Method for producing test piece and mold for test piece

Abstract

To provide a manufacturing method of a test piece capable of accurately analyzing its component by using a glow discharge mass system of a flat cell system.SOLUTION: A mold 1 for a test piece in which an analyzed part space 2 for forming an analyzed part 51, a feeder head part space 3 for forming a feeder head part 53, and a small diameter part space 4 for forming a small diameter part 52 are formed is used. The thickness of the analyzed portion space 2 is 5mm, the inside diameter of the riser portion space 3 is 30mm, and the inside diameter and thickness of the small diameter portion space 4 are 15mm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a test piece and a mold for the test piece, and more particularly to a method for manufacturing a test piece used in flat cell glow discharge mass spectrometry, and a mold for the test piece used to manufacture such a test piece. [Background technology]

[0002] When producing an ingot made of aluminum or an aluminum alloy, first, an aluminum raw material having a predetermined purity is melted so as not to be contaminated by other metal elements. Next, the composition of the molten metal is adjusted by adding specified metals, and the molten metal is then subjected to a slag removal process to remove foreign matter such as non-metallic inclusions and a degassing process to remove hydrogen gas.The molten metal is then passed through a filter to remove foreign matter before being poured into a casting machine. The molten metal poured into the casting machine is cooled in the casting machine and solidified into a cylindrical or rectangular prism shape to obtain an ingot.

[0003] In order to confirm the composition of ingots made of aluminum or aluminum alloy, samples of the molten metal are collected and analyzed at any point along the path from the melting furnace to the casting machine during continuous casting.

[0004] Specifically, a test piece (sample) is made from the collected molten metal, and the sample is subjected to analysis using glow discharge mass spectrometry (GDMS). The obtained analysis results are then used as the representative analysis values ​​for the cast ingot.

[0005] Glow discharge mass spectrometry includes the "pin cell method," in which glow discharge mass spectrometry is performed on a pin-shaped test piece, and the "flat cell method," in which glow discharge mass spectrometry is performed on a flat, plate-shaped test piece (for example, Patent Document 1).

[0006] The test piece (sample) used in the "flat cell type" glow discharge mass spectrometry has been formed in a cylindrical shape (see, for example, paragraph

[0015] of Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 7-122606 [Patent Document 2] Japanese Patent Application Publication No. 2017-220360 Summary of the Invention [Problem to be solved by the invention]

[0008] Here, in the case of high-purity aluminum, the amount of solute elements contained is so small that accurate analysis is required to quantify them, but accurate analysis could not always be performed with conventional test pieces (samples).

[0009] The present invention has been devised in view of the above points, and aims to provide a method for manufacturing a test piece whose components can be accurately analyzed using flat cell glow discharge mass spectrometry, and a test piece mold for manufacturing such a test piece. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the method for manufacturing a test piece of the present invention is a method for manufacturing a test piece having a flat analysis target portion and a riser portion connected to the analysis target portion via a small diameter portion, and comprises a casting step of pouring a predetermined molten aluminum into a test piece mold made of a material with a thermal conductivity of 200 W / (m·K) or more and 400 W / (m·K) and casting the test piece, the test piece mold comprising: an analysis target portion space, which is a space for forming the analysis target portion and has a thickness of 4 mm or more and 8 mm or less; a riser portion space, which is a space for forming the riser portion and has a thickness of 5 mm or more; and a small diameter portion space, which is a space for forming the small diameter portion and communicates with the analysis target portion space and the riser portion space, and has a diameter that is 35% or more and 55% or less of the diameter of the analysis target portion space and a thickness that is 10 mm or more and 20 mm or less.

[0011] Here, in the test piece manufacturing method of the present invention, the thickness of the analysis space provided in the test piece mold used is "4 mm or more and 8 mm or less", thereby minimizing the influence of segregation of solute elements and enabling accurate analysis. In other words, rapid solidification is effective in reducing segregation when solidifying the molten metal, and a thinner thickness of the analysis area is preferable. Therefore, in the test piece manufacturing method of the present invention, the thickness of the analysis area space provided in the test piece mold is set to "8 mm or less," thereby suppressing the effects of segregation of solute elements.

[0012] In addition, the surface of the part to be analyzed (the side opposite to the surface connected to the small diameter part of the part to be analyzed) is the starting point of solidification, and the molten metal that first comes into contact with the test piece mold is rapidly cooled, resulting in the molten metal being significantly supercooled. When the supercooling is released and solidification begins, the kinetic energy of the molten metal flow and the interfacial energy with the surface of the test specimen mold are utilized, so the solidification state varies each time a test specimen is manufactured, depending on the surface condition of the test specimen mold and the way the molten metal is poured.In addition, the solidification state is affected by the temperatures of the molten metal and the test specimen mold, so there are many variable factors. That is, since the surface portion of the analyzed portion is the starting point of solidification, the solidification is unstable and segregation is likely to occur. Therefore, it must be removed before glow discharge mass spectrometry, and the thickness must be set taking this into account. For this reason, in the test piece manufacturing method of the present invention, the thickness of the analysis space provided in the test piece mold is set to "4 mm or more," thereby ensuring a thickness that allows removal of surface areas where solidification is unstable.

[0013] Furthermore, in the test piece manufacturing method of the present invention, the thickness of the riser space provided in the test piece mold used is "5 mm or more", so that shrinkage cavities that occur as the solidification of the molten aluminum poured into the test piece mold progresses do not reach the portion to be analyzed.

[0014] On the other hand, if the thickness of the riser space is "less than 5 mm," there is a high possibility that shrinkage cavities will reach the analyzed part, and the analyzed part may not be formed normally. Furthermore, if the thickness of the riser space is extremely large (too thick), the molten metal will be poured at a high speed, which may cause turbulence and draw in air, resulting in molding defects. Therefore, it is necessary to keep the thickness to a level that will not cause molding defects.

[0015] Furthermore, in the test piece manufacturing method of the present invention, the diameter of the small diameter space provided in the test piece mold used is "35% to 55%" of the diameter of the analysis portion space, thereby reducing the heat capacity of the "molten aluminum cast and solidified in the test piece mold" and preventing molding defects due to poor molten metal flow.

[0016] On the other hand, if the diameter of the small diameter space is "less than 35%" of the diameter of the analyzed space, the diameter of the small diameter space is too small, the flow of the molten metal is poor, and the molten metal solidifies on its way to the analyzed space, making normal molding difficult. Furthermore, if the diameter of the small diameter space is "more than 55%" of the diameter of the analysis space, the diameter of the small diameter space is too large, and the heat capacity of the "molten aluminum cast and solidified in the test piece mold" becomes too large, making rapid solidification difficult and resulting in insufficient reduction of segregation.

[0017] Furthermore, in the manufacturing method of the test piece of the present invention, the thickness of the small diameter space provided in the test piece mold used is "10 mm or more and 20 mm or less", so that normal molding can be achieved.

[0018] If the thickness of the small diameter space is "less than 10 mm," the molten metal poured into the test piece mold will reach the analysis space without being decelerated in the small diameter space (it will be poured into the analysis space), which may cause turbulence and draw in air, resulting in molding defects. Furthermore, if the thickness of the small diameter space is "more than 20 mm," the molten metal poured into the test piece mold may solidify in the small diameter space before filling the analysis space, which may result in poor molding due to poor molten metal flow.

[0019] Furthermore, in the test specimen manufacturing method of the present invention, the test specimen mold used is made of a material with a thermal conductivity of 200 W / (m K) or more and 400 W / (m K) or less, thereby minimizing the effects of segregation of solute elements and enabling accurate analysis.

[0020] If the thermal conductivity of the test piece mold is less than 200 W / (m·K), the solidification rate of the molten metal will decrease, making rapid solidification difficult and resulting in segregation. Furthermore, if the thermal conductivity of the test piece mold exceeds 400 W / (m·K), the molten metal will solidify on its way to the space to be analyzed, making normal molding difficult.

[0021] In the test piece manufacturing method of the present invention, it is preferable to pour molten aluminum having a heat capacity of 1 / 35 or less of the material of the test piece mold used.

[0022] In this case, the test piece mold has a heat capacity 35 times or more that of the molten aluminum, which allows the molten aluminum to be rapidly cooled and solidified.

[0023] In the method for producing a test piece of the present invention, it is preferable to pour molten aluminum at a temperature of 800° C. or less, which allows the molten aluminum to be rapidly cooled and solidified.

[0024] On the other hand, if molten aluminum above 800°C is poured, the temperature of the molten aluminum will be too high, causing the test piece mold to overheat, slowing down the cooling rate and making it difficult to rapidly solidify the molten aluminum.

[0025] Furthermore, in the test piece manufacturing method of the present invention, if a removal step is provided in which the analysis portion of the test piece obtained in the casting step is removed by 2 mm or more and 3 mm or less, it is possible to remove the surface portion of the analysis portion, which has unstable solidification, and it becomes possible to perform an accurate analysis.

[0026] Here, if "less than 2 mm is removed," the surface area where coagulation is unstable may not be sufficiently removed, and accurate analysis may not be possible. Furthermore, in order to "remove more than 3 mm," the thickness of the analyzed part before removal must necessarily be made larger than necessary, which increases the heat capacity of the "molten aluminum cast into the test piece mold," making rapid solidification difficult.

[0027] The method for removing the analyzed portion may be any method, such as cutting, grinding, or polishing, as long as it can remove the surface of the analyzed portion.

[0028] In the method for producing a test piece of the present invention, the purity of the aluminum may be 99.99 wt % or more.

[0029] Even when using a high-purity aluminum molten metal with a purity of 99.99 wt% or more, the test piece manufacturing method of the present invention can provide a test piece in which the effects of segregation of solute elements are suppressed, thereby enabling accurate analysis.

[0030] Furthermore, in order to achieve the above-mentioned object, the test piece mold of the present invention is a test piece mold used to manufacture test pieces having a flat analysis target portion and a feeder portion connected to the analysis target portion via a small diameter portion, the test piece mold comprising: an analysis target portion space, which is a space for forming the analysis target portion and has a thickness of 4 mm to 8 mm; a feeder portion space, which is a space for forming the feeder portion and has a thickness of 5 mm or more; and a small diameter portion space, which is a space for forming the small diameter portion and communicates with the analysis target portion space and the feeder portion space, and has a diameter that is 35% to 55% of the diameter of the analysis target portion space and a thickness of 10 mm to 20 mm; and the test piece mold is made of a material with a thermal conductivity of 200 W / (m·K) to 400 W / (m·K).

[0031] Here, the thickness of the analysis space provided in the test piece mold of the present invention is "4 mm or more and 8 mm or less," which minimizes the influence of segregation of solute elements and enables accurate analysis, as explained in the test piece manufacturing method of the present invention.

[0032] Furthermore, in the test piece mold of the present invention, the thickness of the riser space provided therein is "5 mm or more," and therefore, as explained in the test piece manufacturing method of the present invention, shrinkage cavities that occur as the solidification of the molten aluminum poured into the test piece mold progresses do not reach the portion to be analyzed.

[0033] Furthermore, in the test piece mold of the present invention, the diameter of the small diameter space provided therein is "35% to 55%" of the diameter of the analysis portion space, which reduces the heat capacity of the "molten aluminum cast and solidified in the test piece mold" and prevents molding defects due to poor molten metal flow, as explained in the test piece manufacturing method of the present invention.

[0034] Furthermore, in the test piece mold of the present invention, the thickness of the small diameter space provided therein is "10 mm or more and 20 mm or less," so that normal molding can be achieved, as explained in the manufacturing method of the test piece of the present invention.

[0035] Furthermore, the test specimen mold of the present invention is made of a material with a thermal conductivity of 200 W / (m K) or more and 400 W / (m K) or less, which minimizes the effects of segregation of solute elements and enables accurate analysis, as explained in the test specimen manufacturing method of the present invention. [Effects of the Invention]

[0036] The test piece manufacturing method and test piece mold of the present invention can provide a test piece whose components can be accurately analyzed using flat-type glow discharge mass spectrometry. [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a test piece mold to which the present invention is applied. [Figure 2] FIG. 2 is a schematic diagram illustrating a semi-finished product obtained using a test piece mold. [Figure 3] 1A to 1C are schematic diagrams for explaining a method for manufacturing a test piece. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, a mode for carrying out the invention (hereinafter referred to as "embodiment") will be described.

[0039] [Configuration of test specimen mold] FIG. 1 is a schematic diagram illustrating an example of a test piece mold to which the present invention is applied. The test piece mold 1 (1A, 1B) shown here is used by placing it on a bottom plate (not shown) and is composed of two parts (first mold 1A and second mold 1B) that are divided into two halves left and right from the center.

[0040] The test piece mold 1 is a mold for producing a semi-finished product 5 as shown in FIG. 2 (since FIG. 2 is a simple schematic view, shrinkage cavities are not shown). The semi-finished product 5 shown here has a flat analysis section 51 (thickness 5 mm, indicated by symbol b in Figure 2) that is circular in plan view (outer diameter 30 mm, indicated by symbol a in Figure 2), and a riser section 52 that is cylindrical (outer diameter 30 mm, indicated by symbol c in Figure 2, height 25 mm, indicated by symbol d in Figure 2).

[0041] In addition, the semi-finished product 5 has a small diameter section 53 between the analyzed section 51 and the riser section 52, which has a cylindrical shape with a smaller diameter than both (the analyzed section 51 and the riser section 52) (outer diameter indicated by symbol e in Figure 2 is 15 mm, and height indicated by symbol f in Figure 2 is 15 mm).

[0042] By removing 2.5 mm of the surface (lower surface in FIG. 2) of the analyzed portion 51 from the semi-finished product 5, a test piece (a test piece for "flat cell type" glow discharge mass spectrometry) can be obtained.

[0043] The test piece mold 1 is provided with an analysis space 2, a feeder space 3, and a small diameter space 4. Molten aluminum is poured into these spaces (the analysis space 2, the feeder space 3, and the small diameter space 4) and solidified to obtain a semi-finished product 5 as shown in Figure 2.

[0044] Here, the analysis area space 2 is a space for forming the analysis area 51, and is a flat space (thickness indicated by symbol B in Figure 1 is 5 mm) that is circular in plan view (inner diameter indicated by symbol A in Figure 1 is 30 mm). The riser space 3 is a space for forming the riser 52, and is a cylindrical space (with an inner diameter of 30 mm indicated by reference symbol C in FIG. 1 and a thickness of 25 mm indicated by reference symbol D in FIG. 1).

[0045] Furthermore, the small diameter section space 4 is a space for forming the small diameter section 53, and is a cylindrical space (inner diameter indicated by symbol E in Figure 1 is 15 mm, thickness indicated by symbol F in Figure 1 is 15 mm), and is connected to the analysis section space 2 and the riser section space 3. The inner diameter (15 mm) of the small diameter space 4 is 50% of the inner diameter (30 mm) of the analysis portion space.

[0046] The test piece mold 1 shown here is made of aluminum, and the thermal conductivity of the test piece mold 1 (aluminum) (at 300 K) is 273 W / (m / K). Furthermore, the test piece mold 1 made of aluminum has a heat capacity 35 times or more as compared with the heat capacity of the semi-finished product 5 obtained by the test piece manufacturing method described below.

[0047] [Test piece manufacturing method] A method for producing a test piece using the above-described test piece mold 1 will be described below. That is, an example of a method for producing a test piece to which the present invention is applied will be described.

[0048] To manufacture the test specimens, first, aluminum raw materials (aluminum bullion, scrap aluminum alloy products, etc.) are melted in a melting furnace, and predetermined metals are added to the molten metal to adjust the composition (see symbol S1 in Figure 3). The purity of aluminum in this embodiment is 99.99 wt % or more.

[0049] Next, the molten metal is subjected to a slag removal process to remove foreign matter such as non-metallic inclusions, and a degassing process to remove hydrogen gas, and then passed through a filter to remove foreign matter.

[0050] Next, a portion of the molten metal that has passed through the filter is sampled midway through the path that is being passed through the trough (molten metal flow path) into the casting machine (see symbol S2 in Figure 3), and the sampled molten metal is poured into the test piece mold 1 (see symbol S3 in Figure 3). The temperature of the collected molten metal was 780°C.

[0051] Specifically, the first mold 1A and the second mold 1B are placed in a closed state on a bottom plate (not shown), and molten aluminum is poured from above (from the riser space 3 side).

[0052] The molten metal poured into the test piece mold 1 (first mold 1A, second mold 1B) flows from the riser space 3 through the small diameter space 4 to the analysis space 2, where it is rapidly cooled and solidified by contact with the test piece mold 1 and the bottom plate (not shown) (see symbol S4 in Figure 3). The step indicated by the reference numeral S3 and the step indicated by the reference numeral S4 correspond to the "casting step" of the present invention.

[0053] Next, the test piece mold 1 is divided into left and right halves, and the cast and hardened material is removed to obtain a semi-finished product 5. After that, 2.5 mm of the surface of the semi-finished product 5 (the lower surface in Figure 2) is removed by cutting to obtain a test piece (see symbol S5 in Figure 3). The step indicated by the reference symbol S5 corresponds to the "removal step" of the present invention.

[0054] [effect] In the above-described method for manufacturing a test piece to which the present invention is applied, the thickness of the analysis space 2 is as thin as 5 mm, the thickness of the riser space 3 is not excessively large at 25 mm, the diameter and thickness of the small-diameter space 4 are appropriate, and furthermore, the thermal conductivity (at 300 K) of the test piece mold 1 (aluminum) is 273 W / (m / K), and the temperature of the molten metal taken in is 780°C. Therefore, the molten metal poured into the test piece mold can be rapidly cooled and solidified, and a semi-finished product 5 can be obtained in which segregation of solute elements is minimized.

[0055] Furthermore, the test piece obtained by removing the surface of such semi-finished product 5 has very little segregation of solute elements, and even if the aluminum is of high purity, such as 99.99 wt% or more, it can be subjected to accurate glow discharge mass spectrometry using the "flat cell method." [Explanation of symbols]

[0056] 1. Mold 1A First mold 1B Second mold 2 Analyzed part space 3. Riser space 4 Small diameter space 5 Semi-finished products 51 Analyzed part 52 riser section 53 Small diameter section

Claims

1. 1. A method for producing a test piece having a flat analysis target portion and a riser portion connected to the analysis target portion via a small diameter portion, comprising: an analysis region space for forming the analysis region, the thickness of which is 4 mm or more and 8 mm or less; a riser space for forming the riser, the riser space having a thickness of 5 mm or more; a small diameter section space is formed, the small diameter section space being a space for forming the small diameter section, the small diameter section space communicating with the analysis section space and the riser section space, the small diameter section space having a diameter of 35% to 55% of the diameter of the analysis section space and a thickness of 10 mm to 20 mm; The casting process involves pouring a specified molten aluminum into a test piece mold made of a material with a thermal conductivity of 200 W / (m.K) or more and 400 W / (m.K) or less. Test specimen manufacturing method.

2. The casting step involves pouring molten aluminum having a heat capacity of 1 / 35 or less of the material. A method for manufacturing the test piece according to claim 1.

3. The casting step involves pouring the molten aluminum at a temperature of 800°C or less. A method for manufacturing the test piece according to claim 1.

4. a removing step of removing the analyzed portion of the test piece obtained in the casting step by 2 mm to 3 mm. A method for manufacturing the test piece according to claim 1.

5. The purity of the aluminum is 99.99 wt% or more. A method for manufacturing the test piece according to claim 1.

6. A test piece mold used to manufacture a test piece having a flat analysis target portion and a riser portion connected to the analysis target portion via a small diameter portion, an analysis region space for forming the analysis region, the thickness of which is 4 mm or more and 8 mm or less; a riser space for forming the riser, the riser space having a thickness of 5 mm or more; a small diameter section space is formed, the small diameter section space being a space for forming the small diameter section, the small diameter section space communicating with the analysis section space and the riser section space, the small diameter section space having a diameter of 35% to 55% of the diameter of the analysis section space and a thickness of 10 mm to 20 mm; Made of a material with a thermal conductivity of 200W / (m・K) or more and 400W / (m・K) or less Mold for test specimens.

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