JP4280406B2 - Fast heating furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-speed heating furnace for circulating a hot air to raise a workpiece to a predetermined heat treatment temperature at a high speed, and more specifically, to a fast heating furnace having a higher temperature-raising efficiency structurally.
[0002]
[Prior art]
Aluminum alloy can be adjusted in strength, formability and other properties by cold working, solution treatment, age hardening treatment, annealing, etc. As an alternative material, it is frequently used in aircraft, vehicles and the like.
[0003]
Among them, 2000 series (Al-Cu) alloy and 5000 (Al-Mg) series alloy are known as typical aluminum alloys in which solid solution strengthening and age hardening, which are typical physical properties of aluminum alloys, are notable. Yes. These alloys can have strength and rigidity comparable to iron by T4 treatment (solution treatment → natural aging) and T6 treatment (solution treatment → artificial aging) after forming.
[0004]
The solution treatment refers to a process for obtaining a supersaturated solid solution by holding a work in a solid solution temperature range in a metal phase diagram and quenching after dissolving a precipitated phase in a matrix phase. According to this, since the vacancy concentration is frozen in a supersaturated state, the strengthening of dispersion works strongly and the strength of the material is drastically improved by the pinning action of the precipitated phase to the parent phase by the subsequent aging treatment. .
[0005]
By the way, high work strains such as dislocations are accumulated in workpieces such as forged products and cold-worked products. There is a finding that when the workpiece is solution-treated in this state, the shorter the temperature rise time of the workpiece, the better. That is, after processing, the thermal expansion stress (diffusion coefficient) due to the mass difference between the workpieces is partially uneven due to processing strain, so the recovery rate of the crystal becomes uneven and the quality varies due to elasto-plastic deformation. Arise. Therefore, the workpiece is rapidly heated to minimize the variation.
[0006]
Therefore, in some solution treatment processes, the solution treatment is performed by combining a fast heating furnace and a holding furnace for heating the workpiece uniformly at high speed. FIG. 4 shows an example of the fast heating furnace. The fast heating furnace 1 is concentrically disposed in the furnace chamber 2, which is surrounded by a refractory wall 21 having a work inlet 22 on the side surface and provided with a heating means B such as a burner at the bottom. The cylindrical workpiece storage chamber 3 and a circulation fan (radial fan) 4 provided on the upper opening 33 side of the workpiece storage chamber 3 are configured.
[0007]
A work shelf 31 for placing the work W is provided inside the work storage chamber 3, and a work transport path 32 that communicates with the work transport port 22 of the furnace chamber 2 is integrated with the work shelf 31. Is provided. A door D for closing the work transfer port 22 is provided on the outer wall surface of the work transfer port 22 so as to be openable and closable.
[0008]
By operating the circulation fan 4, the hot air in the workpiece storage chamber 3 heated directly by the heating means B is sucked up from the upper opening 33 and passes through the circulation passage 5 between the furnace chamber 2 and the workpiece storage chamber 3. After descending as a vortex, it is led again to the workpiece storage chamber 3 from the lower opening 34 of the workpiece storage chamber 3 together with the burner flame of the heating means B.
[0009]
According to this, the atmosphere in the furnace chamber 2 including the workpiece storage chamber 3 is rapidly heated, and the workpiece W in the workpiece storage chamber 3 can be rapidly and uniformly heated to a desired heat treatment temperature. became.
[0010]
[Problems to be solved by the invention]
However, when the temperature raising efficiency of the workpiece W is further increased, the workpiece conveyance path 32 is provided in the circulation path 5 of the hot air sent from the circulation fan 4 in the conventional configuration described above. Becomes a resistance, and the vortex generated by the circulation fan 4 cannot be uniformly lowered, and the flow rate and uniformity to the lower opening 32 of the work storage chamber 3 may be uneven.
[0011]
Further, when the vortex generated downward is guided again upward into the work storage chamber 3, a part of the hot air stagnates in the vicinity of the lower opening 34 of the work storage chamber 3 to generate a turbulent flow. The turbulent flow may also become an inflow resistance to the work storage chamber 3.
[0012]
Therefore, the present invention has been made to solve the above-described problems, and the object thereof is to eliminate the obstacles to the hot air circulation path in the furnace chamber, and to increase the temperature raising efficiency of the workpiece structurally. It is to provide a fast heating furnace.
[0013]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention is surrounded by a fireproof wall having a work transfer port, and a furnace chamber provided with heating means composed of a burner toward the inside thereof, and the furnace chamber from the inner wall surface thereof A cylindrical work storage chamber provided concentrically with a predetermined gap and provided with a mounting shelf on which a work is placed, and an atmosphere in the furnace chamber heated by the heating means are connected to the work storage chamber. In the high-speed heating furnace provided with a circulation fan forcibly circulating via, the workpiece storage chamber has a second workpiece transfer port arranged to face the workpiece transfer port of the furnace chamber The second work transfer port is provided with an openable / closable door. When the door is closed, the atmosphere circulates over the entire circumference between the inner wall of the furnace chamber and the outer wall of the work storage chamber. That a circulation path is secured. It is a symptom.
[0014]
According to this, the door is closed when the workpiece is heated, and there is no air resistance in the circulation passage provided between the furnace chamber and the workpiece storage chamber, so that hot air circulation closer to the ideal state can be obtained. It is done.
[0015]
In the present invention, it is preferable in design that the door can be opened and closed in a double-sided manner toward the workpiece transfer port of the furnace chamber, but in addition to this, a sliding door that slides along the workpiece storage chamber is provided. There is no particular limitation as long as the door is closed along the workpiece storage chamber when the door is closed.
[0016]
In order to introduce the hot air circulated through the furnace chamber more efficiently into the work storage chamber, the atmosphere generated in a vortex shape by the circulation fan passes through the circulation passage on the suction side of the storage chamber. It is preferable that a rectifying plate for maintaining the vortex flow is provided when guided to the storage chamber.
[0017]
The rectifying plate is preferably provided in an arc shape so as to converge from the outer peripheral direction of the storage chamber toward the axial direction in the same direction as the rotation direction of the circulation fan. The workpiece is accelerated and guided into the workpiece storage chamber, and as a result, the temperature raising efficiency of the workpiece is increased.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the present invention will be described. FIG. 1 is a side sectional view schematically showing a fast temperature raising furnace according to this embodiment. It should be noted that the same reference numerals are used for components that are considered to be the same as or the same as those of the conventional apparatus of FIG. 4 described above.
[0019]
This fast heating furnace 1a is surrounded by a fireproof wall 21 having a workpiece transfer port 22 (hereinafter referred to as a first workpiece transfer port) on its side surface, and a heating means B such as a burner is provided toward the inside thereof. The chamber 2, a cylindrical workpiece storage chamber 3 concentrically disposed in the furnace chamber 2, and a circulation fan (radial fan) 4 disposed on the upper opening 33 side of the workpiece storage chamber 3 are provided.
[0020]
A furnace chamber door D that opens and closes the first work transfer port 22 is provided in front of the first work transfer port 22 of the furnace chamber 2. In this embodiment, the furnace chamber door D is connected to lifting means (not shown), and slides up and down in the vertical direction when the workpiece W is transported. The opening / closing mechanism of the furnace chamber door D is not particularly limited.
[0021]
In this embodiment, the heating means B is a high-calorie burner using city gas or the like, and is coaxially disposed on the lower side of the furnace chamber 2 so as to blow out a burner flame toward the lower opening 34 of the work storage unit 3. ing.
[0022]
The work storage chamber 3 is formed of a heat-resistant metal cylindrical body (both rectangular cylinders) having both ends opened, and the furnace chamber is provided with a bracket (not shown) at a predetermined interval from the inner peripheral surface 23 of the furnace chamber 2. 2 are arranged concentrically at approximately the center. Inside the work storage chamber 3, a placement shelf 31 on which the work W is placed is provided. In this embodiment, the mounting shelf 31 is provided in a hook shape parallel to the conveyance direction of the workpiece W (see FIG. 2).
[0023]
A second workpiece transfer port 35 for transferring the workpiece W into the workpiece storage chamber 3 is provided on the side surface of the workpiece storage chamber 3 facing the first workpiece transfer port 22 of the furnace chamber 2. In this embodiment, the second work transfer port 35 is opened so as to have substantially the same opening width and opening height as the first work transfer port 22.
[0024]
As shown in FIG. 2 (cross-sectional view taken along the line AA in FIG. 1), the second work transfer port 35 is provided with a work storage chamber door 7 for opening and closing the opening. The work storage chamber door 7 includes two door bodies 71 a and 71 b formed in an arc shape along the outer peripheral wall of the storage chamber 3. In this embodiment, each door body 71 a and 71 b is the first work transfer port 22. It is attached to the door so that it can be opened and closed in a double-spread manner.
[0025]
The door bodies 71a and 71b and the storage chamber 3 are connected by hinge portions 73 and 73, and the door bodies 71a and 71b are provided on the outside of the furnace chamber 2 via an opening / closing shaft 72. It is connected to the door opening / closing means. In this embodiment, it is preferable that the hinge part 73 is formed in the shape which made resistance of hot air as small as possible. The inner wall 23 of the furnace chamber 2 is preferably formed in a cylindrical shape along the outer peripheral surface of the work storage chamber 3.
[0026]
According to this, when each door body 71a, 71b is closed, hot air generated by the circulation fan 4 is circulated in the furnace chamber 2 between the furnace chamber 2 and the work storage chamber 3 over the entire circumference. A circulation passage 5 is secured when the operation is performed. That is, since there is nothing blocking the circulation passage 5, hot air can pass stably to the lower part of the storage chamber 3.
[0027]
On the side of the lower opening 34 of the work storage chamber 3, there is provided a rectifying plate 6 for further accelerating the vortex flow circulating in the work storage chamber 3. As shown in FIG. 3, the rectifying plate 6 includes a large number of blades 61 that converge in an arc shape from the outer peripheral direction of the storage chamber 3 toward the axial direction.
[0028]
In this embodiment, the blade 61 is converged in the same direction as the rotation direction of the circulation fan 4, and according to this, a vortex in the same rotation direction as the rotation direction of the circulation fan 4 is easily generated inside the storage chamber 3. The hot air can circulate in the storage chamber 3 without resistance. Further, a reinforcing rib 62 is provided on the lower side of the rectifying plate 6 so as to project toward the burner B direction.
[0029]
Referring again to FIG. 1, the circulation fan 4 includes a fan body 41 having a U-shaped cross section that is open on the lower side, and a rotating shaft 42 that transmits rotational force to the fan body 41. In this embodiment, the fan body 41 is a radial fan having a large number of blades (not shown) on its periphery, and sucks up hot air in the work storage chamber 3 by rotating a rotating shaft 42 connected to a driving means (not shown). The air is blown into the circulation passage 5 between the furnace chamber 2 and the work storage chamber 3.
[0030]
A series of operations of the fast heating furnace 1 configured as described above will be described. With the circulating fan 4 circulating hot air at a predetermined temperature in the furnace chamber 2, the furnace chamber door D and the work storage chamber door 7 are opened, and the work W held by the transfer means (not shown) is transferred to the first transfer port. After being placed on the placement shelf 31 in the workpiece storage chamber 3 from the second transfer port 35 from 22, the workpiece storage chamber door 7 and the furnace chamber door D are closed. The opening / closing sequence may be the furnace chamber door D side first, or the work storage chamber door 7 side first.
[0031]
In any case, since the work storage door 7 is closed, a substantially uniform circulation passage 5 is secured between the furnace chamber 2 and the work storage chamber 3 over the entire circumference. Circulating the inside, it is possible to raise the temperature of the workpiece W to a desired processing temperature in a high speed and stable state. After the temperature of the workpiece W is increased, the workpiece W is again taken out from the furnace through the workpiece transfer ports 22 and 25 and transferred to a holding furnace (not shown).
[0032]
In the above embodiment, the work storage chamber door 7 is constituted by a double door, but may be a sliding door that can be opened and closed along the work storage chamber 3. Any configuration that does not hinder can be selected as appropriate.
[0033]
Moreover, in the said embodiment, although the one workpiece | work W is mounted in the mounting shelf 31, you may make it form in larger diameter and mount several workpiece | work W. FIG. In this case, when taking out the workpiece W, the mounting shelf 31 may be configured as a turntable, and such an aspect is also included in the present invention.
[0034]
【The invention's effect】
As described above, according to the present invention, there is no resistance in the circulation passage between the furnace chamber and the work storage chamber in the high-speed heating furnace that rapidly heats the work by circulating hot air. , The temperature raising efficiency of the workpiece can be further increased.
[0035]
Further, by providing a current plate at the lower end of the work storage chamber to generate a strong eddy current in the work storage chamber, the temperature raising efficiency can be further increased.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a fast heating furnace according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
3 is a cross-sectional view taken along line BB in FIG.
FIG. 4 is a side sectional view of a conventional fast heating furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1a Fast heating furnace 2 Furnace chamber 21 Fire wall 22 1st workpiece conveyance port 3 Work storage chamber 31 Mounting shelf 32 Work conveyance path 33 Upper opening 34 Lower opening 35 Second workpiece conveyance port 4 Circulation fan 41 Circulation fan main body 42 Rotation Shaft 5 Circulation passage 6 Current plate 61 Blade 7 Work storage chamber doors 71a and 71b Door body 72 Opening and closing shaft 73 Hinge part D Furnace chamber door B Heating means

Claims (4)

Surrounded by a refractory wall having a work transfer port, and arranged in a concentric manner with a predetermined gap from the inner wall surface in the furnace chamber provided with heating means comprising a burner toward the inside, A cylindrical workpiece storage chamber provided with a mounting shelf for mounting a workpiece thereon, and a circulation fan for forcibly circulating the atmosphere in the furnace chamber heated by the heating means via the workpiece storage chamber; In a fast heating furnace equipped with
The work storage chamber has a second work transfer port disposed to face the work transfer port of the furnace chamber, and the second work transfer port is provided with an openable / closable door. A high-speed heating furnace characterized in that a circulation passage is provided through which the atmosphere circulates around the entire circumference between the inner wall of the furnace chamber and the outer wall of the work storage chamber when is closed. The fast heating furnace according to claim 1, wherein the door can be opened and closed in a double-speech manner toward the workpiece transfer port in the furnace chamber. A rectifying plate is provided on the suction side of the storage chamber to maintain the vortex flow when the atmosphere generated in a vortex shape by the circulation fan is guided to the storage chamber through the circulation passage. The fast heating furnace according to claim 1 or 2. 4. The high-speed heating furnace according to claim 3, wherein the current plate is provided in an arc shape so as to converge from the outer peripheral direction of the storage chamber toward the axial direction in the same direction as the rotation direction of the circulation fan.

Images