Nisshin Steel Co., Ltd.

Dai Nippon Printing Co., Ltd.

Dai Nippon Printing

Yasuo Imamura

Masahiro Shimose

Kazuhiro Takagi

Michio Kubota

Kazunori Kato

Takeshi Tsuda

Norio Tsukiji

Takashi Matsukura

Yoshiaki Ishimoto

Low carbon steel strip is cold rolled with rolling reduction of 15 to 35% in final cold rolling step and annealed in form of tight coil at temperature of 520 to 600.degree. C. to provide product having grain size number of 4 to 7 and coercive force of not greater than 2.0 Oersted as measured with initial magnetization field of 25 Oersted. The product is especially suitable for manufacturing shadow mask of Braun tube for color TV.

Process for producing steel strip material for use in manufacture of

A shadow mask of a Braun tube for a color TV made of a steel alloy having the following compositions in weight percent: C.ltoreq.0.12, 0.2.ltoreq.Mn.ltoreq.1.5, 0.3.ltoreq.Si.ltoreq.1.5, 1.0.ltoreq.2Si+Mn, 0.005.ltoreq.Al.ltoreq.0.030, and the balance being Fe and unavoidable impurities. A cold rolled and annealed strip made from such a steel alloy has a Vickers hardness of at least 110 so that it can be easily and satisfactorily processed in the subsequent hole-formation step.

Shadow mask of braun tube for color TV and process for manufacturing the

In process for manufacturing shadow mask of Braun tube for color TV comprising steps of subjecting strip of low carbon steel to cold rolling finish, forming holes in the rolled material, cutting it into individual flat masks, annealing each mask at elevated temperatures, conditioning the annealed mask and press-forming the mask into desired shape, the improvement residing in controlling the finish cold rolling reduction within the range between 10 and 35%, whereby the annealing temperature is reduced to 520.degree. to 750.degree. C. The process is applicable to steel strip material containing up to 0.10% by weight of carbon.

Process for manufacturing shadow mask of Braun tube for color TV

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Urawa, Japan

Yasuo Imamura