JPS63238221A - Continuous bright annealing furnace - Google Patents

Abstract

PURPOSE:To permit execution of efficient slow cooling of a material after bright annealing by forming a cooling zone between a heating zone and taking out part, circulating part of a combustion gas thereto and circulating the gas cooled by being passed through a heat exchanger provided on the circulation path to the cooling zone. CONSTITUTION:A muffle 4 is provided on the upper part of a work chamber 3 provided with a material supply port 1 and a material take-out port 2 to form the circulation path for an atmospheric gas. The heat exchanger 7 is internally provided on the material taking out side in the muffle 4 to cool the atmospheric gas blown out to the material taking out side by a heat exchange. This gas is admitted as the circulation gas C for the slow cooling zone into the chamber 3 from the junction between the chamber 3 and the material taking out side of the muffle 4. While the gas C is again sucked by a circulation fan 5, the heated material 18 for treatment traveling in the chamber 3 is slowly cooled and is sent to the port 2. The easy adjustment of the heating and cooling conditions suitable for the material for treatment is thus permitted by this mechanism.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a continuous annealing furnace for brightly annealing metal materials (hereinafter simply referred to as materials) in an atmosphere in which combustion gas is circulated in the furnace, especially after heating. This process processes materials that require slow cooling in an oxygen-free or low-oxygen atmosphere.

[Conventional technology]

Conventionally, when bright annealing a material, a work chamber (3°) with a material supply port (1') at one end and a material outlet (2') at the other end is installed, as shown in Figure 3. At the top of the annealing furnace, there is a matsufuru (4°) connected at one end to the material supply side of the work chamber (3°) and at the other end to the material take-out side of the work chamber (3°) to circulate the atmospheric gas. form a road.

Matsuful (
A circulation fan (5') is attached to the connection part (4'), and the direction of rotation of the fan (5') is the direction in which atmospheric gas flows from the work chamber (3') to the upper matsufuru (4'). Furthermore, there is a burner (6") on the upper wall of Matsuful (4").
), and then install the fuel gas adjustment valve (9°) and air adjustment valve (
Oxygen-free or low-oxygen combustion gas (Ao) obtained by supplying fuel gas and air adjusted by 10°) to the burner (6°) is circulated in the above direction using a circulation fan (5°). The treated material (1B') is annealed by running from the supply port (1'') to the outlet (2'').

When this treated material (18') is taken out of the furnace and cooled, it is then fed into a water or oil quenching device (not shown) with the outside air shut off to a temperature at which the surface of the material is oxidized and its brightness is not impaired. After cooling down, it is taken out into the atmosphere. In addition, the combustion gas (Ao) is passed through a temperature sensor (8°) so that the temperature at which the treated material (18') is heated is a predetermined temperature, and the brightness of the treated material (18°) is not impaired by the atmosphere. The fuel gas regulating valve (9') and the air regulating valve (10') are controlled by the engine, and the air-fuel ratio is always kept constant. A gas seal device (13') is installed at the outlet (1°) of the main annealing furnace to maintain the atmosphere surrounding the furnace and the internal environment, and the exhaust gas is passed through the exhaust pipe (14°) on the supply port (1') side. is discharged from.

However, the above method cannot be applied to materials in which the heat treatment conditions change significantly due to rapid cooling after annealing, and the purpose of annealing cannot be achieved. A work chamber (3°) with a supply port (1°) and a material outlet (2°) at the other end.
) is provided with a heating furnace body (20) equipped with a heater (19) that directly heats the work chamber (3°) on the material supply side, and cooling water that directly cools the work chamber (3°) on the material removal side. (D) A water cooling jacket (21
) is used. The annealing furnace has a supply port (1゛)
The treated material (18°), which is transported from the to the outlet (2'), is indirectly heated and annealed in the heating furnace body (20), indirectly cooled in the water cooling jacket (21), slowly cooled, and then exposed to the atmosphere. The temperature is lowered to a point where it will not oxidize even if taken out.

In this case, the atmospheric gas (E) is N2, N2, or a non-oxidizing gas such as butane or a modified gas of natural gas, which is separately produced outside the annealing furnace and introduced into the work chamber (3'). Note that the material outlet (2゛) of this annealing furnace is equipped with a gas sealing device @ (13'), so the atmospheric gas (E) introduced into the work chamber (3゛) is passed through the material supply port (1). °).

[Problems to be solved by the invention] The above-mentioned annealing furnace that introduces atmospheric gas is more energy efficient than an annealing furnace that uses a combustion gas atmosphere, and both heating and cooling of the material are performed indirectly. Since heating and indirect cooling are used, the heating efficiency and cooling efficiency are extremely low, and it has been strongly desired to improve this.

(Means for Solving the Problems) In view of this, the present invention has been developed as a result of various studies.In order to increase the thermal efficiency and to increase the cooling efficiency to the extent that the material does not cool down rapidly, the present invention uses combustion gas to directly heat the material. We found that direct cooling using atmospheric cooling gas is the best method, and after a thorough study, we developed a continuous bright annealing furnace that is suitable for materials that require gradual cooling to a temperature that does not impair the bright state after bright annealing. It was developed.

One of the present inventions is a bright annealing furnace for metal materials, in which a combustion gas atmosphere adjusted to an oxygen-free or low oxygen concentration is circulated in the furnace, and the processed material is supplied from one end, heated by the combustion gas, and taken out from the other end. A cooling zone is formed between the heating zone and the extraction section to circulate part of the combustion gas, a heat exchanger is provided in the gas circulation path of the cooling zone, and the cooling gas heat exchanged through the heat exchanger is transferred to the cooling zone. It is characterized by cooling the processed material by circulating it.

Another aspect of the present invention is to circulate a combustion gas atmosphere adjusted to an oxygen-free or low oxygen concentration in the furnace, supply the processed material from one end, heat it with the combustion gas, and take out the metallic material from the other end. In an annealing furnace, a cooling zone is formed between the heating zone and the extraction section to circulate part of the combustion gas, a circulation air pressure adjustment valve is installed in the heating zone and the cooling zone, and a heat exchanger is installed in the gas circulation path of the cooling zone. A part of the combustion gas is heat-exchanged through the heat exchanger, and the cooled gas is circulated to the cooling zone to cool the processed material.

(Function) A cooling zone is provided following the heating zone of the annealing furnace, and a part of the combustion gas used as a heat source for heating is exchanged with the atmosphere used for cooling. This is because there is no need to newly create an oxygen-free or low-oxygen concentration atmosphere outside the furnace, which is essential for processing, and it is economical.In addition, the process material can be efficiently This is because slow cooling can be performed. A good way to achieve this is to install a fan between the heating zone and the cooling zone, and the fan mixes the high-temperature combustion gas used to heat the material with the low-temperature combustion gas used for cooling. This suction combustion gas can be distributed again to the heating zone and the cooling zone and circulated.

On the other hand, the reason why the circulating air volume adjustment valves are provided in the heating zone and the cooling zone of the annealing furnace is that these adjustment valves can change the ratio of the circulating air volume of the heating combustion gas and the cooling combustion gas, and therefore the heating conditions This is because the cooling conditions can be changed not only by the temperature of the circulating gas but also by the air volume. In addition, the reason why fans for circulating the combustion gas in the annealing furnace are provided independently in the heating zone and the cooling zone is that the combustion gas at the highest temperature and the lowest temperature are circulated independently without mixing. This is to increase the efficiency of gas heating and cooling.

〔Example〕

The continuous bright annealing furnace of the present invention will be explained based on examples.

Example■ As shown in Fig. 1, one end is located on the upper part of the work chamber (3), which has a material supply port (1) at one end and a material outlet (2) at the other end. A matsufuru (4) is provided whose other end is connected to the material extraction side of the work chamber (3) to form a circulation path for atmospheric gas. A circulation fan (
5) is attached so that the atmosphere inside the work chamber (3) is sucked and blown out to both the material supply side and the material take-out side of the upper matsufuru (4). Furthermore, the upper matsufuru (4
) A burner (6) is installed at an angle on the earthen wall on the material supply side so that the combustion gas (A) is injected toward the material supply side, and is blown out to the material supply side of the upper Matsufuru (4) by a circulation fan (5). The heating zone circulating gas (
B) is formed, and the work chamber (3) is connected from the material supply side connecting part of the work chamber (3) and the upper matsufuru (4).
), and the circulating gas CB) flows into the circulation fan (・5
), the treatment material (18) inserted through the supply port (1) and running inside the work chamber (3) is heated and annealed.

In addition, there is a heat exchanger (
7) is installed internally, and the upper matsufuru (
The atmospheric gas blown out to the material take-out side of 4) is cooled by heat exchange and is passed through the work chamber ( 3) The circulating gas (C
) is sucked again by the circulation fan (5), while the heated processing material (1) travels inside the work chamber (3).
8) is slowly cooled and sent to the outlet (2).

The combustion gas (A) from the burner (6) is supplied with a heating zone temperature sensor (8) near the blowing part so that the heating zone circulating gas (B) is blown into the work chillen bar (3) at a predetermined temperature. ), thereby controlling the fuel gas regulating valve (9) by PID control and at the same time controlling the combustion gas (A).
The air adjustment valve (10) is controlled so that the residual oxygen inside does not impair the brilliance of the treatment material (18), and the air-fuel ratio is always kept constant.

In addition, in order to ensure that the temperature at which the slow cooling zone circulating gas (C) is blown into the work chamber (3) reaches a predetermined temperature, a slow cooling zone temperature sensor (11) is installed near the blowing section, and the refrigerant regulating valve [12) is PID controlled, and the heat exchanger (7
) controls the flow rate of refrigerant flowing through the refrigerant.

Note that the material outlet (2) of the work chamber (3) forms an atmospheric gas sealing device (13), and excess atmospheric gas is exhausted from the exhaust pipe (14) on the material supply side.

In addition, a heating zone circulation wind control valve (15) is installed in the gas flow path on the material supply side of the connection between the upper matsufuru (4) and the work chamber (3), and a slow cooling gas flow path is also provided in the gas flow path on the material removal side. By providing the zone circulation & single volume adjustment valve (16), the heating conditions and slow cooling conditions can be changed not only by the temperature of the gas but also by the air volume of the gas flowing through the heating zone and slow cooling zone, allowing for more accurate control. It makes it possible.

Using the above continuous bright annealing furnace, the combustion gas components were changed to C01,
5%, 821.5%, 82013.5%, GO210
The wire rod was run through a furnace adjusted to 5%, j'4273% for continuous annealing, and then taken out into the atmosphere from the outlet, but the wire did not undergo surface oxidation due to oxygen in the atmosphere, and its brightness was impaired. It was found that the temperature had been sufficiently cooled to a temperature that would not exceed 100%.

Example ■ As shown in Figure 2, a work chamber (3) with a material supply port (1) at one end and a material outlet (2) at the other end is divided into two in the longitudinal direction by a partition plate (17) at the top. The upper matsufuru (4a) (4b) are provided. The heating zone upper matsufuru (4a) on the material supply side is connected to the work chamber (3) at one end of the material supply side, and the work chamber (3) and the upper matsufuru (4a) are connected roughly to the partition plate (17). A heating zone circulation fan (5a) to be connected is attached, and the ambient gas inside the work chamber (3) on the supply side is sucked and blown out and circulated to the upper part of the heating zone (4a). On the other hand, the upper part of the slow cooling zone (4b) on the material extraction side is connected to the work chamber (3) at one end on the material extraction side, and the partition plate (4b) is connected to the work chamber (3) at one end on the material extraction side.
A slow cooling zone circulation fan (5b) connecting the work chamber (3) and the upper matsufuru (4b) is installed adjacent to the work chamber (3) to suction the ambient air gas inside the work chamber (3) on the extraction side. The air is blown and circulated in the upper Matsuful (4b) of the cold zone.

In addition, combustion gas (
The burner (6) is installed tilted so that A) is injected toward the material supply side, and the heating zone circulation gas is mixed with the atmospheric gas blown out to the upper part of the heating zone (4a) by the heating zone circulation fan (5a). (8) is formed and poured into the chamber (3) through the material supply side connection part of the work chamber (3) and the heating zone upper matsufuru (4a), and the processing material (18) running inside the chamber (3) is Heat,
The heating zone circulation fan (5a) is again used to suck and circulate the heating zone.

On the other hand, there is a heat exchanger (7) in the upper Matsuful (4b) of the cooling zone.
The atmospheric gas blown out by the slow cooling zone circulation fan (5b) is cooled by heat exchange, and the slow cooling zone circulating gas (C
), the chamber (
3), the heated processing material (18) traveling in the chamber (3) is cooled, and is again sucked into the slow cooling zone circulation fan (5b) and circulated.

A heating zone temperature sensor (8) is attached to the flow path so that the combustion gas (A) from the burner (6) flows into the work chamber (3) at a predetermined temperature. The fuel gas regulating valve (9) and the air regulating valve (10) are automatically controlled via the fuel gas regulating valve (9) and the air-fuel ratio are always kept constant.

Zarani slow cooling zone circulating gas (C) is in the work chamber (3)
A slow cooling zone temperature sensor (11) is attached to the flow path so that the temperature flowing into the heat exchanger (7) is automatically controlled via the slow cooling zone temperature sensor (11), and the refrigerant regulating valve (12) is automatically controlled via this sensor to control the flow rate of the refrigerant flowing into the heat exchanger (7). is under control.

In addition, a heating zone circulation air pressure adjustment valve (15) is provided at the suction port of the heating zone circulation fan (5a), and a heating zone circulation fan (5b)
A cooling zone circulation air volume adjustment valve (16) is provided at the suction port of the cooling zone to control the circulation Jllffi and control the heating conditions and cooling conditions.

In addition, an atmospheric gas sealing device (13a) is installed at the material supply port (1) and material outlet (2) of the work chamber (3).
(13b), and excess atmospheric gas is exhausted from the exhaust pipe (14) on the extraction side.

Using the above continuous bright annealing furnace, the inside of the furnace was C01.5%, 8
21.5%, 82013.5%, QQ210.5%
.

Continuous annealing was performed by running the wire in a combustion gas atmosphere adjusted to 73% N2, but the wire taken out from the outlet showed no oxidation discoloration and was found to be sufficiently cooled. Moreover, an energy saving effect of 30 to 40% was obtained compared to the device of the example construction.

(Effects of the Invention) As described above, according to the present invention, materials that require slow cooling after bright annealing can be efficiently and continuously performed in the same furnace, and heating and cooling conditions suitable for the treated materials can be adjusted. It is easy to perform and has remarkable industrial effects.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing one embodiment of the present invention, FIG. 2 is a side sectional view showing another embodiment of the present invention, and FIGS. 3 and 4 are side sectional views showing conventional examples, respectively. It is. 1.1°...Material supply port 2.2'...Material outlet 3.3°...Work chamber 4.4°...Upper Matsufuru 4a...Heating zone upper Matsufuru 4b... Upper part of slow cooling zone 5.5°...Circulation fan 5a...Heating zone circulation fan 5b...Slow cooling zone circulation fan 6.6°...Burner 7...Heat exchanger 8.8° ...Heating zone temperature sensor 9.9゛...Fuel gas regulating valve 10, 10'...Air regulating valve 11...Low cooling zone temperature sensor 12...Refrigerant regulating valve 13, 13a, 13b, 13°... Atmosphere gas sealing device 14, 14'... Exhaust pipe 15... Heating zone circulation air volume adjustment valve 16... Gradual cooling zone circulation air outlet adjustment valve 17... Partition plates ia, ia'. ...Treatment material 19...Heater 20...Heating furnace body 21...Water cooling jacket A, A'...Combustion gas B...Heating zone circulating gas C...Learning zone circulating gas 0. ...Cooling water E...Atmosphere gas

Claims (4)

[Claims] (1) In a bright annealing furnace for metal materials, a combustion gas atmosphere adjusted to an oxygen-free or low oxygen concentration is circulated in the furnace, the material to be treated is supplied from one end, heated by the combustion gas, and taken out from the other end. A cooling zone is formed in which a part of the combustion gas is circulated between the cooling zone and the extraction section, a heat exchanger is provided in the gas circulation path of the cooling zone, and the cooling gas heat exchanged through the heat exchanger is circulated to the cooling zone. A continuous bright annealing furnace characterized by cooling the processed material. (2) The continuous bright annealing furnace according to claim 1, wherein a fan is provided between the heating zone and the cooling zone to circulate combustion gas. (3) In a bright annealing furnace for metal materials, a combustion gas atmosphere adjusted to an oxygen-free or low oxygen concentration is circulated in the furnace, the material to be treated is supplied from one end, heated by the combustion gas, and taken out from the other end. A cooling zone is formed in which a part of the combustion gas is circulated between the extraction section, a circulation air volume adjustment valve is provided in the heating zone and the cooling zone, a heat exchanger is installed in the gas circulation path of the cooling zone, and the heat exchanger A continuous bright annealing furnace characterized in that a part of combustion gas is heat-exchanged through a cooling zone, and the cooled gas is circulated to a cooling zone to cool a processed product. (4) The continuous bright annealing furnace according to claim 3, wherein fans are provided independently in the heating zone and cooling zone of the furnace to circulate combustion gas.