products.

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When choosing Arnokrome, the following factors

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should be considered:

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• Magnetic characteristics: Arnokrome III is

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best suited for low coercivity applications.

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Br = 11,000 gauss He = 50 - 300 oersteds

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• Workability: Arnokrome III is machinable by

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normal methods prior to magnetic heat

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treatment. After heat treatment, only

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grinding is recommended.

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• Cost: Due to the nature of the heat treat

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cycle required to develop magnetic

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characteristics, the lower coercivities are

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less expensive. Higher coercivity requires a

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longer heat treat cycle.

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Arnokrome™ III is an excellent substitute for

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Vicalloy, Cunife, and cobalt steels in many

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applications.

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Contact your Arnold Sales

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Representative or call Arnold directly

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at 815-568-2000 for more

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information.

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For information on Arnold's complete

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line of products, visit our website at

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www. grouparnold. com

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Cast Arnokrome III is machinable with standard

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metal-working tools.

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Chemistry

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Chemical Element

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Chromium

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Cobalt

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Iron

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Physical Properties

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Density

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Diameters Available

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Electrical Resistivity

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(25°C)

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Thermal Conductivity

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(100°C)

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Thermal Expansion

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(30° to 100°)

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Temperature Range

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Coefficient

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30° to 400°C

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30° to 300°C

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30° to 200°C

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30° to 100°C

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Arnokrome I

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26 - 30%

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7 -10%

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Balance

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.277 lbs/cu in

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(7.6 g/cc)

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1.250" to 0.010"

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69 X 10 s ohm-cm

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0.05 cal/sq cm/cm/sec/°C

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8.67 X 10"4 cm-cm"1-°C"1

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Mean Expansion

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(cm-cm"1-°C"1)

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10.4 X 10"6

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10.2 X 10 s

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9.84 X 10 s

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8.67 X 10 s

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Mechanical Properties

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Solution Heat Heat Treated

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(Treated condition) (For desired He)

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Tensile Strength 75.000 psi 120,000 psi

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Yield Strength 50,000 psi 115.000 psi

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% Elongation 25 6

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Hardness Rb 75 Rc 25

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Magnetic Properties

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Magnetic Remanence (gauss)

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Coercivity (Oersteds)

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Energy Product (MGOe)

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Reversible Temperature

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Coefficient of Magnetization

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Curie Temperature

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Orientation

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9,000- 12,000 Br

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50 - 300 He

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0.4-1.2

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-0.02% l°C

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625°C

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Isotropic

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June, 2004

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