FR2739998A1 - Cooking vessel for use with electromagnetic induction heating system - Google Patents

Abstract

The container for use on an electromagnetic induction cooking plate comprises a main container body (10) with a layer of aluminium or aluminium alloy (12) attached to the surface. A sheet of stainless steel (13) is then attached to the outside of the aluminium creating a sandwich of material layers. At least one of the layers making up this structure has holes formed in it, reducing the area, the rate of reduction being between 10 and 50%. This improves the strength of attachment of the layers of the structure. In order to prevent the layers separating when heated, channels may be formed in one of the surfaces in order to correspond to projecting ribs formed in the adjoining surface.

Description

 The present invention relates to an electromagnetic cookware container and method of manufacturing the same, which uses a main body of aluminum or aluminum alloy container (hereinafter referred to as both aluminum) and a Ferrite series stainless steel as a body material generating electromagnetic induction heat, in particular an electromagnetic cooktop container and a method of manufacturing same in which a heat generating body made of stainless steel is attached to a main container body by using a plating material consisting of a first layer of aluminum and a second layer of stainless steel, wherein the first layer is brought into contact with the main body of the aluminum container and the assembly is subjected to solid phase thermal fixation.

 An electromagnetic hob pan heats a cooking material using the heat creation of the pan itself by electromagnetic induction. For this purpose, a ferromagnetic stainless steel is used as the material of constitution of the body generating heat, aluminum as the main body of the pan incorporating the cooking material and the pan is constituted by joining the two by fixation.

 Figs. 1A and 1B are views showing a typical electromagnetic cookware container, of which Fig. 1A is a sectional view and Fig. 1B is a bottom figure. A container main body 21 is normally made of a non-ferromagnetic material such as aluminum, copper, etc. and a recessed portion 23 is formed on the outer surface of the bottom portion. A heat generating body plate 22 having a ring-like shape made of a ferromagnetic material such as a stainless steel plate made of SUS 430, etc. is welded under pressure to the periphery of the recessed portion 23. A plurality of perforations 22a are formed in the heat-generating body plate 22 to assist in achieving fixation between the recessed portion 23 and the generating body plate of the heat 22. This is to further mechanically strengthen the attachment between the outer face of the bottom portion of the container main body 21 and the heat generating body plate 22 by pressing the bottom portion of the container main body 21 having significant ductility within the respective perforations 22a by securing together the recessed portion 23 and the heat generating body plate 22. In addition, the deterioration of adhesion between the main container body 21 and the Heat generating body plate 22 driven by a thermal gap is prevented by providing a difference similar to a step 23 a at the periphery of the recessed portion 23 and a step-shaped gap 23b at the edge portion of the outer face of the bottom portion of the container main body 21 (see Japanese utility model publication) unexamined number 23292/1986).

 By actually using the electromagnetic hob container constituted as above, the container is first installed on an electromagnetic hob top plate and an electromagnetic hob power supply switch is turned on. The electromagnetic cooktop is provided with an electromagnetic coil located below the top plate and current flows through the coil and a magnetic field is generated by turning on the power supply switch. Then, magnetic flux driven by the magnetic field induces an eddy current in the heat generating body plate 22 installed at the bottom portion of the main body of the container 21. When the eddy currents flow into the As a heat generating body plate 22, heat is generated by the Joule effect and the heat generating body plate 22 generates heat so that the object contained in the container main body 21 can be heated.

 However, a load having a heat cycle due to heating and cooling normally acts on the container when the above-mentioned baking container is actually used.

According to the usual pressurized welding process, the resistance of the fastener against the thermal stresses entrained by the load having a heat cycle is deficient and the heat generating body plate 22 can be exfoliated from the main container body 21 at the mounting interface. In addition, in the case of attaching the heat generating body plate 22 to the container main body 21 by solid phase thermal fixation, the heat generating body plate 22 may be exfoliated in the process of drop the temperature of a manufactured container. In either of these cases, the exfoliation is entrained at the attachment interface between the container main body 21 and the heat generating body plate 22 since the thermal stresses are generated by the difference in thermal expansion between the different fixed materials, and the resistance of the fastener can not withstand the thermal stresses.

 Also, according to the usual technology described in Unexamined Japanese Utility Model Publication No. 23292/1986, although a strengthening of the adhesion is obtained by providing the perforations 3 etc., since a steel plate stainless steel is pressure-welded to the aluminum pan main body, the strength of the fastener between the two elements is not sufficient, and in accordance with the usual technology, the perforations are arranged at the body generating heat , made of stainless steel, and, therefore, the heat creation performance is lowered since the current due to electromagnetic induction does not circulate at these parts.

 On the other hand, as another usual pan for electromagnetic cooktop, an electromagnetic cooktop pan has been described as being constituted by laminating an aluminum plate having excellent thermal conductivity on the outer face of the bottom. of a stainless steel pan main body, further laminating a stainless steel plate having perforations and filling the aluminum perforations (International Patent Publication No. 510468/1994).

 However, even with the usual technology described in International Patent Publication No. 510468/1994, there are two fixed faces made of different materials namely stainless steel and aluminum and aluminum and aluminum. therefore, the strength of the fastener is low and sufficient fastening strength is not ensured when an electromagnetic cooktop container is subjected to a thermal history of heating and cooling.

 It is an object of the present invention to provide an electromagnetic cooktop container and a method of manufacturing it capable of promoting the strength of the fastener between a container main body and a heat generating body plate. and capable of preventing the heat generating body plate from being exfoliated from the container main body at the attachment interface due to the repeated receipt of heat.

 An electromagnetic cooktop container according to the present invention is provided with an aluminum or aluminum alloy container main body and a cladding plate which is formed by plating aluminum or aluminum alloy. and ferrite series stainless steel and which is fixed on the outer face of a bottom portion of the main container body, by solid phase thermal fixation. In addition, the reduction rate of at least one of the bottom portion of the main container body and the aluminum or aluminum alloy material of the coating plate is between 10 and 50% by setting the coating plate on the outer face of the bottom portion of the main container body by solid phase thermal fixation.

 It is preferable that a protruding portion is arranged on the outer face of the bottom portion of the container body and that a through hole or recessed portion on which the protruding portion is arranged, is arranged at the coating plate and that the cover plate is positioned with respect to the outer face of the bottom portion of the main container body by arranging the projecting portion in the through hole or the recessed portion and after this the entire is subjected to solid phase thermal fixation. In addition, it is preferable that a recessed portion is arranged at the outer face of the bottom portion of the main container body and that a projecting portion in the recessed portion is arranged at the the cladding plate and the cladding plate is positioned relative to the outer face of the bottom portion of the main container body by arranging the projecting portion in the recessed portion and that the assembly is subjected to thermal fixation in solid phase.

 It is also preferable that one or more grooves or projections are formed at the outer face of the bottom portion of the main container body. When the grooves are formed, it is preferable that grooves other than the grooves mentioned above extend in the radial direction on the outer face of the bottom portion of the main container body.

 Incidentally, the rate of reduction is defined as the rate of change in thickness of a plate obtained by comparison with the thickness of the original plate before and after contacting the press.

 In accordance with the method of manufacturing an electromagnetic cooktop container according to the present invention, the aluminum or aluminum alloy of a cladding plate in which the aluminum or aluminum alloy and a steel ferrite series stainless steel are plated together, is brought into contact with the outer face of a bottom portion of a main body of aluminum or aluminum alloy container and a solid phase thermal fixation is performed with a rate of reducing at least one of the bottom portion of the main container body and the aluminum or aluminum alloy of the coating, which is 10 to 50%.

 According to the present invention, the cover plate is fixed on the outer face of the bottom portion of the main container body with a predetermined reduction ratio by solid phase thermal fixation and, accordingly, an excellent electromagnetic cooktop container. having a high fixation strength can be manufactured without causing exfoliation at the attachment interface. Moreover, by providing the protruding portion and the recessed portion, etc., on the other side respectively of the bottom portion of the container main body and the cover plate, the positioning accuracy when fixing the plate coating on the outer face of the bottom portion of the main container body can be promoted and the time of the positioning operation can be shortened.

 In addition, by forming a plurality of grooves or projections on the outer face of the bottom portion of the container main body, the relative sliding area at the fixed interface of the container main body and the cover plate is enlarged by so that the strength of the attachment can be further increased. In addition, in the case where the grooves are each formed in a ring-like shape consisting of a concentric circle, forming grooves in the direction of a radius extending radially from the center of the outer face of the groove. bottom portion of the container body, the fixed portion without exfoliation can be provided by allowing gases remaining at the fixed portion to escape therefrom.

 On the other hand, another electromagnetic hotplate container according to the present invention is provided with a main body of aluminum or aluminum alloy container and having grooves or projections on the outer face of the bottom portion and a coating plate which is formed by plating a first layer of aluminum or aluminum alloy and a second layer of ferrite series stainless steel and which is fixed on the outer face of the bottom portion of the main container body by fixing the first layer on the outer face of the bottom portion of the main container body, by solid phase thermal fixation.

 According to another electromagnetic cooking plate container according to the present invention, instead of arranging grooves or projections on the outer face of the bottom portion of the main container body, grooves or projections are arranged on the first layer of the coating plate and the coating plate is fixed on the outer face of the bottom portion of the main container body by fixing the first layer on the outer face of the bottom portion of the main container body by solid phase thermal fixation.

 It is preferred that the grooves or projections have a shape extending to form one or more circular arcs of concentric circles, or extend to form straight lines intersecting each other to form a shape similar to a lattice or have a form of points.

 According to the present invention, a mechanical fastening is provided in addition to the metallic creep fastening of the aluminum so that the strength of the fastening can be promoted since the grooves or projections are arranged on the outer face of the bottom portion. of the main container body. In addition, in the present invention, perforations or the like are not arranged at the second layer, of stainless steel, which constitutes the heat generating body and therefore the function of the heat generating container. is not damaged.

The present invention will now be described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1A is a sectional view showing a conventional electromagnetic cooking plate container and FIG. 1B is a top view thereof,
FIG. 2 is a graph showing the relationship between the reduction ratio and a press-contacting force in which the ordinate axis indicates the press-contact force and the x-axis designates the reduction rate and the temperature of the material is 400 or 450 ° C, respectively,
FIG. 3 is a graph showing the relationship between the reduction ratio and the strength of the fastener, on which the ordinate axis indicates the strength of the fastener and the abscissa indicates the reduction ratio, and the temperature of the material during fixation is 450 ° C,
FIG. 4 is a graph showing the relationship between the reduction ratio and the deformation ratio of an outer peripheral diameter, the ordinate axis denoting the deformation ratio (after deformation / before deformation) of the outer peripheral diameter of the bottom portion of the main container body and the x-axis designating the reduction ratio,
Fig. 5 is a graph showing the relationship between the reduction ratio and the amount of dispersion, wherein the ordinate axis refers to the amount of dispersion of the outer circumferential diameter of the bottom portion of the main container body and the x-axis designates the reduction rate,
FIG. 6 is a graph showing the relationship between the temperature of a mold and the reduction ratio when the main container body and the cladding plate are fixed to each other by the same force of setting. press contact (600 tonnes) and at the same material temperature (450 ° C), the ordinate axis designating the reduction ratio and the abscissa axis designating the temperature of the mold,
Figs. 7A and 7B are sectional views showing the bottom portion of an electromagnetic cooktop container according to an embodiment of the present invention, Fig. 7A showing a cladding plate prior to attachment and Fig. 7B showing the coating plate after fixing,
Figs. 8A and 8B are cross-sectional views showing the bottom portion of an electromagnetic cooktop container according to one embodiment of the present invention, Fig. 8A showing a cladding plate prior to attachment and Fig. 8B showing the coating plate after fixing,
FIG. 9 is a sectional view showing the bottom portion of an electromagnetic cooking plate receptacle, in which a plurality of grooves are arranged at the outer face of the bottom portion of the main container body,
FIG. 10 is a sectional view showing specific examples of shapes of the grooves,
FIGS. 11A, 11B and 11C are diagrammatic top views respectively showing specific examples of arrangements of the grooves,
FIG. 12 is a sectional view showing the bottom portion of an electromagnetic cooktop container in which a plurality of projections are arranged on the outer face of the bottom portion of the main container body,
FIG. 13 is a sectional view showing specific shapes of the projections,
FIGS. 14A, 14B and 14C are diagrammatic plan views respectively showing specific examples of arrangements of the projections,
FIG. 15 is a schematic top view showing a modified example of arrangement of the grooves on the outer face of the bottom portion of a container main body having grooves, and
Fig. 16 is a schematic top view showing a modified example of arrangement of the projections on the outer face of the bottom portion of the container main body having projections.

 The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. As shown in Figs. 7A and 7B, in accordance with an electromagnetic cooktop container according to this embodiment, a container main body 1 and an aluminum plate 2 consisting of a cover plate are secured together by thermal fixation. in solid phase by bringing the coating plate constituted by the aluminum plate 2 and a ferrite series stainless steel plate 3, in contact with the outer face of a bottom portion of the aluminum container main body 1 or aluminum alloy (hereinafter both referred to as aluminum), or by bringing the aluminum plate 2 into contact with the outer face of the bottom portion of the main container body 1 and compressing the two in a hot state.

The reduction rate in this case is 10 to 50%.

 The inventors of the present invention have conducted various experimental investigations to improve the strength of the fastener existing between the main container body and the heat generating body plate which is attached to the outer face of the bottom portion thereof. and to prevent the heat generating body plate from being exfoliated from the main container body. As a result, they found that when the heat generating body plate is a coating plate made of an aluminum plate and a ferrite series stainless steel plate and that the coating plate is fixed on the outer face of the bottom portion of the main container body, the reduction rate of the bottom portion of the main container body or the cover plate as a function of the total thickness thereof influences the resistance fixing.

 That is, when the reduction rate of the bottom portion of the main container body or the cover plate is increased, the relative slip therebetween is increased and a shaping rate of a virgin metal face on the surfaces of the container main body and the coating plate at the attachment interface is increased. Therefore, by increasing the reduction rate of the main container body and the cladding plate, the metal fastening is accelerated between the fixed metals, and the strength of the fastening is further increased.

 Subsequently, we will give the explanation of the reason leading to limit the rate of reduction. The reduction ratio influences the state of fixation between the main container body and the liner plate and the shape of the main container body after attachment.

That is, when the cover plate is attached to the outer face of the bottom portion of the main container body, if the reduction rate of the aluminum alloy material of the bottom part of the body The main container or coating plate is below 10%, the exfoliation is driven at the fixed interface. In addition, if the reduction rate exceeds 50%, the amount of deformation of an outer peripheral diameter of the bottom portion of the main container body and the dispersion thereof are increased so that it becomes difficult to provide a container having a predetermined shape. Therefore, the reduction rate of at least one of the bottom portion of the main container body and the aluminum alloy material of the coating plate is between 10 and 50%.

 The positioning accuracy when attaching the cover plate to the main container body can be promoted and the time of the positioning operation can be shortened by providing a projecting portion or a recessed portion at the the central portion of the outer face of the bottom portion of the main container body and providing a through hole or a recessed portion or projection adapted thereto, at the coating plate. Incidentally, the through hole may have a circular hole-like shape and a slot-like shape and the shape thereof in the thickness direction may be parallel to the thickness direction of the plate coating and a conical shape. Incidentally, when the protruding portion, or recessed portion, etc., is arranged at the outer face of the bottom portion of the main container body and the cladding plate, the reduction rate mentioned above is a value existing at an area where the projecting portion, the recessed portion, and the like are not arranged.

 Subsequently, a specific explanation will be given regarding the materials of the main container body and the cover plate. The main container body can be made using Qi an Al-Si series aluminum alloy (die casting alloys consisting of ADC1, ADC12, etc.), pure industrial aluminum (No. 1100, etc.). Al-Mn series aluminum alloys (number 3003, etc.) and the like. On the other hand, with respect to the cladding plate, it is preferable to use a cladding plate having a ferrite series stainless steel plate and an aluminum alloy plate. As the aluminum alloy of the cladding plate, Qi of pure industrial aluminum (No. 1100), Al-Mn series aluminum alloy (No. 3003) and the like can be used.

 Although the container may be manufactured by any of the combinations of the above-mentioned materials for the main container body and the cover plate, a combination of, especially Qi, a series aluminum alloy is often used. Al-Si for the main container body and O of pure industrial aluminum or an Al-Mn series aluminum alloy for the cladding plate.

 As a manufacturing condition, the temperature of the main container body and the coating plate (hereinafter referred to as "material temperature") is preferably between 350 and 5000C. This is because when the temperature of the material is below 350, an effective fixation state can not be assured and when it exceeds 500 ° C, the amount of deformation of the main container body is increased and it can not be achieved. not manufacture a container of high quality.

In addition, when the temperature of the material exceeds 450 ° C, in the case where the vessel is made using Al-Si series die-casting alloy, blisters form on the surface. material temperature is equal to or less than 450 ° C to prevent blistering.

 It is preferred that the temperature of the mold used to secure the main container body and the cover plate is between 180 and 4500C. The reason for this is that when the mold temperature is below 1800C, an effective fixation state can not be ensured and when greater than 450 "C, the sliding capacity between the mold and the main container body, and the mold and the coating plate, is deteriorated and traces of seizure appear significantly on the container produced.

 Incidentally, combinations of the material temperature and the mold temperature are arbitrary as long as the respective temperatures are in the temperature ranges mentioned above, for example the temperature of the material is 450 ° C when the temperature of the mold is 180 ° C, or the material temperature is 450 ° C when the mold temperature is 250 ° C.

It is preferred that the pressure of the press 2 is 1 to 5 tons / cm. The reason for this is that when the press pressure is below 1 2 ton / cm 2, sufficient fastening strength between the body container main and the cladding plate 2 can be assured and when it exceeds 5 tons / cm2, the deformation of the main container body is increased. Incidentally, when both the temperature of the material and the temperature of the mold fall on the upper limit values mentioned above, the pressure of
2 the press can be at least 1 ton / cm 2 or more, but when both the material temperature and the mold temperature fall to the lower limit values mentioned above, it is necessary that the pressure of the press is approximately 5 tons / cm2.

tons / cm
Although the method of making the container per se is not particularly limited, a container of good quality can be manufactured by manufacturing it through a die casting process. In addition, the container made from the main container body and the cover plate may be a saucepan, casserole or the like.

 According to the present invention, the positioning of the cover plate can be performed easily and with high precision by providing a protruding portion at the central portion of the outer face of the bottom portion of the container main body, by arranging a through-hole in which is arranged the projecting portion or a recessed portion in which is arranged the projecting portion at the level of the covering plate which is fixed on the outer face of the container pal and the cover plate, the relative slip area at the fixed interface can be increased by flowing the aluminum alloy of the liner plate into the grooves and as a result the strength of the fastening can be further increased. Incidentally, when the grooves are formed so as to extend continuously in a circular form, the gases can remain at the level of the fixed part. It is preferable to arrange other grooves in the radial direction at the outer surface of the bottom portion of the main container body in the case of a container having grooves, to allow gases to escape.

 In addition, by forming one or more projections on the outer face of the bottom portion of the main container body, upon attachment of the container main body and the cover plate, the projections are caused to bite into the alloy. of the facing plate so that the relative sliding area at the fixed interface is increased and the strength of the fastening can be further increased as in the case where the grooves are formed on the outer face of the bottom portion of the main container body. Incidentally, when the projections are formed to extend continuously in a circular shape as in the case of the grooves of the aforementioned container having grooves, gases may remain at the fixed portion. Therefore, in this case of the container having protrusions, the gases can escape by providing a circular projection having a shape such that it is separated into two or more circular arcs.

 Subsequently, an explanation will be given of the method of manufacturing an electromagnetic cooktop container according to the present invention. According to the invented method, the aluminum alloy of the coating plate is fixed on the outer face of the bottom portion of the main container body by solid phase thermal fixation. In addition, the reduction ratio of the bottom portion of the main container body or the aluminum alloy of the coating plate is between 10 and 50%, as mentioned above. Thus, the cover plate may be attached to the outer face of the bottom portion of the main container body to provide high strength.

 It is effective to increase the rate of reduction to increase the force applied during attachment (hereinafter referred to as "press-in force") and to increase the temperature of the material. However, when problems such as blistering on the surface of the container main body, or the like, are caused by raising the temperature of the material, the reduction rate can be increased by increasing the temperature of the mold used in setting the material. main container body and liner plate even if the material temperature is not very high.

 Subsequently, an explanation will be given of the actual manufacture of an electromagnetic cooktop container according to embodiments of the present invention and a result of the evaluation of its function with reference to the accompanying drawings.

In this embodiment, a container main body (outer circumferential diameter of the bottom portion, 240 mm) made of an ADC1 aluminum alloy and a cladding plate was used.
2 (surface: 275 cm 2), having a ring-like shape, made of JIS 1100 aluminum alloy and ferrite series stainless steel, having an outer periphery diameter of 200 mm and an inner periphery diameter of 170 mm. The aluminum alloy plate and the cladding plate were heated in a heating furnace, they were then removed and the aluminum alloy plate of the cladding plate was attached to the outer face of the cladding plate. bottom portion of the main container body by solid phase thermal fixation. The temperature of the material, the temperature of the mold and the speed of the press are indicated in Table 1 which follows.

Table 1

<tb><SEP> Temperature <SEP> Material <SEP> 4500C <SEP> (Partly <SEP> 400 "C) <SEP>
<tb> Temperature <SEP> of <SEP> mold <SEP> 1800C <SEP>
<tb> Speed <SEP> of <SEP> press <SEP> 300 <SEP> mm / sec.
<Tb>

 When attaching the container main body and the cladding plate under the conditions described above, fixing was performed by varying the reduction ratio. The result is represented by the graphs of Figures 2 to 6.

 Fig. 2 is a graph showing the relationship between the reduction ratio and the press-contacting force, in which the ordinate axis indicates the press-contact force and the abscissa indicates the rate of reduction and in which the temperature of the material is 400 ° C (O,) and 4000 ° C (D, respectively) The state of fixation was assessed by the presence or absence of exfoliation at of the fixation interface by observing the interface by sawing the interface after fixing the main container body and the cladding plate As shown in the graph of Figure 2, it has been found that a reduction rate of 10% or more is required to provide a correct fastening condition It has also been found that the higher the temperature of the material, the higher the rate of reduction can be provided when the same press-contacting force is applied. on the main body ipal container and coating plate.

 Fig. 3 is a graph showing the relationship between the reduction ratio and the fixing force, in which the ordinate axis indicates the strength of the fastener and the abscissa indicates the rate of reduction and in which the temperature At the time of attachment, the material is 450 ° C. As shown in the graph of Fig. 3, it has been found that the higher the rate of reduction, the higher the strength of the fastener. plating on the outer face of the bottom portion of the main container body, it is effective, to increase the strength of the fastener, to increase the rate of reduction.

 FIG. 4 is a graph showing the relationship between the reduction ratio and the outer periphery deformation ratio, in which the abscissa indicates the deformation ratio (after deformation / before deformation) of the outer peripheral diameter of the bottom portion of the main container body and the abscissa axis indicates the reduction rate. As shown in the diagram of FIG. 4, the greater the reduction ratio, the greater the outer peripheral diameter of the bottom portion of the main container body, ie the diameter of the outer face of the container. the bottom part. When the diameter is increased by 1.2 times the diameter before fixation or more, it is difficult to control the shape of the main container body. Accordingly, it has been found necessary that the reduction ratio be 50% or less to make the deformation ratio of the diameter at the outer face of the bottom portion of the container main body equal to 1.2 or smaller. .

 Fig. 5 is a graph showing the relationship between the reduction ratio and the amount of dispersion, in which the ordinate axis indicates the amount of dispersion of the outer circumferential diameter of the bottom portion of the main container body and the x-axis is the rate of reduction. Incidentally, the amount of dispersion in this graph indicates a gap between the maximum value and the minimum diameter value at the outer face of the bottom portion of the container main body when four containers are made by attaching coating plates to the outer faces of the bottom portions of the main container bodies under the same conditions. As shown in the graph, when the reduction rate exceeds 50%, the amount of dispersion is increased and it becomes difficult to manufacture a container having a uniform shape. As a result, it is necessary that the reduction rate be 50% or smaller.

 Fig. 6 is a graph showing the relationship between the mold temperature and the reduction ratio, in which the y-axis indicates the reduction ratio and the x-axis indicates the mold temperature and wherein the coating is fixed on the outer face of the bottom portion of the main container body under the same press-contacting force (600 tons) and the same material temperature (450 ° C.) As shown in this graph, when the press-contacting force and the temperature of the material remain the same, the higher the temperature of the mold, the greater the reduction rate can be achieved.

 In this way, the reduction rate can be increased by increasing the temperature of the mold without further increasing the temperature of the material. Normally, the higher the temperature of the aluminum alloy container main body that is made by the die casting process, the more blisters are likely to appear on the surface of the main container body. Therefore, the reduction rate can be increased without unduly raising the temperature of the main container body by raising the temperature of the mold.

 Subsequently, the description will be given of an electromagnetic cooking plate container as a second embodiment of the present invention in which a projecting portion is arranged at the central portion of the outer face of the portion. bottom of the main container body and a recessed portion in which the projecting portion is arranged is provided at the coating plate.

Figs. 7A and 7B are cross-sectional views showing the bottom portion of an electromagnetic cooktop container according to this embodiment, Fig. 7A showing a cladding plate prior to attachment and Fig. 7B showing cladding plate after fixation. Incidentally, in this embodiment as in the first embodiment mentioned above, the container main body 1 uses an ADC1 aluminum alloy and the cover plate uses an aluminum alloy plate 2 consisting of JIS 1100 aluminum alloy and a stainless steel plate 3 made of a ferrite series stainless steel, both being joined by plating.

 As shown in Figs. 7A and 7B, a projecting portion 1a is formed at the central portion of the outer face of the bottom portion of the container main body 1 and a recessed portion 2a is formed at the portion center of the disc-shaped cladding plate. When the projecting portion 1a and the recessed portion 2a are accurately formed respectively at the container main body 1 and the cover plate in this manner, by attaching the cover plate to the outer face of the portion of bottom of the main container body 1, the positioning of the fastener can be performed easily by simply arranging the projecting portion la in the recessed portion 2a. Also, the same effect can be obtained through a through hole in which is arranged the projecting portion la, instead of the recessed portion 2a.

 Next, an electromagnetic cooktop container will be described as a third embodiment of the present invention, wherein a recessed portion is formed at the central portion of the outer face of the bottom portion of the housing. main container body and a protruding portion is formed at the central portion of the cladding plate. Figs. 8A and 8B are sectional views showing the bottom portion of an electromagnetic cooktop container according to the embodiment of the present invention, Fig. 8A showing a cladding plate before attachment and Fig. 8B showing the coating plate after fixing. According to this embodiment, as in the first embodiment mentioned above, the container main body 4 uses an ADC1 aluminum alloy and the cover plate uses an aluminum alloy plate 5 consisting of a JIS 1100 aluminum alloy and a stainless steel plate 6 made of a ferrite series stainless steel, both being pressed together.

 As shown in FIGS. 8A and 8B, a recessed portion 4a is formed at the central portion of the outer face of the bottom portion of the container main body 4 and a projecting portion 5a is formed at the portion center of the cladding plate. Therefore, when the recessed portion 4a and the projecting portion 5a are accurately formed, by attaching the cover plate to the outer face of the bottom portion of the container main body 4, the positioning of the attachment may be easily achieved by simply arranging the protruding portion 5a in the recessed portion 4a.

 Subsequently, a description will be given of an electromagnetic cookware container constituting a fourth embodiment of the present invention in which a plurality of grooves are formed at the outer face of the bottom portion of the main container body. . Fig. 9 is a sectional view showing the bottom portion of the electromagnetic cooktop container in which a plurality of grooves are formed on the outer face of the bottom portion of the main container body and Fig. 10 is a sectional view showing specific examples of groove shapes. According to this embodiment, as in the first embodiment mentioned above, for example, the container main body 10 uses an ADC1 aluminum alloy and the cover plate 11 uses an aluminum alloy plate 12 made of JIS 1100 aluminum alloy and a stainless steel plate 13 made of a ferrite series stainless steel, both being pressed together.

 As shown in Fig. 9, in accordance with this embodiment, a plurality of grooves 14 are formed at the outer face of the bottom portion of the container main body 10. As shown in Fig. 10, the sectional shapes of these grooves are, for example, a semicircular shape 14a, a U-shaped shape 14b, a V-like shape 14c, a channel-like shape 14d, and the like.

 Figs. 11A, 11B and 11C are schematic views showing specific examples of arrangements of the grooves which are formed on the outer face of the bottom portion of the container main body 10.

When the grooves 14 are formed on the outer face of the bottom portion of the container main body, the arrangement thereof may have a ring-like shape consisting of concentric circles as shown in Fig. 11A, a similar form to a lattice as shown in Fig. 11B or a dot-shaped form as shown in Fig. 11C.

 In addition, when the grooves formed on the outer face of the bottom portion of the main container body 10 are each in a ring-like shape consisting of a concentric circle, as shown in Fig. 11A, a fixed portion without exfoliation may be provided by forming grooves in the direction of a radius extending radially from the center of the bottom portion of the container main body since gases remaining in the attached portion may escape when the cover plate is secured on the outer face of the bottom portion of the main container body 10.

 When the plurality of grooves are formed in this manner on the outer face of the bottom portion of the main container body 10, by attaching the cover plate 11 to the outer face of the bottom portion by solid phase thermal fixation, the surface relative slip existing at the fixed interface is increased since the aluminum alloy plate 12 of the cover plate 11 is caused to flow inside the grooves 14 so that the mechanical fixing force is increased and as a result the strength of the fastening between the container main body 10 and the cover plate 11 can be further increased.

 Subsequently, a description will be made of an electromagnetic cooktop container constituting a fifth embodiment of the present invention wherein a plurality of projections are formed on the outer face of the bottom portion of the main container body. Fig. 12 is a sectional view showing the bottom portion of an electromagnetic cooktop container, wherein a plurality of projections are arranged at the outer face of the bottom portion of the main container body and Fig. 13 is a sectional view showing specific examples of projection shapes.

 As shown in Fig. 12, according to the present invention, a plurality of projections 14 are formed on the outer face of the bottom portion of the container main body 10. As shown in Fig. 13, the sectional shapes of these projections may be, for example, a triangular shape 14a, a semicircular shape 15b, a U-like shape 15c, a quadrangular shape 15d, etc.

 Figs. 14A, 14B and 14C are schematic views showing specific examples of arrangements of the projections formed on the outer face of the bottom portion of the container main body 10. When the projections 15 are formed on the outer face of the portion of the container main body 10, the arrangement may have a ring-like shape consisting of concentric circles as shown in Fig. 14A, a lattice-like shape as shown in Fig. 14B and a dot-like shape shown in Figure 14C.

 When the projections formed on the outer face of the bottom portion of the container main body 10 are each formed into a ring-like shape of a concentric circle as shown in Fig. 14A, a fixed portion without exfoliation may be provided dividing these projections into two or more circular arcs thereby providing grooves for allowing the remaining gases in the fastener to escape.

 When the plurality of projections are formed in this manner on the outer face of the bottom portion of the container main body 10, by attaching the coating plate to the outer face of the bottom portion by solid phase thermal fixation, the projections are bitten in the aluminum alloy plate 12 of the cladding plate and the relative sliding surface existing at the fixed interface is increased and the strength of the fastening can be further increased as in the fourth embodiment of FIG. realization mentioned above.

 In accordance with the electromagnetic cookware container, the first aluminum layer of the cover plate is caused to flow in the grooves and the mutual relative slip existing at the fixed interface is increased by arranging the existing grooves at the of the fixed face of the plating material on the outer face of the bottom portion of a container made of aluminum. In this way, the surface area of contact of the fixed interface is increased and the metal attachment area is enlarged, so that the strength of the attachment is increased. In addition, the increase of the strength of the fastening not only by the metal fastener but by the mechanical fastening is ensured by penetrating a material of a first side into the grooves of a counterpart material.

 In addition, by arranging the projections at the fixed face of the outer face of the bottom portion of an aluminum container, the projecting portions are allowed to bite into the first layer made of existing aluminum of the material of the plating and flow of the first aluminum layer portion on the side of the coating plate in contact with the projections is activated, the mutual relative slip between the fastening materials is increased, and correspondingly the surface area of the Fixed interface contact is increased and the range of the metal fastener is also increased so that the strength of the fastening is increased. The more grooves or projections are numerous, the more the strength of the attachment is increased.

 Moreover, as mentioned above, when the coating plate is fixed on the outer face of the bottom portion of the container by solid phase thermal fixation by providing a plurality of grooves each having a shape of a circular arc formed from concentric circles, gas storage is likely to form inside the grooves or the fixed interface. In the case of a large storage among gas storage, occurs a phenomenon in which the plating side of the bottom of a pan after press contact is partially blistered and the fixed interface is exfoliated at this level. part. Similarly, when the coating plate is fixed by solid phase thermal fixation on the outer face of the bottom portion of the container by providing the projections each in concentric circular form, gas storage is likely to form at the of the fixed interface.

 Therefore, in the first case, the gases stored in throat portions are evacuated or dispersed by providing one or more grooves extending from the innermost grooves towards the outermost grooves in the direction of a radius. on the outer face of the bottom portion of the main container body. That is, in the case of grooves or projections formed to extend continuously in a circular form, the gases may have remained at the fixed portion. As shown in FIG. 15, in the case of the container having the grooves 14, a groove 17 extending in the direction of a radius is arranged to evacuate the gases.

 In addition, in the second case, the gases stored at the fixed interface are evacuated or dispersed by separating the projections each having a concentric circular shape in several circular arcs.

That is, as shown in Fig. 15, in the case of a container having the projections 15, it is preferable that the projections extending in the same diameters are separated into projections 16a and 16b consisting of two groups of arcs of circles. The number of protrusion separations extending in the form of a circular arc may be three or more.

 In each case, it is possible to obtain an improvement in the state of the fastener which is deteriorated by the absence of evacuation of the gases. Incidentally, the greater the number of grooves extending in the direction of a radius or that of the notches concentric circle projections for the evacuation of gas is important, the more this is preferred.

 According to the present invention, a through-hole, etc., as in the usual example, is not arranged at the level of the second layer of stainless steel which is the body generating heat and therefore, the resistance of the fastener. can be increased without lowering the heat generating function itself of the container.

 Subsequently, an explanation will be given as to the actual manufacture of an electromagnetic cooktop container according to embodiments and test results of the effects.

Table 2 below shows the results of tests of the strength of the fixation in a thermal cycle test. With regard to the thermal cycle, a cycle in which a product consisting of an electromagnetic cooktop pan was heated to 300 ° C and cooled rapidly by water to normal temperature, was repeated 10 times, time, 30 times and 40 times as described in the table, the number of samples was 10, respectively.) With respect to sample production conditions, the outer peripheral diameter of the main body of the pan was 240 mm, the surface of the cover plate
It was 275 cm (outer peripheral diameter: 200 mm, inner peripheral diameter: 70 mm), and the material temperature was 450 ° and the press speed was 300 mm / sec. of a grooved sample (Embodiment 1) and a protruded sample (Embodiment 2) according to the embodiments of the present invention were measured at the flat portions other than the groove portions. The grooves and projections have been arranged in a press contacting range (outer circumferential diameter: 200 mm, inner circumferential diameter: 70 mm) of the bottom portion of a cast pan. aluminum pressure in a concentric circular shape with the center of the bottom of the pan at uniform intervals having a pitch of 4 mm in the direction of a radius The sectional shape of the groove of the embodiment 1 was that of the groove 14b (see Figure 10) having a width of 1 mm and a depth of 1.5 mm and the bottom portion of the groove was provided with a radius of curvature of 0.5 mm. In addition, the sectional shape of the projection of Embodiment 2 was that of protrusion 15a (see Fig. 13) constituting a triangular shape having a width of 1 mm and a height of 1 mm. Incidentally, any exfoliation of the fixed side was a partial exfoliation. The rate of reduction indicates a quantity of change in thickness divided by the thickness before reduction, in percentage.

Table 2

<tb><SEP> Tempera- <SEP><SEP> Rate of <SEP><SEP> Number <SEP> of Samples
<tb><SEP> ture <SEP> of the <SEP><SEP><SEP> ducting having <SEP> a <SEP> face <SEP> fixed
<tb><SEP> mold <SEP> aluminum <SEP> exfoliated <SEP> (pieces)
<tb><SEP> when <SEP> of <SEP> of <SEP> the <SEP> pla
<tb><SEP> the <SEP> manufacturer <SEP> that <SEP> from <SEP> re
<tb><SEP> cation <SEP> garment
<tb><SEP> 10 <SEP> 20 <SEP> 30 <SEP> 40
<tb><SEP> times <SEP> times <SEP> times <SEP> times
<tb> equation <SEP> 1 <SEP> 1800C <SEP> 20 <SEP>% <SEP> 0/10 <SEP> 0/10 <SEP> 0/10 <SEP> 0/10
<tb> (throats)
<tb> Realization <SEP> 2 <SEP> 1800C <SEP> 19 <SEP>% <SEP> 0/10 <SEP> 0/10 <SEP> 0/10 <SEP> 0/10
<tb> (Stallions)
<tb> Example <SEP> as <SEP> 1800C <SEP> 22 <SEP>% <SEP> 5/10 <SEP> 6/10 <SEP> 6/10 <SEP> 6/10
<tb> parative
<Tb>
Table 2 shows the result of a test on the strength of the fixation by the thermal cycling test. As shown in Table 2, it has been found that the strength of the fastener can be increased by arranging grooves or projections at the fixed side of the bottom portion of a pan and providing the grooves or protrusions. is effective in reducing the rate of defective parts.

 The power consumption was measured in the case where the grooves were provided at the fixed side of the bottom portion of the pan (Embodiment 1), in the case where the projections were provided (embodiment 2) and in the case where the grooves and projections were not provided (comparative example). As a result, the electricity consumption in these cases was 1200 W when a heater with an output of 1300 W was used. As a result, it was found that there was no difference in the heat creation function.

 Subsequently, in order to confirm the effect of the separation of grooves or arcuate projections for the evacuation of gases, with respect to an electromagnetic cooking plate receptacle in which grooves each having a concentric circular shape were arranged at the bottom portion of a pressure cast pan and a cover plate was affixed to the outer face of the bottom portion thereof by solid phase thermal fixation, the state of the fixation during solid phase thermal fixation was compared with respect to the one having grooves for gas evacuation arranged in the direction of a radius and that having no such grooves. The result is shown in Table 3 below.

 The grooves each having a concentric circle shape have been arranged in a press-contacting zone (external peripheral diameter 200 mm, internal peripheral diameter: 70 mm) at the bottom portion of a pressure-cast pan. in a concentric circular shape with the center of the bottom of the pan, at uniform intervals having a pitch of 4 mm in the direction of a radius. The groove had a sectional shape having a width of 1 mm, a depth of 1.5 mm and the bottom portion of a groove had a radius of curvature of 0.5 mm.

With regard to the die-casting pan having the grooves each in a concentric circle, eight grooves having the same cross-sectional shape as that of the groove having the concentric circle have been formed so as to extend in the direction of a radius radially from the center of the bottom portion of the pan at approximately 45 "angular intervals in a region of diameter from 70 mm to 200 mm.

<Tb>

Number <SEP> of <SEP> defects <SEP> in <SEP> of <SEP> Number <SEP> of <SEP> defects <SEP> in <SEP> of
<tb><SEP> samples having <SEP><SEP> gor- <SEP><SEP> samples having <SEP> not <SEP> of
<SEQ><SEP> Evacuation <SEP><SEP> Gas <SEP> Evacuation <SEP> SEP
<tb><SEP> 0 <SEP> 3
<Tb>
The number of samples was respectively in the case where the gas evacuation grooves were arranged and in the case where they were not arranged. Incidentally, the defects were determined as a result of an inspection of the appearance when a portion of the plated side of the bottom of the pan was swollen and the exfoliation was confirmed. As shown in Table 3, exfoliation defects can be avoided by arranging gas discharge grooves extending in the direction of a radius. In contrast to this, the lack of exfoliation appeared in 3 out of 10 of the die-cast pans in the case where the grooves in the direction of a spoke were not arranged.

Claims (13)

 1. Container for electromagnetic cooktop having  a container main body (1; 4; 10) made of aluminum or aluminum alloy, and  a cladding plate (2, 3; 5, 6) formed by plating joining an aluminum or aluminum alloy material (2; 5) and a ferrite series stainless steel material (3; 6), said coating plate being fixed on the outer face of the bottom portion of the main container body by solid phase thermal fixation,  characterized in that during solid-phase thermal fixation between the cladding plate and the outer face of the bottom portion of the main container body, the rate of reduction of at least one of the bottom portion of the main body container and the aluminum or aluminum alloy material of the coating plate is 10 to 50%.  An electromagnetic hob container according to claim 1, characterized in that a protruding portion (1a) is arranged on the outer face of the bottom portion of the container main body (1) and a through hole or a recessed portion (2a) in which the protruding portion (la) is fitted, is arranged at the level of the cover plate, the cover plate is positioned relative to the outer face of the bottom portion of the main container body by fitting the projecting portion into the through hole or the recessed portion and the cladding plate and the container main body are secured together by the solid phase thermal fixture.  Electromagnetic hotplate container according to claim 1, characterized in that a recessed portion (4a) is arranged at the outer face of the bottom portion of the main container body (4) and a portion thereof. projection (5a) fitting in the recessed portion is arranged at the level of the cover plate, the cover plate is positioned relative to the outer face of the bottom portion of the main container body by fitting the projecting portion. in the recessed portion, and the cladding plate and the container main body are secured together by the solid phase thermal fixation.  Electromagnetic hotplate container according to one of Claims 1 to 3, characterized in that one or more grooves (14) are formed at the outer face of the bottom portion of the main container body ( 10).  Electromagnetic hotplate container according to one of Claims 1 to 3, characterized in that one or more projections (15) are formed at the outer face of the bottom portion of the main container body ( 10).  An electromagnetic cookware container according to claim 4, characterized in that grooves (17) extending in the direction of a radius are formed at the outer face of the bottom portion of the main container body. (10).  7. A method of manufacturing an electromagnetic cooking plate receptacle characterized in that it comprises the steps of  supplying an aluminum or aluminum alloy material (2; 5) with a coating plate formed by plating the aluminum or aluminum alloy material and a series stainless steel material ferrite (3; 6) in contact with an outer face of a bottom portion of a container main body (1; 4 10) made of aluminum or aluminum alloy, and  attaching the container main body and the cladding plate by solid phase thermal fixation with a reduction rate of 10 to 50% of at least one of the bottom portion of the container main body and the aluminum material or aluminum alloy of the cladding plate.  8. Container for electromagnetic hob characterized in that it comprises  a container main body (1, 4; 10) made of aluminum or aluminum alloy, having grooves (14) or projections (15) at the outer face of the bottom portion thereof; ci, and  a cladding plate formed by plating a first layer (2; 5) made of aluminum or aluminum alloy and a second layer (3; 6) made of ferrite series stainless steel, said plate coating material being secured to the outer face of the bottom portion of the container main body by attaching the first layer to the outer face of the bottom portion of the container main body by solid phase thermal fixation.  9. Container for electromagnetic hob, characterized in that it comprises  a container main body (1, 4; 10) made of aluminum or aluminum alloy, and  a cladding plate formed by joining by plating a first layer (2; 5) of aluminum or aluminum alloy to a second layer (3; 6) of ferrite series stainless steel, of which the first layer (2; 5) is provided with grooves (14) or projections (15), said cover plate being fixed on the outer face of the bottom portion of the main container body by fixing the first layer (2). 5) on the outer face of the bottom portion of the main container body by solid phase thermal fixation.  Electromagnetic hotplate container according to claim 8 or 9, characterized in that the grooves (14) or projections (15) extend in one or more circular arcs, each having a concentric circle shape. .  Electromagnetic hotplate container according to claim 9 or 10, characterized in that the grooves (14) or projections (15) extend into straight lines which intersect each other to form a shape. similar to a lattice.  Electromagnetic hotplate container according to claim 9 or 10, characterized in that the grooves (14) or projections (15) have a dot-shaped shape.  Electromagnetic hotplate container according to claim 9 or 10, characterized in that grooves (17) are formed extending in the direction of a radius.