Toyo Kohan Co., Ltd.

Osamu Yubuta

Giichiro Nomura

The present invention provides both inner shield materials and its manufacturing method with superior magnetic characteristics and rust protection, which does not require conventional blackening process. Another object of the present invention is to provide the inner-shield manufacturing method, by which steel sheet or strip passing is smoothed in the plating process and Ni-plated steel sheet or strip is prevented from sticking in the annealing process.

Inner-shield material to be attached inside a color cathode ray tube

A method of making, for cathode ray tubes and the like, an inner shield material that has superior magnetic characteristics and rust resistance. The method does not require conventional blackening processes. Sheet steel or strip is nickel-plated with a nickel-iron diffusion layer and then annealed. The annealing improves the magnetic characteristics. The sheet is cold-rolled prior to annealing to provide a roughened surface, which decreases the chances of sticking during the annealing process. In one embodiment the sheet is pickled, cold-rolled, annealed, cold rolled again, nickel plated, and then annealed again. Annealing between the first and second cold-rolling operations improves the magnetic characteristics.

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Kudamatsu, Japan

Osamu Yubuta