Title:
METHOD FOR MANUFACTURING SPRING AND DEVICE FOR HEATING BY PASSAGE OF ELECTRIC CURRENT
Document Type and Number:
WIPO Patent Application WO/2012/014672
Kind Code:
A1
Abstract:
A method for manufacturing a spring, wherein the time required for a heating treatment step for removing a processing strain produced by a forming step is reduced. This manufacturing method comprises a forming step (S10) for forming spring steel into a spring shape, and a heating treatment step (S12) for removing a processing strain produced in the spring steel by the forming step. The heating treatment step is performed by heating by the passage of an electric current, wherein the spring steel is heated by passing the electric current through the spring steel. The heat treatment step has a first step for heating the spring steel to a preset set temperature, and a second step for maintaining the spring steel at the set temperature for a preset set time after the first step. The set temperature is set higher than 430°C and not higher than 500°C.
Inventors:
HIRATA YUICHI (JP)
SUZUKI HIDEKAZU (JP)
OGISO HIROYUKI (JP)
SUZUKI HIDEKAZU (JP)
OGISO HIROYUKI (JP)
Application Number:
PCT/JP2011/065886
Publication Date:
February 02, 2012
Filing Date:
July 12, 2011
Export Citation:
Assignee:
CHUO HATSUJO KK (JP)
HIRATA YUICHI (JP)
SUZUKI HIDEKAZU (JP)
OGISO HIROYUKI (JP)
HIRATA YUICHI (JP)
SUZUKI HIDEKAZU (JP)
OGISO HIROYUKI (JP)
International Classes:
C21D9/02; B21F35/00; C21D1/40; F16F1/02
Foreign References:
| JPS6164812A | 1986-04-03 | |||
| JPS6130246A | 1986-02-12 | |||
| JPS5591946A | 1980-07-11 | |||
| JPH01184234A | 1989-07-21 | |||
| JP2003105498A | 2003-04-09 |
Attorney, Agent or Firm:
KAI-U PATENT LAW FIRM (JP)
Patent business corporation KAI-U Patent Law Firm (JP)
Patent business corporation KAI-U Patent Law Firm (JP)
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Claims:
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