FORMING INSULATED CONDUCTORS USING A FINAL REDUCTION STEP AFTER HEAT TREATING

摘要

A method for forming an insulated conductor heater includes placing an insulation layer over at least part of an elongated, cylindrical inner electrical conductor. An elongated, cylindrical outer electrical conductor is placed over at least part of the insulation layer to form the insulated conductor heater. One or more cold working/heat treating steps are performed on the insulated conductor heater. The cold working/heat treating steps include: cold working the insulated conductor heater to reduce a cross-sectional area of the insulated conductor heater by at least about 30% and heat treating the insulated conductor heater at a temperature of at least about 870 C. The cross-sectional area of the insulated conductor heater is then reduced by an amount ranging between about 5% and about 20% to a final cross-sectional area.