Wire material for canted coil spring and canted coil spring

A wire material for a canted coil spring, the wire material comprising:

• a core wire composed of a steel having a pearlite structure;
• a copper plating layer covering an outer peripheral surface of the core wire, the copper plating layer being composed of copper or a copper alloy;
• and
• a hard layer disposed adjacent to an outer periphery of the copper plating layer, the hard layer having a higher hardness than the copper plating layer,
• the steel containing 0.5% or more by mass and 1.0% or less by mass carbon, 0.8% or more by mass and 2.5% or less by mass silicon, and 0.3% or more by mass and 0.9% or less by mass manganese, the balance being iron and unavoidable impurities,
• wherein the steel further contains more than 0.5% by mass and 1.8% or less by mass chromium,
• wherein the wire material has a tensile strength of 900 MPa or more and 3,000 MPa or less, and
• wherein an oxygen concentration at an interface between the core wire and the copper plating layer is 10% or less by mass.