JPH09103361A - Container for electromagnetic cooker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To firmly bond a container main body made of aluminum and a cladding material, and prevent a heating part from being peeled even when a heat cyclic load is received. SOLUTION: A cladding material 15 is bonded on the external surface of the bottom part of a container main body 10 made of aluminum or an aluminum alloy. The cladding material 15 comprises a first layer 11 made of aluminum or an aluminum alloy and a second layer 12 made of a ferrite-stainless steel, and has one or a plurality of through holes 13. Then, the first layer 11 is subjected to hot solid-phase welding to the container main body 10. The through hole is a slit-shaped or circular hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container for an electromagnetic cooker using a container body made of aluminum or an aluminum alloy (hereinafter, both are simply referred to as aluminum) and ferritic stainless steel as a heating element by electromagnetic induction, In particular, a container for an electromagnetic cooker in which a stainless steel heating element is joined to a container body by bringing a clad material of an aluminum first layer and a stainless steel second layer into hot contact by contacting the first layer with the aluminum container body. Regarding

[0002]

2. Description of the Related Art A pan for an electromagnetic cooker heats a cooking object by utilizing heat generated by the pan itself due to electromagnetic induction. For this reason, a ferromagnetic stainless steel is used as the heating element, aluminum is used as the pot body in which the food is stored, and the two are joined together.

FIG. 7 is a view showing a conventional pot for an electromagnetic cooker (Japanese Utility Model Application Laid-Open No. 61-23292), wherein FIG.
(B) is a bottom view. In the pot for an electromagnetic cooker, the pot body 1 is made of a non-ferromagnetic material such as aluminum or copper, and a recess 4 is provided on the bottom surface of the center of the pot bottom of the pot body 1. A heating element plate 2 made of an annular ferromagnetic material is pressed on the surface. This prior art,
The concave portion 4 is provided on the bottom surface of the pot body 1 in order to absorb the thermal distortion caused by the difference in the coefficient of thermal expansion between the pot body 1 and the heating element plate 2 pressed thereon. By providing the concave portion 4, thermal distortion is absorbed, and deterioration of the adhesion of the heating element plate 2 to the pot body is prevented. Further, in this conventional technique, the through hole 3 is provided in the heating element plate 2, and the material forming the pan main body 1 is press-fitted into the through hole 3 at the time of press contact, so that a mechanical joining effect is obtained.
In this prior art, SU pan is attached to an aluminum pan body.
The stainless steel plate of S430 is joined.

Further, an aluminum plate having good heat conductivity and a stainless steel plate provided with a perforation thereon are laminated on the outer bottom surface of the pot body made of stainless steel, and the inside of the perforation is filled with aluminum. A constructed pot for an electromagnetic cooker is disclosed (Japanese Patent Laid-Open Publication No. Hei 6-51).
No. 0468).

[0005]

[Problems to be solved by the invention]
In the prior art disclosed in Japanese Patent No. 1-223292, since a stainless steel plate is pressed against an aluminum pot main body, the through-hole 3 is provided to improve the adhesion, but the bonding strength between the two is low. Not enough.

[0006] In an actual use environment of a cooking pot, a heat cycle such as heating and cooling is applied. However, in this conventional technique, the joining strength is insufficient with respect to the thermal stress due to the thermal cycle load, and therefore peeling at the joining interface becomes a problem.

Also, in the prior art disclosed in Japanese Patent Application Laid-Open No. 6-510468, since two dissimilar metals of stainless steel, aluminum and stainless steel are provided, the bonding strength is low. It cannot be said that it has sufficient bonding strength as a container for electromagnetic cooking that receives the heat history of heating and cooling.

The present invention has been made in view of such a problem, and enables the aluminum container main body and the clad material to be firmly joined to each other, and the heating element to be peeled off even when subjected to a heat history. It is an object to provide a container for an electromagnetic cooker.

[0009]

A container for an electromagnetic cooker according to the present invention has a container body made of aluminum or an aluminum alloy and a clad material joined to the outer surface of the bottom of the container body. Alternatively, it is a clad material comprising a first layer made of an aluminum alloy and a second layer made of ferritic stainless steel, and having one or a plurality of through holes, the first layer being a hot solid phase on the container body. It is characterized by being joined. The through hole may have a slit shape or a circular hole.

[0010]

In the present invention, the aluminum container body is brought into contact with the aluminum first layer of the clad material on the outer surface of the bottom of the container body, and after positioning for centering, both are heated, or the container is heated. After heating the main body and the clad material, they are brought into contact with each other and then pressed against each other to perform hot solid-phase bonding between the aluminum container body and the clad material. As a result, the aluminum container body and the aluminum first layer of the clad material are metal-to-metal bonded, and both are firmly bonded.

In this case, in the present invention, during the hot joining, the aluminum of the clad material flows into the through-holes, the relative slippage at the joining interface is promoted, and the rolling reduction during the hot joining is increased. It is possible to increase the hot joining strength. Further, due to this relative slip, the oxide film on the material surface of both materials is broken and the new surface of the metal is exposed, so that metal bonding at the bonding interface is promoted. Therefore,
Bonding strength is further increased. The slip of the material at the time of hot joining occurs not only in the aluminum first layer of the clad material but also in the aluminum of the container body.
Bonding strength is further increased.

[0012]

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a method for manufacturing an electromagnetic cooker container according to an embodiment of the present invention.
As shown in FIG. 1A, an aluminum first layer 11 and a ferritic stainless steel second layer 1 are formed on the outer surface of the bottom of a container body 10 of an aluminum die cast container (pot, pot, etc.).
The clad material 15 composed of a laminated body with the aluminum alloy is laminated by bringing the aluminum first layer 11 into contact with the container body 10. A plurality of through holes 13 are formed in the clad material 15.

The clad material 15 and the container body 10 are heated and pressed against each other to bring the clad material 15 and the container body 10 into pressure contact with each other. Then, as shown in FIG. 1B, the aluminum first layer 11 of the clad material 15 flows and flows into the through holes 13. Also, at the time of this pressure contact, the container body 1
Aluminum of 0 also flows and rises in the through hole 13. As described above, since the aluminum material flows and escapes into the through hole 13 during press contact, when the pressing force (press contact force) is the same as in the case where there is no through hole, the reduction rate is increased and the thermal indirection is increased. The combined strength can be increased.

Further, since relative slippage of aluminum occurs, the oxide film on the surface of the material is ruptured and the new surface is exposed, so that the new surfaces are bonded at the bonding interface, metal bonding is promoted, and bonding strength is improved. .

In particular, in the through hole 13, the aluminum of the clad material 15 and the aluminum of the container body 10 flow and are joined to each other in the through hole, so that the joining interface of the fluidized portion 14 is a new surface. With high power,
Even in the through hole 13, the clad material 15 and the container body 10
Since a bonding interface is generated between the container and the container, the bonding force between the container body 10 and the clad material 15 is also improved.

If the through hole 13 is not present, sufficient bonding strength may not be obtained even by hot solid phase bonding. For this reason, peeling may occur between the clad material and the container body in the process of lowering the temperature of the pan product for an electromagnetic cooker after pressure welding. This is because the bonding strength cannot withstand the thermal stress generated due to the difference in thermal expansion between different materials to be bonded. In order to obtain the necessary rolling reduction in order to increase the bonding strength, an excessive pressing force is inevitably required, which causes not only an increase in pressing energy but also a decrease in die life.

In this embodiment, since the through hole is provided, the pressing force can be increased to increase the rolling reduction ratio.
A good bonded state can be obtained, and peeling at the bonded interface can be made difficult to occur. On the other hand, in this embodiment, if the joining force is the same as in the case where there is no through hole, the required pressing force can be reduced. As a result, the life of the mold can be extended and the pressing energy can be reduced.

The container body is made of an Al--Si type aluminum alloy (for example, die-cast alloy of JIS ADC1 and ADC12) and industrial pure aluminum (for example, JIS.
1100), an Al-Mn-based aluminum alloy (for example, J
It can be manufactured from aluminum or an aluminum alloy such as IS3003). Further, for the aluminum first layer of the clad material, industrial aluminum or Al-Mn-based aluminum alloy can be used.

Next, the results of evaluating the characteristics of a pan for an electromagnetic cooker manufactured by hot-solid bonding a clad plate to an aluminum die casting pan body will be described. This pan has a maximum practical temperature of about 200 ° C.

FIG. 2 is a diagram showing a pressure welding process between the container body and the clad plate. First, as shown in FIG. 2 (a), the aluminum die cast pan body 22 and the clad plate 21 are heated to a predetermined temperature, and then, on the bottom outer surface of the pan body 22,
The clad plate 21 is placed so that its aluminum side overlaps with the pan body 22.

Then, as shown in FIG. 2 (b), a laminated body of the pot main body 22 and the clad plate 21 is arranged between the press-contact lower mold 24 and the press-contact upper mold 23. The lower die 24 is provided with a pot body receiver 25 on the peripheral edge thereof.
Is supported by the lower mold 24 via a spring 26. The receiver 25 is a ring-shaped one having a projection for positioning the open end of the pan body 25.

In this way, by holding the pot body 22 in a state of floating from the lower mold 24 via the spring 26, the pot bottom joint does not come into direct contact with the mold during material installation, so the pot is It is possible to prevent the temperature of the main body 22 and the clad plate 21 from decreasing.

After that, as shown in FIG. 2C, the upper mold 23 is lowered toward the lower mold 24, and the clad plate 21 is pressed against the pot main body 22. As a result, as shown in FIG. 2D, the pan for the electromagnetic cooker in which the stainless steel of the clad plate is joined to the outer surface of the bottom of the pan is completed.

In this case, the pot main body 22 is pushed down by the upper die 23 by the lowering of the upper die 23 and descends together with the upper die 23, and then comes into contact with the lower die 24 and is pressed down. Therefore, even if the pot body 22 is slightly incompletely installed on the receiver 25 and the pot body 22 is inclined, the pot body 22 is fitted into the protrusion of the pot body receiver 25 by the contact of the upper mold 23. The posture is corrected, the lower die 24 is brought into contact with the lower die 24 in a correct posture with the center position, and then the lower die 24 is subjected to reduction. Therefore, the pan body 22 does not receive the reduction in an incomplete posture,
Deformation that is biased in one direction due to the eccentricity of center positioning is prevented.

In this forging pressure welding step, when the pot main body 22 and the clad plate 21 are individually heated as in the above-mentioned embodiment, and then the both are positioned and installed on the lower die 24. Not limited to this, for example, after heating individually, the pot main body may be set in the mold, and then the clad plate may be placed thereon, or both may be positioned and simultaneously heated and then set in the mold. Alternatively, both may be positioned and placed on the lower mold 23, and then the pot body 22 and the clad plate 21 may be heated.

Tables 1 and 2 below show the bonding conditions and the bonding strengths obtained in Examples and Comparative Examples of the present invention. The container body is ADC1 die cast material, the pressure contact area has a diameter of 200 mm, the plate thickness is 4 mm, the stainless steel second layer of the clad material has a thickness of 0.6 mm, and the aluminum first layer has a thickness of Is 1.7 mm. In the comparative example, a clad material having no through holes was used for hot joining. Other conditions are the same as in the embodiment. The pressure welding conditions are a material temperature of 450 ° C., a mold temperature of 180 ° C., and a pressing speed of 300 mm / sec. As a pretreatment of the bonding interface, ultrasonic cleaning was performed with an organic solvent. Methylene chloride was used as the organic solvent.

[0027]

[Table 1]

[0028]

[Table 2]

FIG. 3 shows a planar shape of the clad plate 21 of the embodiment. As shown in FIG. 3, the through hole of the embodiment has a central hole 28 having a diameter of 18 mm and diameters of 106 mm and 15 mm.
The holes 27 are 6 mm in width and 4 mm in width and are concentric with a quarter circumference of a slit.

FIG. 4 shows the test piece 2 in the obtained joint member.
9 shows the sampling positions. In addition, FIG. 5 shows the collected test piece 29.
It is a figure which shows the test piece for joining strength measurement processed from. This joint strength measurement test piece is used for the bottom part 3 of the aluminum pan body.
0, aluminum first layer 31 and stainless steel second layer 3
A clad material consisting of 2 is joined and has a length of 5
The clad material on one side is cut off, and the bottom of the container body on the other side is cut off, centering on the mm portion. Therefore,
When the tensile test is performed by gripping both ends of this test piece, it is 5 mm.
The joint strength in the length portion of is measured as a tensile test value.

In Tables 1 and 2, the reduction ratio is represented by the reduction ratio of aluminum on the clad material side. However, the reduction rate is {(amount of change in Al thickness) / (Al thickness before reduction)} × 100. Further, the rolling reduction and the bonding strength are average values of four samples.

As is clear from the measurement results of the bonding strengths shown in Tables 1 and 2, in the examples of the present invention, a large reduction rate can be obtained and a large reduction can be obtained, as compared with the comparative examples having no through holes. Bonding strength can be obtained.

FIGS. 6A and 6B show modified examples of the shape of the through hole. As shown in this figure, the through hole may have any shape as long as aluminum can flow and escape, and various shapes are possible.

The cross-sectional shape of the through hole may be such that the side edge of the through hole is vertical to the surface or may be inclined.

[0035]

As described above, according to the present invention,
Since the clad material having the through holes is hot solid-phase bonded to the aluminum container body, both can be firmly metal-bonded at a high pressure. Further, since the aluminum flows easily, the newly-formed surfaces of the metals can be hot-joined, so that the joining strength can be further increased.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a pressure welding method of the present embodiment.

FIG. 3 is a schematic view showing a shape of a through hole according to an example.

FIG. 4 is a diagram showing a sampling position of a test piece.

FIG. 5 is a view showing a shape of a bonding strength measurement test piece.

FIG. 6 is a diagram showing a modification of the shape of the through hole.

FIG. 7 is a schematic view showing a conventional pan for an electromagnetic cooker.

[Explanation of symbols]

 1: Pan main body 2: Heating element 3: Through hole 4: Recessed portion 10: Container body 11: Aluminum first layer 12: Stainless steel second layer 13: Through hole 14: Flowing portion 15: Clad material 21: Clad plate 22: Pan body 23, 24: Pressure welding mold

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kanji Yokoe 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Incorporated company Kobe Steel, Ltd. Tokyo headquarters (72) Inventor Shojiro 15 Kinugaoka, Moka City, Tochigi Prefecture Kamito Steel Works Moka Works (72) Inventor Takeo Sakurai 15 Kinugaoka, Moka City, Tochigi Prefecture Kamido Steel Works Moka Works (72) Inventor Hiroshi Iwamura 14-1 Nagafu, Shimonoseki City, Yamaguchi Prefecture Kobe Steel Co., Ltd. Chofu Works

Claims (2)

[Claims] 1. A container body made of aluminum or an aluminum alloy, and a clad material joined to the outer surface of the bottom of the container body, the clad material comprising a first layer made of aluminum or an aluminum alloy and ferritic stainless steel. A container for an electromagnetic cooker, which is a clad material with the second layer and has one or a plurality of through holes, and the first layer is hot solid-phase bonded to the container body. 2. The container for an electromagnetic cooker according to claim 1, wherein the through hole has a slit shape or a circular hole.