JPH0428483A - Manufacturing method of honeycomb structure material - Google Patents

Abstract

PURPOSE:To improve joining strength of the honeycomb structural material without generating strain or a dent by applying a pulsative current for a specified time to two steel plates and a corrugated steel plate while these plates being pressurized by two rolls facing each other separately and capable of energizing. CONSTITUTION:The two steel plates 1 and 2 and the corrugated steel plate 3 are passed while being brought into contact with the two rolls 4 and 5 facing each other separately and capable of energizing. At this time, the two rolls pressurize the temporarily fixed two steel plates 1 and 2 and corrugated steel plate 3. At the time of this pressurization, the honeycomb structural material is the subjected to resistance welding by passing the instantaneous pulsative current of <=5ms. Accordingly, welding where the joining strength can be maintained stably can be performed without generating the strain and dent.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a honeycomb structure material in which a corrugated steel plate is sandwiched between two steel plates.

(Conventional technology) Traditionally, the most widely used technology for reducing the weight of products is to improve the strength of the material, thereby reducing the thickness of the material used in the product while maintaining the strength of the product. The goal is to reduce Of course, there are other technologies other than those that improve the strength of materials, such as replacing the material itself with other materials that have higher strength and lower specific gravity. has greatly contributed to reducing the weight of various products.

However, a common problem with these technologies is that as materials become thinner, material and product stiffness (e.g., tensile stiffness)
is to decrease.

Therefore, techniques to prevent such a decrease in rigidity due to thinning of the material have been studied.
For example, a material with a corrugated cross-section is sandwiched between two sheets of thinner material, and these are combined to create a so-called sandwich structure (honeycomb structure), which solves the problem of reduced rigidity caused by thinning. Measures to eliminate and improve these conditions are widely used.

Currently, there are a wide variety of products that use this type of honeycomb structure. Specific examples of such products include, for example, paper, which is widely known as cardboard, plastics, and even metal materials (for example, steel plates), of which there are a large number of Class 11 products.

Among these, the characteristics of honeycomb structure materials made of metal materials are:
- For boat fishing, it has greater strength and superior heat resistance when compared to honeycomb structure materials made of other materials.

FIG. 1 shows the cross-sectional shape of a honeycomb structure material made of a steel plate, which is a typical example of a honeycomb structure material made of a metal material.

In FIG. 1, 1 and 2 are an upper plate and a lower plate made of steel plates as skin materials, respectively. Between these upper plate 1 and lower plate 2 is a corrugated plate made of a steel plate with a corrugated cross-sectional shape. 3 is being held.

As you can see from Figure 1, between the two upper and lower steel plates,
These steel plates, namely the upper plate 1,
It is necessary to join the lower plate 2 and the corrugated plate 3.

The bonding method currently used in -C is bonding with adhesive. For example, an epoxy resin-based adhesive is applied to the surface of a corrugated steel plate and then joined.

Further, as a joining method other than adhesion, there is a method using brazing material. This consists of an upper plate 1, a lower plate 2, and a corrugated plate 3 fixed so that the cross-sectional shape is as shown in FIG.
Brazing material is a means of joining by dipping it into oak.

(Problems to be Solved by the Invention) By these methods, it is possible to manufacture a honeycomb structure material that satisfies various required performances (particularly strength).

By the way, when comparing honeycomb structural materials made of steel plates and honeycomb structural materials made of other materials, the advantage of the honeycomb structural materials made of steel plates in large quantities is that they are resistant to heat.

However, the heat resistance of honeycomb structural materials bonded using the above-mentioned methods, for example, with adhesives, is effectively controlled by the heat resistance of the adhesive, and the heat resistance of the honeycomb structural materials as a whole does not improve, and is essentially a steel plate. The excellent heat resistance that should be possessed by the honeycomb structure material made of the material is not effectively exhibited.

In addition, in the case of honeycomb structural materials joined by brazing material,
As mentioned above, it is necessary to newly install cypress wood for the brazing material during the manufacturing process. Therefore, this increases manufacturing costs due to additional steps, which is unfavorable in terms of production efficiency.In addition, the solder metal adheres not only to the points to be joined but also to the entire surface, and the heat resistance varies depending on the thermal properties of the solder metal. As a result, the excellent heat resistance of the steel plate used as the material cannot be effectively utilized, as in the case of adhesives.

That is, with these manufacturing methods for honeycomb structural materials in which a steel plate with a corrugated cross-sectional shape is sandwiched between two steel plates, it is difficult to manufacture honeycomb structural materials with excellent heat resistance.

Therefore, as a method to solve the above-mentioned problem, welding may be used instead of adhesion or brazing material. f! 7j
An example of I-welding is resistance welding (seam welding) in which spot welding is performed continuously by using two disc-shaped electrodes and rolling the electrodes under pressure.

(Problem to be Solved by the Invention) However, according to studies conducted by the present inventors, it is possible to join a honeycomb structural material made by sandwiching a corrugated steel plate between two steel plates by resistance welding. It has been found that the following problems may occur. In other words, ■The heat generated during welding causes distortion in the upper plate 1, the lower plate 2, and the corrugated plate 3, which impairs the accuracy of the joint.■As mentioned above, distortion and indentations occur during welding. In order to prevent (1) and (2) above, if the welding heat input is reduced by adjusting the welding droplet as appropriate, the welding strength will be reduced.

Here, the object of the present invention is to provide a honeycomb structure that can solve the problems shown in (1) to (3) above when joining a honeycomb structure material formed by sandwiching a corrugated steel plate between two steel plates by welding. The object of the present invention is to provide a method for manufacturing materials.

(Means for Solving the Problems) The present inventors have conducted various studies in order to solve the above problems.

First, we examined in detail what causes the above-mentioned problems.

As a result, we obtained the following knowledge.

In other words, when performing resistance welding by applying a continuous waveform current (regardless of direct current or alternating current) that is commonly used when performing seam welding, in order to obtain sufficient welding strength, the welding speed must be adjusted. The appropriate current value is selected accordingly. If this current value is insufficiently selected, for example, in addition to the joint shown in Figure 1, the surrounding area will also be heated, causing distortion called an indentation on the surface of the plate in contact with the joint of the upper plate 1 and the lower plate 2. I do it,
Its surface also changes color due to heat. Furthermore, since the area around the part of the corrugated sheet 3 that comes into contact with the joint is also heated, it is deformed by the pressure applied by the energized roll, making it impossible to obtain the desired dimensional accuracy (shape).However, in order to prevent these problems, If the current value is reduced, satisfactory bonding strength cannot be obtained.

Therefore, as a result of further studies, the present inventors decided to change the current waveform applied during resistance welding by applying pulsed current with repeated instantaneous interruptions, instead of the general continuous current (including DC and AC). We have demonstrated that it is possible to perform welding that does not generate distortion or indentations and can ensure stable joint strength.

However, such pulsed energization is also used in conventional seam welding, and the present inventors further investigated what causes such a difference.

As a result, by applying pulsed energization with an extremely short energization time of 5 ms or less, which is not used in conventional seam welding, it is possible to perform welding that does not generate distortion or indentations and can stably ensure joint strength. After discovering that it is possible, the present invention was completed.

Here, the gist of the present invention is a method for manufacturing a honeycomb structural material in which a corrugated steel plate is sandwiched between two steel plates, the corrugated steel plate being arranged between the two steel plates. After that, while pressing the two steel plates and the corrugated steel plate using two rolls that face each other in a spaced manner and can be energized, the two steel plates and This is a method for manufacturing a honeycomb structure material, which is characterized by resistance welding corrugated steel plates.

In the present invention, "pulsed current with a current application time of 5 ms or less" refers to a current whose current value changes intermittently by repeated application and rest, and the maximum value of one application time is 5 S. The rest time is not particularly specified, and can be determined based on the rotational speed of the energizing roll and the number of bonding points required per unit length (area).The current value when energized is 1. It may be adjusted in proportion to the area to be bonded per pulse.

(effect) Hereinafter, the present invention will be explained in detail together with its effects.

Briefly, the present invention has the following features.

First, a corrugated steel plate is temporarily fixed between two opposing steel plates. The temporary fixing means is not limited in any way. For example, as shown in FIG. Also, as shown in Figure 3,
When manufacturing from a steel plate cut to predetermined dimensions, 2
A steel plate and a corrugated steel plate are passed through two rolls that face each other at a distance and are energized while being in contact with each other. At this time, the two rolls press the two temporarily fixed steel plates and the corrugated steel plate. The rolling blade during this pressing is adjusted to a value that is greater than or equal to a value that does not cause a cut in the joint portion and less than a value that does not deform the steel plate due to the rolling blade.

During this pressing, in the present invention, the honeycomb structure material is resistance welded by applying an instantaneous pulsed current of 3 or less. In this case, the two steel plates and the corrugated steel plate may be a continuous coil, or may be a steel plate cut into predetermined dimensions.
The figure is a schematic cross-sectional view showing the case of manufacturing from continuous coils.

On the other hand, Fig. 3 uses a steel plate cut to predetermined dimensions.
FIG. 2 is a schematic cross-sectional view showing a case where a honeycomb structure material is manufactured in a batch manner.

In FIG. 2, an upper plate 1, a lower plate 2, and a corrugated plate 3 unwound from a payoff reel (not shown) are pressed by energized rolls 4 and 5.

In the example shown in FIG. 3 in which a steel plate cut into predetermined dimensions is used, the traveling direction of the materials to be joined may be either the direction a or the direction b.

As mentioned above, the reason why the current waveform is a pulsed current is because
This is because when a continuous current is applied, the surroundings other than the welded area are heated depending on the welding conditions, causing distortions called indentations on the plate surface and discoloration due to the heat generated during welding.

Furthermore, since the periphery of the corrugated plate 3 in contact with the joint portion is also heated, if the applied current value is lowered, a satisfactory strength cannot be obtained.

In addition, in conventional seam welding, pulsed energization (for example, repeating several cycles of energization followed by several cycles of rest) was sometimes performed, but with such conventional pulsed energization, basically, There cannot be a significant difference in the bonding situation and the above-mentioned problem cannot be avoided, that is, the instantaneous "pulse-like current" in the present invention
This is a pulsed current that repeats energization and rest, and the time for one energization is up to 5-3. The reason why the maximum value of the energization time is set to 5 ms is because if a current that exceeds 5 ms is passed continuously, the bonding situation will be similar to the case of continuous energization described above. This is because it cannot be achieved. In other words, the energization time is 5-
With a pulsed current of 5 or less, only the bonding interface is heated and melted, and the surrounding area is not significantly affected by heat, so problems such as distortion and poor shape can be completely solved.

Note that the current application time in the present invention depends on the thickness of each material (third
If the thickness of each plate (see 1.2.3 in the figure) becomes thinner, it is desirable to set the time shorter than the maximum value of 5 ms. Also, the current value should be set appropriately considering the area to be bonded per pulse. Since the energization time is shorter than in the case of conventional continuous energization, the current must be increased accordingly.

In this way, by applying a pulsed current with a current conduction time of 5+*s or less, it is possible to join two steel plates and a corrugated steel plate while solving the conventional problems, and between the two steel plates. A honeycomb structure material can be manufactured by sandwiching corrugated steel plates having a corrugated cross-sectional shape.

As described in detail above, according to the present invention, it is possible to perform welding that does not cause distortion or indentations and can stably ensure joint strength.

Further, the present invention will be explained with examples, but these are merely illustrative examples of the present invention, and the present invention is not limited thereby.

(Example) In FIG. 3, a honeycomb structure material was manufactured using steel plates 1.2 and 3 made of low alloy steel and having a plate thickness of 0.3 m.

The manufacturing method is a batch method shown in Figure jR3. Further, the roll pressing distance was set to b shown in the figure. The moving speed of the roll is Is/mf, which is 200 m5+ in the product.

The results are summarized in Table 1 along with the conditions.

Note that the bonding strength in Table 1 was determined by a beer test, and cases in which interfacial peeling occurred were judged as failures (x marks), and cases in which fractures penetrated into the base material were judged as passes (marks O).

In addition, the appearance and accuracy will be judged by the degree of depression on the board surface after joining, and specifically, the maximum depression depth is 20
Pass those that are below jjI (O mark), 20 to 100-
A test result of 100- or more was considered a failure (marked with Δ), and a score of 100- or higher was judged as a failure (marked with an x).

Table 1 (Note) is outside the scope of the present invention As shown in Table 1, it can be seen that the samples that satisfy the current application conditions within the scope of the present invention are excellent in bonding strength, appearance, and accuracy.

(Effects of the Invention) As detailed above, according to the present invention, it has become possible to perform welding that does not generate distortion or indentation and can stably ensure joint strength.

The practical effects of the present invention having such effects are extremely remarkable.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a honeycomb structural material; FIG. 2 is a schematic explanatory view showing an example of implementing the present invention using continuous coils; and FIG. FIG. 2 is a schematic explanatory diagram showing an example of carrying out the present invention using a steel plate cut to the dimensions of FIG.

Claims (1)

[Claims] A method for manufacturing a honeycomb structural material consisting of a corrugated steel plate sandwiched between two steel plates, the method comprising: placing the corrugated steel plate between the two steel plates, and then separating and opposing two energized steel plates. A honeycomb characterized in that the two steel plates and the corrugated steel plate are resistance welded by applying a pulsed current for a duration of 5 ms or less while pressing the two steel plates and the corrugated steel plate with a roll. Method of manufacturing structural materials.