Chuo Hatsujo Kabushiki Kaisha

Shingo Mimura

Tomohiro Nakano

Masami Wakita

Takayuki Sakakibara

Takanori Kuno

A manufacturing method of a coil spring for an automobile suspension includes forming a material into a coil shape; performing a heat treatment step on the material; performing a warm shot peening step on the material, and performing a hot setting step on the material. By performing the warm shot peening step prior to the hot setting step, a stronger compressive residual stress is imparted in a direction along which a large tensile stress acts during actual use of the coil spring, thereby improving sag resistance and durability of the coil spring. A coil spring is also manufactured according to this method.

Coil spring for automobile suspension and method of manufacturing the same

A high-strength spring steel and a spring are provided that have superior corrosion fatigue strength. The spring steel comprises, in mass percent, 0.35-0.55% C, 1.60-3.00% Si, 0.20-1.50% Mn, 0.10-1.50% Cr, and at least one of 0.40-3.00% Ni, 0.05-0.50% Mo and 0.05-0.50% V, the balance being substantially Fe and incidental elements and impurities.

Spring steel and spring having superior corrosion fatigue strength

A spring steel and spring having superior corrosion fatigue strength and a strength on the order of HRC 53 to HRC 56 are disclosed. The spring steel comprises a tempered martensite and 2.1 to 2.4% Si in terms of percent by mass of the total mass of the spring steel.

The present application provides a high strength spring steel and a high strength spring that have superior corrosion fatigue strength. The spring steel comprises, in terms of percent by mass, 0.35-0.55% C, 1.60-3.00% Si, 0.20-1.50% Mn, 0.10-1.50% Cr and at least one element selected from 0.40-3.00% Ni, 0.05-0.50% Mo 0.05-0.50% V, the balance being at least substantially Fe and incidental elements and impurities.

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Nagoya, Japan

Shingo Mimura