JPS59198343A - Method for measuring bonding strength of multi-layered material having carvature - Google Patents

Abstract

PURPOSE:To make it possible to obtain an accurate measured value, by using an auxiliary tool having a carvature corresponding to that of a multi-layered material to be measured and a piercing hole capable of passing a cast structure provided to the central part thereof. CONSTITUTION:Solder (Sn 70%, Pb 30%) melted under heating at 350 deg.C is cast into a preheated casting mold from an upper large opening to attach a casting mold structure 11. A piercing hole 50 has an inner diameter larger than the diameter of the casting mold structure 11 so as to be capable of freely passing said structure 11. As mentioned above, by using auxiliary tools 40-43 each having a carvature corresponding to that of a multi-layered material to be measured and the piercing hole 50 capable of passing the casting mold structure provided to the central part thereof, tensile load can be uniformly applied and, therefore, an accurate measured value can be obtained as compared with a case using no auxiliary tools.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the adhesive strength of a multilayer material consisting of at least two layers and having curvature, such as a half-cylindrical bearing, and in particular, a method for measuring the adhesive strength of a multilayer material having at least two layers and having a curvature, such as a half-cylindrical bearing. Cu, Ni
, Zn plating layer, Cu r on bearing with overlay
The present invention relates to a method for measuring the adhesive strength of strike plating such as Ni r Zn, or layers such as aluminum alloy and Kelmet alloy.

In the technology of measuring the adhesive strength of conventional plain bearings,
Measurement methods provided for this purpose include:
There are knife tests, heat treatment blistering tests, bending tests, etc.

Such conventional technology has the following drawbacks.

1) Adhesive strength cannot be measured quantitatively.

2) In order to measure adhesive strength, a special so-called dummy test piece must be prepared as a test piece, separate from the actual product.

There was a drawback.

Patent application No. 57-6370, which is the earlier application by the inventor of the present invention
No. 2 was developed to eliminate such drawbacks in the prior art, and provides a method for routinely measuring the adhesive strength of multilayer materials accurately and quickly using extremely simple steps.

When using the method of this prior invention, a test piece can be obtained directly from an actual product, and there is no need to prepare a special test piece, and the adhesive strength of the product itself can be measured.

In developing the above-mentioned invention, we mainly focused on flat multilayer materials, placed a special mold on one surface of the multilayer material, and conducted a tensile test to check the adhesive strength of the multilayer material. A dummy test is carried out by casting a cast structure that will be one gripping part for measurement by integrally casting it with the surface of the multilayer material, and performing a tensile test using the multilayer material or a holder of the material as the other gripping part. We have completed a method and material that can accurately measure the contact strength of a multilayer material as a test material without using pieces.

For thin multilayer materials and semi-cylindrical multi-layer materials with curvature, it is necessary to correct the actual measured values using a correction curve created in advance through experiments. Since measurement errors are large for materials with curvature such as shaped multilayer materials, and sometimes for thin multilayer materials, it has become necessary to improve the measurement method so that such errors can be reduced to a minimum. In order to meet this requirement, measurement accuracy is basically improved by using the method of the prior invention, and in addition, by using various convex lens-shaped auxiliary tools that correspond to the curvature and thickness of the inner concave surface of the multilayer material. We have also developed a reliable measurement method.

The present invention improves the prior invention and provides a measuring method and an auxiliary tool that can minimize the difference between the actual adhesive strength and the measured strength of multilayer materials with curvature. From this point of view, the invention is an improvement on the earlier invention. As already mentioned, the invention of this application basically has many parts in common with the invention of the earlier application, so those common parts will be explained below by quoting the explanation in the specification of the invention of the earlier application with some modifications. .

To summarize the parts of the present invention that are common to the prior invention, a mold is placed on one surface of the multilayer material to be tested, a brazing material is poured into the mold, A cast structure consisting of a first pillar part that stands up almost perpendicular to the surface, a sloped part that gradually increases in diameter from the top end of the pillar part, and a second pillar part that rises from the top end of the sloped part. a step of attaching a body to one surface of the multi-layered material; and a step of attaching the second pillar portion of the cast structure to a three-sided gripping portion, and attaching the multilayer material or a member such as a holder to the material This is a method for measuring the adhesive strength of a multilayer material, which comprises the steps of applying a tensile force in the vertical direction to each layer of the multilayer material by gripping it with the chatter of a tensile tester as the other gripping part. The above-mentioned brazing filler metal is Pb-Sn combined brazing filler metal (
solder), soft solder such as Zn-Sn alloy solder (solder), silver solder (for example, Ag-Cu alloy with addition of P, Cd, Zn, etc., melting point is approximately 700°C). Hard solders such as gold solders and brass solders, Pb-8n-Bi-based low melting point solders,
Pb-Cd, Pb-Ag.

It includes arbitrary materials such as Cd-Zn wax. In short, the optimum brazing material may be selected and used depending on the adhesive strength (adhesive force) of each layer of the object to be measured.

The method of the prior invention will be described below with reference to the drawings.

FIG. 1 shows a partial view of the flat multilayer material to be measured. This test piece 9 has a steel back metal (low carbon steel) layer 5
, for example, Pb 28.0-32.0%, snl, 0% or less, N1 or Ag 2. '0% or less, Fe008% or less, impurities 1.0% or less, balance Cu or pb2
Copper-lead alloy layer 6 consisting of 3.0 to 27.0%, Sn 1.0% or less, N1 or Ag 2.0% or less, FeO 8% or less, impurities 1.0 or less, balance Cu, N1 plating layer 7,
For example, Sn 8.0-14.0%, balance PB, or S
n 8.0-14.0%, C'u 2.0-3.5%
This is a plain bearing consisting of 804 lead alloy surface layers, the remainder being Pb.

The surface of the lead alloy surface layer 8 of this test piece 9 is subjected to degreasing, preheating, 91'F polishing, and flux coating with a mixture of borax, sodium carbonate, sodium chloride, etc. for the purpose of removing oxides, if necessary. After that, place it. This mold 10
is composed of a half mold 14.15 and a holder 13, and when the half mold 14.15 is assembled into the holder 13 and fixed with a tightening screw 16, an upper opening of a large diameter and a lower opening of a small diameter are formed. The @ type is constructed.

A cross-sectional view of the mold 10 placed on the surface of the lead alloy surface layer 80 is shown in FIG. Preferably, the mold 10 is preheated before placement. The preheated mold 10 is filled with 650°C K tin hot melted solder (Sn
70%, Pb 30%) is cast, and the cast structure 11 is installed. The state with the mold 10 removed is shown in FIG. As shown in FIG. 4, the structure 11 has a first cylindrical portion P that is connected to the surface layer 8 and stands up almost vertically.
1, an inclined portion R that gradually expands in diameter and rises from the upper end of the cylindrical portion Pl, and a second cylindrical portion P2 that rises from the upper end of the slanted portion B.0 Here, the first cylindrical portion The diameter of the portion Pl was 8rnm, the diameter of the second cylindrical portion P2 was 2Q am%, and the length Ll of the first cylindrical portion P1 was 6m1n, but this dimension can be determined arbitrarily taking into account the size of the test piece, etc. It is not necessary to specifically limit it. After attaching the structure 11 to the surface) fi 8, the second cylindrical portion P2 is used as one gripping part, and the test piece 9 is used as the other gripping part, and the chuck of the tensile tester is used to bite it, and each Adhesive strength is measured by applying a tensile force in the vertical direction to -. If the overall wall thickness of the test piece 9 shown in FIG. A holder 18 such as that shown in perspective view in FIG. 6 can be used. The holder 18 includes a grip portion 17, a frame member 4 having an opening 19, and a hole 20 provided in the frame member 4. When the structure 11 is passed through the opening 19 and the hole 20, the test piece 9 is caught on the opening 19 side of the hole 20, and a tensile force is applied between the cylindrical part P2 of the structure 11 and the grip part 17 using a tensile tester. can be granted. Referring to FIG. 5, the relationship between the length Ll of the first cylindrical portion P1 and the tensile strength (g/:IIN) of the first cylindrical portion P is illustrated. FIG. 5 shows the measured values when using a metal alloy of 70% Sn and 60% Pb, and the strength of the pillar portion P becomes weaker as Ll becomes larger. If the adhesive strength of the test piece 9 is a dog, the length of Ll must be made small or the cylindrical portion P1 will be destroyed, making measurement impossible. The length of Ll is selected in consideration of the thickness of the adhesive strength of the test piece 9 and the strength of the brazing filler metal.

Referring to FIG. 9, an explanatory diagram is shown in which a tensile test is conducted using a thick dog specimen 9 as the other gripping portion. The first-,! of structure 11! 7) The diameter of the cylinder part is 8 am, and the lead alloy surface layer 8 has a thickness of 1 = 5' O
Assuming that it is an overlay of tt, in Fig. 9, the adhesive force measurement area - πX (-)" = 50.2"4 a
m” shear area = 2π(-) Xo, 050 = 1.2
56 to 2, the shear area is approximately 1 of the adhesive force measurement area.
/40, which is extremely small, so there is no need to provide the notch 30, which will be explained later with reference to Figure g11.

If a tensile test is performed in the condition shown in FIG. 9, lft8.
It will break at the weaker point of 7.6.

FIG. 10 is an explanatory diagram when the holder 18 is applied to a specimen 9 with a small wall thickness. As explained in FIG. 9, it is possible to measure the adhesive force without providing a notch 30, which will be described later.

FIG. 11 is an explanatory diagram for measuring the adhesive force between layers 8' and 7' in a test piece in which layer 8' has a thickness of 0.1 ttat or more. In FIG. 11, the structure 11
Cutouts 30 must be formed in layers 8' and 7' along the circumference of the first column portion of. The notch 30 is formed by making a cut with a knife, for example. By providing such a cutout 30, layers 8' and 7
′ can be accurately measured.

The adhesive strength of the multilayer material is measured by measuring the tensile strength using the method described above.

Referring to FIG. 7, a steel backing layer 21, a copper-lead alloy layer 22,
A curved test piece 25 consisting of four layers, a Ni plating layer 23 and a lead alloy surface layer 24, is shown with a structure 11 attached thereto in the same process as described above. Of course, the present invention can be applied to a test piece having such a curvature. The small diameter opening edge of the mold 10 is
If it is not adapted to the surface of the lead alloy surface layer 240, the brazing material may flow out from the lower end in the event of a bend, so appropriate measures must be taken.

Referring to FIG. 8, the change in measured tensile strength F (/cg/ηIIIE) is shown for the same multilayer material as shown in FIG. 1 when the material wall thickness W (mm) is varied. ing. a indicates the lower limit of the measured value, and b indicates the upper limit. According to FIG. 8, it can be seen that if the thickness of the test piece is approximately 4 mm or more, stable adhesive strength close to true bond strength can be measured. However, if the test piece is thin, it may be corrected by multiplying by the factor obtained from FIG.

In the above explanation, the adhesive strength of the material of 4 No.
Although it has been described that the adhesion between the plating layer and the bearing alloy layer or the plating layer and the surface layer is measured, the present invention is not limited to such cases.

For example, when manufacturing a five-layer plain bearing consisting of a metal backing layer, an adhesive layer, a bearing alloy layer, a plating layer, and a surface layer, a test piece that is in the middle of manufacturing is taken and the bond between the steel backing layer and the N1, Cu, etc. It can also be applied to measure the adhesive strength between layers.

Examples of measurements carried out by the method of the prior invention are as follows.

(1) In the test piece with the structure shown in Figure 1, the adhesive strength between the copper-lead alloy layer and the Ni plating layer was approximately 4.0 to 5.4#!
/It was the second time. This is a value obtained by first measuring the tensile load of 200 mm when the copper-lead alloy layer and the N1 plating layer peel off, and dividing this value by the area of the bonded portion. In addition,
The thickness of this test piece was 6.9 to 8.2 mm.

(2) When measuring a test piece with the structure shown in Fig. 7 using the same material as shown in Fig. 1, the above (
Almost the same value as the measured value of 1) was obtained.

(3) In the test piece with the structure shown in Figure 7, copper-lead-8
``The test piece was the same as the test piece in (2) except that the gold layer was replaced with an A1 alloy layer having the composition shown in the table below, and the thickness of the test piece was 4.8 to 6.Q mrn. , the adhesive strength between the A1 alloy layer and the Ni plating layer is approximately 1.5 to 5.4 #/de 2
was measured.

Table 1 (Content %) (4) In the test piece having the structure shown in Fig. 7, the - copper-lead alloy layer was replaced with the A1 alloy layer, and the Ni plating layer was replaced with a Cu plating layer. The thickness of the test piece is 6.
The adhesive strength between the A1 alloy layer and the Cu plating layer was (3).
The value was almost the same as that of

(5) In the test piece having the structure shown in Fig. 7, the copper-lead alloy layer was replaced with the A1 alloy layer, the Ni plating layer was replaced with the Ti plating layer, and the thickness of the test piece was 6.5 mm.
The test piece was the same as the test piece (2) except for the fact that the adhesive strength between the Ti plating layer and the A1 alloy layer was almost the same as the value of (3).

Next, the present invention will be explained with reference to FIGS. 12 to 29.

As shown in Figure 7, by multiplying and correcting the test piece of a thin multilayer material with a curvature by the factor obtained from Figure 8, it is possible to measure with an accuracy that can be used in practice, but even more accurate measurement is possible. In order to obtain accurate measurements, it is necessary to use an auxiliary tool for measuring the adhesive strength of thin multilayer materials having a different curvature, without relying on such correction factors. For this purpose, as shown in Figs. 12 to 17, auxiliary tools with different curvatures, such as 40, 41, 42, 43, etc., can be selected and used according to the curvature of the multilayer material to be tested. good.

This curvature needs to be equal to or slightly smaller than the inner diameter of the test piece. This is to prevent stress from concentrating on both ends of the test piece in the circumferential direction when performing a tensile test.

FIG. 12 is a plan view of the auxiliary tool 40, and FIG. 16 is a plan view of the auxiliary tool 40.
14 is a longitudinal cross-sectional plan view taken along the line A-A in the figure, and FIG. 14 is the same (a cross-sectional side view taken along the line B-B).

FIG. 18 is an explanatory diagram when the holder 18 is applied to a thin test piece 26 with a thickness of 4 mm or less via the auxiliary tool of the present invention.

12 to 18 show a first embodiment of the present invention, and reference numeral 50 indicates a through hole with an inner diameter larger than the diameter of the cast structure 11, and the cast structure 11 is It is free to pass through. The auxiliary tool 40 has a curvature corresponding to the curvature of the multilayer material to be measured, and has a through hole 50 in the center through which the cast structure can pass.
-43, it is possible to apply a tensile load evenly to the entire arcuate curved surface of the multi-no material test piece 26 when measuring the contact strength using a tensile test, compared to when no auxiliary tool is used. Measurements closer to the actual adhesive strength can be obtained. Table 2 shows an example of actual measured values when the curvature aid 40 shown in FIG. 16 is used and when it is not used.

Figure 19 shows the change in the measured value due to the use of an auxiliary tool when the upper and lower limits of the tensile adhesive strength of a multilayer material were similarly measured. While the variation due to thickness is shown in the a curve, the lower limit value when using an auxiliary tool moves to a higher value as shown in the a1 curve, and similarly the upper limit value also moves upward from the 6 curve to the b work curve. This brings the adhesive strength even closer to the actual adhesive strength.

Table 2 □ In other words, if an auxiliary tool with a curvature corresponding to the curvature of the test piece is not used as in the past, especially if the wall thickness is 4 squares or less, the test piece will bend during tensile strength measurement. This causes the measured value to be lower than the actual bond strength due to the influence of stress acting on the edges.

In this way, by using the auxiliary tools 40 to 43 of the embodiments shown in FIGS. 12 to 18, the measurement accuracy is improved compared to the case where no auxiliary tools are used, and a certain practical effect can be obtained. However, if a measurement value that is extremely close to the actual adhesive strength is required, there is still room to improve the accuracy, but in the case of the auxiliary tool shown as the first example, the This will result in measurement errors such as:

In the embodiment shown in FIGS. 12 to 18, the auxiliary tools 40 to 43 having the through holes 50 are all made of one piece, and as seen in FIG. An eye gap exists between the outer peripheral surface of the first cylindrical portion P of 26 and the inner peripheral surface of the through hole 50 of the auxiliary tool 40. Because of this void, more specifically, a concentrated load is applied to the contact retaining surface between the lower edge of the inner circumferential surface of the through hole 5o and the bent portion of the test piece 26, causing an error in the measured value. It turns out.

A pair of half-split molds 4 shown in Figs.
The auxiliary tool 44 consisting of 4a and 44b is shown in the second figure which is a bottom view.
0 and 24 which are top views.

Depending on the curvature and thickness of the multilayer material, the aids 45, 46, 47 shown in FIGS. 25 to 27 are used.

The respective plan views, bottom views, and vertical side views of the auxiliary tools 45, 46, and 47 are omitted.

FIG. 20 shows the pair of half-split type auxiliary tools 44a.

44b is a bottom view of a set of auxiliary tools 44, in which symbol 4B is a through hole whose diameter is equal to or slightly larger than the diameter of the first cylindrical portion p1 in the cast structure 11.

21 is an exploded plan view of the half-split auxiliary tool 44 shown in FIG. 20, FIG. 22 is a vertical cross-sectional plan view taken along line A--AB in FIG. 20, and FIG. 24 is a bottom view of FIG. 20. 25, 26, and 27 correspond to the curvature of the auxiliary tool 440 and the length Ll of the first cylindrical portion P1 in FIG. 22, corresponding to the curvature and thickness of the multilayer material to be measured. The parts show auxiliary tools 45, 46, 47 of different dimensions. However, the plan view, vertical side view, and bottom view as shown in FIGS. 20, 26, and 24 are omitted.

Symbol 49 is a seam that occurs when the half-split auxiliary tools 44a and 44b are combined.

Symbol R indicates a tapered concave side surface portion that fits into the circumferential surface of a truncated conical inclined portion that rises from the base end of the first cylindrical portion Pl of the cast structure 11 so that its diameter gradually increases. .

Figure 28 shows a thin multilayer material test piece 26 with a thickness of 4 or less.
18 is an explanatory diagram showing a state in which Hole JX'''18 is attached using an auxiliary tool 44. As in the case where the auxiliary tool 40 shown in FIG. 18 is used, the through hole 50 and the columnar part of the cast structure are There is no noticeable gap between the two, and the first
Since the cylindrical part P and the auxiliary tool 44 are in almost contact engagement, the tensile load is applied evenly to the entire curved (arc) surface of the test piece 26 when measuring the adhesive strength by tension. As shown in Table 6, values closer to the true adhesive strength were obtained.

That is, as can be seen from the graph of FIG.
When compared with the measured value when there is a certain degree of gap, such as between I was able to get the value. That is, by using the auxiliary tool 44, the measured value moves from the lower limit curve a1 of the measured value when using the auxiliary tool 40 to the curve a2, and similarly the upper limit curve b1 moves to the curve I)2. , becomes a higher value,
It was possible to obtain measurements closer to the true adhesive strength.

From Table 6, it can be seen that the smaller the wall thickness of the test piece, the larger the width of the measured value that could be corrected upward by using the auxiliary tool according to the second embodiment. When it comes to Qim, the difference is 0.
1m/1111112, which is the auxiliary tool 4 of the first embodiment.
Even if it is 0, there will be no practical problem.

The present invention has the configuration described above and has the following advantages.

1) Test specimens such as multilayer bearing materials can be cut out from the base material and tested, whether they are semi-finished products during the manufacturing process or finished products. Thus, the adhesion between desired layers can be measured, or the adhesion between the weakest layers of a multilayer material can be measured. Since test pieces can be arbitrarily obtained from actual products, true and accurate adhesive strength can be quantitatively measured. If a dummy test piece had to be specially prepared separately, it would be doubtful whether the adhesive strength of the actual product would be the same, but this is not the case in the present invention.

2) The shape of the test piece is a wall thickness of 4 with a curved bearing surface.
Since a multilayer material as thin as ours can be used, the time required to prepare a test piece and measure it can be dramatically shortened.

6) Since brazing filler metals such as soldering powder can be remelted and reused many times, there is little economic loss. In addition, since test pieces can be easily obtained, testing costs are low.

[Brief explanation of the drawing]

FIGS. 1 to 11 show prior inventions by the inventor of the present application. Figure 1 is a partial cross-sectional view of a plain bearing test piece made of multilayer material, Figure 2 is a perspective view of a reservoir mold into which the brazing filler metal is cast and its parts, and Figure 6 is a mold for the test piece in Figure 1. Fig. 4 is a sectional view showing the state in which the mold is removed from the state in Fig. 6, and Fig. 5 is the first column of the cast structure. Diagram showing the relationship between the length of the part and the tensile strength,
Figure 6 is a perspective view of the holder that serves as one gripping part for the test piece;
FIG. 7 is a cross-sectional view showing a cast structure attached to a flat bearing test piece with curvature; FIG. 8 is a diagram showing the relationship between the thickness of the multilayer material and the value of contact strength obtained by measurement; 9th
The figure is an explanatory diagram of a tensile test without using a holder when the specimen is within the thickness. Figure 10 is an explanatory diagram of a tensile test using a holder when the specimen is thin. Figure 11 is an explanatory diagram of a tensile test using a holder when the specimen is thin. FIG. 7 is an explanatory diagram showing a method for accurately measuring the adhesive force between the bottom layer and the layer immediately below it in the case of . FIG. 12 to FIG. 29 are drawings showing embodiments of the present invention. 12 is a plan view of the auxiliary tool 40, FIG. 13 is a longitudinal sectional front view along A-AK in FIG. 12, and FIG.
The sectional views taken along B-BMl in the figure, from Figure 15 to Figure 17, are different auxiliary tools from the auxiliary tool shown in Figure 16, which are applied to multi-nod materials with thick walls and small radius of curvature. 41.42.
43, FIG. 18 is a longitudinal side view when an auxiliary tool is applied to the measurement of a test piece with a wall thickness of 41 mm or less and a curvature, and FIG. The upper and lower limit values will shift upward due to the difference in wall thickness when used! Graph showing gI7, FIG. 20 is a top view of the auxiliary tool of the second embodiment of the present invention, FIG. 21 is a top view of the half-split type auxiliary tool shown in FIG. The figure is a cross-sectional front view taken along line A-A in Figure 20, Figure 26 is the same cross-sectional side view taken along line B-B, and Figure 24 is a lower elevation of the half-split type assistive device in Figure 20. 25 to 27 show an auxiliary tool of a different size than the auxiliary tool shown in FIGS. The figure is a cross-sectional side view showing the state in which the auxiliary tools shown in Figs. 20 to 26 are applied to the contact strength measurement of a test piece with a wall thickness of 4 or less and a curvature of M. , the actual measured values when using the aids shown in Figures 20 to 26 are shown in Figure 1.
12 is a graph showing a state in which the measured value moves upward and is corrected compared to when the auxiliary tool of Example 1 is used and when it is not used. The correspondence between numbers or symbols in the drawings and constituent members or parts of the present invention is shown below. 10: Mold, 11: @Remains, 18: Holder, 26:
Test piece of multilayer material, 40-43: Auxiliary tool of the first laugh ■ example,
44: Auxiliary tools of the second embodiment, 44a and 44b = a pair of half-split auxiliary tools constituting the auxiliary tool 44, 45-47: Auxiliary tools different in size from the auxiliary tool 44, 48 two through holes, 5
0: through hole, Pl: first cylindrical part, P2: second cylindrical part, R taper part of the through hole of the two-handed auxiliary tool. Agent crosspiece material Fig. 3 - 242 - Fig. 26 Fig. 8 W (mm) - Fig. 18 Fig. 19 W (mm) -

Claims (1)

[Claims] (1) A mold is placed on one surface in the radial direction of a test piece of a multilayer material having curvature, and a brazing filler metal is cast into the mold. A cast structure consisting of a first cylindrical part that stands up almost vertically, an inclined part that gradually increases in diameter and rises from the base end of the cylindrical part, and a second cylindrical part that rises from the base end of the inclined part. , integrally casting onto the one surface of the multilayer material; and having a through hole through which the cast structure can pass, and a radially outer surface having the same curvature as the radially inner surface of the test piece. placing an auxiliary tool having an auxiliary tool on the inner surface of the test piece through the through hole of the cast structure; is accommodated in a tensile test holder and the second cylindrical portion is protruded outward from one side of the holder; is used as the other gripping part to apply a tensile force to the multilayer material in the vertical direction, and by the auxiliary tool interposed in engagement engagement between the inner curved surface of the test piece and the inner surface of the holder. A method for measuring adhesive strength of a multilayer material having curvature, comprising the step of measuring tensile strength by reducing deformation of the test piece due to tensile stress. (2. In the method set forth in claim 1: the auxiliary tool is formed by incorporating a pair of split auxiliary members that are symmetrical about the axis and are detachable, and the first part of the cast structure is It consists of a first circular hole that is sufficient to allow the cylindrical part to pass through, and a 20th inner hole part that has the same taper as the tapered circumferential surface part of the cast structure and can come into close contact with the tapered part of the cast structure. , a curvature characterized by being interposed between the test piece and the holder in close contact with the outer periphery of the cast structure after the cast structure is cast onto the test piece. A method for measuring the adhesive strength of multilayer materials.