Nippon Steel Corporation

Koichi Sakurai

Munetsugu Matsuo

Ichiro Shimbashi

Takashi Furukawa

Seiji Sugiyama

Hiroshi Takechi

Hiroshi Iida

Hisamoto Wakabayashi

Kazunori Nagai

Hideo Yokoyama

Kouichi Waki

Masao Morimoto

Tatsuru Shibuya

Primary cooling method in continuously annealing steel strip

A cold rolled steel strip having an elevated temperature is continuously cooled to a desired temperature at a desired cooling rate by a process comprising moving the cold rolled steel strip along at least one vertical cooling path, and; bringing a plurality of streams each consisting of a mixture of a cooling gas and a cooling liquid into contact with each surface of the steel strip, each mixture stream being prepared by jetting the cooling gas and liquid independently from others in directions intersecting each other before the vertical path of the steel strip.

Process for cooling a cold rolled steel strip

A dual-purpose production plant for cold rolled steel sheets and hot-dip galvanized steel sheets having, successively disposed in series, a heating zone, a soaking zone, a primary cooling zone, an overaging zone equipped with a controlled cooling facility, a molten galvanizing zone, an intermediate cooling means, a secondary cooling zone, a temper rolling means, and a chemical treatment means, and a bypass for directly connecting the overaging zone and the secondary cooling zone with each other.

Dual-purpose plant for producing cold rolled steel sheet and hot-dip

An apparatus for continuously producing a high strength dual-phase steel strip or sheet having a chemical composition which produces a dual-phase structure composed of ferrite grains and a low temperature transformed phase when rapidly cooled from the (.alpha.+.gamma.) temperature range or from the .gamma. temperature range. The apparatus has a continuous heat treatment furnace in which the strip moves vertically and which is composed of a heating zone, a soaking zone and a cooling zone, and conventional equipment associated therewith. The cooling zone has an upper hearth roll group, a lower hearth roll group and cooling equipment for cooling the strip at a rate in the range between 1.degree. and 300.degree. C./sec. for retaining the austenite in the steel of the strip. The hearth rolls of each hearth roll group are arranged to guide the strip coming from the soaking zone up and down through the cooling zone from the inlet end to the outlet end, alternately passing around the upper hearth rolls and the lower hearth rolls. The hearth roll at the position where the strip is subjected to straining and begins to work harden as a result of the bending, and the hearth rolls subsequent to such position, have diameters such that the strain induced phase transformation of the retained austenite and consequently the work hardening of the strip when it is turned around the hearth rolls is avoided.

Apparatus for continuously producing a high strength dual-phase steel

Growing community of inventors

Kitakyushu, Japan

Koichi Sakurai