JPH09225561A - Dissimilar metal joined material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dissimilar metal joined member in which a peripheral edge part of a joined surface is not peeled even when it is applied to a ware for electro-magnetic cooking which is repeatedly heated and cooled. SOLUTION: In a joined member, a pot-shaped recessed hole 4 in which the sectional area of the joined member which is imaginarily cut with the section parallel to an opening part is larger than the area of the opening part is provided on a joined surface of a harder metal 2, and a softer metal 1 is engaged with the recessed hole 4 in a filled manner, and a peripheral edge part of the harder metal 2 is supported in a holding manner by a projected part 3 provided on the softer metal 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dissimilar metal joining member applicable to electromagnetic cooking utensils such as pots, pans and rice cookers which are heated by electromagnetic induction.

[0002]

2. Description of the Related Art The above-mentioned electromagnetic cooking utensil is heated by electromagnetic induction and therefore needs to be made of a magnetic material. However, if the whole utensil is made of a magnetic material, the weight becomes heavy and the cost becomes high, so that it is not suitable as a general cooking utensil. Therefore, an electromagnetic cooking utensil using a dissimilar metal joining member in which a magnetic material is joined to a light and inexpensive metal has been proposed. For example, it is an electromagnetic cooking utensil or the like in which the utensil body is made of aluminum (including its alloy, the same applies hereinafter) and a magnetic material as a heating element is joined to the outer bottom surface thereof.

In the case of a cookware in which a heating element is attached to a part of such a heating element body, the heating element may peel off and fall off when heating and cooling are repeated because the thermal expansion coefficient of the heating element differs from that of the heating element body. It was very good.

Therefore, the applicant of the present invention provides a large number of vase-shaped holes, each having a smaller opening area than the internal cross-sectional area, on the surface of the heating element made of a hard metal material, and the surface provided with the holes is made soft. Side of the container body made of metal material that is necessary for electromagnetic induction, and pressed from the container body to the joint surface by forging, etc. A method has been previously proposed (Japanese Patent Application No. 7-226834) in which a heating element is firmly joined to a part of the main body of the article by filling the hole of the item and biting it. The electromagnetic cooking utensil obtained by this method, because the metal material constituting the utensil main body digs into the pot-shaped hole provided in the heating element, sufficient bonding strength is obtained due to the anchor effect generated in this part, It has become possible to provide an electromagnetic cooking utensil in which the heating element does not fall off even after repeated heating and cooling.

[0005]

However, when heating and cooling are repeated over a long period of time with respect to the cooker using the dissimilar metal joining member, the heating element does not fall off, but the peripheral portion of the joined heating element is the main body of the dish. It was found that there was a risk of peeling from the container and a gap between the body of the container and the heating element. If such a gap occurs in the cooking utensil, foreign matter such as oil or dust may be accumulated and spoil the appearance of the utensil, and may cause rust, and the contact area with the main body of the utensil decreases. Therefore, there is a problem that heat transfer to the body of the article is hindered and thermal efficiency is deteriorated.

The present invention has been made in view of the above technical background, and is applied to, for example, an electromagnetic cooking utensil, and even if it is repeatedly heated and cooled for a long period of time, the peripheral edge portion of the joint surface. It is an object of the present invention to provide a dissimilar metal joining member that does not peel off and cause no gap.

[0007]

In order to achieve the above object, a dissimilar metal joining member according to the present invention is a member in which metal materials having different hardnesses are joined together, and the joining surface of the hard side metal material is A pit-shaped biting hole having a cross-sectional area when virtually cut in a cross section parallel to the opening is provided larger than the area of the opening, and the soft side metal material is engaged in the biting hole in a filled state, In addition, the gist is that the peripheral portion of the hard metal material is supported in a holding state by the protrusion provided on the soft metal material.

By adopting the above construction, the anchor effect is exerted in the portion of the bite hole in which the soft side metal material bites into the filled state, and the hard side metal material is firmly joined to the soft side metal material. It Further, the peripheral portion of the hard-side metal material is supported by the projecting portion provided on the soft-side metal material in an embraced state, so that it is more firmly joined to the soft-side metal material. Therefore, the electromagnetic cooking utensil constituted by the dissimilar metal joining member according to the present invention can be stably cooked without peeling at the peripheral portion of the heating element even when repeatedly subjected to heating and cooling for a long period of time.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment in which the dissimilar metal joining member according to the present invention is applied to an electromagnetic cooking utensil will be described.

As shown in FIG. 1, the electromagnetic cooking utensil of the present embodiment is joined to the utensil body (1) which is a pot-shaped metal material on the soft side and the outer surface of the bottom of the utensil body (1). And a heating element (2) which is a plate-shaped hard metal material.

The material of the article main body (1) is not particularly limited, but aluminum is preferable in consideration of heat conductivity, corrosion resistance and light weight because it is a cooking article. Especially good workability, A1050, A1070, A1100, A300
It is more preferable to use an aluminum material such as 3, A3004 or the like.

The heating element (2) is a member that receives heat from a magnetic field generated from the electromagnetic cooker in the electromagnetic cooker to generate heat by induction heating. Therefore, the material needs to be a magnetic material, and a material having high corrosion resistance for use in cooking utensils is preferable. Specifically, SUS4
There may be mentioned magnetic SUS materials such as 30 and SUS405. Further, the heating element (2) does not have to be a single material, and a clad material in which an iron-based material such as SS41 is sandwiched by a SUS plate, or a steel plate immersed in an aluminum solution to give corrosion resistance to the steel plate. A composite material such as a knitted steel plate may be used.

A large number of bite holes (4) are formed on the entire joint surface of the heating element (2). The bite hole (4) is a vase-shaped hole whose cross-sectional area when virtually cut out in a cross section parallel to the opening is larger than the area of the opening. Then, the tool body (1) is inserted into the bite hole (4).
A part of the material is filled in in a bite state. Therefore, the anchor effect is exerted in this portion, so that the container body (1) and the heating element (2) are firmly joined.

The method of engraving the bite hole (4) is not particularly limited, but engraving by irradiation with an electron beam is particularly preferable. This is because the intended shape of the bite hole (4) according to the present invention is naturally realized by the irradiation of the electron beam. Also in this embodiment, the spherical or substantially spherical bite hole (4) is formed by the irradiation of the electron beam.

On the outer surface of the bottom of the container body (1), an annular protrusion (3) is provided so as to surround the heating element (2), and the tip of the protrusion (3) generates heat. The peripheral edge of the body (2) is bent into an L-shaped cross section so as to be pressed against the body (1) of the container. Therefore, the heating element (2) is supported by the projecting portion (3) so that the peripheral portion of the heating element (2) is held, and is firmly joined to the outer bottom surface of the container body (1).

Next, a method for manufacturing an electromagnetic cooking device according to the illustrated embodiment will be described.

First, the container body (1) and the heating element (2)
Is processed into a predetermined shape before joining. The body (1) of the dish is formed into a pot-shaped dish by pressing or the like. Further, the heating element (2) has a thin disc shape, and the bite hole (4) is formed in this.

Next, the article body (1) and the heating element (2) are joined together, and at the same time, the projecting portion (3) is provided on the article body (1).

At the time of joining, a die (5) as shown in FIG. 2 (a) is used, the heating element (2) is placed on it, and the container body (1) is placed on it.

As shown in FIG. 2, the die (5) has an annular groove (5a) located outside the peripheral end of the heating element (2) when the heating element (2) is placed on the die (5). Is provided.
The groove (5a) is used to form a protrusion (3) by filling a part of the container body (1) at the time of joining described later.

Next, as shown by an arrow (A) in FIG. 2B, pressure is applied from the container body (1) toward the heating element (2). By this pressurizing step, a part of the material of the container body (1) is plastically deformed and filled in the bite hole (4) provided in the heating element (2), and the heating element ( 2) is firmly joined. At the same time, a part of the container body (1) passes through the peripheral end of the heating element (2) and is filled in the groove (5a) provided in the mold (5) to form the protrusion (3). It At this stage, the protrusion (3)
The cross-sectional shape of is I-shaped as shown in FIG.

The pressing method is not particularly limited, but in this embodiment, a forging method was adopted. This can press only the part necessary for joining, and the object main body (1) and the heating element (2) which are previously molded into an object shape.
This is because it is suitable for manufacturing cooking utensils, since pressure can be applied also when joining. Further, the forging may be performed cold or hot, but when aluminum is adopted as the main body (1) of the forging, if it is joined by the hot forging method, the deformation resistance of the aluminum is reduced and at the time of forging. It is preferable in that the energy consumed can be reduced. The preferred heating temperature for aluminum during hot forging is 150 to
350 ° C.

Next, the protruding portion (3) obtained by the above method is caulked in the direction of the heating element (2) so that the peripheral portion of the heating element (2) is supported in a held state. The caulking method is not particularly limited, but in the case of this embodiment, the forging method is used as in the case of joining. Specifically, as shown in FIG. 4, the protruding portion (3) protruding in an I-shape is plastically deformed while being tilted toward the heating element (2) by the impact force from another mold (6), and finally Specifically, it is an L-shaped protrusion (3) which is fitted in the mold (6) and holds the peripheral edge of the heating element (2) in a pressure contact state. In this embodiment, in order to facilitate the deformation of the tip of the protrusion (3) in the direction of the heating element (2), the outer surface of the tip of the protrusion (3) is tapered inward toward the tip or circular. It is formed in an arc shape. In order to make the tip of the protrusion (3) have the above-described shape, the groove (5) of the mold (5) is
a) is also formed in a corresponding shape.

The above-mentioned electromagnetic cooking utensil comprises an utensil body (1).
The heating element (2) made of a magnetic material is firmly bonded to a part of the article body (1) by the anchor effect caused by filling a part of the bite hole (4) with the article body (1). Since the protruding portion (3) provided in (1) supports the peripheral portion of the heating element (2) in a held state, peeling of the peripheral portion of the joint surface is effectively prevented. Therefore, the electromagnetic cooking utensil can be sufficiently used even if it is repeatedly heated and cooled over a long period of time.

[0025]

Next, an embodiment of the present invention will be described. In this example, the dissimilar metal joint member according to the present invention was subjected to a heat cycle test in which heating and cooling were repeated assuming that the joint member was applied to an electromagnetic cooking utensil, and the peeling condition of the peripheral portion of the joint surface was observed. The details of this embodiment will be described below.

As a sample to be subjected to the cycle test, a sample was manufactured according to the following procedure.

As the soft side metal material, an aluminum alloy having a thickness of 3 mm and a diameter of 200 mm (JIS A3004)
A disk made of metal was prepared.

On the other hand, the hard side metal material has a thickness of 0.
A disk made of SUS430 having a diameter of 7 mm and a diameter of 150 mm was prepared. Further, a vase-shaped bite hole was formed by an electron beam on the joint surface of the hard side metal material. The bite hole (4)
The conditions for creating are as follows.

The bite hole (4) was formed in a spherical shape or a substantially spherical shape in each case, and was formed uniformly over the entire joint surface. The diameter of the opening of the biting hole is 0.5
.About.0.6 mm and the depth was 0.3 to 0.4 mm. The electron beam conditions are as follows: acceleration voltage 100 kv, filament current 19 to 20 mA, feed rate 200 mm / s,
The degree of vacuum was set to 1 × 10 ^{−4 to} 5 × 10 ⁻³ mmbar.

Next, the hard-side metal material is placed on the die, the soft-side metal material is placed thereon, and the forging machine is used to intermittently move from the soft-side metal material to the hard-side metal material. And the two parts are joined while the biting hole (4) is filled with a part of the soft side metal material by plastic deformation, and the groove (5a) provided in the die (5) is also filled with the protruding portion. (3)
Was formed. The joining energy applied from the forging tool at this time was 300 J.

Next, the hard-side metal material and the soft-side metal material are turned upside down and forged by using a die (6) different from that at the time of joining, and the I-shaped protruding portion ( 3)
Was pushed down toward the hard side metal material, and the protrusion (3) was crimped in an L shape.

Further, as a comparative example, a hard side metal material having a bite hole similar to that of the example and a soft side metal material are joined on a grooveless mold in which a protrusion (3) is not formed, A joining member joined only by the anchor effect in the bite hole (4) was prepared. The joining energy of this cooking utensil was set to 300 J, which is the same as in the example.

Next, a heat cycle test was performed on the examples and comparative examples, and then the specimen was vertically cut to observe the peripheral edge of the joint surface, and the peeling condition was observed. Table 1 shows the results. The heat cycle test was conducted at a heating rate of 50 ° C.
After raising the temperature to 500 ° C at 1 / sec, quenching with a refrigerant at -20 ° C,
This is repeated as one cycle.

[0034]

[Table 1]

Generally, the heat cycle test is performed for 150
It is evaluated that what does not cause peeling on the peripheral edge of the joint surface even after repeated times is practically usable as an electromagnetic cooking utensil, and it can be seen from Table 1 above that the product of the present invention satisfies this condition.

[0036]

As described above, according to the present invention, since the soft side metal material is partially filled in the bite hole of the required shape provided in the hard side metal material in the retaining state, the anchor is formed in this portion. The effect is exhibited, and metal materials having different hardnesses are strongly bonded. Furthermore, since the protruding portion provided on the soft metal material supports the peripheral edge of the hard metal material in a held state, peeling of the peripheral edge of the joint surface is effective even under conditions where heating and cooling are repeated. Can be prevented. Therefore, even when the dissimilar metal joining member according to the present invention is applied to an electromagnetic cooking utensil, it can be used stably for a long period of time.

[Brief description of drawings]

1A is a cross-sectional view schematically showing an example of an electromagnetic cooking utensil according to an embodiment of the present invention, and FIG. 1B is an enlarged cross-sectional view of a joint portion with the utensil body.

FIG. 2 is a schematic cross-sectional view showing a state in which a projecting portion is formed at the same time when the container body and the heating element are joined.

FIG. 3 is a cross-sectional view showing an intermediate state of manufacturing the dissimilar metal joining member according to the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of a method for caulking a protrusion.

[Explanation of symbols]

 1 ... Instrument body (soft side metal) 2 ... Heating element (hard side metal) 3 ... Projection part 4 ... Penetration hole 5, 6 ... Mold 5a ... Groove

Claims (1)

[Claims] 1. A member formed by joining metal materials having different hardnesses, wherein a cross-sectional area when virtually cut in a cross section parallel to the opening on a joining surface of the metal material on the hard side is larger than the area of the opening. Is also provided with a large pot-shaped bite hole, the metal material on the soft side is engaged in the bite hole in a filled state, and the peripheral portion of the metal material on the hard side is formed by the protrusion provided on the metal material on the soft side. A dissimilar metal joining member supported in a held state.