Nippon Steel Corporation

Katsuhiko Yui

Jiro Ohno

Hirokatsu Yashiro

Hiroshi Ikegami

Hirotoshi Kawamura

Yoshiteru Matsuo

Hiroshi Nishikawa

Yuichi Kato

Norichika Nagira

Kenzo Sawada

Masamitsu Wakoh

Ryuichi Hiratsuka

Masatsugu Uehara

Takeo Dazai

Yasuo Misawa

Takashi Ishizawa

Tadashige Namba

Yoshio Saitoh

Junichi Kinoshita

Haruo Kitamura

Tetsuo Nakamura

Daijiro Mizukoshi

For measuring the sizes of particles in the falling state, electromagnetic waves having different frequencies are transmitted from a transmitter/receiver onto the particles in the falling state and reflected electromagnetic waves having different frequencies reflected from the particles in the falling state are received by the transmitter/receiver. Data of the distribution of sizes of the particles and the average size of the particles are derived from the detected intensities of the received reflected electromagnetic waves.

Measurement of sizes of falling particles

A method of oscillating a continuous caster mold at high frequencies comprises disposing a plurality of oscillators having substantially the same oscillating characteristic at appropriate intervals along or in the vicinity of a line where liquid metal contacts an inner lining of a mold, connecting the tip of each oscillator to the inner lining so that the axis of the oscillator extends at right angles to the surface of the inner lining, and supplying power from an oscillation generator to each oscillator so that the oscillation frequencies of any two adjoining oscillators are differentiated within the limit of 2 KHz. Thus, any two adjoining oscillators oscillate the inner lining at right angles to the surface thereof at mutually differentiated frequencies.

Method of oscillating continuous casting mold at high frequencies and

For measuring the sizes of particles in the falling state, electromagnetic waves having different frequencies are transmitted from a transmitter/receiver onto the particles in the falling state and reflected electromagnetic waves having different frequencies reflected from the particles in the falling state and received by the transmitter/receiver. Data of the distribution of sizes of the particles and the average size of the particles are derived from the detected intensities of the received reflected electromagnetic waves.

The present invention relates to a method for cooling a steel strip in a continuous-annealing furnace. Conventionally, the steel strip is cooled by a water medium and, thus, oxidation is inevitable. Recently developed roll cooling methods can prevent oxidation but are disadvantageous in that the steel strip (1) is nonuniformly cooled as seen in its short width direction. The present invention attains uniform cooling by means of feedback-feedforward control, in which the blowing width of the gas-jet cooler (21, 53) is controlled by detecting the sheet temperature distribution with thermometers (24, 55, 60).

Method for cooling a steel strip in a continuous annealing furnace

In controlledly cooling steel strip in a continuous annealing line, the heat transfer rate needed for attaining the desired cooling rate is calculated from an equation including strip thickness, the cooling starting and finishing temperatures, and the desired cooling rate, and the obtained heat transfer rate is corrected according to the effect of natural cooling in idle-pass zones preceding and following the coolant spray zone. The flow rate of coolant is determined and set by using an equation expressing the predetermined relationship between the heat transfer rate and coolant flow rate. The length of the coolant spraying region extending in the direction of strip travel is calculated from the running speed of the strip, the cooling starting and finishing temperatures, and the desired cooling rate. The nozzles are set to turn on and off so that the coolant is sprayed from such a number of nozzles as correspond to the length of the spraying region thus calculated. Based on these settings, the coolant flow rate is corrected by re-calculating the heat transfer rate when strip thickness varies in the course of controlled cooling. Also, the on-off pattern of the nozzles is corrected by re-calculating the length of the coolant spraying region when the running speed of the strip varies.

Method of controlled cooling for steel strip

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Kimitsu, Japan

Katsuhiko Yui