JPH01313144A - Method for measuring solid phase ratio in semi-molten metal - Google Patents

Abstract

PURPOSE:To make measurement easily and directly by arranging a detecting head providing a primary coil and a detecting coil near semi-molten metal, impressing oscillating voltage to the primary coil and detecting eddy current in the detecting coil. CONSTITUTION:The semi-molten metal 2, which is made fine under solid-liquid coexisting condition, is contained in a crucible 1 and the detecting head 3 providing the primary coil 5 and the detecting coil 7 is arranged near the surface of the metal. At the time of impressing the oscillating voltage from an oscillator 4 to the primary coil 5, an eddy current is generated in the semi-molten metal 2. Then, an eddy current is induced in the detecting coil 7 by variation of magnetic field. By detecting this eddy current with a detector 6, the solid phase fraction of the semi-molten metal 2 is directly obtd. under non-contacting condition from the solid phase fraction-eddy current curve experimentally obtd. By this method, the direct measurement of solid phase fraction can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for measuring the solid fraction of a metal in a semi-molten state.

[Prior Art] In recent years, so-called semi-melt processing processes have been developed and are being put into practical use for the purpose of saving energy and resources. This semi-melt processing process is a combination of a casting process and a hot working process, and refers to a method of directly manufacturing a primary product from molten metal without going through any intermediate processes. That is, the molten metal is cooled to a predetermined temperature range to crystallize a fine solid phase in the liquid phase at a predetermined ratio (solid phase ratio) to form a semi-molten metal in a solid-liquid coexistence state, and then this is semi-molten. This method involves molding the material in its original state to create a primary product with a shape as close to the final product as possible.

This semi-molten processing process can save energy and resources, and because the casting process is omitted and the process is directly formed, a uniform structure with no casting defects such as internal cracks or segregation can be achieved. of products are obtained.

[Problems to be Solved by the Invention] What is important in the semi-molten processing process is that the solid phase ratio of molten metal is, for example, 0.2 to 0.8, and in the case of steel, 0.5 to 0.
The purpose is to control the value to a constant value within the range of 6. If the solid fraction is too large, the crystal grain size will become coarse and the characteristics of the semi-melt processing process will be lost. On the other hand, if the solid fraction is too small, it will be difficult to omit the casting process and directly process and mold.

Therefore, it is essential to measure the solid fraction of molten metal in the semi-molten metal processing process. And in this case,
It is desirable to measure directly and without contact without sampling the molten metal.

However, no such method has been developed so far.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method for directly and easily measuring the homophase ratio of semi-molten metal in a non-contact manner.

[Means for Solving the Problems] The method for determining M1 of the solid phase ratio of semi-molten metal of the present invention includes arranging a detection head equipped with a primary coil and a detection coil in close proximity to the semi-molten metal in a solid-liquid coexistence state. The solid phase ratio of the semi-molten metal is determined by applying an oscillating voltage to the primary coil to generate an eddy current in the semi-molten metal and detecting the eddy current by the detection coil. .

[Operation] It is a well-known phenomenon that eddy currents are generated in a conductor when the conductor is placed in a time-varying magnetic field. When this eddy current is generated in a semi-molten material, the magnitude of the eddy current changes depending on the solid phase ratio of the semi-molten material. This is probably because the resistivity of the semi-molten material changes as the solid fraction of the semi-molten material changes. The present invention applies this phenomenon to the measurement of the solid fraction of a semi-molten material. Although there is an example of a sensor using eddy current being applied to detect the level of a molten metal, there is no example of its application to measuring the solid phase ratio of a semi-molten material.

As the solid fraction of the semi-molten material increases, eddy currents flowing through the semi-molten material are generated. Therefore, if the relationship between the rate of eddy current flowing in a semi-molten material and the solid phase ratio of the semi-molten material is determined by experiment, the rate of eddy current flowing in the semi-molten material can be measured. The solid phase rate can be known immediately. The present invention is based on such a principle.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a cross-sectional view for explaining a method for measuring the solid fraction of a semi-molten metal according to an embodiment of the present invention. Inside Ruppo 1, which is made of ceramic refractories, molten metal is kept at a predetermined temperature.
For example, dendrites that have been cooled to 1500°C and have grown ↑l in size due to cooling are separated by a stirring means (not shown),
A finely divided semi-molten metal 2 in a solid-liquid coexistence state is accommodated. A detection head 3 is provided close to the surface of this semi-molten metal 2. The detection head 3 has an oscillator 4
The primary coil 5 is connected to the detector 6, and the detection coil 7 is connected to the detector 6. Note that the primary coil 5 and the detection coil 7 are arranged in parallel near the surface of the semi-molten metal 1.

The solid phase ratio of the semi-molten metal 2 in the crucible 1 is measured as follows. First, when the oscillator voltage from the oscillator 4 is applied to the primary coil 5, an eddy current is generated in the semi-molten metal 2 inside the ruppo 1. This eddy current of the semi-molten metal 2 affects the magnetic field around the detection coil 7 and changes the eddy current generated in the detection coil 7. By detecting the current generated in this detection coil with the detector 6, the semi-molten metal 2
The magnitude of the eddy current generated can be determined.

Based on the eddy current generated in the semi-molten metal 2 obtained in this way, the in-phase ratio of the semi-molten metal obtained in advance can be determined by experiment, for example, as shown in the graph of Fig. 2. .

In the above embodiment, the detection head was provided close to the surface of the semi-molten metal 2 in the crucible 1, but the present invention is not limited to such a case, and the detection head is not limited to such a case. It is also possible to provide the detection head outside the molten metal flow path.

[Effects of the Invention] As explained above, according to the present invention, the solid phase ratio of semi-molten metal that needs to be determined in the semi-molten processing process can be
It is possible to easily measure directly and without contact without sampling the molten metal. This method is extremely useful in semi-molten processing of steel and the like.

[Brief explanation of the drawing]

FIG. 1 is a sectional view for explaining one embodiment of the present invention,
FIG. 2 is a graph showing the relationship between eddy current and solid fraction. DESCRIPTION OF SYMBOLS 1... Crucible, 2... Semi-molten metal, 3... Detection head, 4... Oscillator, 5... Primary coil, 6...
Detector, 7...detection coil. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Solid phase ratio ('/,) Figure 2

Claims (1)

[Claims] A detection head equipped with a primary coil and a detection coil is disposed close to the semi-molten metal in a solid-liquid coexistence state, and an oscillation voltage is applied to the primary coil to generate an eddy current in the semi-molten metal, and the detection A method for measuring a solid fraction of a semi-molten metal, comprising determining the solid fraction of the semi-molten metal by detecting the eddy current with a coil.