KR19990043751A - Friction force measuring device between mold and cast of hydraulically driven resonant mold - Google Patents

Abstract

The present invention relates to a device for measuring the frictional force acting between the mold and the cast from the vibration displacement and the hydraulic measurement value of the hydraulic drive using the dynamic mechanism of the hydraulic driven resonant mold, the molten steel flows into the mold A plurality of hydraulic cylinders installed by supporting the lower part of the mold to the hydraulic piston to cushion the mold from oscillating up and down, and the mold and the supporting frame to keep the mold horizontal and reduce the load of the mold by elastic action. A plurality of leaf springs placed between and supporting the mold, a displacement measuring sensor installed at one end of the piston rod of the hydraulic cylinder, for detecting vibration displacement of the mold, and a vibration force of the hydraulic driving unit installed at the side of the hydraulic cylinder. And a plurality of hydraulic pressure measuring sensors for detecting the pressure, the hydraulic pressure measuring sensors and vibration displacement measuring sensors. And a data processor for converting the output analog signal into a digital value, and repeatedly calculating the friction force between the mold and the slab from the digitally converted vibration displacement value and the vibration force to repeatedly calculate and display the friction force on the screen. Characterized in that made.

Description

Friction force measuring device between mold and cast of hydraulically driven resonant mold

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulically driven resonance mold player, and in particular, between a mold and a cast using a vibration displacement measured through a dynamic mechanism of a hydraulically driven resonance mold and a hydraulic measurement value of the hydraulic actuator. A friction force measuring device for measuring a friction force acting on

Generally, the frictional force acting between the mold and the cast is used to determine the condition of the equipment, to predict the quality of the cast and to predict the breakout of the cast during the casting process. Since the cast is made in contact with the mold, the frictional force affects the surface quality of the cast and measures the friction during operation, so that if the friction is large, the mold flux should be introduced to increase the lubrication between the mold and the cast. Sticky cast rupture is a phenomenon in which the cast steel adheres to the wall of the mold and the outer surface of the cast steel is torn and liquid steel leaks, which causes the operation to be stopped for a long time and damage to the equipment.

Conventional methods for measuring the frictional force acting between such a mold and a slab utilize the fact that the strain is proportional to the stress by finding the point where the deformation is large when the oscillating molder is in operation. Since the deformation force cannot directly measure the frictional force between the mold and the cast steel, the conventional method works when the casting machine is operated without molten steel in the mold and when the molten steel is poured into the mold and continuous casting is performed. The difference in deformation force was used as the friction force. Since this conventional method is not a method of directly measuring the frictional force, the frictional force could not be accurately measured under different casting conditions such as casting speed, mold vibration frequency, width of cast steel, and the like.

The present invention has been made in view of the above-mentioned problems of the prior art, and uses the dynamic mechanism of a hydraulically driven resonant mold to measure the frictional force acting between the mold and the slab from the vibration displacement and the hydraulic measurement of the hydraulic drive. Its purpose is to provide a device for this purpose.

1 is a schematic block diagram of an apparatus for measuring frictional force between a resonant mold mold and a slab according to the present invention.

*** Explanation of symbols for main parts of drawing ***

1: Data Processor 2: Template

3: leaf spring 4: support frame

5: Hydraulic sensor 6: Hydraulic cylinder

7: piston 8: displacement measuring sensor

9: data collection device 10: inside the mold

Friction force measuring device between the mold and the cast of the hydraulic drive-type resonant mold according to the present invention for achieving the above object, the hydraulic piston in the lower part of the mold to buffer the vertical vibration of the mold when the molten steel flows into the mold A plurality of hydraulic cylinders installed and supported on the plurality of cylinders, a plurality of leaf springs placed between the mold and the support frame to support the molds in order to maintain the horizontality of the molds and to reduce the load of the molds by elastic action. A displacement measuring sensor installed at one end of the piston rod of the mold to detect vibration displacement of the mold, and a plurality of hydraulic measurement sensors installed at the side of the hydraulic cylinder to detect the excitation force of the hydraulic drive unit; And data for converting an analog signal output from the hydraulic sensor and vibration displacement sensor into a digital value. The home device, calculating a friction force (friction force) to produce a repetitive friction between the digital conversion of the vibration displacement and a group effort to from the mold and the slab repeats having a data processor for display on the screen, characterized by comprising.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic block diagram of an apparatus for measuring frictional force between a resonant mold mold and a slab according to the present invention. Referring to this figure, when the molten steel flows into the interior 10 of the mold, the hydraulic cylinder 7 vibrates to cause the mold to vibrate up and down. At this time, the molten steel is cooled in contact with the wall surface of the mold (2) to become a solid steel (steel) called the cast steel is drawn out to the bottom of the mold. The process of making casts by mold vibration in molten steel is called continuous casting, and the resonant casting equipment by hydraulic driving is made of mold (2), leaf spring (3), hydraulic cylinder (6), hydraulic piston (7), etc. It is composed. The present invention is a device that is attached to the existing resonant casting equipment as a hydraulic pressure sensor (5), vibration displacement measuring sensor (8) and a data acquisition device for converting and outputting the analog signal output from each sensor to a digital value ( 9) and a data processor 1 which repeatedly calculates the frictional force between the mold and the slab from this digital value and displays it on the screen.

The friction force measuring method using the friction force measuring device between the mold and the slab of the hydraulic drive-type resonant mold according to the present invention described above is as follows. First, the hydraulically driven resonant mold 2 is controlled to perform sinusoidal vibration as shown in Equation 1 below.

[Equation 1]

In [Formula 1] above ω = 2πf F is the oscillation frequency, and Points the width of the vibration. When the mold vibrates, the speed v (t) and acceleration a (t) of the mold are as shown in Equation 2 below.

[Formula 2]

= -ω ² ⋅s (t)

The force acting on the mold by the leaf spring 3 connected to the mold 2 can be expressed by the following [Equation 3].

[Equation 3]

F _s = K⋅ (s ₀ + s (t))

Here, K is the elastic proportional constant of the leaf spring (3), s ₀ Is the starting position of vibration of the initial mold. In addition, the vibration acceleration and gravity acceleration force of the mold are as shown in Equation 4 below.

[Equation 4]

F _a (t) = m⋅ (a (t) + g)

In Equation 4, m is the mass of the mold (2), g is the earth gravitational acceleration (= 9.8 m / s ² ). The vibration velocity of the mold is related to the frictional force acting between the mold and the slab with damping factors. The force acting on the speed is shown in Equation 5 below.

[Equation 5]

F _v (t) = D⋅v (t) + F _r (t) ⋅sign (v _c -v (t))

In Equation 5, D is a damping constant, F _r (t) is a frictional force, and sign () is a sign function that maps "1" if the value in parentheses is positive and "-1" if negative. Indeed, since the mold is continuously subjected to an excitation force, the force due to the damping constant D can be neglected, so F _v (t) can be regarded as the frictional force acting between the mold and the slab.

The electromotive force Fe (t) for driving the mold is the sum of the forces exerted on the mold, the force F _s (t) the plate spring acts on the mold, as shown in Equation 6 below, and the inertial force F _a (t) of the mold. , The sum of the frictional forces, F _v (t), between the mold and the slab.

[Equation 6]

F _e (t) = F _s (t) + F _v (t) + F _a (t)

In [Equation 6], the frictional force between the mold and the cast steel is F _v (t). Therefore, in order to calculate the friction force, Equation 6 may be replaced with Equation 7 below.

[Formula 7]

F _v (t) = F _e (t)-[F _s (t) + F _a (t)]

= F _e (t)-[(K _s0 + mg) + (K-mw ² ) s (t)]

In the above [Formula 7], F _e (t) is a pressure applied to the hydraulic cylinder that changes over time t is a hydraulic difference in the upper and lower cylinders around the piston (7), the hydraulic sensor ( 5) can be installed to calculate the difference between the signal values of the up and down sensors. s (t) is the vibration displacement of the mold that changes with time t, and the displacement value is obtained using the displacement measuring sensor 8. Since the pressure applied to the mold and the vibration displacement of the mold can be taken from the sensor, the frictional force F _v (t) between the mold and the cast can be calculated.

The frictional force is calculated in a computer, which is the data processing processor 1, and displays this value on the screen. The operator can detect the abnormality by identifying the state of the casting operation by reading the friction force displayed on the screen of the computer.

According to the friction force measuring device between the mold and the slab of the hydraulically driven resonant mold according to the present invention as described above, by measuring the friction force acting between the mold and the slab during operation to increase the lubrication action between the mold and the slab when the frictional force is large By taking measures such as casting mold flux or reducing casting speed, the surface quality of cast steel can be prevented from deteriorating and cast rupture can be prevented.

Claims (1)

Multiple hydraulic cylinders installed by supporting the lower part of the mold to the hydraulic piston to prevent the mold from vibrating up and down when molten steel flows into the mold, and the mold load is maintained by the elastic action to keep the mold horizontal when the mold is vibrated. A plurality of leaf springs placed between the mold and the support frame to support the mold, a displacement measuring sensor installed at one end of the piston rod of the hydraulic cylinder, for detecting vibration displacement of the mold, and on the side of the hydraulic cylinder. Installed a plurality of hydraulic measuring sensors for detecting the vibration force of the hydraulic drive unit, a data collection device for converting analog signals output from the hydraulic measuring sensors and vibration displacement measuring sensors into digital values, the digitally converted vibration displacement values And the friction force between the mold and the slab is repeatedly calculated from the vibration force and the friction force is repeatedly calculated. Friction force measuring apparatus between the mold and the cast steel of the oil pressure drive type resonator, characterized in that the mold having been made in the data processor for display at the surface.