Nhk Spring Co., Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Shinko Wire Company, Ltd.

Satoru Tendoh

Noritoshi Takamura

Nobuhiko Ibaraki

Sumie Suda

Tadayoshi Fujiwara

Tetsuo Jinbo

Atushi Inada

Disclosed is a steel wire rod for hard-drawn springs capable of exhibiting fatigue strength and sag resistance equivalent to or higher than springs made of an oil-tempered wire. The steel wire rod contains carbon in a range from 0.5 to less than 0.7 mass %, silicon in a range from 1.4 to 2.5 mass %, manganese in a range from 0.5 to 1.5 mass %, chromium in a range from 0.05 to 2.0 mass %, and vanadium in a range from 0.05 to 0.40 mass %, and has an area ratio Rp with respect to pearlite which satisfies the mathematical expression (1):(area %)&#x2267;55&#xd7;[]+61&#x2003;&#x2003;(1)where [C] denotes the content (mass %) of carbon.

Steel wire rod for hard drawn spring, drawn wire rod for hard drawn spring and hard drawn spring, and method for producing hard drawn spring

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Ina, Japan

Satoru Tendoh