JPH0469034B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method of closing holes formed in a casting by welding.

Prior Art For example, in the case of automobile parts, when installing parts that are common to various types of cars, that is, standardized parts, the mounting position of the parts may differ depending on the car model, so it is necessary to install parts that are compatible with all car types. In some cases, more mounting holes are formed for a part than are required for a certain vehicle type. Therefore, if the above-mentioned part is, for example, a part that allows cooling water to flow inside, extra holes may be created when the part is attached to the body of a certain type of car, so in order to prevent cooling water from leaking, The extra holes must be plugged. In addition, when casting hollow castings, it is necessary to support the core during casting, so a supporting shape is provided on the outer mold or the core mold.
Since that portion remains in the product as a hole, it is necessary to fill the hole in a subsequent process. Therefore, in such cases, conventionally, a seat 1 is provided at the lower end as shown in Fig. 1.
The insert material 3 is fitted into the hole 2 in which the hole 2 is formed, and the insert material 3 and the main body 4 are welded together over the entire circumference of the hole 2, thereby sealing the hole 2.

However, the conventional hole filling method has the following problems. In other words, it is necessary to manufacture an insert material 3 to fit into the hole 2, and
In order to position the insert material 3 in the hole 2, some means such as forming a seat 1 as shown in the figure is required, which is troublesome and increases costs. Furthermore, insert material 3 has the minimum necessary thickness for functionality.
Since the shape is much smaller than the main body 4,
Since the insert material 3 and the main body 4 have different heat capacities, it is necessary to prevent the insert material from melting through due to the difference. Therefore, in order to eliminate this difference as much as possible, the thickness of the insert material 3 must be made significantly larger than the functionally necessary thickness, which results in an increase in weight and, as mentioned above, In the case of a component through which cooling water flows, there is also the problem that the flow path is narrowed, resulting in an increase in resistance or pressure loss.

In addition, since the welding area is limited to the contact area between the insert material 3 and the main body 4, for example, the tip of the consumable electrode wire must be positioned with high accuracy, resulting in troublesome work and poor workability. .

Therefore, in Japanese Patent Application No. 58-227302, the present applicant has proposed a method in which a weld bead is continuously formed from the periphery of a hole formed in a metal body toward the center, and the hole is sealed by the bead. We proposed a method for filling holes in metal objects. According to this method, as shown in FIG. As shown in FIG.
, and finally the hole 10 is closed with a built-up bead 11. Therefore, according to the method, hole 1
Since no special part, such as an insert material, is used to close the hole 10, there is no need to provide any means for processing the part and positioning it in the hole 10, thereby reducing costs.

Problems to be Solved by the Invention However, upon further examination of the method for filling holes in metal bodies described in the above-mentioned Japanese Patent Application No. 58-227302, it became clear that there was room for further improvement in the following points. It became.

First, the method disclosed in Japanese Patent Application No. 58-227302 has a cost problem in that an expensive filler rod is required for overlaying. In addition, when the tip for feeding power to the welding wire wears out, the aiming position of the welding wire changes. For example, when the welding wire aims at the inside of the hole 10, the wire droplet passes through the hole 10 and falls, making it impossible to build up the welding wire. There is this inconvenience. Therefore, special management is required for the positional accuracy of the torch and the positional accuracy of the hole 10 in the workpiece, and there is a problem that automation using a robot or the like is difficult. moreover,
In order to close the hole by overlaying by welding, it is necessary to add thickness to the workpiece later, and it is necessary to check whether the overlay metal and the workpiece are metallurgically connected, that is, the airtightness after filling the hole. The problem was that it was difficult to judge from In addition, the above special request
When specifically implementing the method described in No. 58-227302, it is necessary to bring the welding wire into contact with the workpiece at the start of welding to generate an arc. Hole 10 also needs to be set on the outside.
The shape of the workpiece in the vicinity of the torch must be shaped so as not to interfere with the torch, and there is a problem in that there are restrictions on the shape of the workpiece that can be applied.

The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object of the present invention to provide a casting hole filling method that does not require auxiliary parts or expensive materials.

Means for Solving the Problems In other words, the method for filling holes in a casting according to the present invention is to provide a casting having a hole with an annular surplus wall along the hole, and to melt the surplus wall. The hole is then closed.

This invention will be explained in more detail below with reference to FIGS. 4 and 5. As shown in FIG. 4, according to the method of filling holes in a casting of the present invention, first, an annular surplus portion 22 is formed around the periphery of the hole 20 of a casting 21 having a hole 20. .
The hole 20 corresponds to a core support hole or the like when the casting 21 is cast. Further, the excess wall portion 22 can be formed by being integrally cast when the casting 21 is cast.

Next, according to the method of the present invention, as shown in the figure, the excess flesh portion 22 is melted to close the hole 20 to form a closed portion 23.

The excess flesh portion 22 is melted by a non-electrode welding method, for example, by irradiating the excess flesh portion 22 with an arc from the electrode 25 of a TIG welding torch 24, as shown in FIG. That is, as shown in the figure, by positioning the welding torch 24 above the hole 20 and moving the aim position of the arc generated from the electrode 25 so as to draw a circumference along the excess meat part 22, The excess metal portion 22 can be melted all around, and the molten metal can be caused to flow in the direction of gravity (direction of arrow A). As the molten metal solidifies within the hole 20,
Closing part 2 that closes hole 20 as shown in FIG.
3 is formed. In other words, the molten metal generated by melting the excess metal portion 22 flows down the hole 20 due to surface tension or a surface oxide film.
After the discharge from the electrode 25 ends, the molten metal solidifies within the hole 20 to form a closed portion 23 that is metallurgically joined to the workpiece.

Example Examples of this invention are described below.

The core support hole of an aluminum casting part was closed by applying the present invention. The diameter of the core support hole is 12
mm, and the depth was 6 mm. On the other hand, when casting parts, a height of 5 mm is placed around the core support hole.
mm, and a width of 6 mm was formed. After casting the cast part, the excess flesh is melted with a TIG welding torch.
A closed part that closed the core support hole was obtained.

The obstructed portion obtained as described above was visually inspected to determine the presence or absence of defects. As a result, it was found that airtightness could be sufficiently guaranteed for those for which no defects were found by visual inspection.

Effects of the Invention As described above, according to the method for filling a hole in a casting according to the present invention, the ring-shaped surplus portion provided in advance around the hole in the casting is melted to close the hole. Therefore, there is no need to use an expensive filler rod to fill the holes in the casting, and the cost for filling the holes in the casting can be reduced. In addition, a non-consumable electrode is used to melt the excess metal, and there is no wear on the electrode support parts of the melting torch parts, so there is little variation in the arc generation position, which results in a uniform melting process that prevents the casting hole from being blocked. An airtight solidified layer is obtained from the molten metal layer. Furthermore, unlike the method of adding overlay metal from the outside to close the hole, it is possible to accurately judge the filling state inside the hole based on the appearance, and the appearance inspection can be used to check the airtightness of the closed part. can be judged with high precision and quality control can be performed. In addition, according to the present invention, there is no need for a special part to close the hole, and along with this, there is no need for a means for positioning the part in the hole, and the peripheral part of the hole can be made thinner, resulting in cost savings. It is possible to reduce the amount of heat and reduce the weight, and furthermore, the hole can be easily sealed without the need for a skilled person or a highly accurate automatic welding machine.

[Brief explanation of the drawing]

Fig. 1 is a sectional view for explaining a conventional hole filling method, Fig. 2 is a sectional view showing a starting state of hole filling in an embodiment of the hole filling method proposed previously, and Fig. 3 is a sectional view for explaining the hole filling method as well. 4 and 5 are cross-sectional views showing the completed state, and FIG. 4 is a cross-sectional view showing the steps of an embodiment of the present invention. FIG. FIG. 2 is a sectional view showing the vicinity of the workpiece after hole filling is completed. 20... Hole portion, 21... Casting, 22... Excess flesh portion, 23... Closing portion.

Claims (1)

[Claims] 1. A method for filling a hole in a casting, which comprises providing a ring-shaped surplus wall along the hole at the periphery of the hole in a casting having a hole, and melting the surplus wall to close the hole.