JPS5929643B2 - Continuous atmosphere heat treatment furnace - Google Patents

Description

[Detailed description of the invention] The present invention continuously performs non-oxidation annealing or bright annealing of a long object to be heated, such as a pipe or a rod-shaped material, in an inert gas or reducing gas (hereinafter referred to as non-oxidizing gas) atmosphere. The present invention relates to a heat treatment method.

FIG. 1 shows an example of a conventional continuous atmosphere heat treatment furnace.

In the figure, 1 is a charging table, 2 is an entrance door, 3 is a front chamber, 4 is a heating chamber, 5 is a soaking chamber, 6 is an electric resistance heating element, 7 is a cooling chamber, 8 is a rear chamber, and 9 is an outlet Door, 10 is extraction table,
11 is a transport roll; 12 is a windproof curtain made of heat-resistant fibers suspended from the ceiling in the front room; 13 is a windbreak curtain made of heat-resistant fibers suspended from the ceiling in the rear room; 14
is an exhaust gas collection and discharge device provided above the charging table 1.

A non-oxidizing gas is supplied to the heating chamber 4, soaking chamber 5, and cooling chamber 7 from a gas generator (not shown) through a pipe 15, and the heating chamber 4, soaking chamber 5, and cooling chamber 7 are filled with this atmospheric gas. I'm letting you do it.

The object to be heated a is conveyed in the order of the front chamber 3, the heating chamber 4, the soaking chamber 5, and the cooling chamber 7 by 110 rotations of the conveyor roll, but when the object to be heated is a long object such as a pipe or a rod-shaped material, , heating chamber 4
Since hot air does not easily flow into a long space such as the inside of a pipe or the gap between several stacked rods when it is transported into a warehouse, it has the disadvantage that it takes a long time to achieve uniform heating.

In addition, in the case of cooling, the efficiency is also extremely low in the case of long objects to be heated.In contrast, in the past, the only way to increase the processing capacity was to increase the length of the furnace, which resulted in high equipment costs. It had drawbacks.

The present invention aims to provide a continuous atmosphere heat treatment method for long objects to be heated, which eliminates the above-mentioned drawbacks.

Next, one embodiment of the present invention will be described with reference to FIGS. 4 to 8.

The same reference numerals used in FIGS. 4 to 8 as those in FIGS. 1 to 3 described above indicate the same parts, and the explanation thereof will be omitted.

Reference numerals 16 and 17 indicate plenum chambers provided at the ceiling and the bottom of the front chamber 3, respectively. ), several short cylindrical nozzles 19 are protruded from the plenum chamber 16 on the ceiling, and short cylindrical nozzles 18 are slanted in the same direction and protrude from the plenum chamber 16 at a symmetrical position to the nozzles 19. and supply non-oxidizing gas to the plenum chambers 16 and 17 via air supply pipes 20 and 21, respectively.

Then, non-oxidizing gas at room temperature is injected obliquely from the tips of the nozzles 18 and 19 onto the objects to be heated a, a, . . . .

Each object to be heated a, a... is carried into the front chamber 3 with its longitudinal direction parallel to the direction of movement, and is carried in with an appropriate distance g between it and the following object to be heated. .

Therefore, as shown by the arrow in Fig. 5, the non-oxidizing gas in the upper and lower portions collides at the interval g, and the non-oxidizing gas flows into the pipe from the open end of the object to be heated, and the air inside the pipe is absorbed by the non-oxidizing gas. It is expelled by the dynamic pressure of oxidizing gas.

Therefore, several nozzles 1B and 19 are provided above and below.
At the same time, the atmosphere gas inside the furnace is completely shut off from the outside by the gas curtain that is ejected from the surface of the heated objects a, a, etc., and at the same time, the remaining air is removed from the outside by the gas that is forced into the inside from the tip of the pipe. This prevents oxidizing air from being brought into the heating furnace 4.

Furthermore, in the present invention, plenum chambers 22 and 23 are provided oppositely at the ceiling and bottom of the heating chamber 4, and the object to be heated a.

A... A large number of ventilation holes 24 and 25 are provided on the surface facing the plenum chamber 23 at the bottom, and several short strips are provided at intervals between the conveyor rolls 110 and are inclined in the direction opposite to the direction of movement of the heated object. A cylindrical nozzle 27 is made to protrude, and a short cylindrical nozzle 26 that faces symmetrically with this nozzle 27 is made to protrude from the plenum chamber 22 on the ceiling while being inclined in the same direction.

As shown in FIG. 8, in the plenum chambers 22 and 23, non-oxidizing gas heated to a high temperature after passing through a heat generating part 28 such as an electric heater or a combustion burner is sucked in by the rotation of a fan 29, and the non-oxidizing gas is sucked in by the rotation of a fan 29. Since the gas is fed under pressure through the branch pipe 30, high-temperature non-oxidizing gas is injected from the ventilation holes 24, 25 and nozzles 26, 27 onto the objects a, a, . . . .

Therefore, the gas injected from the nozzles 26 and 27 is
By colliding at intervals g between heated objects a, a..., as shown in Fig. 7, dynamic pressure is generated along the longitudinal direction of the heated objects a, a... and flows into the pipe. heated object a
, a... are heated from the inside.

The heating chamber 4 is constantly supplied with non-oxidizing gas from the air supply pipe 31, and this gas is force-fed to the plenum chambers 22, 23 by a fan 290 rotations and circulated back into the heating chamber 4.

Therefore, by passing through the heating chamber 4, the heated objects a, a.
... absorbs heat from the inner and outer surfaces at the same time and the temperature rises rapidly.

In the soaking chamber 5, plenum chambers 32 and 33 are provided at the upper and lower sides of the heated objects a, a, . . . , which are heated in the heating chamber 4. . . . The objects to be heated a, a .

Although not shown, the non-oxidizing gas injected from the plenum chambers 32, 33 is sucked in by the fan, heated, and circulated to the plenum chambers 32, 33 again.

Non-oxidizing gas is constantly supplied into the soaking chamber 5 from the air supply pipe 34.

In addition, plenum chambers 35 and 36 that eject non-oxidizing gas cooled to a low temperature are provided on the ceiling and bottom of the cooling chamber 7, and are arranged opposite to the objects to be heated a, a, and so on. In addition, the plenum chamber 36 at the bottom has a short cylindrical nozzle 38 inclined in the direction of movement of the heated objects a, a, and so on, and a short cylindrical nozzle 38 inclined in the opposite direction. Cylindrical nozzles 40 are made to protrude at intervals between transport rolls 110, and these nozzles 3 are projected from the plenum chamber 35 in the ceiling.
8. Protrude opposite short cylindrical nozzles 37°39 inclined in the same direction as 40 to symmetrical positions.

As in the case of the heating chamber, the non-oxidizing gas injected from these nozzle groups collides with the objects to be heated a, a,... at the interval g, thereby causing the objects to be heated, a, a...・Dynamic pressure is generated along the longitudinal direction and flows into the pipe, causing the heated object a,
a... is also cooled from the inside.

The cooling chamber 7 is supplied with non-oxidizing gas through an air supply pipe 41, and the non-oxidizing gas is cooled through a water-cooled heat exchanger (not shown) and sent to the plenum chambers 35, 36 by a fan.
It is pumped into the cooling chamber 7 and ejected into the cooling chamber 7.

As a result, the heat objects a, a, .

As explained in the embodiments above, the continuous atmosphere heat treatment method of the present invention injects non-oxidizing gas from an inclined nozzle into the inside of the pipe or into the gap between the rods in a long object to be heated such as a pipe or rod. The object to be heated is rapidly heated or cooled to the temperature of the non-oxidizing gas from the inner and outer surfaces, and no time is required for heat transfer, so even though it is small, it can process a large amount of object to be heated and has extremely high efficiency operation. It has the effect that can be achieved.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing a conventional continuous atmosphere heat treatment furnace, Fig. 2 is an enlarged cross-sectional view taken along line A-A in Fig. 1, and Fig. 3 is a vertical cross-sectional view showing a conventional continuous atmosphere heat treatment furnace.
FIG. 3 is an enlarged cross-sectional view taken along line B-B in the figure. FIG. 4 is a longitudinal sectional view of a furnace body showing an embodiment of the continuous atmosphere heat treatment method according to the present invention, FIG. 5 is an enlarged view of the front chamber in FIG. 4, and FIG. 7 is an enlarged view of the heating chamber in FIG. 4, and FIG. 8 is a sectional view taken along line D--D. a, a... Heated object, 3... Front chamber, 4.
... Heating chamber, 5 ... Soaking room, 7 ...
...Cooling chamber, 16,17...Blenheim chamber, 18,19...Nozzle, 22゜23...
・Blenheim chamber, 26, 27... nozzle,
28... Heat generating part, 29... Fan, 3
2゜33...Blenheim chamber, 35,36.
...Blenheim Chamber, 37, 3B, 39, 40
······nozzle.

Claims (1)

[Claims] 1. In an atmospheric heat treatment furnace in which a long object to be heated, such as a pipe or a rod-shaped material, is supported on a conveyor roll with its longitudinal direction parallel to the direction of movement and conveyed from the heating chamber to the cooling chamber, the heating chamber and A plenum chamber is provided at the bottom and ceiling of the cooling chamber, and several short cylindrical nozzles are protruded from the bottom plenum chamber at a distance between the transport rolls and are inclined in the direction in which the heated object travels or in the opposite direction. From the plenum chamber in the ceiling, a short cylindrical nozzle that faces symmetrically with the above-mentioned nozzle is inclined in the same direction and protrudes, so that when the heated object is carried into the heating chamber and the cooling chamber, the subsequent heated object is The high-temperature non-oxidizing gas for heating and the low-temperature non-oxidizing gas for cooling are injected from both plenum chambers through the nozzles, respectively, with an appropriate interval between the objects to be heated. Long pipes or rod-shaped materials that generate dynamic pressure along the length of the heated object by colliding with each other to cause each non-oxidizing gas to flow into the inside of the pipe of the heated object or into the gap between the rod-shaped materials. Continuous atmosphere heat treatment method for heated objects.