JPH0711021B2 - Method for spheroidizing molten cast iron - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for spheroidizing a molten cast iron for producing ductile cast iron.

[Conventional technology]

When spheroidizing the molten cast iron to form ductile cast iron, it is usual to use a conventional ladle or a ladle provided with a reaction chamber.

In the production of ductile cast iron, in order to change the graphite morphology in the structure from flaky to spherical, a spheroidizing material is added or inserted into the molten metal to perform spheroidizing treatment.

This spheroidizing method is a pouring method in which the spheroidal material is added to the ladle in advance and the molten metal is poured into the ladle, and a block-shaped (candy-type) spheroidizing material is inserted into the molten metal in the ladle. However, there is a candy method in which spheroidizing treatment is performed.

Fig. 17 shows the spheroidizing treatment method by the conventional infusion method.
FIG. 18 shows a spheroidizing method by the conventional candy method.

In the conventional pouring method shown in FIG. 17, a necessary amount of spheroidizing material 2 and a cover material 8 for suppressing a reaction are arranged in advance in the ladle body 1.

The molten metal 4 for ductile cast iron in the melting furnace is poured into the ladle body 1, and the molten metal 4 is spheroidized.

In the conventional candy method shown in FIG. 18, after pouring molten metal 4 for ductile cast iron into the ladle body 1, for example, about 60% of the ladle capacity, a candy stick 9 having a block-shaped spheroidizing material (candy) 2 is introduced. The molten metal scattering prevention cover 8 provided is set on the ladle body 1. Then, the block-shaped spheroidizing material 2 is inserted into the molten metal 4, and the spheroidizing treatment of the molten metal 4 is performed.

[Problems to be Solved by the Invention]

In the method of spheroidizing the molten metal for ductile cast iron in the conventional method, a violent flash and a large amount of white smoke are generated during the reaction of the spheroidizing material, and not only the environment in the factory is significantly deteriorated, but also as a pollution source, It is a social problem.

Also, since the bubbling phenomenon of the molten metal is severe during the sudden reaction of the spheroidizing material, not only can the spheroidizing process of the molten metal of about 60% of the capacity of the ladle can be performed, but there is also the risk of accidents due to scattering of the molten metal. It is a big issue and is a safety issue.

As a method of solving these problems, conventionally, a method in which a sturdy lid is provided on the upper part of the ladle, the entire ladle is treated as a substantially closed pressure vessel, and a spheroidizing treatment is also devised,
The workability is very poor and the effect is not sufficient, so it has not yet been put to practical use.

INDUSTRIAL APPLICABILITY The present invention is a spherical cast iron melt capable of resolving pollution problems in molten spheroidizing treatment for ductile cast iron, deterioration of environment in a factory, dangerous work and workability (complexity, difficulty). The present invention is intended to provide a chemical treatment method.

[Means for Solving the Problems]

The method of spheroidizing the molten cast iron according to the present invention is as follows.

(1) The inside of the spheroidizing ladle body is divided into a molten metal receiving part and a spheroidizing part containing the spheroidizing material by communicating the lower part with a partition wall, and there are continuous pores above the spheroidizing part. Provided with a cover made of a porous body having a three-dimensional network structure, having a spheroidizing treatment method of cast iron molten metal, characterized in that the molten metal is injected from the molten metal receiving portion and spheroidizing treatment is performed in the spheroidizing treatment portion. To do.

(2) In the invention of (1), the spheroidizing of the cast iron molten metal is characterized in that the molten metal is injected by using a porous body having continuous pores in a partition wall that separates the molten metal receiving portion and the spheroidizing treatment portion. A processing method is also provided.

[Action]

In the present invention of the above (1), the molten cast iron is poured into the spheroidizing ladle body from the molten metal receiving portion. The injected molten metal enters the spheroidizing part from the molten metal receiving part, where the molten cast iron and the spheroidizing material come into contact with each other to cause a chemical reaction, resulting in a rapid and large amount of white smoke (containing MgO as the main component). Although a flash of light is generated, MgO in white smoke is covered by a three-dimensional mesh structure porous body cover with continuous pores that is provided above the spheroidization processing part.
Fine particles such as are captured and adsorbed, and the emission of white smoke to the atmosphere is significantly suppressed.

Also, due to the cover of the porous body having continuous pores, the gas generated in the spheroidizing treatment section in the ladle body due to the reaction between the cast iron molten metal and the spheroidizing material is released to the atmosphere, The gas pressure decreases, bubbling of the molten cast iron is prevented, and there is almost no danger of the molten cast iron splashing.

In the present invention of (2), in addition to the action of the present invention of (1), by forming a partition wall that separates the molten metal receiving portion and the spheroidizing treatment portion from a porous body having continuous pores, a spherical shape In carrying out the spheroidizing treatment method, various effects of preventing external emission of white smoke generated in the spheroidizing portion, lowering the gas pressure of the generated gas and preventing the molten metal from scattering are further improved.

〔Example〕

A spheroidizing ladle which is a background to which the present invention is applied will be described with reference to FIGS. 1 and 2.

After arranging a necessary amount of the spheroidizing material 2 (a cover material may be disposed on the spheroidizing material 2 if necessary) in the ladle body 1, the upper part of the ladle body 1 is placed. A porous cover 3 having continuous pores (for example, a heat-resistant filter having a three-dimensional mesh structure with air permeability) is attached to the entire surface of the.

In such a ladle, the ladle body 1 is arranged in the vicinity of the melting furnace 10, the molten metal 4 for ductile cast iron in the melting furnace 10 is poured onto the porous body 3 having continuous pores, and the molten metal 4 is poured. It is poured into the ladle body 1 through the porous cover 3.

In the ladle main body 1, the poured molten metal 4 for ductile cast iron and the spheroidizing material 2 come into contact with each other, and a rapid and large amount of white smoke and flash light are generated by a chemical reaction.

The above-mentioned porous cover 3 having continuous pores prevents the mixture of molten slag when pouring the molten metal 4 for ductile cast iron into the ladle body 1 and prevents the white smoke generated during the spheroidizing treatment.
It captures and adsorbs fine particles such as MgO, and greatly suppresses the emission of white smoke into the atmosphere.

Further, since the porous cover 3 having continuous pores has air permeability, the generated gas in the ladle body 1 can be easily released into the atmosphere, so that the gas pressure in the ladle body 1 is reduced. Since it is remarkably reduced, the risk of splashing of the molten metal is almost eliminated, and bubbling of the molten metal is prevented, and a large amount of molten metal is injected into the ladle body 1 in combination with the shielding by the cover 3 of the porous body. You can

In such a ladle, as a cover 3 for a porous body having continuous pores, a ceramic porous body having a three-dimensional network structure (silicon carbide; apparent specific gravity: 0.35 to 0.55, porosity: 80 to 90)
%, The number of cells 6/25 mm mouth) was used as a heat-resistant filter, and the result of an attempt to spheroidize 50 kg of cast iron molten FCD400 was
The amount of white smoke generated could be suppressed to about 1/10 of that of the conventional method, and the molten metal could be prevented from scattering during the reaction.

A first embodiment of the present invention will be described with reference to FIGS. 3 and 4.

The ladle body 1 is made of a refractory upper partition wall 6 extending downward from the upper side of the ladle body 1 and having a lower end spaced upward from the bottom surface thereof.
It is divided into and. The reaction section 1a is provided with a lower partition wall 7 standing upright from the bottom surface, and a reaction chamber 1b is formed in the lower part of the partition wall. Further, the reaction chamber 1a is covered with a porous body cover 3 having continuous pores ( For example, a heat-resistant filter having a three-dimensional mesh structure is attached. As shown in the drawing, the hot water inlet 5 has a shape in which the horizontal cross-sectional shape of the upper part spreads laterally and is opened upward, so that it is easy to receive hot water. .

The spheroidizing material 2 (a cover material may be disposed on the spheroidizing material 2 if necessary) is placed in the reaction chamber 1b.

In this embodiment, the molten metal 4 for ductile cast iron in the melting furnace 10 is injected from the open portion above the hot water inlet 5, and the molten metal descends in the hot water inlet 5 and is injected into the reaction part 1a. To be done. In this case, the hot water inlet 5 is connected to the melting furnace 10 as described above.
The shape is such that it is easier to receive hot water, and pouring is easily performed.

When the molten metal 4 for ductile cast iron and the spheroidizing material 2 come into contact with each other in the reaction chamber 1b, flash light and white smoke are generated. The generated white smoke passes through the porous cover 3 having continuous air-permeable pores and is diffused into the atmosphere. At that time, in the white smoke
For fine particles such as MgO, cover 3 of porous body with continuous pores.
Almost all of them are captured and adsorbed on the surface of the reaction chamber 1 and the generation of white smoke can be remarkably suppressed, and the generated gas in the reaction portion 1b generated by the above reaction also passes through the porous cover 3 having continuous pores and is generated in the reaction portion 1b. The gas pressure is reduced, and it is possible to prevent the molten metal from scattering and the bubbling of the molten metal from occurring.

Further, the upper partition wall 6 prevents the reaction gas during the spheroidizing process from flowing out of the reaction section 1a to the hot water inlet 5 side.

A second embodiment of the present invention will be described with reference to FIGS.

In the ladle body 1 of this embodiment, in order to facilitate injection of the molten metal 4 for ductile cast iron in the melting furnace 10 and casting of the molten metal into a mold (not shown), the hot water receiving portion 5 is enlarged as shown in the drawing,
Moreover, the ladle body 1 has a horizontal drum type, and has the same configuration as that of the first embodiment except for the shape of the ladle body 1.

Also in this embodiment, similar to the first embodiment, effects such as suppression of white smoke, prevention of molten metal scattering, prevention of bubbling of molten metal, and ease of work can be achieved, and a large hot water receiving portion 5 is provided. This makes it easy to inject the molten metal 4 for ductile cast iron into the ladle body 1 and to cast it into the mold.

A third embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the upper partition wall 6 of the first embodiment shown in FIGS. 3 and 4 is made of a porous body having continuous pores (for example, a heat-resistant filter having a three-dimensional mesh structure having air permeability). .

The present embodiment can exert the action and effect of the first embodiment, and further lowers the gas pressure in the inner space of the ladle body 1 by the upper partition wall 6 made of a porous body having continuous pores. Can be made.

In this embodiment, as the cover 3 and the upper partition wall 6 of the porous body, a ceramic porous body having a three-dimensional network structure (a blend type of cordierite and alumina, an apparent specific gravity of 0.35 to 0.60, and a porosity of 80 to 90%). , Cell number 13 cells / 25 mm mouth)
As a result of carrying out spheroidizing treatment of 500 kg of FCD400 molten metal, it is possible to suppress the emission of white smoke into the atmosphere,
It was also possible to prevent the molten metal from scattering.

In each of the above-mentioned examples, as the porous body having continuous pores, a silicon carbide material, a ceramic porous material having a three-dimensional network structure such as a blend type of cordierite and alumina, or the like can be used.

A fourth embodiment of the present invention will be described with reference to FIGS. 9 to 11.

This embodiment is the reaction part 1a of the ladle body 1 of the second embodiment.
A metal cover 13 is provided to cover the opening 13a of the cover 13.
The (slag opening) is filled with a porous body 16 having small pores of small coke 12 and having continuous pores.

As a result of performing a spheroidizing treatment of 500 kg of molten FCD400 using the small coke bodies shown in Table 1 for the porous body 16,
Similar to each of the above-mentioned examples, the emission of white smoke into the atmosphere during the spheroidizing treatment was almost suppressed, and the molten metal was prevented from scattering.

In addition, vermiculite (flint stone), perlite (pearl stone), shirasu balloon (pumice stone) is used for the porous body with continuous pores.
Similar results were obtained when small blobs such as the above were applied.

A fifth embodiment of the present invention will be described with reference to FIG.

In this embodiment, instead of the porous body having continuous pores of the fourth embodiment, a stainless wire mesh 23 (mesh opening: 0.75 m / m
And 1.50 m / m) 8 to 10 sheets in various combinations, laminated with a refractory material (for example, alumina powder + Georgia kaolin + PVA solution, casting mold coating material, etc.) on the surface and having continuous pores Body 26 was used.

Also in this embodiment, the effect of suppressing white smoke and preventing the molten metal from scattering can be obtained.

A sixth embodiment of the present invention will be described with reference to FIG.

In this embodiment, instead of the porous body having continuous pores of the fourth embodiment, a porous body 36 having continuous pores is used as a fine piece of a ceramic ball and a fibrous heat-resistant material (for example, glass wool, silica). Wool) is mixed and a non-caking heat resistant material adjusted to have a porosity of 50 to 90% is sealed in a stainless wire mesh box 33 (mesh opening: 0.75 m / m).

Also in this embodiment, the same effects as white smoke suppression and molten metal scattering prevention can be obtained as in the fourth and fifth embodiments.

A seventh embodiment of the present invention will be described with reference to FIGS. 14 to 16.

In this embodiment, the porous body cover and the hot water receiving portion of the ladle body in the second embodiment are changed as follows.

That is, the ceramic porous body 46 having continuous pores in the opening 13a of the metal cover 13 similar to the fourth to sixth embodiments.
(Silicon carbide, apparent specific gravity 0.35 to 0.55, porosity 50 to 90%,
20 cells / 25 mm mouth) were filled.

In addition, a box-shaped hot water receiving portion 45 is provided to facilitate hot water reception of the ladle body 1, and a strainer 40 is arranged below the hot water receiving portion 45 to prevent impurities from entering and white smoke from being emitted. Planned.

In this example, 700 kg of molten FCD500 was spheroidized, and as a result, the effect of suppressing the emission of white smoke into the atmosphere and the effect of preventing the molten metal from scattering were remarkable, and the yield of magnesium was greatly improved. Moreover, the decrease in molten metal temperature was smaller than that of the conventional method, and the quality could be improved.

〔The invention's effect〕

In the present invention according to claim (1), the molten metal receiving part and the spheroidizing treatment part are divided by a partition wall in the ladle body, and the three-dimensional mesh structure having continuous pores above the spheroidizing treatment part. Since a method of providing a cover made of a porous body and injecting molten metal from the molten metal receiving part to perform spheroidizing treatment in the spheroidizing treatment part,
In addition to the effects of (1) to (4), the molten metal can be easily injected into the ladle body, which improves workability.

Furthermore, in the present invention described in claim (2), the molten metal is formed by forming the partition walls of the molten metal receiving part and the spheroidizing part in the invention of claim (1) with a porous body having continuous pores. In order to make the method of injecting, in addition to the effect of the present invention according to claim (1), lowering the gas pressure in the space inside the molten metal receiving part, preventing the external emission of white smoke and preventing the scattering of molten metal The effect can be further enhanced.

(1) The amount of white smoke generated during the reaction between the molten cast iron and the spheroidizing material can be greatly suppressed into the atmosphere, which is effective in improving the environment and preventing pollution.

(2) It is possible to reduce the gas pressure in the ladle when the molten cast iron reacts with the spheroidizing material, and the safety is improved by dramatically reducing the scattering of the molten metal.

(3) The ladle body can be downsized by reducing the amount of molten metal splashing (bubbling).

(4) Compared to a conventional ladle with an upper cover, the present invention can reduce the weight of the ladle and has good operability.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a ladle for spheroidizing treatment which is a background to which the present invention is applied, FIG. 2 is a plan view of the same ladle, and FIG. 3 is a vertical cross-sectional view of a first embodiment of the present invention. FIG. 4 is a plan view of the same embodiment, FIG. 5 is a longitudinal sectional view of a second embodiment of the present invention, FIG. 6 is a plan view of the same embodiment, and FIG. 7 is a third view of the present invention. 8 is a plan view of the same embodiment, FIG. 9 is a perspective view of a fourth embodiment of the present invention, and FIG. 10 is a vertical sectional view of a ladle of the same embodiment. FIG. 11 is a longitudinal sectional view of an essential part of the same embodiment, FIGS. 12 and 13 are longitudinal sectional views of an essential part of the fifth and sixth embodiments of the present invention, and FIG. FIG. 15 is a perspective view of the seventh embodiment, FIG. 15 is a plan view of the same embodiment, FIG. 16 is a longitudinal sectional view of the same embodiment, and FIGS. 17 and 18 are respectively a conventional pouring method and a candy method. It is sectional drawing which shows the spheroidization processing method of cast iron molten metal. 1 ... Ladle body, 2 ... Spheroidizing material, 3 ... Porous body cover with continuous pores, 4 ... Molten metal for ductile cast iron, 5 ... Hot water inlet, 6 ... Upper partition wall, 7 ... Lower partition wall, 8 …… Molten metal dispersion prevention cover, 9 …… Candy stick, 10 …… Smelting furnace, 12 …… Small coke, 13 …… Cover, 13a …… Opening, 16,26,36,46 …… Porous body with continuous pores, 23 …… wire mesh, 33 …… wire mesh box, 40 …… strainer, 45 …… hot water inlet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroo Sato 5007 Itozaki-cho, Mihara-shi, Hiroshima Mitsubishi Heavy Industries, Ltd.Mihara Works (72) Inventor Kiyotaka Nagai 5007 Itozaki-cho, Mihara-shi, Hiroshima Mitsubishi Heavy Industries Mihara In-house (56) References Japanese Patent Publication Sho 36-8907 (JP, B1)

Claims (2)

[Claims] 1. A spheroidizing ladle main body is divided into a molten metal receiving part and a spheroidizing part containing a spheroidizing material by connecting a lower part thereof with a partition wall, and above the spheroidizing part. Spheroidizing of cast iron molten metal, characterized in that a cover made of a porous body having a three-dimensional mesh structure having continuous pores is provided, and the molten metal is injected from the molten metal receiving part to perform spheroidizing treatment in the spheroidizing treatment part. Processing method. 2. The cast iron according to claim 1, wherein the molten metal is injected by using a porous body having continuous pores in a partition wall that divides the molten metal receiving portion and the spheroidizing treatment portion. Method for spheroidizing molten metal.