Title:
STRESS RELIEVING ANNEALING METHOD FOR CORE FOR COILED IRON CORE EXCELLENT IN EXPANDING OPERABILITY
Document Type and Number:
Japanese Patent JP3420942
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To reduce the adhesion between steel sheets and to easily execute a core expanding operation by executing the annealing that removes working strains generated at the time of forming a grain oriented silicon steel sheet in such a manner that the concn. of oxygen in the atmosphere is controlled to a specified one.
SOLUTION: At the time of subjecting the one obtd. by coiling a grain oriented silicon steel sheet into a cylindrical shape (core) to bending and forming it into a prescribed form, mechanical strains in the steel sheet caused by the bending are removed by annealing in the atmosphere in which the concn. of oxygen is <1.0%. At this time, among the atmospheric gases, as to the gas seeds excluding an oxidizing gas, all kinds of gas can be used if only it is the inert one, but, argon, helium or the like is particularly preferable, and, moreover, the atmosphere may be incorporated with hydrogen. Furthermore, in the case the annealing atmosphere contains water vapor, by controlling the concn. of water vapor in the atmosphere to ≥+1°C to <+30°C expressed in terms of the dew point, the core easy to expand can be obtd., and, moreover, the discoloration of a film does not occur.
Inventors:
Hiroyasu Fujii
Osamu Tanaka
Koji Yamazaki
Kimihiko Sugiyama
Tomoji Kumano
Osamu Tanaka
Koji Yamazaki
Kimihiko Sugiyama
Tomoji Kumano
Application Number:
JP21315198A
Publication Date:
June 30, 2003
Filing Date:
July 28, 1998
Export Citation:
Assignee:
Nippon Steel Corporation
Nippon Steel Plant Design Co., Ltd.
Nippon Steel Plant Design Co., Ltd.
International Classes:
C21D1/26; C21D1/76; C21D9/00; C21D9/46; H01F41/02; (IPC1-7): C21D9/46; C21D1/26; C21D1/76; C21D9/00; H01F41/02
Domestic Patent References:
| JP4165082A | ||||
| JP339484A |
Attorney, Agent or Firm:
Takashi Ishida (2 outside)