JP2002153971A - Melting and holding furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a melting and holding furnace in which molten metal of non-ferrous metal, such as aluminum, can be supplied into a holding chamber and a molten metal treating chamber without dropping the molten metal temperature and also, without mixing oxide and inclusion caused by turbulent flow. SOLUTION: This melting and holding furnace is provided with a first partition plate 61 with which a molten metal charging hole 3 and the holding chamber 42 are partitioned and an underpassage 34 communicating the molten metal charging hole and the holding chamber at the lower part is formed and direct contact of the molten metal in the molten metal charging hole with the air, is prevented and also, the development of the turbulent flow is prevented when the molten metal is supplied from the molten metal charging hole into the hollow chamber, with a pressurizing means 71 pressurizing the molten metal in the molten metal charging hole so as to supply the molten metal from the molten metal charging hole to the holding chamber, with a second partition plate 62 with which the inside of the holding chamber 42 are partitioned into the front and the back parts and an overflow passage 44 communicating the partitioned first chamber 42a and second chamber 42b at the upper parts is formed and the development of turbulent flow is prevented when the molten metal is supplied from the first chamber to the second chamber, with a third partition plate 63 partitioning the second chamber 42b and the molten metal treating chamber 52a and with a fourth partition plate 64 partitioning the molten metal treating chamber 52a and a molten metal discharging chamber 52b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a melting and holding furnace for melting or holding an aluminum alloy.

[0002]

2. Description of the Related Art In a molten metal replenishing system, there is a system in which molten metal is transported from a centralized melting furnace to a hand-held furnace dedicated to a holding furnace using a ladle or the like and distributed. In the method using a centralized melting furnace, the temperature of the molten metal drops during the hot water distribution process.Therefore, it is necessary to raise the temperature of the molten metal from the centralized melting furnace by the reduced amount. However, there is a problem that the cleanliness of the hot water distribution is deteriorated.

Therefore, various melting and holding furnaces for continuously melting and holding a non-ferrous metal such as aluminum have been proposed. Conventional melting and holding furnaces have a preheated material supply tower, a melting chamber in which a melting burner is installed, and a soaking chamber in which the molten metal melted by the flame of the melting burner flows in and is stored. And a tapping chamber that communicates with the soaking chamber and stores the molten metal flowing out of the soaking chamber, and pumps out the molten metal therefrom.

[0004]

However, in the conventional melting and holding furnace, a turbulent flow occurs when the molten metal is distributed by the ladle, and a considerable amount of oxide inclusions accompany the molten metal. The impurity inclusions do not settle in the holding chamber or the processing chamber for a long time because they are soared by the turbulent flow generated at the same time. For this reason, the quality of the molten metal decreases,
In particular, in the case of casting products requiring strength and reliability, such as aluminum products, rejected products continue to be generated, resulting in an increase in product defects and a decrease in yield.

An object of the present invention is to provide a melting and holding furnace capable of supplying a molten metal of a non-ferrous metal such as aluminum to a holding chamber or a molten metal processing chamber without generating turbulence.

[0006]

SUMMARY OF THE INVENTION A melting and holding furnace according to the present invention has a holding chamber provided with a melt inlet for charging a melt and a heating means for heating the melt so that the temperature of the melt does not drop before processing. In a melting and holding furnace having a molten metal processing chamber for removing impurities from the molten metal and a tapping chamber for discharging the processed molten metal, the molten metal charging port and the holding chamber are partitioned, and the molten metal charging port and the holding chamber are located at a lower portion. A first partition plate that forms an under passage communicating with the first opening and prevents the molten metal in the molten metal inlet from coming into direct contact with the atmosphere and prevents turbulence when the molten metal is supplied from the molten metal inlet to the holding chamber; And a pressurizing means for pressurizing the molten metal in the molten metal inlet to supply the molten metal from the molten metal inlet to the holding chamber, and partitioning the holding chamber back and forth, and the first and second chambers partitioned by the upper part. An overflow passage communicating with the first chamber is formed. A second partition plate for preventing generation of turbulence when the molten metal is supplied to the second chamber, a third partition plate for separating the second chamber and the molten metal processing chamber, a molten metal processing chamber and a tapping chamber And a fourth partition plate for partitioning the second partition.

[0007] The first, second, third and fourth partition plates may be heat conductive boards made of ceramics such as carbon, SiC, a mixture of C / SiC, etc. having excellent thermal conductivity. preferable.

[0008] Further, it has a melting furnace having a tower inlet into which a substance to be melt is charged, and a bent passage inclined at a predetermined angle with respect to the tower inlet and communicating with the second chamber. Is preferred. It is more preferable that the bent passage is bent at an angle of about 90 ° with respect to the vertical tower inlet. Such a bent passage prevents the moisture-absorbing material containing undissolved matter and water from flowing directly into the holding chamber.

Further, it is desirable that a flow hole for flowing the molten metal is formed in an intermediate portion of the third partition plate. Further, it is desirable that the molten metal processing chamber is selectively provided with at least one of a degassing unit, a filtering unit, a rotary degassing unit, and a flux processing unit depending on the application. After the molten metal is degassed and / or filtered in the molten metal processing chamber, it flows from the molten metal processing chamber to the tapping chamber through the underflow hole, and is immediately discharged from the tapping chamber, so that the purified molten metal from which impurities have been removed. Is almost completely oxidized.

It is desirable that the molten metal inlet, the holding part, and the tapping part be unitized so that they can be freely assembled and disassembled. It is further desirable that the first, second, third, and fourth partition plates are detachably attached to each unit.

[0011] In the melting and holding furnace according to the present invention, the molten metal passes through the under passage when pressure-fed from the molten metal inlet, and reaches the holding chamber without directly contacting the atmosphere. Further, since the molten metal passes through the under passage defined by the first partition plate and then passes through the overflow passage defined by the second partition plate, the turbulent flow does not occur and the front and rear of the holding chamber are not generated. Supplied to the room.

[0012]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the melting and holding furnace 1 includes a melting furnace 2, a molten metal receiving section 3, a holding section 4, and a processing / tapping section 5. The holding unit 4 as a furnace body is located substantially at the center, and a processing / water tapping unit 5 is attached to the front side of the holding unit 4 so as to sandwich the holding unit 4 from front and rear. A melt receiving part 3 is attached. The melting furnace 2 is detachably attached to the left side of the holding unit 4.

As shown in FIGS. 2 to 8, the molten metal receiving portion 3,
The holding unit 4 and the processing / water tapping unit 5 are supported by a shared base 11. The melting furnace 2 is supported by a frame 12 further stacked on a common base 11.

The molten metal receiving portion 3 includes a lining refractory 31 covered with a steel shell, and the lining refractory 31 surrounds the molten metal inlet 32. A slide lid 33 is placed over the molten metal inlet 32. The slide lid 33 is slidably supported in a horizontal direction by a hydraulic cylinder mechanism (not shown). When the molten metal inlet 32 is opened by moving the slide lid 33, the molten metal 9 is charged from a container such as a ladle (not shown) into the molten metal inlet 32 through an upper opening. When the slide lid 33 is closed after charging the molten metal, the inside of the furnace is made substantially airtight.

As shown in FIG. 6 and FIG.
The gas supply pipe 71 penetrates through the slide lid 33, and the gas introduction port 71 a opens into the furnace at the molten metal inlet 32. The gas supply pipe 71 communicates with a gas supply source via a pressure control valve (not shown). The gas supply source contains, for example, nitrogen gas as an inert gas. The pressurizing device 7 includes a pressure control valve (not shown) for controlling the gas supply pressure.

The holding part 4 is made of a refractory lining 4 covered with a steel shell.
The holding chamber 42 is surrounded by the refractory lining 41. Two doors 45 are provided on the right side of the holding portion 4.
a, 45a and two heating burners 46a, 46b, respectively. The two doors 45a, 45a are arranged at substantially the same height on the side surface of the holding chamber 42, and can be opened at the time of maintenance and inspection. The two heating burners 45a and 45b are arranged at substantially the same height on the side surface of the holding chamber 42, and the surface 9a of the molten metal 9 accommodated in the holding chamber 42.
The molten metal 9 is heated by spraying a flame.

A first partition plate 61 is provided between the holding chamber 42 and the molten metal inlet 32. This first partition plate 6
1 is a rectangle, and the upper side and both sides are lined with refractories 3
1 and 41, respectively, and the lower side is free. The lower side of the first partition plate 61 is separated from the bottom refractory 31 or 41, where the under passage 34 is formed.

A pair of refractory guides 41a and 41b extend from the left and right side walls of the holding chamber 42 toward the center, respectively, and have narrow portions 42c which are narrower than other portions in the holding chamber 42.
Are formed. The second distance between the tip of one refractory guide 41a and the tip of the other refractory guide 41b
Is provided, and the inside of the holding chamber 42 is partitioned into a first chamber 42a and a second chamber 42b by the second partition plate 62. The second partition plate 62 has a rectangular shape, and the lower side and both sides are supported by the lining refractory 41, respectively, and the upper side is free. The upper side of the second partition plate 62 is separated from the ceiling refractory 41, and the overflow passage 44 is formed here.

The second chamber 42b of the holding chamber and the molten metal processing chamber 52a
A third partition plate 63 is provided between the first partition and the third partition. The third partition plate 63 has a rectangular shape, and the upper side, the lower side, and both sides are supported by the lining refractory 41, respectively.

The third partition plate 63 has a through hole 63a at a lower intermediate portion. The flow holes 63a are sized to allow the molten metal 9 held in the second holding chamber 42b to flow toward the molten metal processing chamber 52a at an optimum flow rate. The opening size of the flow hole 63a is appropriately selected and determined according to the stirring ability of the stirrer 8, etc. The treatment / water tapping unit 5 includes a lining refractory 51 covered with a steel shell. Thereby, the molten metal processing chamber 52a and the tapping chamber 52b are each surrounded. As shown in FIG. 10, a stirrer 8 is provided in the molten metal processing chamber 52a, and the molten metal 9 is rotated and stirred by a screw 81 of the stirrer 8, so that a dissolved gas in the molten metal is degassed. . In the molten metal processing chamber 52a, the molten metal 9 is stirred to settle the impurity inclusions accompanying the molten metal 9 or float on the molten metal surface 9a. A lance (not shown) for gas injection may be provided in the molten metal processing chamber 52a, and an inert gas such as an argon gas may be injected into the molten metal 9 to perform degassing processing.

A fourth partition plate 64 is provided between the molten metal processing chamber 52a and the tapping chamber 52b. The fourth partition plate 64 has a rectangular shape, and is supported by the lining refractory 51 of a type in which all three sides are fitted from above. The lower side of the fourth partition plate 64 is separated from the bottom refractory 41 by a predetermined distance, and a second underpass 65 is formed here.

The first, second, third, and fourth partition plates 6 described above.
1, 62, 63 and 64 are made of ceramics having excellent thermal conductivity. It is preferable to use, for example, carbon, SiC, or a mixture of carbon and SiC for such a ceramic having good thermal conductivity.

The melting furnace 2 is attached to the left side of the holding part 4 and has a tower inlet 22, a bent passage 23, and two doors 25.
a, 25a and two heating burners 26a, 26b. The tower slot 22 extends vertically upward,
An openable / closable lid (not shown) is attached to the upper opening. A hopper (not shown) is provided above the tower insertion port 22 so that a substance to be melted such as scrap material is injected into the tower insertion port 22.

As shown in FIGS. 2 and 3, the bent passage 23 is bent at substantially 90 ° with respect to the tower inlet 22, and communicates with the side surface of the first chamber 42a of the holding chamber 42 through the inflow port 24. are doing. By providing the bent passage 23 in this manner, the undissolved material and the moisture-absorbing material containing water can be supplied to the tower inlet 2.
2 is prevented from flowing directly into the holding chamber 42, and contamination of the molten metal 9 and steam explosion are prevented.

Next, a case where the molten metal is melted and held using the melting and holding furnace described above will be described with reference to FIGS.

Since the molten metal 9 has already been stored in the holding part 42 of the melting and holding furnace 1, the second molten metal 9 is supplied to define the overflow passage 44 as shown in FIG. Up to the upper end of the partition plate 62
Rises. The molten metal 9 already contained in the melting and holding furnace 1 is mainly melted by using the melting furnace 2, and as shown in FIG. It is introduced into the first chamber 42a.

The slide cover 33 is closed to make the molten metal inlet 32 airtight. The molten metal 9 in the molten metal processing chamber 52a is agitated by the agitator 8, and impurity inclusions are removed by a filter device (not shown). The processed molten metal 9 is sent from the molten metal processing chamber 52a to the tapping chamber 52b through the under passage 65. During the molten metal processing, the molten metal 9 in the first chamber 42a of the holding chamber is heated by the burner 46a, and the molten metal 9 in the second chamber 42b is heated by the burner 46b.

After the degassing treatment and the filtration treatment, the treated molten metal 9 is discharged from the tapping chamber 52b. FIG. 1
As shown in FIG. 1 (b), the second surface 42b of the holding chamber, the molten metal processing chamber 52a, and the molten metal surface 9a of the tapping chamber 52b are respectively lowered.

Next, a pressurized gas is introduced into the molten metal inlet 32 by the pressurizing device 7 to pressurize the molten metal 9 in the molten metal inlet 32. The pressurized molten metal 9 moves from the molten metal inlet 32 into the first chamber 42a of the holding chamber through the under passage 34, and flows through the overflow passage 44 as shown in FIGS. 11 (c) and 11 (d). From the first chamber 42a to the second chamber 42b
Overflowing to At this time, since the first partition plate 61 defines the under passage 34, the molten metal 9 flows into the first chamber 42 a quietly from the molten metal inlet 32 without generating turbulence.

As shown in FIG. 11E, the molten metal inlet 3
The pressurizing device 7 is stopped when the molten metal surface 9a in 2 has dropped to the upper end of the under passage 34. The lid is opened, and as shown in FIG.
The molten metal 9 is put into the inside. As a result, as shown in FIG. 11 (g), the molten metal inlet 32 and the molten metal surface 9a of the first chamber 42a.
Rises.

In the above embodiment, since the molten metal is supplied from the molten metal inlet to the holding chamber through the under passage 34, the molten metal is not oxidized, and no turbulent flow occurs in the flow of the molten metal. For this reason, it is possible to supply a clean molten metal into which the foreign material is less mixed into the holding chamber.

In the above embodiment, the holding chamber is divided into the first chamber and the second chamber by the partition plate 62, and the molten metal overflows from the first chamber to the second chamber. Impurity inclusions are likely to settle or float.

In the above embodiment, the partition plates 61, 6
Since 2, 63 and 64 are excellent in thermal conductivity, the temperature difference between the chambers is reduced, and the soaking in the furnace is promoted.

Further, according to the above embodiment, the provision of the bent passage prevents the undissolved material or the moisture-absorbing material containing water from flowing directly from the tower inlet into the holding chamber, thereby preventing molten metal contamination and steam explosion. Effectively prevented.

[0036]

According to the present invention, by providing a temperature control function in the second chamber, it is possible to reduce the temperature of the melt of a non-ferrous metal such as aluminum without substantially reducing turbulent flow of the oxide or the like. It is possible to prevent and reduce the inclusion of inclusions and supply the molten metal to the holding chamber or the molten metal processing chamber, so that the level of the molten metal can be maintained at a constant height at the tap hole.

[Brief description of the drawings]

FIG. 1 is a plan view of a melting and holding furnace according to an embodiment of the present invention.

FIG. 2 is a front view of the melting and holding furnace according to the embodiment of the present invention.

FIG. 3 is a rear view of the melting and holding furnace according to the embodiment of the present invention.

FIG. 4 is a left side view of the melting and holding furnace according to the embodiment of the present invention.

FIG. 5 is a right side view of the melting and holding furnace according to the embodiment of the present invention.

FIG. 6 is a sectional view showing the melting and holding furnace taken along the line AA in FIG. 1;

FIG. 7 is a sectional view showing the melting and holding furnace taken along the line BB in FIG. 1;

FIG. 8 is a sectional view showing the melting and holding furnace taken along the line CC in FIG. 1;

FIG. 9 is a schematic plan view of a melting and holding furnace.

FIG. 10 is a schematic side view of a melting and holding furnace.

FIGS. 11A to 11G are flowcharts showing a series of operations from the reception of molten metal to the discharge of molten metal in the melting and holding furnace of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Melting holding furnace, 2 ... Melting furnace, 22 ... Tower inlet, 23 ... Bent passage, 24 ... Inlet, 25a, 25a ... Door, 26a, 26b ... Heating burner, 3 ... Melt receiving part, 32 ... Mouth, 33: slide lid, 34: under passage, 4: holding part (furnace main body), 41a, 41b: refractory guide, 42: holding chamber, 42a: first chamber, 42b: second chamber, 42c: narrow Part, 44 ... overflow passage, 45a, 45a ... door, 46a, 46b ... heating burner, 5 ... treatment / bathing part, 52a ... molten metal treatment chamber, 52b ... tapping chamber, 61, 62, 63, 64 ... partition plate, 63a … Flow hole, 65… under passage, 71… pressurized gas supply pipe, 8… stirrer, 81… screw, 9… molten metal, 9a… metal surface.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kazutoshi Nagai 1015-2 Higashi-Dongasa, Asaba-cho, Iwata-gun, Shizuoka Prefecture (72) Inventor Kazuhiko Kirinbayashi 571-1 Nakase, Hamakita City, Shizuoka Prefecture (72) ) Inventor S. Oma 3-12-19 Asahimachi, Nerima-ku, Tokyo F-term (reference) 4K045 AA06 BA03 RA12 RA16

Claims (5)

[Claims] 1. A molten metal inlet, into which a molten metal is introduced, a holding chamber provided with heating means for heating the molten metal so that the temperature of the molten metal does not drop before processing, a molten metal processing chamber for removing impurities from the molten metal, In a melting and holding furnace having a tapping chamber for discharging a treated molten metal, the molten metal charging port is partitioned from the holding chamber, and an underpassage is formed in which the molten metal charging port and the holding chamber communicate with each other at a lower portion. And a first partition plate for preventing direct contact with the atmosphere and preventing turbulence when the molten metal is supplied from the molten metal inlet to the holding chamber, and supplying the molten metal from the molten metal inlet to the holding chamber. For this purpose, a pressurizing means for pressurizing the molten metal in the molten metal inlet and a holding chamber are partitioned back and forth, and an overflow passage is formed in which the partitioned first and second chambers communicate with each other at an upper portion. Turbulence occurs when molten metal is supplied to two chambers A second partition plate for preventing raw water, a third partition plate for partitioning the second chamber and the molten metal processing chamber, and a fourth partition plate for partitioning the molten metal processing chamber and the tapping chamber. Melting and holding furnace characterized. 2. The melting and holding furnace according to claim 1, wherein said first, second, third, and fourth partition plates are heat conductive boards made of ceramics having excellent heat conductivity. 3. A melting furnace having a tower inlet into which a substance to be melt is charged, and a bent passage inclined at a predetermined angle with respect to the tower inlet and communicating with the first chamber. The melting and holding furnace according to claim 1, further comprising: 4. The melting and holding furnace according to claim 1, wherein a flow hole for flowing the molten metal is formed in an intermediate portion of the third partition plate. 5. The molten metal processing chamber is provided with at least one of a degassing unit, a filtering unit, a rotary degassing unit and a flux processing unit according to the intended use. 2. The melting and holding furnace according to 1.