Covered wire and automobile-use wire harness

1. An insulated electric wire, comprising:

a conductor portion consisting of one or more first wires and one or more second wires which are stranded together;

wherein said first wires are constituted by metal wires made from at least one type of metal selected from a group consisting of copper, copper alloy, aluminum and aluminum alloy,

said second wires are constituted by stainless steel, and have a relative permeability of 1.1 or less, and content amount of process induced martensite of 26% by volume or less, and

the tensile strength of the conductor portion is 400 MPa or more and 700 MPa or less.

2. The insulated electric wire according to claim 1 , wherein the content amount of the strain induced martensite of said second wires is 10% by volume or less.

3. The insulated electric wire according to claim 1 , wherein the stainless steel is metastable austenite stainless steel.

4. The insulated electric wire according to claim 1 , wherein a terminal portion is provided at the end portion of the conductor portion,

said terminal portion is made from a metal different from at least one of the first wires and the second wires, and

the corrosive electric-potential difference between the first wires and the second wires, the corrosive electric-potential difference between the first wires and the terminal portion and the corrosive electric-potential difference between the second wires and the terminal portion are all 0.5 V or less.

5. The insulated electric wire according to claim 1 , wherein the conductor portion has a conductivity within the range of 2 to 60% IACS.

6. An automobile wire harness comprising the insulated electric wire according to any one of claims 1 to 5 .