Nippon Steel Corporation

Mitsui High-tec Incorporated

Hiromichi Koshiishi

Hiroshi Sato

Akira Sakaida

Tetsuo Kimoto

Yasuhiro Shinkai

Kunio Mori

Hisahumi Sakamoto

Sigeki Eguchi

Hisayoshi Kuramasu

Hisao Takahashi

Toshimi Kawabata

The present invention relates to a method for annealing a core blank of a transformer or the like so as to relieve the stress generated in the electrical steel sheet sections due to blanking. The present invention is an improvement over the conventional resistance or gas-heating method in the light of heating efficiency and time and is characterized by induction-heating a core blank at a power input range of from 0.5 to 3 kW/kg of the core blank. This range attains a small variation in the shape of a core blank due to induction-heating.

Method for annealing a core blank used in electric machinery and devices

In finish annealing process for a grain-oriented electrical steel strip or sheet, an improvement is disclosed which comprises coating the grain-oriented electrical steel strip or sheet with an annealing separator having a water content adjusted to not more than 10%, drying the coated strip or sheet, forming it into a strip coil, and finish annealing the strip coil within the inner cover of an annealing furnace while controlling the pressure of the gas atmosphere within the inner cover.

Finish annealing process for grain-oriented electrical steel strip or

A box annealed steel strip having small strains is produced by: pretreating a steel strip in such a manner that a side edge portion thereof is thermally treated under a different condition from another condition under which the remaining portion, including an opposite side edge, thereof is thermally treated, so as to cause the longitudinal length of the side edge portion to be different from that of the remaining portion; winding the pretreated steel strip under tension to form a coil in such a manner that greater tensile stresses are produced in the other one of the side edge portion and the remaining portion, which one has a longitudinal length smaller than that of the other one, than those produced in the other one; placing the coil on a base plate so that a side edge included in the portion having the greater stresses comes into contact with the base plate, and; box annealing the coil on the base plate in a box annealing furnace.

Process for box annealing a steel strip coil

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Kitakyushu, Japan

Hiromichi Koshiishi