Coil spring resistive to delayed fracture and manufacturing method of the same
AssigneesChuo Hatsujo Kabshiki Kaisha, Honda Giken Kogyo Kabushiki Kaisha
InventorsToshinori Aoki, Taisuke Nishimura, Takashi Otowa
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Abstract
A coil spring made of an oil-tempered steel wire with internal hardness of more than Hv 550 in cross-section, the surface hardness of the oil-tempered steel wire being determined in an extent between Hv 420 in a minimum value and hardness defined by subtraction of Hv 50 from the internal hardness in a maximum value.
Claims5
A coil spring made of an oil-tempered steel wire with internal hardness of more than Hv 550 in cross-section, the surface hardness of the oil-tempered steel wire being determined in an extent between Hv 420 in a minimum value and hardness defined by subtraction of Hv 50 from the internal hardness in a maximum value.
A manufacturing method of a coil spring made of an oil-tempered steel wire with internal hardness of more than Hv 550 in cross-section, comprising the steps of:
- decarburizing the surface of the oil-tempered steel wire during heating prior to a quenching process thereof to determine the surface hardness of the oil-tempered steel wire in an extent between Hv 420 in a minimum value and hardness defined by subtraction of Hv 50 from the internal hardness in a maximum value;
- and
- coiling the oil-tempered steel wire for making a coil spring.
Dependencies are inferred from the claim text.