thermal bimetal yuan layer with low thermal expansion coefficient,
the passive layer;Another group of yuan layer with high thermal
expansion coefficient, to active layer.Sometimes, in order to
obtain special properties of thermal bimetal, can also join the
third or fourth layer metal or alloy.Usually, the passive layer are
type invar alloy containing Ni34 ~ 50%;Active layer, the brass, Ni,
Fe - Ni - Cr, Fe - Ni - Mn and Mn - Ni - Cu alloy, etc.Through
different combination of active and passive layer material, you can
get different kinds of thermal bimetal, such as high temperature,
medium temperature, low temperature, high sensitive, corrosion
resistant, resistance and quick action, etc.
The basic characteristic of the thermal bimetal is changing with
temperature and temperature deformation, resulting in a certain
moment.Many devices use this feature to convert heat energy into
mechanical work to achieve automatic control.Thermal bimetal used
for control system and temperature sensor in the measuring
instrument.
Main features: Linear temperature range is higher, low thermal
performance, can be used at high temperature.
| shop sign | ASTM TM11 |
| With brand | |
Composite layer
alloybrand | High expansion layer | Ni22Cr3 |
| middle layer | Ni |
| Low expansion layer | Ni36 |
Chemical composition
| shop sign | Ni | Cr | Fe | Co | Cu | Zn | Mn | Si | C | S | P |
| ≤ |
| Ni36 | 35.0~37.0 | - | allowance | - | - | - | ≤0.60 | ≤0.3 | 0.05 | 0.02 | 0.02 |
| Ni | ≥99.3 | - | ≤0.15 | - | ≥0.15 | | - | - | 0.15 | - | 0.015 |
| Ni22Cr3 | 21.0~23.0 | 2.0~4.0 | allowance | - | - | - | 0.3~0.6 | 0.15~0.30 | 0.25~0.35 | 0.02 | 0.02 |
production process
Cold rolled →go oil → pickling → annealing cold-rolled →oil →
pickling → annealing cold-rolled → conform to the requirements of
the use of thermal bimetal strip
Thermal bimetal strip is by the different expansion coefficient of
two or more than two layers of metal or metal solid combination,
and along the entire interface varies with temperature and the
thermal function of shape changes in composite materials.One of
high expansion coefficient become active layer, low expansion
coefficient becomes passive.When requirements with high
resistivity, but heat sensitive resistance performance is
essentially the same type of thermal bimetal series, can be added
between the two layers of different thickness of middle layer as a
shunt layer, is to achieve the purpose of control different
resistivity.
