JPH0511538B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing a vibration-damping composite steel plate having excellent resistance weldability and high adhesiveness. [Background Art] In recent years, vibration damping composite steel plates have attracted attention as various noise prevention materials. The uses of this damping steel plate include:
It has come to be widely used in fields such as automobile parts, various machines, electrical parts, motor covers, and construction materials, but because the damping resin that plays a role in preventing vibrations is an electrical insulator, it is difficult to assemble. It has the disadvantage that it is impossible to weld unless a short circuit is provided during resistance welding such as spot welding during processing.
This has become a major obstacle in its use. Therefore, in order to eliminate the drawbacks of damping steel plates, a steel plate was embossed (Japanese Unexamined Patent Application Publication No. 1983-1999).
145142) etc. have been devised. [Problems to be Solved by the Invention] By the way, the means of embossing in the above-mentioned Japanese Patent Application Laid-Open No. 59-145142 is probably roll processing, judging from the contents disclosed therein. In this way, when a rollable embossing means is used, as shown in FIGS. 7 and 8, unevenness 102 is formed on both sides of the steel plate 101, and each unevenness 102 is rounded. It will be filled with. Note that FIG. 7 shows a damping steel plate in which only one steel plate is embossed, and FIG. 8 shows a damping steel plate in which both steel plates are embossed. Therefore, it is presumed that the effect of making the upper and lower steel plates electrically conductive cannot be expected to be very effective, and for this reason, in the invention, in order to increase the conductivity, the metal fibers mixed in the damping resin 103 are mixed at 3% by volume.
The conductivity is ensured by increasing the number of layers. By the way, if a large amount of metal fiber is mixed into the damping resin 103 for the purpose of improving resistance weldability, the adhesive strength between the damping resin 103 and the steel plate 101 and the damping performance, which is the original function of the damping steel plate, will be reduced. This is not desirable. Furthermore, if more expensive metal fibers are used, the cost of the damping steel plate will naturally increase. Therefore, the present invention was created with the aim of solving the above-mentioned problems and providing a method for producing a vibration damping steel plate that has excellent vibration damping performance, high adhesive strength, and is inexpensive and has excellent resistance weldability. It was done. [Means for Solving the Problems] The present invention provides a control system in which adhesive vibration damping resin mixed with conductive metal powder or metal fibers is interposed between two steel plates, and they are laminated by thermocompression bonding. The present invention relates to a method for producing a vibration-damping composite steel plate with excellent resistance weldability, characterized in that the joint surface of the steel plate with the vibration-damping resin is subjected to grid blasting treatment in advance. [Operation] Grid blasting is generally a polishing method in which grit (coarse particles that are contained in a powdered compound and do not align with other parts) is sprayed onto the item using compressed air or centrifugal force. In the invention, this means is applied to the joint surface of the steel plate with the damping resin. As shown in Fig. 1, the treated surface of the steel plate formed by this grid blasting treatment has concave portions 1 and convex portions 2 that are irregularly formed, and the sizes of the concave portions are sparsely scattered, and the concave portions are irregularly formed. It is characterized in that both the tip of the convex portion 1 and the corner of the convex portion 2 have acute angles. Therefore, as shown in FIG. 2, the contact area between the conductive metal powder 4 mixed in the damping resin 3 and the steel plates 5a and 5b increases, and the metal powder 4 is a small amount and small particles. Even in such a case, each steel plate 5
Good electrical conductivity between a and 5b can be ensured. Furthermore, in addition to the above-mentioned effect on electrical conductivity, when the steel plates 5a and 5b are thermocompression bonded via the damping resin 3, the sharp unevenness exerts a greater anchoring effect, and high adhesive strength is obtained. There are advantages. Although the case where the metal powder 4 is mixed into the damping resin 3 has been described, the same can be said when metal fibers are used. [Example] A steel plate with a thickness of 0.8 mm was subjected to grid blasting under the following conditions, the thickness of the damping resin was set to 0.07 mm, and the size of the metal powder particles was varied to produce a vibration-damping composite steel plate.

[Table] The reason why the shot material is gridded in the shot blasting process is to achieve the grinding effect of the grid, and the above particle size of the shot material is optimal for forming the required unevenness. Furthermore, the projection angle was set at 40 degrees ± 5 degrees in order not to damage the steel plate itself. The projection density was selected within the standard range. Note that a polyolefin resin was used as the damping resin, and iron powder was used as the metal powder, and the amounts thereof were two types, 0.5% and 1.0% of the volumetric capacity of the damping resin. In manufacturing a vibration-damping composite steel plate, the resin film described above is spread on a steel plate, metal powders according to the sizes shown in Tables 1 and 2 are dispersed on the resin film, and then another steel plate is coated. was placed on a resin film, passed through a hot pressure roll, and then pressure bonded using a hot press. The vibration-damping composite steel plates manufactured in this manner are then assembled into vibration-damping composite steel plates 11a and 11 as shown in FIG.
b Spot welded with comrades. Note that 12 is a spot welding electrode. The conditions for this spot welding are as follows.

[Table] Regarding the weldability of this example, Table 1 shows the case where the metal powder dispersion amount is 0.5%, and Table 2 shows the case where the metal powder dispersion amount is 1.0%. Weldability was good. In other words, metal powder with a diameter of #(+)250 to (-)200 or more can be welded with a dispersion amount of 0.5% by volume, and metal powder with a diameter of #(-)250 can be welded with a dispersion amount of 1.0.
It can be understood that welding is possible even if the volume is %. However, each number indicates a mesh (German style), and the symbols in parentheses indicate + for what remains when sifted through that mesh, and - for what falls through the mesh. Therefore, the metal powder diameter is #(-)250 (the powder diameter is
0.062 mm or less), it is now possible to weld with a dispersion amount of 1.0% by volume, so the diameter of the metal powder dispersed as a conductive material in the damping resin layer is 90 to 100% of the thickness of the damping resin layer. It is possible to produce a vibration-damping composite steel plate that can sufficiently ensure resistance weldability even if the resistance weldability is small. Adhesion was also investigated, and the results of shear strength and T-peel strength as shown in FIGS. 4 and 5, respectively, were obtained. From this result, the product of the present invention has almost no influence from metal powder and has high strength. Furthermore, in order to examine the vibration damping function, the loss coefficient was measured, and as shown in FIG. 6, excellent vibration damping performance was obtained that was the same as when no metal powder was mixed. [Effects of the Invention] As described above, the present invention makes it possible to manufacture a vibration-damping composite steel plate with excellent resistance weldability, and
To provide a vibration-damping steel plate that maintains high adhesiveness between a vibration-damping resin and a steel plate without being affected by metal powder or metal fibers, and also has excellent vibration-damping properties, which are its original characteristics. Furthermore, since it has become possible to improve resistance weldability, the amount of dispersion of metal powder and metal fibers can be reduced, and vibration damping steel plates with the required properties can be manufactured at low cost. It is also owned.

【table】

【table】 [Brief explanation of the drawing]

Figures 1 and 2 are diagrams for explaining the basic concept of the present invention. Figure 1 is a cross-sectional view showing the surface of a steel plate when grid blasting is applied to the steel plate, and Figure 2 is a vibration damping diagram. A cross-sectional view of a composite steel plate is shown. FIG. 3 shows a schematic diagram of spot welding vibration-damping composite steel plates together. Figure 4 is a graph showing the shear strength of a damping composite steel plate, with the horizontal axis showing the mesh range showing the particle size of the metal powder and the vertical axis showing the shear strength. The mesh range indicating the diameter is plotted on the vertical axis by T.
Figure 6 is a graph showing the peeling strength of the vibration-damping composite steel plate. A graph showing vibration characteristics is shown. FIGS. 7 and 8 show cross-sectional views of conventional damping steel plates. 1... Concave portion, 2... Convex portion, 3... Vibration damping resin, 4
... Conductive metal powder, 5a, 5b ... Steel plate, 11
a, 11b... vibration damping composite steel plate, 12... electrode for spot welding.

Claims (1)

[Claims] 1. In a method of manufacturing vibration-damping composite steel plates in which two steel plates are laminated by interposing adhesive vibration-damping resin mixed with conductive metal powder or metal fibers and bonding them under heat, vibration damping of steel plates is performed. A method for manufacturing a vibration-damping composite steel plate with excellent resistance weldability, characterized by applying grid blasting treatment to the joint surface with resin in advance.