Datasheet

Kanthal Appliance Alloys Handbook 9
1
MANGANINA 43
has been developed to satisfy many precision
and high stability requirements at, or close
to, room temperature.
In some applications it is essential that the
resistance of the electronic components does
not change either with age or with such
changes of temperature as may be encoun-
tered in normal use. These requirements are
fulfilled perfectly by MANGANINA 43.
The resistance of MANGANINA 43 in-
creases very slightly from 15 °C to approxi-
mately 25 °C. Above 25 °C the resistance
decreases so that the resistance at 35 °C is
about the same as at 15 °C. The maximum
change in resistance to be expected is less
than 15 parts per million per degree centi-
grade. Therefore, for an instrument, which is
calibrated at 25 °C, the change in resistance
over the temperature range from 15-35 °C is
negligible, except in instances where the
work is of very high precision.
Artificial ageing of assembled coils has
been found necessary to avoid a slow de-
crease in resistance with time. Baking at a
temperature between 120 °C and 140 °C
for a period of 24 to 72 hours commonly
does this.
The higher temperature limit must not be
exceeded if damage to enamel or fabric insu-
lation is to be avoided. Regarding E.M.F.
versus copper, MANGANINA 43 generates
not more than 0.003 mV/°C between 0 and
100 °C.
The main application is in shunts.
CUPROTHAL 49
(universally known as Constantan) is manu-
factured under close control from electrolytic
Copper and pure Nickel.
CUPROTHAL 49 has a number of special
characteristics – some electrical, some
mechanical – which make it a remarkably
versatile alloy. For certain applications, its
high specific resistance and negligible tem-
perature coefficient of resistance are its most
important attributes. For others, the fact that
CUPROTHAL 49 offers good ductility, is
easily soldered and welded and has good
resistance to atmospheric corrosion is more
significant.
Although the range of applications of
CUPROTHAL 49 is so wide, its uses fall into
four principal categories:
– An ideal alloy for winding heavy-duty in-
dustrial rheostats and electric motor starter
resistance. High specific resistance, together
with good ductility and resistance to corro-
sion are all important requirements in this
category, and CUPROTHAL 49 satisfies
the most demanding specifications.
– CUPROTHAL 49 is widely used in wire-
wound precision resistors, temperature-sta-
ble potentiometers, volume control devices
and strain gauges. (See the Precision Wire
Handbook). In the resistor field, its high
resistance and negligible temperature coef-
ficient of resistance are its main attractions.
– The third main category of application
exploits another characteristic of
CUPROTHAL 49. This is the fact that it
develops a high thermal E.M.F. against
certain other metals. CUPROTHAL 49 is
therefore commonly used as a thermo-
couple alloy.
– Low temperature resistance heating
applications, such as heating cables.
Copper-Nickel Alloys