JP2013146741A - Solution treatment furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solution treatment furnace that enables regeneration of core sand through the use of heat on heat treatment, while tar caused by burning of an organic binder is removed at the same time as an aluminum casting is subjected to solution treatment.SOLUTION: A solution treatment furnace, in which an aluminum casting cast by a die provided with a sand core is subjected to solution treatment, includes: a first heat treating furnace having an inlet to which a casting before shakeout after casting is input; a second heat treating furnace having an outlet; a shutter provided between the first heat treating furnace and the second treating furnace; a conveyer for casting transportation that transports the casting from the inlet to the outlet; and a conveyer for sand transportation provided under the conveyer for casting transportation in the first heat treating furnace. The conveyer for casting transportation is configured to have a mesh structure on a surface where the casting is placed, and causes the core sand when the sand core is collapsed to pass through downward and then fall onto the conveyer for sand transportation.

Description

  The present invention relates to a solution furnace for solutionizing cast products, and more particularly to a solution furnace for regenerating core sand at the same time as solution forming.

  For example, in a cylinder head of an engine, a hollow portion having a complicated shape such as an intake port, an exhaust port, or a water jacket is formed. A product having such a complicated cavity is manufactured by casting in advance inside a mold using a sand core. As the core sand in the sand core, conventionally, core sand in which natural sand particles are used as an aggregate and an organic binder is applied on the surface thereof has been used.

  Conventionally, in a cast product using such a sand core, the cast product is cooled to near room temperature after the casting is finished, and the sand constituting the sand core is discharged from the cast product, and then the solution is formed. To be reheated. However, these processes have many energy losses and have practical problems. Therefore, as a method for solving this problem, a casting product manufacturing method has been developed that uses the heat of the casting product and puts it in a heat treatment furnace before cooling down to reduce energy loss (for example, Patent Documents). 1). The technology in Patent Document 1 uses a residual heat (400 ° C. to 500 ° C.) of the molten metal immediately after solidification to perform quenching and tempering treatment in a heat treatment furnace without cooling the casting, and at the same time, sand core. This is a method of removing sand by disintegrating the binder with the heat of the molten metal.

  However, in the above technology, if the heat treatment and the sand removal are simultaneously performed without cooling after casting, the heat treatment furnace is damaged due to the resin generated when the binder used in the sand core is roasted. There was a risk.

  Recently, attempts have been made to reduce costs by reusing the core sand used for the sand core. In order to reuse the core sand discharged from such a cast product, it is necessary to completely remove the organic binder attached to the surface of the sand. However, in the conventional core sand, the aggregate sand particles are not spherical, and since the surface has irregularities, even if the core sand is regenerated by baking, the organic binder on the surface is difficult to peel off, Therefore, the process of grind | polishing the surface with an organic binder was also required. In addition, since conventional core sand is natural sand grains, it has a problem that it has a non-uniform composition and poor crushability, and is easily cracked by expansion transformation during heat treatment.

JP-A-6-210437

  Accordingly, the present invention has been made to solve the above-described problems, and is a core sand that utilizes heat of heat treatment while removing a cast caused by roasting of an organic binder simultaneously with solutionization of an aluminum cast product. An object of the present invention is to provide a solution furnace capable of regenerating the steel.

  The solution furnace of the present invention is a solution furnace for solutionizing an aluminum cast product cast by a mold having a sand core, and is provided with an input port for introducing a cast product after casting and before sand removal. A first heat treatment furnace, a second heat treatment furnace provided with a discharge port, a shutter provided between the first heat treatment furnace and the second heat treatment furnace, and a cast product from the input port to the discharge port. A casting product transporting conveyor, and a sand transporting conveyor provided below the casting product transporting conveyor in the first heat treatment furnace, the casting product transporting conveyor placing a casting product The surface has a mesh-like structure, and is configured to allow the core sand when the sand core is collapsed to pass downward and to drop onto the sand conveying conveyor.

  According to the solution heat treatment furnace of the present invention, while the solution heat treatment of the aluminum casting product is performed through the first heat treatment furnace and the second heat treatment furnace, at the same time, in the first heat treatment furnace, while removing the spear caused by roasting of the organic binder, The core sand can be regenerated using the heat of the heat treatment.

  In the solution furnace of the present invention, an air discharge port and an air supply port are provided at the upper and lower portions of the first heat treatment furnace, respectively, and heating means for heating the air discharged from the air discharge port It is preferable to circulate and heat the air in the first heat treatment furnace. According to this aspect, the air in the first heat treatment furnace discharged from the air discharge port is heated by the heating means to thermally decompose the ani included in the air in the first heat treatment furnace, and then the ani is heated. The decomposed air can be returned to the first heat treatment furnace again from the air supply port, and the dust in the first heat treatment furnace can be removed.

  Furthermore, it is preferable that the casting product conveying conveyor and the sand conveying conveyor have the same conveying direction and conveying speed. According to such a configuration, core sand can be prevented from being brought into the second heat treatment furnace.

  Moreover, it is preferable that said 1st heat processing furnace is equipped with the discharge port for sand which discharges | emits the core sand conveyed by the said conveyor for sand conveyance. According to such an aspect, the regenerated core sand can be easily put out of the furnace through the sand discharge port.

  According to the present invention, it is possible to provide a solution furnace capable of regenerating core sand using heat of heat treatment while removing the resin generated by roasting of an organic binder simultaneously with solution forming of an aluminum casting product. Can do.

It is the cross-sectional view which showed one Embodiment of the solution heat treatment furnace of this invention. It is the longitudinal cross-sectional view which showed one Embodiment of the solution heat treatment furnace of this invention.

  Hereinafter, the solution furnace of the present invention will be specifically described with reference to the drawings. FIG. 1 is a transverse sectional view showing an embodiment of the solution furnace of the present invention, and FIG. 2 is a longitudinal sectional view showing an embodiment of the solution furnace of the present invention.

  The solution furnace 1 of the present invention forms a cast aluminum product 2 cast by a mold having a sand core and simultaneously coats the surface of the core sand using the heat of solution treatment. This is a solution furnace capable of regenerating core sand by roasting an organic binder. As shown in FIG. 1, in the solution furnace 1 of the present invention, a first heat treatment furnace 3 and a second heat treatment furnace 4 are provided along the conveying direction of the cast product 2. 3, an inlet 5 and an outlet 6 that are openable and closable are provided on the side of the upstream side 3 and the side of the downstream side of the second heat treatment furnace 4, respectively. A casting product conveyor 7 is provided from the charging port 5 to the discharging port 6, and when the cast product 2 before sand removal after casting is charged from the charging port 5, sand is discharged from the discharging port 6 after the solution treatment. The removed casting 2 is carried out.

  In the first heat treatment furnace 3, a sand transporting conveyor 8 is provided below the casting product transporting conveyor 7 in parallel with the casting product transporting conveyor 7. The core sand 9 is transported at the same speed as the transport speed 2. Further, the casting product conveying conveyor 7 has a mesh structure on the surface on which the casting product 2 is placed, and allows the core sand 9 when the sand core is collapsed to pass downward. It is configured to drop onto the conveyor 8.

  In the solution furnace 1 of the present invention having such a configuration, first, an aluminum casting 2 cast by a mold having a sand core is transported by a casting transporting conveyor 7 and is fed from the inlet 5 to the first. One heat treatment furnace 3 is charged. When the heat treatment is started in the solution furnace 1 heated to about 500 ° C., the organic binder covering the surface of the core sand 9 constituting the sand core in the casting 2 is roasted. The sand core is collapsed into the core sand 9. Then, the collapsed core sand 9 collapses from the cast product 2, passes through the mesh-like structure on the placing surface of the cast product transport conveyor 7, and falls onto the sand transport conveyor 8 disposed below. . At this time, the core sand 9 that has fallen is preferably in a state in which the organic binder has been completely removed from the surface by roasting, but even when the organic binder still remains, the furnace temperature is about 500 ° C. Therefore, roasting of the organic binder is continued during the conveyance by the sand conveying conveyor 8, and the core sand 9 is further regenerated. Here, in the solution furnace 1 of the present invention, the sand core is actively collapsed and dropped from the casting 2 such as a mechanism for rotating the casting in an arbitrary direction and a mechanism for blowing hot air into the sand discharge hole of the casting. Means may be provided.

  Further, in order to promote such organic binder roasting on the sand transporting conveyor 8, a method of blowing hot air against the core sand 9 on the sand transporting conveyor 8, hot air from the lower side like a fluidized bed. The core sand 9 can also be agitated by a method of blowing up. Thereafter, the regenerated core sand 9 is put out of the furnace through the sand discharge port 10. The staying time of the medium sand piece 9 in the first heat treatment furnace 3 is longer than the time until Iglos (organic dirt on the sand surface) is completely eliminated, and the type and size of the sand, the type of the binder and the coating It is necessary to change according to thickness etc. Furthermore, in the solution furnace of the present invention, it is preferable that the casting product conveyor 7 and the sand conveyor 8 have the same conveying direction and conveying speed. According to such a configuration, it is possible to prevent the core sand 9 from being brought into the second heat treatment furnace 4.

  Further, a shutter 11 that can be freely opened and closed is provided between the first heat treatment furnace 3 and the second heat treatment furnace 4, and is configured to circulate the heated air in each furnace. In the roasting of the organic binder as described above, the organic binder is not completely volatilized and becomes tar-like scum and adheres to the furnace, which may damage the furnace. Therefore, by providing the shutter 11 as described above as a measure against such a spear, it is possible to prevent the spear from entering the second heating furnace 4.

  Further, in the first heat treatment furnace 3, it is preferable to provide a compressed air supply means 12 as shown in FIG. This compressed air supply means 12 can reduce the generation of spear by increasing the atmospheric oxygen concentration in the furnace and promoting the roasting of the organic binder. At this time, the compressed air supplied by the compressed air supply means 12 is preferably heated by using waste heat of the furnace or the like before reaching the inside of the furnace. Energy loss can be avoided.

  Furthermore, in the solution furnace 1 of the present invention, the air discharge port 13 and the air supply port 14 are respectively provided at the upper and lower portions of the first heat treatment furnace 3, and further heat the air discharged from the air discharge port 13. It is preferable that a heating unit 15 that performs the heating and a pump 16 that sends air from the air discharge port 13 to the air supply port 14 are provided. Here, the resin generated by roasting of the organic binder is lighter than air and tends to stay upward, so that the air discharge port 13 is located above the first heat treatment furnace 3 and the compressed air supply means 12 and It is necessary to provide the air supply port 14 in the lower part of the first heat treatment furnace 3.

  In such a configuration, the air in the first heat treatment furnace 3 is discharged from the air discharge port 13 by the pump 16, sent to the heating means 15, and heated to a temperature of about 700 to 800 ° C. by the heating means 15. Thereby, the spear contained in the air in the first heat treatment furnace 3 is pyrolyzed, and then the air in which the spear is pyrolyzed is returned to the first heat treatment furnace 3 from the air supply port 14 again. Any dirt in the furnace 3 is removed.

  Next, the aluminum casting 2 from which the sand core has been removed by collapsing is appropriately opened by the shutter 11 provided between the first heat treatment furnace 3 and the second heat treatment furnace 4, and the casting product conveyer 7 is provided on the downstream side. To the second heat treatment furnace 4. In the second heat treatment furnace 4, the cast product 2 from which the core sand 9 has been completely removed is heated to about 500 ° C. in an atmosphere that does not contain any spear generated by roasting of the organic binder, and is subjected to a solution treatment. Will continue. Thus, according to the solution furnace of the present invention, the core sand is regenerated using the heat of the heat treatment while removing the resin generated by roasting of the organic binder simultaneously with the solution forming of the aluminum casting product. Can do.

In the solution furnace of the present invention, the core sand used for the sand core is not made of natural sand grains, but aggregates with high sphericity and a smooth surface, for example, artificial sand are made of Al. It is preferable to use an aggregate or the like generated by ₂ O ₃ or SiO ₃ combustion flame melting. Since such an aggregate has a smooth surface, the surface properties are easily maintained, and since the components are uniform, the hardness is high, and furthermore, since there is no transformation point at the casting / regeneration temperature, it is difficult to break. It has the following advantages. Moreover, when the aggregates as described above are used, the amount of the organic binder applied to the surface can be reduced, and sand discharge performance is improved. Thereby, the core sand can be easily discharged by heating at the time of the solution treatment, and the organic binder remaining in the sand discharged into the furnace can be decomposed by the heat of the solution treatment.

DESCRIPTION OF SYMBOLS 1 ... Solution furnace, 2 ... Cast article, 3 ... 1st heat treatment furnace, 4 ... 2nd heat treatment furnace, 5 ... Input port,
6 ... discharge port, 7 ... conveyor for casting products, 8 ... conveyor for sand transport, 9 ... core sand,
DESCRIPTION OF SYMBOLS 10 ... Sand discharge port, 11 ... Shutter, 12 ... Compressed air supply means, 13 ... Air discharge port,
14 ... Air supply port, 15 ... Heating means, 16 ... Pump

Claims (4)

A solution furnace for solutionizing an aluminum casting cast by a mold having a sand core,
A first heat treatment furnace provided with an inlet for introducing a cast product before casting after casting,
A second heat treatment furnace provided with a discharge port;
A shutter provided between the first heat treatment furnace and the second heat treatment furnace;
A casting product conveyor for conveying the casting product from the inlet to the outlet;
A sand transport conveyor provided below the cast product transport conveyor in the first heat treatment furnace,
The casting product conveyor has a mesh structure on the surface on which the casting is placed, and allows the core sand when the sand core is collapsed to pass downward and drop onto the sand conveyor. A solution furnace characterized by being configured as described above.   An air discharge port and an air supply port are provided at the upper and lower portions of the first heat treatment furnace, respectively, and further provided with heating means for heating the air discharged from the air discharge port, The solution furnace according to claim 1, wherein air is circulated and heated.   The solution furnace according to claim 1 or 2, wherein the casting product conveyer and the sand conveyer have the same conveying direction and conveying speed.   The solution heat treatment furnace according to any one of claims 1 to 3, wherein the first heat treatment furnace includes a sand discharge port for discharging the core sand conveyed by the sand conveyance conveyor.

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