Chace 2400 Thermal bimetal strip
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
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. |
Composition
Grade |
Chace 2400 |
High expansion layer |
Ni22Cr3 |
Low expansion layer |
Ni36 |
Style of supply
Alloys Name |
Type |
Dimension |
|
Chace 2400 |
Strip |
W= 5~120 mm |
T= 0.1~5 mm |
Typical Physical properties
Density (g/cm3) |
8.2 |
Electrical resistivity at 20ºC(OMmm2/m) |
0.8±5% |
Thermal conductivity, λ/ W/(m*ºC) |
22 |
Elastic Modulus, E/ Gpa |
147~177 |
Bending K / 10-6 ºC-1(20~135ºC) |
14.3 |
Temperature bending rate F/(20~130ºC)10-6ºC-1 |
26.2%±5% |
Allowable temperature (ºC) |
-70~ 350 |
Linear temperature (ºC) |
-20~ 180 |