OhmAlloy-5J1480 (Bimetallic strip)
(Common Name: 135)
Bimetallic strip is used to convert a temperature change into
mechanical displacement. The strip consists of two strips of
different metals which expand at different rates as they are
heated, usually steel and copper, or in some cases steel and brass.
The strips are joined together throughout their length by riveting,
brazing or welding. The different expansions force the flat strip
to bend one way if heated, and in the opposite direction if cooled
below its initial temperature. The metal with the higher
coefficient of thermal expansion is on the outer side of the curve
when the strip is heated and on the inner side when cooled
The sideways displacement of the strip is much larger than the
small lengthways expansion in either of the two metals. This effect
is used in a range of mechanical and electrical devices. In some
applications the bimetal strip is used in the flat form. In others,
it is wrapped into a coil for compactness. The greater length of
the coiled version gives improved sensitivity.
Diagram of a bimetallic strip showing how the difference in thermal
expansion in the two metals leads to a much larger sideways
displacement of the strip.
Composition
| Grade | 5J1480 |
| High expansion layer | Ni22Cr3 |
| Low expansion layer | Ni36 |
Chemical composition (%)
| Grade | C | Si | Mn | P | S | Ni | Cr | Cu | Fe |
| Ni36 | ≤0.05 | ≤0.3 | ≤0.6 | ≤0.02 | ≤0.02 | 35~37 | - | - | Bal. |
| Grade | C | Si | Mn | P | S | Ni | Cr | Cu | Fe |
| Ni22Cr3 | ≤0.35 | 0.15~0.3 | 0.3~0.6 | ≤0.02 | ≤0.02 | 21~23 | 2.0~4.0 | - | Bal. |
Typical Physical properties
| Density (g/cm3) | 8.2 |
| Electrical resistivity at 20℃(Ωmm2/m) | 0.8±5% |
| Thermal conductivity, λ/ W/(m*℃) | 22 |
| Elastic Modulus, E/ Gpa | 147~177 |
| Bending K / 10-6℃-1(20~135℃) | 14.3 |
| Temperature bending rate F/(20~130℃)10-6℃-1 | 26.2%±5% |
| Allowable temperature (℃) | -70~ 350 |
| Linear temperature (℃) | -20~ 180 |
Application: The material is mainly in automatic control devices
and instrumentation (eg: exhaust thermometers, thermostats, voltage
regulators, temperature relay, automatic protection switching,
diaphragm meters, etc.) make temperature control, temperature
compensation, current limit, temperature indicator and other
heat-sensitive components.
Feature: The basic characteristics of Thermostat Bimetallic is
bending deformation with temperature changes, resulting in a
certain moment.
Thermostat Bimetallic Strip expansion coefficient is different from
the two or more layers of metal or alloy along the entire contact
surface firmly bonded, having atemperature-dependent shape change
occurs thermosensitivefunctional composites. Wherein thehigher
expansion coefficientofthe activelayer is a layer called a low
coefficient of expansion of the layer is named passive layer.
