Strand for wiring harness and wiring harness
A strand for a wiring harness includes a first element wire and a second element wire twisted around the first element wire and made of copper or a copper alloy. The first element wire includes a core portion made of stainless steel and a covering layer covering the core portion and made of copper or a copper alloy.
1. A strand for a wiring harness, the strand comprising:
a first element wire; and
a second element wire twisted around the first element wire and made of copper or a copper alloy,
wherein the first element wire includes
a core portion made of stainless steel, and
a covering layer covering the core portion and made of copper or a copper alloy,
wherein the stainless steel constituting the core portion is an austenitic stainless steel,
wherein the austenitic stainless steel has an MS point of −400° C. or lower, the MS point being calculated by formula (1):
MS=1032−1667·(% C+% N)−27.8·% Si−33·% Mn−61·% Ni−41.7·% Cr (1)
wherein % C, % N, % Si, % Mn, % Ni, and % Cr are contents (unit: mass %) of carbon, nitrogen, silicon, manganese, nickel, and chromium, respectively, in the austenitic stainless steel.
2. The strand for a wiring harness according to claim 1 , wherein a plurality of the second element wires are twisted so as to surround an outer periphery of the first element wire.
3. The strand for a wiring harness according to claim 1 , wherein a plurality of the first element wires and a plurality of the second element wires are twisted together.
4. The strand for a wiring harness according to claim 1 , wherein the first element wire further includes a Ni layer disposed between the core portion and the covering layer.
5. The strand for a wiring harness according to claim 4 , wherein the Ni layer has a thickness of 0.05 μm or more and 5 μm or less.
6. The strand for a wiring harness according to claim 1 , wherein the first element wire further includes, on a surface of the covering layer, at least one selected from the group consisting of a Au layer, a Ag layer, and a Sn layer.
7. The strand for a wiring harness according to claim 6 , wherein the Au layer, the Ag layer, and the Sn layer each have a thickness of 0.3 μm or more and 20 μm or less.
8. The strand for a wiring harness according to claim 1 , wherein a passivation film on a surface of the core portion has a thickness of 5 nm or less.
9. The strand for a wiring harness according to claim 1 , wherein the covering layer has a thickness of 1 μm or more and 20 μm or less.
10. The strand for a wiring harness according to claim 1 , wherein the second element wire and the covering layer are made of brass, phosphor bronze, a Corson alloy, or beryllium copper.
11. The strand for a wiring harness according to claim 1 , wherein the second element wire and the covering layer are made of the same material.
12. The strand for a wiring harness according to claim 1 , wherein in a section perpendicular to a longitudinal direction, an area ratio of the first element wire to the second element wire is 7:3 to 2:8.
13. The strand for a wiring harness according to claim 1 , wherein the strand has a conductivity of 50% IACS or more and 90% IACS or less.
14. The strand for a wiring harness according to claim 1 , wherein the strand has a tensile strength of 600 MPa or more and 1000 MPa or less.
15. A wiring harness comprising:
a first strand; and
a second strand welded to the first strand,
wherein the first strand and the second strand are each the strand for a wiring harness according to claim 1 , and
the second element wire of the first strand and the second element wire of the second strand are electrically connected together.