JPH0219753B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for joining resin-laminated steel plates by arc welding.

In recent years, measures to reduce noise from many noise-generating machines, such as transportation machines and metal processing machines, have become a major issue. Such countermeasures should be taken from both the structure and constituent materials of the noise generating body, and resin-laminated steel sheets, generally called vibration-damping laminated steel sheets, are useful materials from the latter point of view.

A vibration-damping laminated steel plate is a composite steel plate in which a viscoelastic resin material is sandwiched between two steel plates.The strength of the material is provided by the steel plate, and the sound damping effect is provided by the intermediate viscoelastic material. It should be done in The sound reduction effect of vibration damping laminated steel plates is mainly related to the absorption of solid sound when the structure itself using the plate is the sound source, and is the most effective noise countermeasure. Moreover, the viscoelastic material that makes up the vibration-damping laminated steel plate is a very thin layer compared to the constituent steel plates, and can generally be treated in the same way as a normal steel plate, so this laminated steel plate can be applied to a wide range of fields. It is something.

However, even though the viscoelastic layer of the damping laminated steel plate is very thin, its physical properties are very different from those of the steel plate, so some care must be taken when processing it. That is, since a viscoelastic body is normally an electrical insulator, when performing resistance spot welding in assembling a structure, a special method such as the film control method specified in the Japanese Welding Association standard WES7301 must be used. Furthermore, it is known from Japanese Patent Application Laid-Open No. 133000/1983 that there are problems with the state of the end surface during cutting depending on the application. As in these examples, when using vibration-damping laminated steel plates, there may be cases where conventional techniques cannot be used due to processing technology.

There are many uses for vibration-damping laminated steel sheets, but continuous welding is often essential, such as in oil pans among automobile parts. An oil pan is a part located directly below the cylinder of an automobile engine to store engine oil.Since the oil pan receives vibrations from above, it generates a lot of noise, so vibration-damping laminated steel plates are used to reduce noise. Extremely effective. However, when joining members during assembly, airtightness and high strength are required of the joining joint. For this reason, when conventional steel plates were used, arc welding was used. The joint type in this case is generally a butt joint or a lap fillet joint.

However, when vibration-damping laminated steel plates are used as members, continuous arc welding becomes extremely difficult. This is due to the fact that viscoelastic materials are generally organic substances and are electrical insulators, and that at high temperatures such as in arc welding, gas is generated due to evaporation, thermal decomposition, etc. This is because it is difficult. Therefore, when welding is required, the following methods are generally used.

The first method is to remove the viscoelastic body from the vicinity of the portion that will become the welded joint during the manufacture of the damping laminated steel plate. Although this method is possible when the member is a large flat plate, it is not suitable for a member having a complicated shape such as a pressed product.

The second method is to heat the part of the member that will be the welded joint with a gas fire or the like, and remove the viscoelastic material before welding. This method causes large deformation of the member, so it cannot be said to be a sufficient method.

A third method is with a resistive seam solution. However, although this method is possible if consideration is given to the film control method at the start of welding, its use is limited by the type of welded joint and the structure of the welding machine that pressurizes the material to be welded by two electrodes. That is, since only a lap joint can be used as a joint type, the shapes of the materials to be welded are limited to three types as shown in a, b, and c in FIG. 1. The figure schematically shows the cross-sectional shape of the material to be welded, where 1 and 2 indicate the material to be welded, and 3 indicates the welded portion. In the cases shown in FIGS. 1a and 1b, depending on the shape of the materials 1 and 2 to be welded, there may be cases where the welding machine cannot be used due to the structure of the welding machine. In addition, in the case of Fig. 3c, welding is possible, but protrusions are formed on the outside, so it is not necessarily the best method when there are severe dimensional restrictions, such as in an oil pan, for example.

The fourth method is to weld the parts of the members that will become welded joints using a resistance seam solution machine, and to remove the viscoelastic body in advance. Similar to the third method, this method may not be usable depending on the shape of the member.

The fifth method is to obtain a sound weld by making arc welding penetration smaller than the thickness of the steel plate constituting the vibration-damping laminated steel plate. This method is effective when the plate thickness is large because the penetration must be controlled to a small level, but if the thickness of the constituent steel plate is 1.0 mm or less, the penetration will reach the viscoelastic body and welding will not be possible. It becomes possible. Furthermore, in this method, the force is transmitted at the welded joint through one of the constituent steel plates, and therefore sufficient strength cannot be imparted to the welded joint.

In the conventional techniques as described above, when using vibration-damping laminated steel plates, it has not been possible to obtain a continuous joint that requires airtightness and sufficient strength, such as in an oil pan. Therefore, the present inventors first investigated the causes of poor welding in vibration-damping laminated steel plates, and based on this, devised a possible and practical joining method.

First, in order to investigate the cause of poor welding of vibration-damping laminated steel plates, bead-on welding, the most basic form of welding, was performed. The welding used at this time was shielded arc welding and gas shielded arc welding. This revealed the following. That is, when aiming for welding with deep penetration as shown in FIG. 2a, the actual weld penetration is limited to 111 constituent steel plates as shown in FIG. 2b. This is because while weld penetration depends on heat conduction from the steel plate surface, sufficient heat transfer does not occur to the lower steel plate 12 because the intermediate viscoelastic body 13 acts as a heat insulating layer. be. In such a case, the bead 14 on the upper steel plate 11 unnecessarily expands, and the arc generation becomes unstable due to the generation of decomposed gas from the viscoelastic body 13.

On the other hand, when aiming for welding with shallow penetration as shown in FIG. 3a, the actual weld penetration extends to 111 constituent steel plates as shown in FIG. 3b. This is because, as in the previous case, the viscoelastic body 13 acts as a heat insulating layer and does not transfer heat to the lower steel plate 12, resulting in heat being concentrated on the upper steel plate 11. In this case as well, the generation of decomposed gas from the viscoelastic body 13 makes the arc unstable.

From the above, it has become clear that it is difficult to control penetration in bead-on welding, and that the arc becomes unstable.

The basic cause of the defects in bead-on welding described above is that the formation of penetration is due to heat conduction from the surface of the steel plate. Therefore, it is thought that welding would be improved if heat could be applied in the thickness direction without relying on heat conduction. This is achieved by applying heat directly to the end face. In other words, welding is considered to be possible if the welded joint type is a lap fillet joint and the end faces of vibration damping laminated steel plates are welded.
Therefore, when welded a lap fillet joint made by combining a damping laminated steel plate and a normal cold-rolled steel plate as shown in Fig. 4, very good welding was obtained.
Here, in FIG. 4, 1 indicates a damping laminated steel plate, 4 indicates a cold rolled steel plate, and 14 indicates a weld bead. Moreover, the cross section of the obtained welded part is shown in FIG.

In this case, decomposition gas from the viscoelastic material is also generated, but since the welding is from the end face, the viscoelastic material part that becomes the penetration part is small and the amount of gas generated is smaller than in bead-on welding, and when welding from the end face. It is thought that the arc was stable because the arc generation point spanned the entire end face and the area of the viscoelastic material therein was extremely small.

Furthermore, in order to confirm this effect, we welded a butt joint between vibration-damping laminated steel plates (total thickness 1.75 mm), and found that if there was no butt gap, the weld was defective, but if the gap was 1.2 In the case of mm, good welding was obtained and the above effects were confirmed.

Next, when applying the above results to the formation of an airtight welded joint for a container such as an oil pan, butt welding in which the butt gap is set and maintained at a constant amount is not practical. Therefore, it is practical to use lap fillet welding of a normal steel plate and a vibration-damping laminated steel plate, and the combination shown in FIG. 5 can be used. In the figure, 1 and 2 are vibration damping laminated steel plates, 4 is a normal steel plate, and 14 is a weld bead.

A specific example of manufacturing an oil pan or the like using such a joint type is shown in FIG. In the figure, 1 and 2 are vibration-damping laminated steel plate members, 4 is a normal steel plate insert, and 14 is a weld bead. In this case, the container body is connected by inserting a ring-shaped ordinary steel plate 4 between the members 1 and 2 made of vibration-damping laminated steel plates. When the weld length is long like this type of welded joint, insert 4
It is desirable to temporarily attach them by spot welding in advance.

Next, an example of attaching a pipe to a container wall is shown in FIGS. 7a and 7b. In the figure, 1 is a vibration-damping laminated steel plate member, 4 is a normal steel plate insert, 5 is a metal tube, and 14 is a weld bead.

7a is based on the same concept as in FIG. 6, but FIG. 7b is a case in which the shape obtained by burring is used to eliminate the need for an insert of a normal steel plate. Although arc-row welding is often used to attach pipes, it can be handled in exactly the same way as welding.

On the other hand, the vibration damping performance of products using vibration-damping laminated steel plates does not deteriorate even if the material contains about 20% normal steel plates as long as it is continuously connected to the vibration-damping laminated steel plates. Therefore, when a normal steel plate as described above is used as an insert member, the product can generally be manufactured without impairing vibration damping performance.

In addition, in the method of the present invention, the thickness of the constituent steel plates is
Welding of damping laminated steel plates with a thickness exceeding 1.0 mm was difficult because the welding heat input increased, the amount of gas decomposed from the viscoelastic body increased, and arc instability occurred.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of an oil pan using a resin-laminated steel plate, Figs. 2 and 3 are illustrations of bead-on welding to a resin-laminated steel plate, and Fig. 4 is an illustration of a welded joint according to the method of the present invention. 5 is an explanatory diagram of various combination examples showing the application of FIG.
The figure is a cross-sectional photograph of a welded area between a resin-laminated steel plate and a regular steel plate according to the method of the present invention. 1, 2: Vibration-damping laminated steel plate, 4: Metal plate, 1
1, 12: Constituent steel plate, 13: Viscoelastic body.

Claims (1)

[Claims] 1. When joining two laminated steel plates with a resin material sandwiched between them with a thickness of 1.0 mm or less by arc welding, a metal plate is used as a joint between the laminated steel plates, and the laminated steel plate and the metal plate are joined together. A method for joining resin laminate members characterized by lap fillet welding.