Facility and method for cold rolling metal strip

Abstract

In a facility for cold rolling a metal strip in a circulating oil-feeding system by jetting a low concentration coolant, in a neighborhood of an inlet side of a work roll and jetting a high concentration coolant at an upstream side of the jetting position of the low concentration coolant to conduct rolling, the metal strip is cold rolled with the cold rolling facility provided with a control equipment for varying a jetting amount of the low concentration coolant in accordance with a rolling rate so that a tip of a liquid pool of the low concentration coolant formed on a surface of a steel sheet at an inlet side of the work roll does not reach a jetting position of the high concentration coolant, whereby the rolling can be performed without losing a plate-out property even if the rolling rate is decreased.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is the U.S. National Phase application of PCT / JP2017 / 015523, filed Apr. 18, 2017, which claims priority to Japanese Patent Application No. 2016-084993, filed Apr. 21, 2016, the disclosures of these applications being incorporated herein by reference in their entireties for all purposes.FIELD OF THE INVENTION[0002]This invention relates to a facility and a method for cold rolling a metal strip and, more particularly, to a facility for cold rolling a metal strip by using a circulating system for supplying a lubricant and a method for cold rolling by using such a facility. Hereinafter, the invention is explained by taking a “steel sheet” as an example for the metal strip.BACKGROUND OF THE INVENTION[0003]Facilities for cold rolling a metal strip are divided, based on a system of feeding a lubricant (rolling oil), into a direct oil-feeding system wherein the rolling oil is directly jetted and fed onto a surface of a steel sheet and at the...

AI Technical Summary

Benefits of technology

The invention controls the tip of the coolant pool on the sheet surface to prevent it from reaching the area where the high concentration coolant is jetted. This allows for better absorption of the coolant and improves the rolling process.

Problems solved by technology

In an actual hybrid rolling, there is a case that a decrease of the rolling rate cannot be avoided due to defects or the like existing in a rolling raw material (base material).

At such a state, the high concentration coolant is jetted toward the low concentration coolant accumulated on the sheet surface, so that the high concentration coolant is mixed with the low concentration coolant and diluted, and hence the oil content in the high concentration coolant cannot reach the sheet surface, and the effect by the hybrid rolling cannot be obtained.

With regard to the above problem, it can be considered to further increase the concentration of the rolling oil in the high concentration coolant, but there is a problem that the amount of the rolling oil used is increased to deteriorate unit consumption.

It is also considered to move the jetting position of the high concentration coolant to an upstream side further separated from a zone forming the liquid pool of the low concentration coolant, but it is actually difficult because there is a restriction on the distance between stands in a cold rolling facility of tandem type or the like.

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