JPH06141977A - Electromagnetic three-layer structured griddle with excellent anti-corrosiveness and thermal conductivity - Google Patents

Abstract

PURPOSE:To improve the thermal conductivity and anti-corrosiveness of a griddle for an electromagnetic cooking apparatus and construct the griddle light in weight. CONSTITUTION:An electromagnetic three-layer structured griddle having excellent anti-corrosiveness and thermal conductivity is composed of a facial layer made from a stainless steel plate excellent in the anti-corrosiveness, an intermediate layer made from aluminum or an aluminum alloy excellent in the thermal conductivity, and a bottom layer made from a carbon steel plate or stainless steel plate having magnetism.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a stainless steel plate for a surface layer to improve corrosion resistance, an intermediate layer for aluminum or aluminum alloy to improve thermal conductivity, and further for weight reduction, and a bottom layer. The present invention relates to a griddle for an electromagnetic cooker using a carbon steel plate or a steel plate having magnetic properties.

[0002]

2. Description of the Related Art FIG. 1 is a view for explaining the outline of a griddle used in an electromagnetic cooker. As shown in FIG. 1, a part of the griddle is heated by the electromagnetic waves generated by the electromagnetic cooker, and the heat is transferred to the cooking range by the heat conduction of the griddle itself and heated to the cooking temperature.

Since the first condition is that the griddle is a magnetic material, a carbon steel plate or a magnetic stainless steel plate has been conventionally used. In the process of increasing the temperature of the griddle, the griddle is deformed due to the temperature difference between the heat generating portion and its periphery due to electromagnetic induction. This deformation increases as the plate thickness of the griddle becomes smaller.
20 mm is often used.

[0004]

However, as the plate thickness of the griddle becomes thicker, it takes time to raise the temperature up to the cooking temperature, and it is required to shorten the heating time. The weight of the griddle is 16 mm thick, 400 mm wide, and 60 mm long.
It is as heavy as about 30 kg at 0 mm, and it is required to be lightweight in terms of handling. Furthermore, the aesthetics of the surface of the griddle is important, and corrosion resistance is required.

In view of the above circumstances, it is an object of the present invention to improve the thermal conductivity and corrosion resistance of the griddle for an electromagnetic cooker, and at the same time, reduce the weight.

[0006]

As a result of intensive studies, the present inventor has found that the problem can be solved by forming the griddle from three specific layers instead of a single body, and has completed the present invention.
In the present invention, (1) a carbon steel plate or a stainless steel plate, which is a magnetic material, is arranged in the bottom layer to secure electromagnetic properties, and (2) aluminum or aluminum alloy having excellent thermal conductivity from the bottom layer is arranged in the intermediate layer. Then, the thermal conductivity is improved, the weight is further reduced, and (3) the stainless steel plate is arranged in the surface layer to improve the corrosion resistance, thereby improving the corrosion resistance, thereby improving the problem.

That is, according to the present invention, the surface layer is composed of three layers of stainless steel plate having excellent corrosion resistance, the intermediate layer is made of aluminum or aluminum alloy having excellent thermal conductivity, and the bottom layer is made of magnetic carbon steel plate or stainless steel plate. The gist of the invention is an electromagnetic three-layer structure griddle excellent in corrosion resistance and thermal conductivity.

The present invention will be described in more detail.

(1) Improvement of thermal conductivity and weight reduction The reason why the griddle is deformed during the temperature rising process of the griddle is due to the temperature difference between the heat generating part and its surroundings due to electromagnetic induction. In order to reduce this temperature difference, it is necessary to quickly transfer the heat generated by electromagnetic induction to the surroundings. In this respect, the thermal conductivity of carbon steel is 0.17 cal / cm · deg (0
As low as ~ 100 ° C, as far as this thermal conductivity is concerned, aluminum (thermal conductivity 0.53 cal / cm · deg (0
It is conceivable to use a material having a good thermal conductivity such as -100 ° C).

However, since aluminum is a non-magnetic substance and does not generate heat in the electromagnetic cooker, in the present invention, the aluminum material is bonded to the upper surface of the carbon steel plate or the stainless steel plate, and the heat generated by the carbon steel plate or the stainless steel plate is applied to the aluminum. We adopted a method to quickly convey it to the surroundings depending on the material. By thus constructing a part of the carbon steel plate or the stainless steel plate with the aluminum material, it was possible to reduce the weight of the griddle.

The explosive pressure bonding method is preferred for joining the carbon steel plate and aluminum.

(2) Improvement of Corrosion Resistance In order to improve the corrosion resistance, the surface (cooking surface) of the aluminum material was entirely covered with a corrosion-resistant stainless steel plate. The aluminum material and the stainless steel plate are preferably joined together by the explosive pressure bonding method.

It is important that the griddle of the present invention has a three-layer structure made of a specific material as described above. To explain the layer thickness, the surface layer has a thickness of 0.3 to 2 mm, and the entire griddle has a layer thickness. Is about 6 to 12 mm, preferably about 8 mm. Further, it is preferable that the bottom layer plate thickness ratio is 10 to 75% of the total thickness of the griddle.

The surface layer has only to have a thickness for ensuring corrosion resistance, and it is preferable that the surface layer also has a beautiful appearance. Generally used cooking pans with a multi-layered structure have a surface layer on the cooking side of at least 0.2 mm or more to ensure durability as a utensil, but in the case of a griddle, such as a knife. Since the cooking utensil may directly act on the cooking side surface, it is preferable to make it somewhat thicker in terms of durability. However, if it is too thick, the heat transfer effect from the intermediate layer may be impaired, which is not preferable. Therefore, the surface layer of the griddle of the present invention is
As described above, it is preferably 0.3 to 2 mm.

The bottom layer may have a plate thickness capable of generating heat by electromagnetic induction, but this plate thickness varies depending on the output of the electromagnetic cooker and the distance between the electromagnetic cooker and the griddle. Cannot be specified. Generally, a plate thickness of 1 mm or less produces sufficient heat, but when used as a griddle, it is necessary to raise the temperature of the surface layer to a temperature at which cooking is possible. It is closely related to plate thickness. For example, if the temperature of the surface layer rises slightly longer than the total thickness of the griddle, but if uniform heating is required in a wide range, the bottom layer should be thin and the intermediate layer should be thick. It is preferable to use the above griddle. Further, when it is necessary to reach the cooking temperature only in a narrow area of the surface layer in a short time, it is preferable to use a griddle having a thin intermediate layer and a thick bottom layer. Therefore, in the griddle of the present invention, the plate thickness of the bottom layer is preferably 10 to 75% of the total thickness of the griddle as described above.

Furthermore, regarding the total thickness of the griddle,
As described above, it is about 6 to 12 mm. This is because it is preferable that the thickness is thicker than about 6 mm in order to prevent deformation due to heating, but an electromagnetic cooker with a low output often has a narrow cooking range, and therefore a small-sized griddle is used. In this case, since the deformation due to heating becomes small, a thinner griddle can be used.
Further, since the griddle of the present invention has a three-layer structure, the time required for the temperature rise on the cooking side surface can be shortened and the soaking property of the surface can be greatly improved.
This effect can be exhibited even by increasing the thickness of the entire griddle by changing the plate thicknesses of the intermediate layer and the bottom layer. Therefore, in the griddle of the present invention, it does not make much sense to make the whole thick, and a function for cooking of about 12 mm is sufficient.

[0017]

【Example】

Example 1 A stainless steel plate having a thickness of 1 mm was used as a surface layer, an aluminum plate having a thickness of 5.5 mm was used as an intermediate layer, and a carbon steel plate having a thickness of 2 mm was used as a bottom layer.
A flat three-layer griddle having a width of 400 mm and a length of 600 mm was manufactured. Further, for comparison, flat griddles having a width of 400 mm and a length of 600 mm were made from carbon steel plates having thicknesses of 8 mm and 16 mm, respectively, by machining.

Then, the following comparative tests were carried out on the three types of griddles.

(1) Each griddle is placed on an electromagnetic cooker (heating range: within a circle of 200 mm in diameter) so that the centers of the griddles coincide with each other, and the output of the electromagnetic cooker is set to a maximum of 3 kW so that the surface temperature of the griddle center is The output was stopped immediately after reaching 200 ° C. The surface temperature distribution and the amount of deformation of the griddle at that time were measured. The results are shown in Table 1.

The amount of deformation was measured as follows. 1000m effective length specified in JISB7514
Using a straight edge ruler of m, the strain in the width direction, the length direction and the diagonal direction of the griddle is measured by a skimmage gauge, and the maximum value is expressed as the deformation amount.

[0021]

[Table 1]

From the results shown in Table 1, the griddle according to the present invention is compared with the commonly used griddle 16 mm,
The arrival time at the center of 200 ° C. is reduced to about 1/2, and the temperature difference in the peripheral portion is small and the heat uniformity is excellent. further,
The weight is also 1/3 of the 16mm griddle.
In addition, Table 1 shows that when the method of thinning the griddle of the conventional material constitution is adopted in order to shorten the heating time to the cooking temperature, the arrival time until the center of the griddle reaches 200 ° C. is almost the same level as that of the present invention. In order to achieve this, it is necessary to set the thickness to about 8 mm. However, in that case, the amount of deformation is too large, and the soaking property and weight are also inferior to those of the present invention.

(2) As in (1), each griddle is placed on the electromagnetic cooker, the output of the electromagnetic cooker is set to a maximum of 3 kw, and immediately after the surface temperature at a radius of 200 mm from the center of the griddle reaches 150 ° C. Stopped output.

The surface temperature distribution and the amount of deformation of the griddle at that time were measured. The results are shown in Table 2.

[0025]

[Table 2]

From the results shown in Table 2, in the griddle according to the present invention, the arrival time of the surface temperature at the position of the radius of 200 mm from the center is shortened to about 1/3 in comparison with the commonly used griddle of 16 mm, Also, compared to a griddle having a thickness of 8 mm for shortening the heating time, it is significantly shortened. Moreover, the temperature difference in the peripheral portion is smaller and the heat uniformity is excellent. Also, it can be seen that the amount of deformation is greatly improved as compared with the 8 mm griddle.

Example 2 A stainless steel plate having a thickness of 1 mm as a surface layer, an aluminum plate having a thickness of 5.5 mm as an intermediate layer, and a carbon steel plate having a thickness of 2 mm as a bottom layer were joined by explosive compression bonding,
A flat three-layer structure griddle having a width of 400 mm and a length of 600 mm was manufactured. For comparison, a flat griddle having a width of 400 mm and a length of 600 mm was manufactured by machining from a carbon steel plate having a thickness of 8 mm.

Then, the following comparative tests were carried out on the two types of griddles.

(1) Each griddle is placed on an electromagnetic cooker (heating range: within a circle of 200 mm in diameter) so that the centers thereof coincide with each other, and the output of the electromagnetic cooker is set to a maximum of 2 kW,
The output was stopped immediately after the surface temperature at the center of the griddle reached 200 ° C. The surface temperature distribution and the amount of deformation of the griddle at that time were measured. The results are shown in Table 3.

[0030]

[Table 3]

From the results shown in Table 3, the griddle according to the present invention is excellent in heat uniformity as compared with the 8 mm griddle,
It is also seen that the amount of deformation has been greatly improved.

(2) As in (1), each griddle was placed on the electromagnetic cooker, the output of the electromagnetic cooker was set to a maximum of 2 kW, and immediately after the surface temperature at a radius of 200 mm from the center of the griddle reached 150 ° C. Stopped output.

The surface temperature distribution and the amount of deformation of the griddle at that time were measured. The results are shown in Table 4.

[0034]

[Table 4]

From the results of Table 4, the griddle according to the present invention has a radius of 200 mm from the center when compared with the 8 mm griddle.
The time to reach the surface temperature of mm is reduced to about 1/2,
Moreover, the temperature difference in the peripheral portion is small, and the heat uniformity is excellent.
Also, it can be seen that the amount of deformation is greatly improved.

[0036]

As described above, the present invention has a three-layer structure using a magnetic carbon steel plate or stainless steel plate for the bottom layer, aluminum or aluminum alloy for the intermediate layer, and a stainless steel plate for the surface layer. By using the griddle consisting of, the thermal conductivity and corrosion resistance are superior to the conventional griddle composed of a single steel plate, and the temperature of the entire griddle can be raised more uniformly in a short time, and thermal efficiency is improved. Is excellent. Further, the griddle of the present invention not only can be significantly reduced in weight by replacing a part of the conventional steel sheet with an aluminum material, but also the griddle of the present invention has a three-layer structure, which makes it possible to reduce the weight. Since the deformation is improved, the plate thickness itself can be made thinner than the conventional one, and from this point also, it is possible to contribute to weight reduction.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a griddle for an electromagnetic cooker.

Claims (1)

[Claims] 1. Corrosion resistance and heat composed of a stainless steel plate having a surface layer having excellent corrosion resistance, an aluminum or aluminum alloy having an intermediate layer having excellent thermal conductivity, and a carbon steel plate having a bottom layer having magnetism or a stainless steel plate. Electromagnetic 3-layer griddle with excellent conductivity.