JPH04193532A - Conductive-type vibration-proof composite steel plate and production thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Second Industrial Application Field This invention is a conductive vibration-damping steel plate that can be subjected to electric resistance welding such as spot welding during processing, and is a conductive steel plate in which metal powder is impregnated in the resin of the intermediate layer. This article relates to technology for improving the electrical conductivity of type composite damping steel plates.

[Prior Art] Composite vibration-damping steel plates, which have a resin layer sandwiched between two steel plates as an intermediate layer, are used in the fields of architecture, machinery, vehicles, etc. as an inexpensive material that has soundproofing and heat insulation effects as well as strength. It is usefully used. Naturally, processing techniques used for general metal plates are also required to be applied to composite damping steel plates, one of which is electric spot welding. ! In spot welding, the composite 5fIA plate and the mating metal plate to be welded are placed on top of each other and sandwiched between electrodes, and a voltage of 8i is applied to conduct electricity for a short time at a high current density. A necessary amount of welding current is required to flow between these steel plates to weld them together. However, resin itself is originally a non-conductor and is not suitable for the purpose of passing a large amount of current.As a way to solve this problem, it has been conventionally considered to make resin conductive.

One method of making the resin conductive is to mix conductive particles into the resin layer, and carbon or metal has been used as the particulate material. For example, in Japanese Patent Application Laid-Open No. 63-57226, N1
Metal powder such as copper, stainless steel, etc. is used as the appropriate material, and 2 to 10 + yt% of metal powder containing 13 wt% or more of particles with a particle size of 0.8 to 15 times the thickness of the resin layer is mixed into the resin. A resin-laminated steel plate in which a synthetic resin is adhered to a steel plate is disclosed.

[Problem H to be solved by the invention] However, in electric spot welding, there is a strong desire to bring the conductivity of a composite vibration-damping steel plate as close as possible to that of a metal plate, and therefore it is necessary to use conductive metal powder as described above. Even if the particles are mixed into the resin by selecting the particle size and determining the mixing amount, as in the technology used in .

This invention was made to solve this problem.
The object of the present invention is to provide a composite damping steel plate that does not cause welding defects by fully utilizing the conductivity of metal particles and reliably bringing about its effects.

[The means to solve the problem and achieve this objective is to use 20w of metal powder whose particle height is the same as the thickness of the resin layer and whose hardness is Hv100 or less.
A conductive composite vibration damping steel plate comprising a resin layer containing t% or more and 30wt% or less and an intermediate layer, and steel plates crimped on the top and bottom of the resin layer, and a manufacturing method thereof, the manufacturing method comprising: When manufacturing a conductive composite vibration damping steel plate having a resin layer formed by pressing a steel plate and forming a resin film as an intermediate layer, the metal powder is contained in an amount of 20 wt% or more and 30 wt% or less, and the particle size of the metal powder is smaller than that of the resin layer. Using a resin film having a thickness of 12 times or more and 1.5 times or less and a hardness of HV100 or less, after crimping the upper and lower steel plates and the resin film, successively using a reduction blade smaller than the reduction blade for this crimping, and This is a method for manufacturing a conductive composite vibration damping steel sheet in which re-rolling is performed while the resin of the resin film is molten.

[Function] The metal powder that exists in the resin layer of the composite damping steel plate and whose particle height is the same as the thickness of the resin layer directly contacts the upper and lower steel plates, and prevents other particles from coming into contact with the upper and lower steel plates. The composite damping steel plate made of such an intermediate layer has good electrical conductivity. However, as will be described later, it is difficult to manufacture such a damping steel plate without using soft metal powder having a hardness of HvlO-0 or less. Further, the higher the mixing density of metal powder in the resin, the higher the conductivity can be expected, but if it is too high, the adhesion between the resin and the steel plate will be reduced, so the mixing rate is set to 20w% or more and 30wt% or less.

FIG. 1 is a diagram showing an outline of the manufacturing process of a conductive composite damping steel sheet according to the present invention, in which 1 is a reroll roll, 2 is a cooling furnace, 4 is a pressure roll, 5 is a laminating roll, and 6 is a spare roll. A heating furnace, 7 a cleaning device, 8 a lower plate, 9 an upper plate, and 10 a resin film. The surfaces of the upper plate 9 and the lower plate 8 are cleaned by a cleaning device 7 and then heated in advance in a preheating furnace 6. Next, a resin film 10 is applied to the lower plate 8 using a laminating roll 5, and then heated in a heating furnace 3 to a temperature several tens of degrees higher than the melting point of the resin. Thereafter, this lower plate and the upper plate 9, which has become the same temperature as the lower plate through preheating, are once crimped by a crimping roll 4, and then further pressurized by a re-pressing roll 1, and then cooled in a cooling furnace 2. A conductive composite damping steel plate is completed.

In a conductive composite vibration damping steel plate whose intermediate layer is a resin film mixed with metal powder, the upper and lower plates (hereinafter referred to as upper and lower plates) are brought into contact with the metal powder by crimping. A conductive circuit is formed, which becomes the welding current circuit. However, when considering in detail the situation in which the pressure roll is applied, it is found that sufficient contact between the upper and lower plates and the metal powder is not necessarily obtained during pressure bonding. Figure 3 shows the state during crimping. In the figure, 11 is metal powder and 12 is resin. The pressure rolls 4 sequentially apply pressure from above and below to the composite material that enters between the rolls, so the resin 12 is pressed against the upper plate 9, and the air hidden between the steel plate and the resin is pushed out in the opposite direction, and The metal powder 11 is crushed. At this time, if the particle size of the metal powder is larger than the thickness of the resin layer, the metal powder is crushed to the thickness of the resin layer. FIG. 2 shows the state of the metal powder during crimping, and the crushed metal powder 11 is in direct contact with the upper plate 9 and the lower plate 8. At this time, in order to increase the contact area of - metal powders, it is better to have a larger particle size. However, if the particles are large, air bubbles are likely to be drawn in during crimping, and the amount of return after pressure removal is also large, which may increase the distance between the upper and lower steel plates. That is, ideally, the particle size should be slightly larger and uniform than the thickness of the resin layer, but in practice, it is appropriate that the particle size be 1.2 times or more and 1.5 times or less the thickness of the product resin layer. be. Also, if the metal powder is hard, it is difficult to crush it to a uniform height, but if the metal powder is soft and the hardness is Hv100 or less, the height of the crushed metal powder will be uniform, and the metal powder will be in direct contact with the steel plate. will increase. However, when the crimped composite steel plate passes through the crimping roll, the rolling blade is released and the gap between the metal powder and the upper and lower plates is determined by the difference between the return of the metal powder and the return of the resin, and the fluidity of the resin. A small amount of resin gets into the area. FIG. 4 schematically shows such a state. Since this slight thin resin film impedes the conductivity of the composite damping steel plate, subsequent pressure bonding is followed by re-pressing to drive out this resin and bring the steel plate into direct contact with the metal powder. If pressure is subsequently applied again after pressure bonding, the resin is still in a molten state and the thin film easily flows out. Further, since the time at which this re-compression is performed is also the cooling shrinkage process of the resin, the effect of re-compression of the resin and the steel plate is also obtained, and the adhesion strength thereof is also improved. During this re-compression, the metal powder should not be crushed, but should only be compared with the resin. However, if the height of the metal powder is reduced, there is a risk that a gap will again occur between the metal powder and the steel plate. Therefore, re-rolling must be performed with a lower rolling force than that used during crimping.

Note that it is appropriate that the metal powder is soft and does not change its physical properties during use, and Sn, Zn, Ni powder, etc. are used. N1 powder generally has a hardness exceeding lvloo, but it can be softened by annealing at 600°C to 800°C. Further, metal-plated steel sheets such as cold-rolled steel sheets, hot-dip Zn-plated steel sheets, electrolytic Zn-plated steel sheets, and alloy-plated steel sheets thereof are used as the steel sheets.

The film is made of polyolefin resin such as polyethylene or polypropylene, or polyvinyl chloride, polyester,
A thermoplastic resin such as polyisobutylene is used.

[Example] A conductive composite was prepared under the conditions of the present invention using alloyed hot-dip Zn-plated steel sheets with a thickness of 04 I as the upper and lower plates, and a thermoplastic resin film containing N1 powder with different hardness and particle size distribution as the intermediate layer. A damping steel plate was manufactured, and its electric spot weldability and adhesion between the resin and the steel plate were examined. At the same time, a comparative example manufactured outside the scope of the present invention and a conventional example manufactured under conventional conditions were similarly investigated and compared.

In the electric spot welding test, a test material with a width of 20 mm and a length of 100 mm and an alloyed hot-dip Zn-plated steel plate with the same width and a length of 110 mm were aligned at one end and the edge in the width direction, and a test material with a thickness of 2 mm and the same width was used.
This was carried out by inserting a spacer of IIIm to a position of 70 am from one end, overlapping the three, and sandwiching them between electrodes from above and below from one end of the opposite side at a bipolar point, applying pressure and passing a current. As a result, in the test piece with poor conductivity, traces of melting of the steel plate were seen around the area where the electrode had been in contact, and this is called a surface defect, and the presence or absence of this surface defect was investigated.

Evaluation was performed on 500 test pieces based on the number of surface defects (hereinafter referred to as the number of defects). The electrode was dome-shaped, the diameter of the tip was 6III+, the pressure was 150 kgf, the welding tt current was 10.5 kA, and the current was applied at 60 Hz for 12 cycles.

Adhesion was evaluated by measuring the shear adhesion between the upper and lower steel plates. That is, a test piece with a width of 25 cm was cut out, a notch was made in the upper and lower plates to limit the area of the test object to 3125 mm, and the upper and lower plates were aligned in the longitudinal direction of the test piece. It was pulled in the opposite direction and the shearing force per ram area when it broke was measured.

The manufacturing conditions and the results of the investigation are summarized in Table 1.

In all examples, the weldability was good with the number of defects being O, and the shear adhesion was 110 kgf/co! The above results were very satisfying. On the other hand, in the comparative example, test NIL, in which the metal powder is hard, is inferior in both weldability and shear force, and test NIL 1o, which includes particles with small particle diameters outside the range, Test 112, in which the rolling blade was too large, and test fm13, in which the metal powder content was too small, had poor weldability. Further, in test \114, in which the metal powder content was too high, the shear adhesion was slightly inferior, and in test IIi [L15, in which re-rolling was not performed, both weldability and shear adhesion were poor. In the conventional example, weldability was poor when the amount of metal powder was small, and both weldability and shear adhesion were poor unless re-pressing was performed.

[Effects of the invention] As described above, according to the present invention, the height of the metal powder in the resin is made to match the thickness of the resin layer during crimping, and the height between the metal powder and the steel plate is further reduced by subsequent re-pressing. Since even the slightest thin resin film is removed, the result is a conductive composite damping steel sheet with excellent weldability and adhesion. The effects of this invention, which imparts such excellent properties to composite vibration damping steel sheets whose applications are expected to expand further in the future, are extremely large.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the manufacturing process to explain the function, Figure 2
The figure is a schematic diagram of a cross section of a damping steel plate to explain the state of metal powder under crimping pressure.
The figure is a schematic diagram showing flaws between the metal powder and the steel plate after the crimping pressure is removed. 1. Reroll roll, 2. Cooling furnace, 4. Pressing roll, 5.
Laminating roll, 6 Preheating furnace, 7...Cleaning device,
8 Lower plate, 9 Upper plate, 10・Resin film, 11・Metal powder, 12・Resin.

Claims (2)

[Claims] (1) The height of the particles is the same as the thickness of the resin layer and the hardness is Hv1
1. A conductive composite vibration damping steel plate characterized in that a resin layer containing 20 wt% or more and 30 wt% or less of metal powder of 0.00 or less is used as an intermediate layer, and steel plates are crimped on top and bottom of the resin layer. (2) When manufacturing a conductive composite vibration damping steel plate in which a steel plate is crimped on top and bottom of a resin film containing metal powder and a resin layer formed by this resin film is used as an intermediate layer, the metal powder is
Contains wt% or more and 30wt% or less, the particle size is 1.2 times or more and 1.5 times or less the thickness of the resin layer, and the hardness is Hv1
00 or less, and after crimping the upper and lower steel plates and the resin film, successively re-rolling the resin film with a rolling blade smaller than the rolling blade for this crimping, and in a state where the resin of the resin film is molten. A method for manufacturing a conductive composite vibration damping steel plate characterized by: