Bi- Metals / Tri-Metals

Bi-Metal/Tri-Metal are composite metals that combined different expanding characteristic metals. Different metals have different degrees of expansion and Hitachi Metals uses bonding methods to enable the same metal material to make physical changes in response to changes in temperature. As a result, Bi-Metals and Tri-Metals can be bent or curved with high precision, and with high corrosion resistance, as well as various electric resistance values.

  • Characteristics: Metal bends according to temperature changes
    High corrosion resistance
    Various electric resistance values
  • Applications: Automobiles, Thermostats, Fuseless breakers, Burnout prevention breakers, Fire alarms
  • Major Types: BL series, BM series, BH series, TRC series,
    BRC series, THC series, BMS series
Materials Material Code Related Specifications Composition Resistivity
(µ Ω.cm)		 Density
(g/cm3)		 Special Deflection
(X10-6/ oC)		 Useful Deflection
Temp. Range (oC)		 Application
Bi-Metals for Low temperature BL-1 JS C2530 Zn-Cu Ni-Fe 12 8.25 14.0 -20 ~ 250 Thermal compensation of scales
BL-2 Ni-Mn-Fe 81 8.05 15.0 Circuit breakers
BL-3 Ni 17 8.40 9.2 Circuit breakers
BL-4 Ni-Cr-Fe 80 8.20 14.5 Thermostats for automobiles, Home electrical appliances, etc.
BL-5 78 8.00 13.8 Thermal compenstors for color CRTs
BL-51 78 8.10 14.4 Thermal protectors, Thermal compensators for color CRTs
Bi-Metals for Medium temperature BM-1 JIS C2530 Ni-Mn-Fe Ni-Fe 76 8.2 14.3 20 ~ 250 Circuit breakers
Bi-Metals for High temperature BH-1 JIS C2530 Ni-Mo-Fe Ni-Fe 72 8.25 10.9 20 ~ 250 Electric Irons, Oventoasters
BH-2 Ni-Cr-Fe 70 8.00 11.5
BH-3 57 8.30 7.0 50 ~ 430 Fan heaters
BH-4 Cr-Fe 68 8.00 6.0 20 ~ 430
High-resistance Bi-Metals BR-1 JIS C2530 Cu-Ni-Mn Ni-Fe 110 7.70 20.0 20 ~ 250 Thermal protectors
BR-2 140 7.50 14.8
NC. BR-1 - Ni-Cu BR-1 105 7.70 17.5
NC. BR-2 135 7.55 13.5
Low-resistance Trimetals TRC-5 ~ 15R JIS C2530 Ni-Cr-Fe Zr-Cu-Ni-Cu Ni-Fe 4.1 ~ 15 8.45 ~ 8.15 10.7 ~ 14.5 20 ~ 250 Non-fusing breakers and protectors
Medium-resistance Trimetals TR-15 ~ 65 Ni-Mn-Fe Ni 17 ~ 67 8.60 ~ 8.10 10.7 ~ 14.5
High-resistance Trimetals TR-95 - Ni-Cr-Fe Cu-Ni-Mn 95 - 14.7
High-sensitive Trimetals BRC-6 ~ 83 - Cu-Ni-Mn Cu-Ni-Cu 6.5 ~ 83 8.05 ~ 7.90 19.6