Nippon Kokan Kabushiki Kaisha

Kuniki Uchida

Shiro Fukunaka

Kenzi Araki

Takao Kurihara

Hirosi Narita

A high tension Al-killed steel of which the yield point is more increased by the ensuing heat treatment after press-forming than that of the properties in which the tensile strength is above 40 to 80 Kg/mm.sup.2, is made by the following main steps:

Process of making high tension cold-reduced Al-killed steel excellent in

A steel consisting essentially of 0.04 to 0.10% C, 0.04 to 0.20% P, not more than 0.02% S, and [S]% .times. 10 to 0.7% Mn is conventionally hot and cold rolled. It is then subjected to the following continuous annealing:

Method of making high strength cold reduced steel by continuous

A steel being substantially made and adjusted within the range of 0.04 to 0.12% C, 0.50 to 2.00% Si, and 0.10 to 1.60% Mn, passed through ordinary hot and cold rolling processes, is subjected to a full continuous annealing process comprising the following steps:

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Yokohama, Japan

Kuniki Uchida