| Type
Analysis: Carbon.....................................0.03%
Manganese..............................0.50%
Silicon.......................................0.35%
Nickel......................................80.00%
Molybdenum............................4.00%
Iron........................................Balance
DESCRIPTION:
Carpenter HyMu "80" ® is an unoriented 80%
nickel-iron-molybdenum alloy which offers extremely high initial permeability with minimum
hysteresis loss.
HyMu "80" is used primarily for transformer cores, tapes
wound toroids and laminations where compactness and weight factors are important. It is
also used for shielding to protect electrical components from stray magnetic fields. It
meets military specification: MIL-N-14411 B (MR) 8/19/66.
MAGNETIC PROPERTIES:
Coercive force from H=10 Oe, Oersted 0.01 to 0.03
Hysteresis loss from H= 10 Oe, erg/cm³ per cycle. 18 to 24
D C Magnetic Properties
Form |
µ at B = 40 G |
µ max |
HCfrom
H=1 Oersted |
Bar, Wire |
50,000 |
200,000 |
0.02 max |
D C hystersis loss
From H = 1 Oe, erg/ cm³ per cycle...................16
Induction,gauss...............................................7,300
Residual Induction, gauss ..............................3,500
(Split strip or split rod specimens)
A C Magnetic Properties, 60 Cycle
Minimum Limits
Thickness |
µ 40 G |
µ 200 G |
µ 2000 G |
Inches |
Centimeters |
0.025
0.014
0.006
0.002 |
0.064
0.036
0.015
0.005 |
30,000
40,000
45,000
50,000 |
35,000
47,000
55,000
60,000 |
50,000
80,000
90,000
110,000 |
(Ring laminations 1½" (3.81 cm) OD
x 1" (2.54 cm) ID specimens)
|
PHYSICAL
PROPERTIES: Specific Gravity............................................8.740
Density - lb/in³...............................................0.316
Thermal conductivity
(BTU inch)/(ft² hr º
F)...........................134.000
cal/(cm sec º
C)......................................0.046
Mean coefficient of thermal expansion
from –90 to 400 ºF, 10-6
/ºF.......................7.2
from –68 to 204 ºC, 10-6
/ºC...................12.9
Electrical resistivity
ohm-cir
mil/ft...............................................349
microhm-cm..................................................58
Temperature coefficient of electrical resisitivity
per º F from 0/930 º
F............................0.0006
per º C from –17.8/499 º
C...................0.0011
Curie Temperature........................860 º F (460º C)
Melting Point.............................2650 º F (1454 º C)
Specific heat, BTU/(lb º F) ; cal/(gº C)...........0.118
HEAT TREATMENT:
In-process anneal: To relieve all strains and restore the alloy to
a soft condition suitable for drawing, spinning, forming, bending and similar operations,
anneal for not more than one hour at 1450/2050 ºF
(788/1121 º C ). Since high nickel, high permeability alloys readily
absorb carbon, sulfur, oxygen and other contaminants from combustion furnace gases, it is
recommended that in-process annealing be done in dissociated ammonia, hydrogen or inert
gas atmosphere.
Hydrogen anneal: For maximum softness and optimum magnetic
and electrical properties, HyMu "80" should be annealed in an oxygen-free, dry
hydrogen atmosphere with a dew point below –40 º F (-40º C) for two to four hours
at 2050 º F (1121 º C). Furnace cool to 1100 º F (593º C) . From 1100/700 º F
(593/371 º C), cool at rate between 350 º F (194 º C) and 600 º F (334 º C) per hour.
Oil, grease, lacquer and all other contaminants must be removed before annealing. The
individual parts should be separated by an inert insulating powder such as magnesium or
aluminum oxide during hydrogen annealing. |
