JPH0619106B2 - Continuous atmosphere heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is intended to fill a furnace with an atmospheric gas and subject a heat-treated object such as a steel material to non-oxidation, reduction, decarburization, etc. based on the atmospheric gas. The present invention relates to a continuous atmosphere heat treatment apparatus for performing heat treatment.

[Prior Art] As is well known, a continuous atmosphere heat treatment furnace is divided into a plurality of temperature zones in the conveying direction of the object to be heated, and the object to be heated passes through each temperature zone to have a predetermined temperature. The temperature is raised according to the curve, and the temperature is kept high and gradually cooled. Then, the composition of the atmosphere gas in the furnace is adjusted so that the object to be heated is subjected to a predetermined heat treatment such as non-oxidative heating, reduction, decarburization or the like. As shown in FIG. 2, this atmosphere gas is generally branched from the gas generator into about three places and supplied into the furnace b. The product is discharged from the product extraction port d.

[Problems of the Prior Art] In the conventional method of supplying the atmospheric gas into the furnace as described above, since the atmospheric gas penetrates longitudinally in the furnace, the composition of the gas in the furnace should be changed for each temperature zone. I can't do anything. However, since the concentration of the atmospheric gas actually required by the object to be heated varies depending on the heating temperature, if the atmospheric gas is supplied as described above, it is possible to change the composition in each temperature zone. Since it is not possible to supply the atmospheric gas to a certain temperature zone in an excessive amount, the consumption amount of the atmospheric gas increases and the running cost increases.

[Means for Solving Problems] Therefore, in the continuous atmosphere heat treatment apparatus of the present invention, in the continuous atmosphere heat treatment furnace in which a plurality of temperature zones are formed in a division in the transport direction of the object to be heated, a plurality of distribution source tubes are provided. Distribution branch pipe is provided, and the atmospheric gas is directly supplied to each temperature zone through the distribution branch pipe, and each distribution branch pipe is provided with a control valve capable of individually controlling the supply amount of the atmospheric gas,
A plurality of collecting / branching pipes are provided in the collecting / collecting pipe, and the furnace gas can be directly recovered from each temperature zone through the collecting / branching pipe, and the collecting amount of the furnace gas can be individually controlled in each of the collecting / branching pipes. A control valve is provided, and the in-furnace gas collected by the collecting branch pipe and the collecting source pipe is purified by passing through a removing device that removes oxidizing gases such as oxygen, carbon dioxide, and steam, and the distributing source pipe and the distributing pipe. It is characterized by being directly recirculated to each temperature zone in the furnace through a branch pipe.

[Example] In the atmosphere heat treatment furnace 1 shown in FIG. 1, the inside of the furnace is divided into five temperature zones 3A to 3E in accordance with the transfer direction of the article to be heated 2, and 4 is a charging door and 5 is a charging door. Is the extraction door. Reference numeral 6 denotes an atmospheric gas generator, 7 denotes a distribution source pipe connected to the atmospheric gas generation device 6, and the tip of the distribution source pipe 7 has a plurality of distribution branch pipes 7.
The gas is branched into A to 7E, and the atmospheric gas can be directly supplied to the temperature zones 3A to 3E through the distribution branch pipes 7A to 7E. 8A to 8E are the respective temperature zones 3A to 3E
A control valve provided in each of the distribution branch pipes 7A to 7B so that the supply amount of the atmospheric gas can be individually controlled. Further, 9 is a collecting source pipe provided on the suction side of the blower 10, the tip of the collecting source pipe is branched into a plurality of collecting branch pipes 9A to 9E, and each temperature zone is provided via the collecting branch pipes 9A to 9E. Three
The in-furnace gas can be directly recovered from A to 3E. 11A to 11E are collecting / branching pipes 9A so that the amount of recovered gas in the furnace from each of the temperature zones 3A to 3E can be individually controlled.
9E to 9E are control valves. Reference numeral 12 is a removing device for removing oxygen and carbon dioxide in the furnace gas recovered from each of the temperature zones 3A to 3E through the collecting / branching pipes 9A to 9E and the collecting and collecting pipe 9, and 13 is the removal device for removing water vapor. The removing device is connected in series with the device 12, and the secondary side of the removing device 13 is connected to the distributor pipe 7.

However, in the atmosphere heat treatment furnace, the collecting branch pipe 9A
9E, the furnace gas is collected by the collecting and collecting pipe 9, and the oxidizing gas in the furnace gas is removed by passing the gas through the removing devices 12 and 13, and the purified gas is distributed again to the distributing pipe 7 and the distributing branch pipe. It can be recycled into the furnace through tubes 7A-7E.
Therefore, the atmospheric gas generator 6 may generate the atmospheric gas to the extent that the shortage of the circulating atmospheric gas is supplemented, and the consumption of the atmospheric gas can be greatly reduced. In addition, FIG. 1 (a) shows the temperature rise curve of the object 2 to be heated in the atmospheric heat treatment furnace 1, and FIG. 1 (b) shows the oxygen released into the furnace by the reduction of the object 2 to be heated. The amount of oxygen and the amount of oxygen invading from outside the furnace are also shown. Thus, the amount of oxygen released from the object to be heated 2 rapidly increases as the temperature rises. Therefore, it is necessary to supply the largest amount of atmospheric gas to the specific temperature zone (in this case, the temperature zones 3C and 3D) in order to prevent oxidation of the object to be heated 2. FIG. 1C shows the composition (CO) ² / CO ₂ of the furnace gas actually required for non-oxidative heating for each temperature zone. In this atmosphere heat treatment apparatus, since the supply amount of the atmosphere gas can be controlled by the control valves 8A to 8E for each of the temperature zones 3A to 3E,
It is possible to control each temperature zone so that the composition of the atmosphere gas in the furnace actually required can be reached, and the supply of the atmosphere gas can be controlled without excess or deficiency in each temperature zone. The consumption of can be reduced.

[Effects of the Invention] As described above, in the continuous atmosphere heat treatment apparatus of the present invention, a distribution branch pipe having a control valve is provided for each temperature zone to supply an atmosphere gas required for each temperature zone and Since a collection and collection pipe with a control valve was provided for each temperature zone so that the required amount of furnace gas could be recovered in each temperature zone, the furnace gas should be longitudinally traversed across the temperature zone as in the past. Therefore, it is possible to prevent the temperature of the gas in the furnace from changing and to change the temperature in each temperature zone without excess or deficiency. Therefore, there is a beneficial effect that the consumption amount of the atmospheric gas can be significantly reduced and the running cost can be reduced without deteriorating the quality.

[Brief description of drawings]

FIG. 1 is a diagram in which a temperature curve, an oxygen release amount, and a gas composition in a furnace are shown together in a piping system diagram of an atmosphere heat treatment apparatus according to the present invention, and FIG. 2 is a piping system diagram of a conventional atmosphere heat treatment apparatus. 1 ... Atmosphere heat treatment furnace, 2 ... Heated object, 3A to 3E ...
Temperature zone, 6 ... Atmosphere gas generator, 7 ... Distribution pipe, 7A-7E ... Distribution branch pipe, 8A-8E ... Control valve, 9 ... Collection pipe, 9A-9E ... Collection pipe , 11A to 11E ... Control valve, 12, 1
3 ... Removal device.

Claims (1)

[Claims] 1. A continuous atmosphere heat treatment furnace in which a plurality of temperature zones are defined and formed in the conveying direction of a material to be heated, a plurality of distribution branch pipes are provided in a distribution source pipe, and an atmosphere gas is supplied to the distribution branch pipes. While directly supplying each temperature zone via each temperature zone, each distribution branch pipe is provided with a control valve capable of individually controlling the supply amount of the atmospheric gas, and a plurality of collection branch pipes are provided in the collection source pipe to supply the gas in the furnace. While directly collecting from each temperature zone through the collecting branch pipe, each collecting branch pipe is provided with a control valve capable of individually controlling the amount of the collected gas in the furnace, and is collected by the collecting branch pipe and the collection source pipe. The furnace gas is purified by passing through a removing device for removing oxidizing gases such as oxygen, carbon dioxide, and steam, and is directly recirculated to each temperature zone in the furnace through the distribution source pipe and the distribution branch pipe. Characterized by Continued atmosphere heat treatment apparatus.