KR100616106B1 - Sampling Cup for thermally analyzing casting liguid metal - Google Patents

Abstract

The present invention relates to a sampling cup for thermal analysis of a molten casting. The sample cup for thermal analysis of the cast molten metal of the present invention is the outer shape is a square shaped cup of the quadrangular pyramid barrel of the light beam upper side, the inner shape is a shape of the quadrangular pyramid barrel of the light beam lower side, each corner is an arc having the same radius Shape. The optimum size of the sample cup of the present invention is 45 mm (mm) ± 3 mm (mm) in height, and the length (L) of one side of the base is 56 mm (mm) ± 3 mm (mm), the length of the upper one side (L ') is 52 mm (mm) ± 3 mm (mm), the optimum internal size is 35 mm (mm) ± 3 mm (mm), the length of one side of the base (l) is 35 mm (mm) ± 3 mm (mm), and the length of the upper one side (l ') is 37 mm (mm) ± 3 mm (mm). Each corner is an arc shape with a radius r of 3 mm (mm) ± 2 mm (mm).

Compared with the conventional sample cup, the sample cup for thermal analysis of the molten casting according to the present invention includes a temperature (TL) at which the molten metal starts to solidify, a start of eutectic freezing, a temperature at which solidification is completed (TS), and the like. Accurate measurement can be performed, and accordingly, accurate analysis and evaluation of sample molten metal can be performed more accurately than conventional sample cups, which not only drastically reduces the defective rate of the cast product, but also improves the yield and greatly reduces the manufacturing cost. There is.

Casting, Smelting, Thermal Analysis, Sample Cup, Cylindrical, Square

Description

Sampling Cup for thermally analyzing casting liguid metal

1A is a cross-sectional view of a conventional cylindrical sample cup.

1B is a plan view of a conventional cylindrical sample cup.

Figure 2a is a cross-sectional view of a four-cornered pyramid shaped sample cup according to the present invention.

Figure 2b is a plan view of a quadrangular pyramid-shaped sample cup according to the present invention

* Description of the symbols for the main parts of the drawings *

1; conventional sample cup. 10; Sample Cup of the Invention

H; Appearance height. h; inner height

L; Length of one side of the bottom surface. l; length of one side of the inner base

L ': Length of the upper upper side l': Length of the inner upper side

30; heat sensitive means 32; temperature sensor

40; sample cup holder part

The present invention relates to a sampling cup for thermal analysis of a molten casting. More specifically, the casting is composed of a container containing a sample molten metal for thermal analysis, a holder of the container, the heat sensitive means built into the container, and a cable connecting the heat sensitive means and the thermal analysis and evaluation device. It relates to the container (or cup) in which the said sample is contained among the sampling apparatuses of the thermal analyzer of molten metal. The sample cup for thermal analysis of the molten cast of the present invention is characterized by having a quadrangular shaped cup.

In general, thermal analysis of a molten metal is to monitor the temperature change of the molten metal over time during the solidification of the molten metal to determine the microstructure and properties of the metal to be cast. It collects the sample from the molten metal (melt) and places it in the sample container (or cup), and records and evaluates the temperature change while the sample is solidified by thermosensitive means well known in the art, such as thermocouples. Technology. Conventionally, as a sample container used for such a technique, when molten casting is aluminum, it is normally manufactured with graphite, and when molten casting is cast iron, it is usually manufactured and used with a ceramic material. The shape and structure are usually cylindrical. For example, it has a structure and shape similar to that of a Dewar container having a cylindrical shape or a double structure as shown in FIGS. 1A and 1B.

The purpose of thermal analysis of cast material is to reduce casting defects, increase yields, and reduce casting costs. Recent factors influencing defects in cast iron and cast products, the overall effect of compounds of chemical components in addition to the content of each element, the rate and amount of graphite precipitation in the melt, the nucleation pattern of the melt ), The amount of shrinkage and micro porosity generated when the molten metal is solidified into the casting, and the prediction of hardness and strength during the solidification of the molten metal have been discussed. In order to be able to analyze or evaluate these many items precisely or accurately, a high degree of software has to be developed, extensive data must be integrated, and the temperature can be accurately detected and thermally contacted with the appropriate melt sample. This is only possible if an optimal sample cup (container) is available to perform the analysis. However, the conventional sample container has a problem that it is insufficient to accurately detect the temperature change according to the solidification time of the molten metal. This is because the conventional sample container is cylindrical and lacks representativeness of the sensing temperature, and its structure and size are also insufficient for representative temperature sensing.

The present invention is to solve the problems of the prior art as described above is to provide a sample cup for thermal analysis of the molten cast can be more precise and accurate thermal analysis.

The present invention is to provide a sample cup for thermal analysis of the molten cast casting can greatly reduce the defective rate of the cast product.

The above object of the present invention can be achieved by configuring a conventional cylindrical sample cup in a quadrangular pyramid shape.

The sample cup for thermal analysis of the molten casting of the present invention is characterized by having a quadrangular pyramid shape. The sample cup for thermal analysis of the molten casting according to the present invention is composed of an optimal structure, shape and size capable of precise thermal analysis. That is, the outer shape is the shape of the quadrangular pyramid barrel of the lower beam upper side, the inner shape is the shape of the quadrangular pyramid barrel of the upper beam lower strait, the outer shape and the inner shape are the inverse quadrangular pyramid barrel shape, and each corner is the arc shape of the same radius. It is a structure of a container (cup) having a bottom surface.

The heat sensitive means is provided inside the sample cup of the shape and structure as described above. The heat sensitive means is a conventionally used heat sensitive means such as a thermocouple or a thermocouple, which is connected to a thermal analysis evaluation device (not shown) by a cup holder and a cable.

The heat sensitive means is installed in the center of the bottom surface of the cup. The temperature sensor portion of the heat sensitive means is configured to be located in the middle of the bottom surface and the inlet inside the cup.

The heat sensitive means is mounted on the floor and fixed to the thermal analysis evaluation device by a cable, and the temperature measurement signal sensed by the temperature sensor unit is transmitted to the thermal analysis evaluation device through the cable.

Referring to the structure and the optimum size of the quadrangular pyramid-shaped cup according to the present invention as follows.

The optimum size of the external shape of the sample cup 10 is 45 mm (mm) ± 3 mm (mm) in height, and the length (L) of one side of the base is 56 mm (mm) ± 3 mm (mm), and the length (L ') of the upper one side is 52 mm (mm) ± 3 mm (mm).

The optimum internal size is 35mm (mm) ± 3mm (mm), the length of one side of the bottom (l ') is 35mm (mm) ± 3mm (mm), The length (l ') of the upper one side is 37 mm (mm) ± 3 mm (mm). Each corner has an arc shape with a radius r of 3 mm (mm) ± 2 mm (mm).

Reference numeral 30 denotes a heat sensitive means placed inside the sample cup 10, and reference numeral 40 denotes a sample cup holder part integrally formed with the sample cup 10 on the outer bottom surface of the sample cup.

The temperature sensor part 32 of the heat sensing means 30 is located at a height of 17.5 mm (mm) ± 2 mm (mm) from the bottom surface which is the middle of the inner height of the cup.

If it is out of the above structure and size, the representativeness of the sensing temperature is insufficient and the accuracy or accuracy of the thermal analysis is inferior.

The molding material of the sample cup according to the present invention is made of the same molding material as the conventional sample cup. For example, it is conventionally cast as a known casting sand coated with a binder such as a phenol resin, or a casting sand prepared by uniformly mixing a silica sand with a binder such as a phenol resin. Foundry sand is widely used in the field. The casting sand or silica sand is preferably in the range of 80 to 100 mesh particle size.

The sample cup according to the present invention is manufactured by the same method as the conventional method for forming a sample cup. For example, the thermocouple may be manufactured by first inserting a thermocouple into a mold and injecting a molding sand coated with a binder into the mold.

The sample cup for thermal analysis of the molten casting according to the present invention is generally used for thermal analysis of the molten casting in two sets (2 cups / set), but only a single cup (1 cup) may be used in some cases. When used for thermal analysis of a molten cast iron in two sets, one of the two cups consists of a cup with a metal tellurium coated on its inner surface, as in a conventional tellurium coated cup. When only a single cup (1 cup) is used, the metal tellurium may be coated or may be uncoated.

The sample cup for thermal analysis of the four-cornered barrel shaped casting molten metal according to the present invention can be applied irrespective of the type of the thermal analyzer or the type of the molten metal such as cast iron or nonferrous metal. The sample cup for thermal analysis of the molten cast of the present invention is a metallurgical process control system of gray cast iron and ductile cast iron of NovaCast AB of Sweden (ATAS) It is a sample cup designed especially for the thermal analysis system of the molten metal called an adaptive thermal analysis system. The thermal analysis system of the molten casting, called ATS, requires much more accurate thermal analysis data than in the prior art, and thus, is configured in a suitable shape and structure.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Sample Cup Production Example]

10 kilograms (kg) of silica sand having a particle size distribution of 80 to 100 mesh and 0.25 kilograms (kg) of phenol resin as a binder are uniformly mixed in a mixer to form a foundry sand, and then a known thermocouple is pre-inserted into a molding machine. Next, the casting sand was injected and molded to prepare 68 sample cups having a weight of 0.147 to 0.15 kg (kg).

The prepared sample cups had an outer wall height of 45 mm (mm), a bottom surface of 56 mm 56 mm (mm), a length of one side of the upper opening was 52 mm (mm), and an inner size of 35 mm Arc-shaped quadrangular pyramid with a diameter of 3 mm (mm), a bottom of 35 mm 35 mm, a top opening of 37 mm 37 mm (mm), and each corner having a radius of 3 mm (mm) It was a barrel shape.

EXAMPLE

The molten metal for casting (C: 3.65%, Si: 2.27, Mn: 0.026%, P: max0.024%, S: 0.015%, Mg: 0.038%, Fe: to 100) were charged and subjected to thermal analysis. The thermal analysis device is an Adaptive Thermal Analysis System (ATAS) from NovaCast AB, Sweden. A system for heavy nodular cast iron was used. The cooling curve and the first negative curve of the melt output from the apparatus are shown in graphs 1 to 4 below and the analysis results are summarized in Table 1.

[Graph 1: Cooling Curve of Example]

[Graph 2: Cooling Curve of Comparative Example]

[Graph 3: First Urethral Curve of Example]

Graph 4: First Urethral Curve of Comparative Example

Item Example Comparative example TL 1151.4 1143.2 TES 1151.4 1143.2 TS 1101.2 1077.0 TEL 1151.4 1143.2 TEH 1151.4 1144.9 Recaescence 3.0 1.7 GRF 1 54 65 GRF 2 35 99 GRF 3 36 65 S 1 One One S 2 48 23 S 3 51 75

  Note) 1.TL is the temperature at which the molten metal starts to solidify.

2.TES is the start of eutectic freezing

3.TS is the temperature at which solidification is completed

4.TEL (TElow) is the temperature at which the molten metal starts to solidify and becomes the very lowest point for the first time.

5.TEH (TEhigh) is a point where graphite is precipitated due to the change of crystal structure as the molten metal solidifies, and the temperature rises due to latent heat caused by the precipitation, and reaches the maximum point.

6.R (Recalescence) is the temperature difference between TEL and TEH.

7.GRF 1 is the time taken to drop 15 degrees Celsius from the TEH point, and the total length of the curve involved.

8.GRF 2 is the first derivative angle at TS.

9.S1 is the area under the curve from TL to TEL or the percentage of the sum of S1 + S2 + S3.

10.S2 is the area under the curve from TEL to TEH or the percentage of the sum of S1 + S2 + S3.

11.S3 is the area under the curve from TEH to TS or the percentage of the sum of S1 + S2 + S3.

12. The S1 + S2 + S3 is 100%.

It can be seen from the thermal analysis result that the sample cup according to the present invention can obtain accurate temperature measurement results compared to the conventional sample cup. That is, the same sample melt was used, but the temperature (TL), start of eutectic freezing, TEL, and TEH at which the melt began to coagulate were lower in the sample cup according to the present invention than the measurement result of the conventional sample cup. It is understood that the thermal analysis by the sample cup of the present invention is much more accurate from the high measurement result and the gentle slope of the curve after TS.

In addition, it can be seen from GRF1, GRF2, GRF3, S1, S2, and S3 that the spheroidization rate is high, the spheroidal graphite number is high, the base structure is dense, the internal shrinkage is small, and the internal inverse chill amount is small.

Compared with the conventional sample cup, the sample cup for thermal analysis of the molten casting according to the present invention includes a temperature (TL) at which the molten metal starts to solidify, a start of eutectic freezing, a temperature at which solidification is completed (TS), and the like. Accurate measurement can be performed, and accordingly, accurate analysis and evaluation of sample molten metal can be performed more accurately than conventional sample cups, which not only drastically reduces the defective rate of the cast product, but also improves the yield and greatly reduces the manufacturing cost. There is.

Claims (4)

delete (correction) In the sample cup for thermal analysis of the molten cast molten metal having a thermocouple as the heat sensitive means 30, the sample cup 10 is formed of casting sand, the outer shape is 4 It is the shape of the pyramid barrel, the inner shape is the shape of the quadrangular pyramid barrel of the Sangsang lower strait, and each corner forms the arc shape of the same radius, the structure of the cup which has a bottom surface, and the outer height (H) is 45 mm ( mm) ± 3 mm (mm), the length of one side of the base (L) is 56 mm (mm) ± 3 mm (mm), the length (L ') of one side of the upper opening is 52 mm ( mm) ± 3mm (mm), the internal height (h) is 35mm (mm) ± 3mm (mm), and the length (l) of one side of the bottom surface is 35mm (mm) ± 3 mm (mm), the length of one side of the upper opening (l ') is 37 mm (mm) ± 3 mm (mm), each corner has a radius (r) of 3 mm (mm) ± 2 Mm Sample cups for the thermal analysis of the cast molten metal, characterized in that an arc shape. delete (correction) The method of claim 2, wherein the sample cup 10 is a combination (2 cups / set) of a cup with a metal tellurium coated and a non-coated cup, or a cup without a metal tellurium coated therein alone Sample cup for thermal analysis of the molten casting, characterized in that used as.

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