Method for determining a stretch of casting line including the closing position of the liquid cone of a continuously cast metal product

Patent metadata

Field	Value
Publication number	US-9399252-B2
Application number	US-201314411471-A
Country	US
Kind code	B2
Filing date	Jul 5, 2013
Priority date	Jul 5, 2012
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

A method for determining if a stretch of casting line includes the closing position of the liquid cone of a continuously cast metal product, where there is provided a casting line including an ingot mold containing the liquid metal and in which a meniscus is defined, one or more soft reduction roll devices, cylinders for actuating the one or more soft reduction devices, at least two oscillation application areas, the oscillation application areas being arranged in the one or more soft reduction roll devices. The oscillation being achieved by the rolls of the one or more soft reduction devices through the actuating cylinders. The method includes the following stages: a) applying an oscillation along the casting line to the cast product through at least two application areas in sequence; b) detecting the oscillating frequency of the meniscus level in the ingot mold; c) comparing the oscillating frequency of the meniscus level in the ingot mold with the oscillating frequency of the at least two areas of application.

First claim

The invention claimed is:

1. A method for determining if a stretch of casting line includes a closing position of a liquid cone of a continuously cast metal product, wherein there is provided a casting line comprising
an ingot mold containing a liquid metal and in which a meniscus is defined,
one or more soft reduction devices with rolls,
actuating cylinders for actuating said one or more soft reduction devices,
at least two areas of application of a periodic oscillating impulse along the casting line, said at least two areas defining end areas of said stretch of casting line,
the method comprising the following stages:
a) sequentially applying a first periodic oscillating impulse to a first area of application represented by a first actuating cylinder, thus causing a first oscillation on the cast product, and then a second periodic oscillating impulse to a second area of application represented by a second actuating cylinder, thus causing a second oscillation on the cast product;
b) detecting an oscillating frequency of a meniscus level in the ingot mold both during the application of said first periodic oscillating impulse and during the application of said second periodic oscillating impulse;
c) comparing the oscillating frequency of the meniscus level in the ingot mold with the oscillating frequency of the first area of application during the application of said first periodic oscillating impulse, and comparing the oscillating frequency of the meniscus level in the ingot mold with the oscillating frequency of the second area of application during the application of said second periodic oscillating impulse,
wherein stage c) is carried out by comparing a frequency spectrum of a signal of the meniscus level in the ingot mold with frequency spectra of force or position of said first actuating cylinder and said second actuating cylinder, respectively; whereby if the compared spectra are superimposable, a liquid core is present in the cast product in either of the first or second areas where the first or second periodic oscillating impulse is applied, respectively, otherwise the cast product is completely solidified,
whereby if, by comparing the oscillating frequency of the meniscus level in the ingot mold with the oscillating frequency of the first area of application, the compared frequency spectra are superimposable, and if, by comparing the oscillating frequency of the meniscus level in the ingot mold with the oscillating frequency of the second area of application, the compared spectra are not superimposable,
a liquid core is present in the cast product at the first area while the cast product is completely solidified at the second area, the closing position of the liquid cone being thus included in said stretch of casting line.

2. A method according to claim 1 , wherein the first periodic oscillating impulse and the second periodic oscillating impulse; are of the sinusoidal type.

3. A method according to claim 2 , wherein said first periodic oscillating impulse and said second periodic oscillating impulse have a duration of application of 1 to 2 minutes and a frequency from 10 −3 to 10 Hz.

4. A method according to claim 3 , wherein the frequency of said first periodic oscillating impulse and said second, periodic oscillating impulse is from 10 −2 to 5 Hz.

5. A method according to claim 1 , wherein the analysis of the frequency spectrum is carried out by applying a Fast Fourier Transform (FFT).

6. A method according to claim 1 , wherein the casting line comprises at least one first pinch roll and one second, pinch roll, and said at least two areas of application of the periodic oscillating impulse are represented by an actuating cylinder of the first pinch roll and by an actuating cylinder of the second pinch roll arranged downstream of the first pinch roll, said first pinch roll and second pinch roll acting as soft reduction devices.

7. A method according to claim 1 , wherein the casting line comprises at least one segment of soft reduction rolls and said at least two areas of application of the periodic oscillating impulse are represented by a pair of actuating cylinders provided at the inlet of a segment of soft reduction rolls and a pair of actuating cylinders provided at the outlet of said segment of soft reduction rolls or a pair of actuating cylinders of a motorized roll arranged within said segment of soft reduction rolls; or said at least two areas of application of the periodic oscillating impulse are represented by a pair of actuating cylinders of a motorized roll arranged within said segment of soft reduction rolls and by a pair of actuating cylinders provided at the outlet of said segment of soft reduction rolls.

8. A method according to claim 1 , wherein the casting, line comprises at least one pinch roll and at least one segment of soft reduction rolls, and said at least two areas of application of the periodic oscillating impulse are represented by an actuating cylinder of a pinch roll and by an actuating cylinder provided at the inlet of a soft reduction segment arranged downstream of said pinch roll, or they are represented by an actuating cylinder of a pinch roll and by an actuating cylinder provided at the outlet of a soft reduction segment arranged downstream of said pinch roll, or they are represented by an actuating cylinder of a pinch roll, downstream of the ingot mold, and by an actuating cylinder of a motorized roll provided within a soft reduction segment, downstream of said pinch roll.

9. A method according to claim 1 , wherein in the case of position-controlled hydraulic actuating cylinders, a position oscillation has an amplitude of less than 5 mm; and wherein in the case of force-controlled hydraulic actuating cylinders, a force oscillation has an amplitude of less than 80% of the nominal value of a force exerted by said hydraulic actuating, cylinders.

Assignees

• Danieli Off Mecc

Inventors

• Fornasier Marcellino

Classifications

• B22D11/16

  Controlling or regulating processes or operations · CPC title

• B22D11/201

  responsive to molten metal level or slag level · CPC title

• B22D2/003

  for the level of the molten metal (B22D11/181 and B22D11/201 take precedence; level indicators in general G01F23/00) · CPC title

• B22D11/207

  responsive to thickness of solidified shell · CPC title

• B22D11/1206

  for plastic shaping of strands (rolling mills B21B1/46) · CPC title