STEEL WIRE AND SPRING

A steel wire is composed of a steel containing: not less than 0.5 mass % and not more than 0.7 mass % carbon, not less than 1 mass % and not more than 2.5 mass % silicon, not less than 0.3 mass % and not more than 1 mass % manganese, and not less than 0.5 mass % and not more than 2 mass % chromium, with the balance being iron and unavoidable impurities. The steel wire has a wire diameter of not less than 0.5 mm and not more than 2 mm, and a tensile strength of not less than 2000 N/mm2 and not more than 2700 N/mm2. The steel has a pearlite structure. A value obtained by dividing a sum of 5.8885×10−3 and a lattice strain S of the steel by the tensile strength T, (S+5.8885×10−3)/T, the tensile strength T being in N/mm2, is not less than 4.8×10−6.