Smith chapter 1 problem 7,  OFHC copper

 

a)      This material is a metal.  OFHC is an acronym for “oxygen free high conductivity” and is a trademark of Phelps Dodge Company.

 

b)      It has high electrical and thermal conductivity ( conductivity = 1 / resistivity)   Anywhere near room temperature, only pure Ag is a better conductor. 

Oxygen atoms dissolved in the metal lattice scatter the electrons, thereby reducing conductivity, so low oxygen improves conductivity.

 

Oxygen also contributes to brittleness in the metal.  OFHC Cu has high ductility, can be drawn into fine wires or deformed into complicated shapes without cracking. 

 

c)      This material is used wherever electricity or heat must be conducted with low loss, for example the windings of electrical transformers and electric motors as well as bus bars in some electricity distribution systems.

 

OFHC copper is NOT used in transmission lines, strung between poles or towers, because it is too expensive and its strength / weight ratio is not as good as certain aluminum alloys which are used for those applications.

 

 

Bibliography:   http://www.anchorbronze.com/wroughtcopper.htm