Kawasaki Steel Corporation

Mitsubishi Jukogyo Kabushiki Kaisha

Norio Ohta

Kuniaki Sato

Yasuhisa Nakajima

Naohiko Soeda

Kenichi Yanagi

Kusuo Furukawa

Takeo Fukushima

Masahiro Harada

Susumu Satoh

Hideo Abe

Susumu Okada

Fumiya Yanagishima

Akira Kishida

Atsushi Nagashima

Toshikazu Kaihara

Masanobu Ochiai

Tojiro Ikeda

Jun-ichi Mano

A method of producing a high-strength cold-rolled steel sheet suitable for working uses which utilizes a steel material having the following composition: not more than 0.006 wt % of C, not more than 0.5 wt % of Si, not more than 2.0 wt % of Mn, and not less than 0.01 wt % but not more than 0.10 wt % of Ti, the Ti, C and N contents being determined to meet the condition of Ti&gt;(48/12) C wt %+(48/14) N wt %, the steel also consisting essentially of not less than 0.0010 wt % but not more than 0.0100 wt % of Nb, not less than 0.0002 wt % but not more than 0.0020 wt % of B, not less than 0.03 wt % but not more than 0.20 wt % of P, not more than 0.03 wt % of S, not less than 0.010 wt % but not more than 0.100 wt % of Al, not more than 0.008 wt % of N, not more than 0.0045 wt % of O, and the balance substantially Fe and incidental inclusions. The steel material is cast and hot-rolled and then subjected to a cold rolling conducted at a sheet temperature not higher than 300.degree. C. under such a condition that the sum of the rolling reductions of passes which meet the following condition between said sheet temperature (T .degree.C.) and the strain rate .epsilon. (S-1) is 50% or greater:

Method of producing high-strength cold-rolled steel sheet suitable for

The present invention relates to method and apparatus for heating a strip of metallic material in a continuous annealing furnace and more particularly to an improvement relating to a method and apparatus for heating a strip of metallic material in a continuous annealing furnace in which annealing of the strip is continuously carried out in such a manner that a gas serving to adjust temperature of the strip, is blown toward the strip through a plurality of gas jet nozzles which are arranged on one side or both sides of the strip, wherein the temperature and flow rate of the strip are properly determined to a required level in response to the changing of the operating conditions such as the heat cycle, line speed, thickness of strip, width of strip and the like. Further, the present invention relates to a method and apparatus for heating a strip of metallic material in a continuous annealing furnace, wherein the temperature of the strip is controlled to reach a target temperature by heating or cooling the strip by means of a gas jet or the like having excellent respondency at a part of the heating zone in the continuous annealing furnace whereby irregular annealing of the strip is effectively inhibited.

Method and apparatus for heating a strip of metallic material in a

The present invention relates to method and apparatus for heating a strip of metallic material in a continuous annealing furnace and more particularly to an improvement relating to a method and apparatus for heating a strip of metallic material in a continuous annealing furnace in which annealing of the strip is continuously carried out in such a manner that a gas, serving to adjust temperature of the strip, is blown toward the strip through a plurality of gas jet nozzles which are arranged on one side or both sides of the strip, wherein the temperature and flow rate of the strip are properly determined to a required level in response to the changing of the operating conditions such as the heat cycle, line speed, thickness of strip, width of strip and the like. Further, the present invention relates to a method and apparatus for heating a strip of metallic material in a continuous annealing furnace, wherein the temperature of the strip is controlled to reach a target temperature by heating or cooling the strip by means of a gas jet or the like having excellent respondency at a part of the heating zone in the continuous annealing furnace whereby irregular annealing of the strip is effectively inhibited.

In a method of continuously annealing and pickling steel strips successively transferred through a continuous annealing apparatus including heating and cooling zones and a pickling apparatus, annealing the steel strips is effected in reducing atmosphere and thereafter pickling is effected at least by nitric acid electrolytic treatment. In an apparatus for continuously annealing and pickling steel strips, including a continuous annealing furnace and a pickling apparatus, the continuous annealing furnace consists of vertical furnaces capable of advancing a steel strip in a manner substantially repeating upward and downward movements alternately in substantially vertical directions and the pickling apparatus comprises at least a nitric acid electrolytic cell. In another aspect, continuous annealing furnace consists of one pass furnace capable of advancing the steel strip only once and forming a high temperature heating zone and a high temperature cooling zone of the annealing furnace, and vertical furnaces respectively forming a lower temperature heating zone and a low temperature cooling zone and capable of advancing a steel strip in a manner substantially repeating upward and downward movements alternately in substantially vertical directions. The one pass furnace is horizontal or vertical.

Continuous annealing and pickling method and apparatus for steel strips

A method and an apparatus for continuously annealing cold rolled steel strips successively passing through a preheating zone, a low temperature heating zone, a high temperature heating soaking zone, a primary cooling zone and a secondary cooling zone. In each zone, the steel strip is driven by hearth rolls alternately upward and downward in a serpentine path. According to the invention, in a high temperature zone such as the high temperature heating zone and the primary cooling zone where the steel strip is prone to heat buckling, the steel strip is caused to pass only once in a single direction without passing along the serpentine path, thereby preventing meandering and heat buckling of the steel strip.

Continuous annealing method and apparatus for cold rolled steel strips

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Chiba, Japan

Norio Ohta