JPS6167550A - Instrument for measuring bulging of steel ingot - Google Patents

Abstract

PURPOSE:To provide a titled instrument which can measure bulging of a high- temp. ingot with high accuracy and has excellent durability by constituting the instrument in such a manner that the displacement of rolls disposed to face each other in the moving direction of the ingot and the displacement of the ingot between the rolls are detected. CONSTITUTION:A sensor attaching arm 25 is fixed to a supporting arm 24 installed to a fixing base 23 and a sensor supporting member 30 mounted with differential transformers 31 and an ultrasonic range finder 32 and a heat shielding plate 37 are longitudinally movably attached to the arm 25 in an instrument 22 for measuring the bulging of the steel ingot 20 moving in an arrow 19 direction. A pair of said differential transformers 31 contact with the extreme top of a pair of the rolls 21 spaced from each other in the moving direction 19 of the ingot 20 via displacing iron cores 40 and small rollers 41 and detect the displacement of the rolls 21. On the other hand, the range finder 32 detects the displacement of the ingot 20 in the central position of the rolls 21, 21. The bulging of the ingot 20 is exactly detected by both detected values.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for measuring bulging of a cast slab.

[Prior art] As shown in Fig. 7, in continuous casting I,
The molten steel inside is injected into a tundish 2 and cast from the tundish 2 into a mold 11 through an immersion nozzle 3.

The 14 pieces 5 in which solidified shells have been formed in the mold 4 are guided to a group of rolls 6 and pulled to the center at a predetermined speed. In this case, the slab 5 is high (3) and therefore lacks rigidity, and due to the static pressure of the molten steel inside the slab 5, the solidified shell of the slab is moved between the rolls 6 as shown in FIG. Bulging, the so-called bulging phenomenon, occurs.This bulging phenomenon tends to occur particularly near the mold 2 (in the slab 5), and when bulging occurs, internal cracks or vertical warping occur inside the slab, and the casting Decrease the quality of one piece.

For this reason, measures such as shortening the roll interval, lowering the slab temperature by strong cooling, increasing the thickness of the solidified shell, or reducing the molten steel static pressure by reducing the radius of curvature for continuous casting, etc. By taking measures, bulging is reduced. However, since the occurrence of this bulging is influenced by casting conditions, it is preferable to measure the bulging m of the slab over time during actual operation. This is because by modifying the casting conditions as needed based on the measurement results, the quality of the slab can be quickly improved.

By the way, as a conventional bulging measuring device, as shown in FIG.
hl, u, Eisen) Volume 98 (1978) No. 2
There are some listed on page 54. This device has a difference v
Since the transformer iron core 11 of the J1-lance 10 is too high, it easily causes thermal expansion, resulting in large measurement errors and lack of durability, making it impractical.

On the other hand, a bulging measurement device using an eddy current distance meter has been proposed (Utility Model Application No. 56-80856). This device can measure the amount of bulging without contacting the slab, and the bulging measurement device uses an eddy current distance meter. However, this device has the disadvantage that the measurement value fluctuates depending on the temperature of the slab surface and roll, and in particular, the magnetic variation Yp, J degree (one point of curie, one point of curie, 770℃
) Since the magnetic properties of steel change above and below the eddy current rangefinder, the output of the eddy current rangefinder is affected by temperature changes.

[Problems to be Solved by the Invention] An object of the present invention is to provide a continuous casting slab bulging measuring device that can measure the amount of bulging of a high-temperature slab with high accuracy and has excellent durability. do.

[Means for solving the problem] The continuous casting slab bulging measuring device according to the present invention has the following features:
An apparatus for measuring inter-roll pulsing of continuously cast slabs, which includes a roll displacement detection means for detecting displacement of a pair of rolls, and an ultrasonic distance meter for detecting displacement of the slab between the rolls. It is characterized by measuring bulging by detecting displacement of pieces and rolls.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a front view of a bulging measuring device according to an embodiment of the present invention, and FIG. 2 is a side view thereof. The slab 20 is moving in the direction of the arrow 19, and a bulging measuring device 22 is installed between the pair of rolls 21. Support arm 2.1.

It is supported by a pair of fixed stands 23 (only one fixed stand 23 is shown in the figure), and a pair of sensors are mounted on the arm 25 at a position directly above between the rolls 21 on this support arm 24. are arranged perpendicularly to the slab 20.

Attachment: The arm 25 is supported by a guide roller 26 attached to the support arm 24 so as to be movable toward the slab 20. For installation, the arm 25 is fixed by a fixture 27 fixed to the support arm 24.
The position relative to the slab 20 can be adjusted by means of the bolts 28 . A sensor support member 30 is attached to the arm 25 so as to be movable in the longitudinal direction of the arm 25.
The cast piece 20 can be pulled up in a direction away from the slab 20 by a winch 36 attached to the fixed base 23 via pulleys 34 and 35 attached to the cast slab 20. A heat shield plate 37 is attached below the sensor support member 30.

The sensor support member 30 has a moving direction 19 of the slab 20.
A pair of differential transformers 31 and an ultrasonic distance meter 3 are spaced apart from each other.
There are 2 desks installed. The differential transformer 31 is the roll 21
The small roller 41 attached to the tip of the transformer iron core 40 of each differential transformer 31 is placed directly above the roll 2.
I am scheduled to be transferred to 1st. The iron core 40 is the small roller 4
1, the differential transformer 31 can detect the position of the roll 21, and since the small roller 41 is rolling on the roll 21, shearing force is applied to the iron core 40. It has no effect. The main body of the differential transformer 31 is 2A! It is covered with a protective cover made of +%, and fj! , chilled water is passed through the protective cover to prevent the temperature of the differential transformer main body from reaching an upper limit, and to prevent this main body from coming into contact with other members and receiving mechanical shock.

Furthermore, the iron core 40 and the small rollers 41 are cooled by spray water or the like, making it possible to withstand long-term use.

The ultrasonic distance meter 32 is installed in the center between the differential transformers 31, and a nozzle 44 is installed at the tip of a cylindrical fixture 42.
are screwed together. Cooling water is introduced into the fitting 42 through an inlet 43, and an O-ring 47 is interposed between the fitting 42 and the nozzle 44.
The threaded part is sealed. Fixture 4 for nozzle 44
A fastener 48 is screwed into the inner part of the inner part of the nozzle 44, and the ultrasonic probe 50 is tightened by the fastener 48 between its flange 49 and the inner flange of the nozzle 44. It is fixed to the nozzle 44. Water is introduced into the nozzle 44 via an introduction pipe 46,
A water column is formed from the reduced diameter portion at the tip of the nozzle 44 toward the center of the transfer point of the roll 21 in the slab 2o. This water column acoustically couples the ultrasonic probe 50 and the slab 20. Note that the nozzle 44 has a gas vent 45.
is formed. The ultrasonic probe 500 cable 51 is led out through the inside of the fixture 42. Cooling water flows through the inside of the mounting n112, and the cable 51
Since the cable 51 is immersed in this water, the cable 51 will not be damaged.

The outputs of the differential lance 31 and the ultrasonic probe 32 are input to the scanner 55 shown in FIG.
J] Signals related to the position of the roll 21 and the position of the slab 20 detected by the lance 31 are taken into the scanner 55. These signals are converted into digital signals by the A/D converter 56 and input to the arithmetic unit 57.

In the arithmetic unit 57, the amount of bulging of the slab is determined, and this determination data is stored on the floppy disk 58 and recorded on the recorder 59. Arithmetic device 57
A personal computer or the like can be used as the recording device 59, and a printing type recording device or a screen display device such as a CRT can be used as the recording device 59.

Next, the operation of the bulging measuring device configured as described above will be explained. First, the support member 30 is lowered,
The ultrasonic probe 32, the differential transformer, and the lance 31 are set at the predetermined positions shown by solid lines in FIGS. 1 and 2, and the small roller 41 of the differential transformer 31 is transferred to the roll 21, and the A water column is formed between the sonic distance meter 32 and the slab 20. After the start of casting, as shown in FIG. 5(a), while the completely solidified slab is passing between the rolls 21 at an extremely slow drawing speed, the ultrasonic distance meter 32 and the differential transformer 31 are activated. The output is input to an arithmetic unit 57 via a scanner 55 and an A/D converter 56. Thereafter, the slab handling speed is increased and regular casting operations begin. Then, the unsolidified slab passes between the rolls 21, and then the outputs of the ultrasonic distance meter 32 and the differential transformer 31 are input to the calculation device 57 at a constant sampling period.

In this case, a state in which the roll 21 is displaced toward the slab 20 while the unsolidified slab 20 is passing through the roll 21 gate is shown in FIG. 5(b), and the roll 21 is moved away from the slab 20. FIG. 5(C) shows a state in which they are displaced in the direction of separation. In any of these cases, the amount of bulging δ of the slab can be determined from the following equation (1).

δ−−Δd+(ΔQA+ΔRin)/'2...(1) However, Δd is the displacement of the stationary slab, and ΔRi8 and Δ
Qe is the displacement of the roll 21. Ultrasonic waves are generated when completely solidified slabs are passing through! When the position of the slab detected by the 12 distance meter 32 is do, and the position of the slab when the unsolidified slab is passing is d, the displacement Δd of the slab is given by ddQ. On the other hand, the position of the roll detected by the differential transformer 31 when a completely solidified slab is passing is λAO and day 0, and the position of the roll when an unsolidified slab is passing is QA and B. Then, the displacement Δ2 of one roll 21
A is given by Q, A-QAa, and the displacement of the other roll 21 is △! 2 days is given by Qe-QBo. The positions of the slab and roll are indicated by the distances (#, etc.) between the ultrasonic distance meter, the differential transformer, and the slab and roll, and therefore, the displacement is the distance between these sensors and the object to be detected. It manifests itself as change. Since the ultrasonic probe 32 detects the position of the slab at the center of both rolling points of the roll 21 and slab 20, (Δ2A+
ΔLo)/2 is the slab displacement when the position of the slab surface changes due to roll displacement when no bulging occurs in the slab 20. Therefore, the displacement Δd of the slab detected by the ultrasonic probe 32 and this (Δ2A+ΔλB
)/2, the inter-roll bulging amount δ of the slab can be determined as shown in equation (1). The bulging amount δ determined by the arithmetic unit 57 is stored on the floppy disk 58 and recorded on the recorder 59. 6th
The figure shows an example of the measurement results of this bulging. The casting conditions in this case are that the distance between the rolls 21 is 540 mm, and the measurement position is molten W (1 point along the IA trace of the slab from the molten metal surface).
The depth of the molten steel is 10.5TrL at 7m. The surface temperature of the slab was 960'C, and the drawing speed of the slab was initially 1. As can be seen from this figure, which is OTrL minute and 1.6 m minute in steady state, according to the present invention, bulging M is actually measured with high precision, and it changes over time. By monitoring the bulging in this way and correcting the casting conditions when the bulging suspension is about to exceed the limit for occurrence of internal abrasion, etc., deterioration in the quality of the slab can be prevented.

After casting is completed and the rear end of the slab passes through the roll liver,
Raise the sensor support member 30 using the winch 3G,
The ultrasonic distance meter 32 and the differential transformer 31 are raised.

After these sensors are retracted, the roll 21 moves upward.

It goes without saying that this invention is not limited to the above embodiments. In particular, the means for detecting roll displacement is not limited to a differential transformer; an ultrasonic distance meter may also be used to detect the position of the roll circumferential surface, and the roll displacement can be detected by detecting the position of the roll rotation axis. It is also possible to detect the position.

[Effects of the Invention] According to the present invention, bulging of a hot slab can be determined with high accuracy during actual operation. The measured value of the second bulging is that the high-temperature cast slab is less affected by heat damage, and the equipment is highly durable.

[Brief explanation of the drawing]

FIG. 1 is a front view of a bulging I11 fixing device according to an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a sectional view of an ultrasonic distance meter, and FIG. 4 is a block diagram of a data processing device. , Fig. 5(a), (b, 1.) (C,) is a diagram explaining the calculation of bulging suspension, Fig. 6 is a graph showing the change in bulging suspension measured by this invention, and Fig. 7 The figure is a schematic diagram of continuous casting, and Figure 8 is the conventional bulging measurement.
It is a schematic diagram showing an apparatus. 20... Slab, 21... Roll, 22... Bulging measuring device, 23... Fixing stand, 24... Support arm, 25... Mounting arm, 30... Support member, 3
1... Differential transformer, 32... Ultrasonic distance meter, 36...
...Winch, 50...Ultrasonic probe, 57...Arithmetic device. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 (b)

Claims (1)

[Claims] An apparatus for measuring bulging of continuously cast slabs, comprising a roll displacement detection means for detecting the displacement of a pair of rolls separated in the direction of movement of the slab, and an ultrasonic distance meter for detecting the displacement of the slab between the rolls. The method is characterized in that bulging is measured by detecting slab displacement and roll displacement.