JPS5828015B2 - How to apply coating to mold - Google Patents

Description

[Detailed description of the invention] The present invention relates to a new method of coating molds for casting.

For example, in a mold that generally uses a metal mold, such as a combination of mold 1 and sand mold 2 and mold 1 placed at the bottom of the mold as shown in Fig. 1, the surface of mold 1 in contact with molten metal 3 is thin. It is customary to apply a coating film 4 before use.

The smoother the mold surface and the thicker the coating film 4 on the mold surface, the easier it is to peel off when the molten metal collides with it.

Therefore, in order to form a coating film 4 on the mold 1 that is as thick as possible and is difficult to peel off, a peening treatment is performed before applying the coating to form irregularities α on the mold surface as shown in Fig. 2, or Rough machining has also been performed to form a rough surface on the mold surface as shown in Figure 3, but even in this case, if the coating becomes thick, peeling cannot be prevented, and previous results According to research, it is known that approximately 0.5 rran is the limit.

Conventionally, most coating molds have been applied manually or mechanically by brush coating, but the results of testing the properties of coating molds by brush coating and spray coating are shown in the table below.

Comparing the cases of brush coating and spray coating according to the above table, spray coating is difficult to peel off and can form a thicker coating, but on the other hand, it has the disadvantage that the casting surface becomes rough.

This is because when spray coating is used, the coating mold surface becomes uneven due to particle formation, and when pouring, a phenomenon similar to so-called scalding occurs, making the casting surface rough, and as a result, the coating mold peels off. It is likely that this will be difficult.

On the other hand, with shaved coating, the applied surface becomes smooth, so
Although the casting surface is fine and beautiful, it has the disadvantage of being easily peeled off.

This is thought to be due to the fact that molten metal slip occurs during pouring, which causes the coating to peel off.

Based on such conventional research, the present invention utilizes the features of paint films applied by brush and paint films applied by spray, and combines them to create a relatively thick coating on the mold surface. It is an object of the present invention to provide a new mold coating method that can apply a coating that is thick and difficult to peel off even when molten metal collides with it.

That is, the mold coating method of the present invention is as shown in FIG.
Brush coating film 4A as the first layer, spray coating film 4 as the second layer
B, or as shown in FIG. 5, apply a spray coating 4B as the first layer and a brush coating 4A as the 12th layer.
Brush coating film 4A and spray coating film 4B on the smooth surface of mold 1
It is a double coated coating.

There are two types of combinations of the brush coating film 4A and the spray coating film 4B, and the selection is made depending on the properties required for the coating mold, but in order to apply a thicker coating film that is difficult to peel off, As shown in FIG. 4, it is preferable to form the first layer as a brush coating film 4A and the second layer as a spray coating film 4B.

′! In addition, the ratio of the thickness of the first layer and the second layer is basically 50:50, and the ratio can be changed as necessary. Examples of the invention will be described.

The table below assumes that the ratio of the thickness of the first layer and the second layer is 50:50.
The properties of each coating type are shown when the first layer is formed by a spray coating and the second layer is formed by a brush coating, and when the first layer is formed by a brush coating and the second layer is formed by a spray coating.

In addition, the actual implementation conditions of the present invention-flJ, which are carried out in order to understand the following coating type characteristics, are as follows.

That is, the mold coating method of the present invention uses 300 to 800 KL.
! It is used in the manufacture of ductile iron castings using a mold of 1,000,000,000, in which case the mold used is a hollow disc-shaped mold made of cast metal or steel plate, and the coated surface is cut with a bite pattern by lathe processing, and has a diameter of about 1008. This is what I posted.

However, the coating applied on the lever, whether by brush coating or spray coating, is the first layer: Zr 02.
Zircon-based water-soluble coating mold 73B whose main component is SiO2
e, 2nd layer: Zircon and graphite mixed aqueous solution coating mold 60Be.

The casting temperature during casting was 1,280 to 1,350°C. According to the results in the above table, J:h indicates that the spray coating and brush coating were 2.
In the case of multiple coatings, it was found that a coating form that was more difficult to peel than the previous 0.5 thickness was observed, especially when the first layer was formed with a brush coating and the second layer was formed with a spray coating. Then, the thickness of the coating mold can be approximately doubled to 1.2rIrjrLt.

As described above, the coating mold application method of the present invention (by combining the features of brush coating and spray coating) allows for thicker peeling to be achieved on a smooth mold surface than before. In particular, the present invention provides a technical means for increasing the thickness of the coating on the mold surface by applying the coating to a relatively thin coating that does not reach the level of a permanent mold. It is useful in that respect.

! In addition, in recent years there has been a push to improve the productivity of cast products and to save energy, and from the perspective of improving the base of mold-cast products, there will be an increasing demand for casting methods that apply the coating as thickly as possible. , the present invention can serve as a useful mold coating technique that meets such demands.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an example of a mold using a metal mold, Figure 2 is a sectional view showing an example of a mold using a metal mold.
3 and 3 are sectional views showing a state in which the surface of the mold is roughened, and FIGS. 4 and 5 are sectional views showing embodiments of the present invention. 1...Mold, 4A...Brush coating film, 4B...Spray coating film.

Claims (1)

[Scope of Claims] 1. A method for applying a mold coating to a mold, which comprises applying a double layer of a brush coating film and a spray coating film when applying the coating mold to a smooth mold surface. 2. The method of coating a mold according to claim 1, wherein the 21st layer is formed by a brush coating, and the 2nd layer is formed by a spray coating. Claims characterized in that the ratio of the thickness of the 31st layer to the second layer is approximately 50:50, and the sum of the thicknesses of the first layer and the second layer is 0.5 to 1.2 mm. The method for coating a mold according to item 1 or 2.