JPS5813607B2 - Heat treatment furnace for pipes with setups - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat treatment furnace for upset pipes in which heating of the upset portion can be completed simultaneously with heating of the pipe body portion.

Generally, when raising the temperature of pipes with upsets in a heat treatment furnace, the required furnace length is determined by the time required to heat the upset part, so if you focus on the pipe body, the furnace length may be too long. In other words, the furnace time is longer and the occurrence of scale increases.In other words, the furnace becomes larger due to the upset portion having a weight of several percent, the amount of scale increases, and the fuel consumption rate also increases.

Therefore, conventional upset preheating devices have been used that preheat only the upset section outside the heat treatment furnace and then charge it into the furnace, and complete heating of the upset section in approximately the same time as the heating time of the tube body. is provided.

However, in the configuration equipped with the above-mentioned upset section preheating device, heating is performed using a method such as a burner or induction heating method, which increases initial costs and running costs, and requires additional equipment. There were drawbacks such as increased size and increased heat treatment time.

This invention was made in view of the above drawbacks, and
The purpose of this is to install a heating device at a predetermined position in the heating zone in a heat treatment furnace equipped with a heating zone and a soaking zone to directly spray high-temperature gas onto the upset section over a predetermined range to heat only the upset section. As a result, the temperature of the upset section can be raised to a predetermined temperature in approximately the same heating time as that of the pipe body, without the need for any other auxiliary equipment, thereby shortening the furnace length and reducing fuel costs. It is an object of the present invention to provide a heat treatment furnace for pipes with upsets that can reduce the amount of damage.

Note that the high-temperature gas in this invention refers to the furnace atmosphere gas in the soaking zone or heating zone, the gas heated by heating this furnace atmosphere gas with an appropriate heating means, or the combustion of the furnace atmosphere gas and a burner, etc. Refers to high temperature gas etc. mixed with other gases.

The present invention will be explained below with reference to an embodiment shown in the drawings.

In FIGS. 1, 2, and 3, an appropriate conveying device (not shown) is installed at the rear of one side wall 1a of a pipe heat treatment furnace with an upset, that is, a furnace body 1 equipped with a heating zone A and a soaking zone B. A charging port 3 for the upset pipe 2 conveyed by the pipe is provided.

Further, within the furnace body 1, a plurality of guide rollers 5 are arranged at predetermined intervals to guide the upset pipe 2 along the rear wall 1b on which a plurality of heating burners 4 are disposed.

Further, inside the furnace body 1, there is a fixed beam 6a extending in the furnace length direction, and an appropriate drive device (not shown).

) causes roughly rectangular motion (including roughly circular motion).

) are arranged alternately with the moving beams 6b.

Then, the tubular body portion 2a of the upset pipe 2 conveyed onto the guide roller 5 is received from below by the moving beam 6b and placed on the fixed beam 6a, and then the moving beam 6b is moved. It is designed to be sequentially transferred in the furnace length direction.

On the other hand, both side walls 1a, 1a in the heating zone A in the furnace body 1
A pair of upset part heating devices 7, 7 for heating the upset part 2b of the upset pipe 2 are installed at predetermined positions nearby.

As shown in FIG. 2, this upset section heating device 7 includes a circulation fan 9 that is driven by a drive device 8 provided outside the furnace body 1 to suck in the atmosphere inside the furnace body 1, and a circulation fan 9 that sucks the atmosphere inside the furnace body 1. It consists of a duct 11 leading to a nozzle header 10 provided in the lower part of the furnace body 1, and a plurality of hot air blowing nozzle pipes 12 connected to the nozzle header 10 and blowing high-temperature gas upward.

As shown in FIGS. 1 and 4, the hot air blowing nozzle pipes 12 are connected to the upset pipe 2 at predetermined intervals below the upset portion 2b and over a predetermined range along the transfer route. It is arranged so as to extend in the axial direction.

In the above configuration, each heating burner 4 is currently ignited, and the drive devices 8, 8 of the upset section heating devices 7, 7 are being driven. It is assumed that the long upset pipes 2 are sequentially conveyed onto the guide rollers 5 through the charging port 3 of the furnace body 1 by an appropriate conveyance device.

The upset pipe 2 conveyed onto the guide rollers is scooped up from below by the moving beam 6b, and
It is placed on the fixed beam 6a and sequentially transferred at a predetermined pitch in the furnace length direction.

During this time, the tube body portion 2a and the upset portion 2b of the upset pipe 2 are heated together in the heating zone A by the radiant heat from the ceiling wall by the heating burner 4 and the secondary radiant heat from the hearth. .

On the other hand, both circulation fans 9, 9 are driven by drive devices 8 of both upset section heating devices 7, 7, and the furnace main body 1
The atmosphere inside is sucked and introduced into the nozzle header 10 via the duct 11, and the sucked atmosphere gas is blown upward from each hot air blowing nozzle pipe 12 connected to the nozzle header 10.

Then, from the time when the upset portions 2b reach the vicinity of the hot air blowing nozzle pipe 12 of the upset portion heating device 7 to when the atmospheric gas is sucked by the hot air blowing nozzle pipe 12, the atmospheric gas is sucked into the lower side. It is heated by being blown directly from the

Therefore, the temperature of the upset part 2b is completed by heating by radiant heat transfer and heating by direct blowing of atmospheric gas, and the temperature rise is completed in approximately the same heating time as the heating time of the tube part 2a by radiant heat transfer only, and the temperature rise is completed in the soaking area. Transferred to B.

In FIG. 5, the diameter of the tube body part 2a of the pipe 2 with upset is 73.0φ, the thickness is 5.51t, and the upset part 2b
The diameter of 78.6φ and the thickness of 8.31t are heated together in a heat treatment furnace without an upset section heating device, and the hot air blowing nozzle pipe 12 of the upset section heating device 7 according to the present invention is heated in a heat treatment furnace without an upset section heating device. It is a graph which shows the temperature rise state of the tube part 2a and the upset part 2b when integrally heated by the heat treatment furnace provided only on the lower surface side of the pipe 2 with an upset.

In the graph, the horizontal axis shows the heating time, the vertical axis shows the temperature, and the curve A shows the temperature rise state of the tube body 2a when the upset part heating device 7 is not provided. Curve C, which is indicated by a dotted line, shows the temperature increase state of the upset portion 2b when the upset portion heating device 7 is provided.

As is clear from this graph, according to the heat treatment furnace according to the present invention, the time required to heat the tube body portion 2a and the upset portion 2b to a predetermined temperature, for example, approximately 700°C, is longer than that of the conventional heat treatment furnace. Compared to this, it was possible to shorten the time by about 15 to 20%.

In the above embodiment, a case has been described in which the upset section 2b is heated only by the furnace atmosphere gas as the high-temperature gas, but for example, as shown in FIGS. 6 and 7, the circulation fan 9 In the duct 11 on the discharge side of
An auxiliary burner 4a may be provided to further raise the temperature of the furnace atmosphere gas before use.

FIG. 8 shows another embodiment of this invention, in which a pair of hot air blowing nozzle pipes 12 are arranged above and below the upset part 2b so as to sandwich the upset part 2b.
This pair of hot air blowing nozzle pipes 12 blows high-temperature gas onto the upset portion 2b from both above and below to heat it.

According to this configuration, the upset portion 2b can be heated evenly and quickly.

9 and 10 show still another embodiment of this invention, in which the hot air blowing nozzle pipe 12 of the setup section heating device 7 on one side is replaced with two types of long and short nozzle pipes 12a, 12.
b, and these two types of nozzle pipes 12a, 1
2b are arranged alternately, and the damper 13 is switched according to the length of the upset pipe 2, and the nozzle pipes 12a,
12b.

According to this configuration, the upset portion 2b can be efficiently heated regardless of the length of the upset pipe 2.

In each of the above embodiments, the nozzle pipe 12 is used as the nozzle, but as shown in FIG. It's okay.

Furthermore, it goes without saying that the means for conveying the upset pipe 2 is not limited to the walking beam type, but may be a walking hearth type or a chain conveyor type.

As described above, according to the present invention, at a predetermined position of the heating zone in the heat treatment furnace for the upset pipe equipped with the heating zone and the soaking zone, along the upset section moving path of the pipe with amplifier set, A heating device is provided that includes nozzles arranged over a predetermined range, a circulation fan that sucks the atmosphere inside the furnace, and a duct that supplies high-temperature gas to the nozzle, and the high-temperature gas is blown from the nozzle toward the upset section. Therefore, by heating the upset part by radiant heat transfer and heating by direct blowing of high-temperature gas, it is possible to complete the temperature rise in approximately the same heating time as the heating time of the tube part only by radiant heat transfer.

Therefore, it is possible to shorten the heating time of the entire pipe with upset without installing other auxiliary equipment, which means that the furnace length can be shortened, construction costs can be reduced, and fuel consumption can be reduced. can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention, and FIG.
The figure is a cutaway view taken along the I-I line in Figure 1, and Figure 3 is a cross-sectional view of Figure 2.
4 is an enlarged view of the main parts of the present invention, FIG. 5 is a graph showing the heating state of the pipe with upset, FIG.
FIG. 7 is a longitudinal sectional view showing a modification of the heating device of the present invention;
FIG. 8 is a longitudinal sectional view showing another embodiment of the invention, FIG. 9 is a plan view showing still another embodiment of the invention, and FIG. FIG. 11 is a plan view showing a modification of the nozzle according to the present invention. 1...Furnace body, 2...Pipe with upset, 2a-...Pipe body part. zb...Upset part, 4...Heating burner, 7...
...Heating device, 9...Circulation fan, 10...
...Nozzle header, 11...Duct, 12.
...Hot air blowing nozzle pipe.

Claims (1)

[Claims] 1. In a heat treatment furnace equipped with a pipe conveying device that sequentially transports pipes with upsets carried into the furnace in a direction perpendicular to the axial direction thereof, a circulation fan that sucks the high-temperature atmosphere inside the heat treatment furnace, and this circulation fan. and a nozzle disposed over a predetermined range along the upset section transfer path of the upset pipe to blow high-temperature gas toward the upset section. A heat treatment furnace for pipes with an upset.