Nippon Steel Corporation

Hiroshi Iida

Koichi Sakurai

Ichiro Shimbashi

Ikuo Umehara

Tetuya Ohara

Masakatu Tuji

Yasuo Takeda

Masao Morimoto

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 gas-liquid cooling apparatus having a group of gas jet nozzles and a group of liquid jet nozzles so that the gas jet stream from the gas jet nozzles intersects with the liquid jet stream from the liquid jet nozzles at an acute angle so as to form a gas-liquid mixture, the improvement comprising a liquid guide means for collecting the liquid which is separated from the gas-liquid mixture and which is reflected from a material to be cooled and for carrying the collected liquid away from the material.

Gas-liquid cooling apparatus

A method of controlling steel strip temperature in a process of continuously heating steel strip in heating equipment having a preheating zone and a rapid-heating zone. The preheating zone has a number of gas-injecting preheating units that can be individually put into and taken out of operation. In normal operation, the in-operation length of the preheating zone is prefixed irrespective of strip thickness, and the temperature of the rapid-heating zone is preset depending on the strip thickness so that the strip acquires the desired temperature at the exit end thereof. In such operation, the strip is preheated in the preheating zone of the prefixed in-operation length and rapidly heated in the rapid-heating zone at the preset temperature. In irregular operation, such as treating a following strip the thickness of which has changed, the temperature of the rapid-heating zone is changed from the preset one to a second one optimum for the following strip. In the transition period in which the preset temperature of the rapid-heating zone changes to the second one, the in-operation length of the preheating zone is adjusted to control the strip temperature at the exit end thereof. Thus the desired strip temperature at the exit end of the rapid-heating zone can be achieved irrespective of strip thickness.

Method of controlling steel strip temperature in continuous heating

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Himeji, Japan

Hiroshi Iida