JPS6055563B2 - heating furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heating and rolling of steel billets, particularly in the step of rolling heated steel billets in a rolling mill with a very large reduction rate such as a planetary rolling mill. This invention relates to a heating furnace that is devised so that steel slabs can be rolled while being heated or heat-retained in the furnace to prevent heat dissipation and cooling of the steel slabs.

FIG. 1 shows an equipment layout diagram for the heating and rolling process in the prior art.

The cold steel billet or warm steel billet 5 is selected and aligned on the charging side of the heating furnace by the charging roller table 13, and then transferred into the furnace by the billet charging machine 12 and placed inside the heating furnace 1. The movable skid drive device transports the inside of the furnace from the preheating zone 2 side to the soaking zone 3 side while alternately placing it on the movable skid 5 and fixed skid 6 in a drive cycle as shown in Fig. 6. It is heated while being exposed.

The heated steel billet is carried out by the billet extraction machine 14 onto an extraction roller table 18 outside the furnace, and then transferred from this roller table 18 into a heat retention furnace 16 provided on the same line as the roller table 18. be transported.

Since the temperature of this steel slab is about 125σC, a water-cooled in-furnace roller 17 is provided in the heat retention furnace to support the steel slab and at the same time feed it to the rolling mill. In the heating furnace 1, the combustion exhaust gas used to heat the steel billets flows from the high-temperature heating zone 3 side to the low-temperature zone 2 side, and the flue gas flows while heating the steel billets in the furnace and releasing energy. The gas is sucked into the exhaust port 4, passes through a flue (not shown), and is discharged from a chimney (not shown).

The temperature of the exhaust gas in the flue is around 500 to 8 degrees Celsius due to heat exchange with the cold steel billets in the furnace.
Furthermore, this waste heat is recovered by preheating the combustion air using a heat exchanger (not shown) provided in the flue. On the other hand, in the heat retention furnace 16, the steel pieces in the furnace are almost uniformly 125C.
) Since the temperature is approximately C', the heat retention state is maintained by the burner 11 so that the temperature does not drop even during rolling. The temperature of this exhaust gas is almost the same over the entire length of the furnace, and it is also very high temperature (1250 to 18 μC). Since exhaust heat cannot be recovered, the temperature is lowered to about 800°C by blowing cold air, and then the heat is exchanged and released, or the heat is released at a high temperature. In the conventional method, heat loss in the heat retention furnace is extremely large due to the following reasons, and improvement of this problem is desired. (a) A steel billet heated in a heating furnace is once taken out of the furnace and then placed in a heat retention furnace. (b) The steel billets in the heat retention furnace are brought into rolling speed (a) with some of them being caught in the rolling mill 19. 5~5TT? , 1 min) and at the same level, the furnace roller 17
has been adopted.

Moreover, since the temperature inside the furnace is as high as 1250 to 130 degrees, these furnace rollers 17 are internally water-cooled and their outer surfaces are not insulated (if they are wrapped with heat insulating material, they will not fall off during conveyance of the billet). heat loss from the roller surface is (
150-250) x 103 kca11 h, which is extremely large. (c) In the heat retention furnace, the temperature of the steel billet is 125 (s).
The temperature of the gas in the furnace is very high at 1250-130 (slightly higher than that of the steel slabs) because of the need to maintain heat at a certain temperature (same level as the soaking zone in a heating furnace). Since the waste heat cannot be passed through the heat exchanger, the waste heat must be recovered after cooling it by blowing cold air to the safe level of 800℃ for the heat exchanger, which deteriorates thermal efficiency and increases the size and cost of the heat exchanger. is causing In a heat retention furnace, there is almost no need to heat up the steel billet and it is sufficient to keep it at that temperature, but in the conventional method, there are many water-cooled rollers, so there is a large amount of water cooling loss, so it is necessary to keep the temperature inside the furnace low. In reality, in order to maintain a predetermined temperature, a large amount of heat loss occurs, and fuel is injected to compensate for this loss.

If heat loss. If a heat retention furnace with very little loss were developed, fuel consumption could be greatly reduced. In order to solve the problems of the prior art, the present invention aims to improve the following points and provide a new heating furnace with the aim of effectively utilizing thermal energy and saving energy. be.

(a) The rolling mill is installed near the extraction side of the heating furnace, and the portion corresponding to the conventional heat retention furnace is omitted.

(b) A part of the TOp side of the steel billet being rolled is taken out of the furnace, but the rest is left in the heating furnace to prevent heat radiation from being cooled to the atmosphere.

(C) A walking-type first conveying device that conveys the steel billet from the charging side to the extraction side in the heating furnace and a second conveying device that sends the heated steel billet to the rolling mill are provided. The second conveying device adopted a double-walking mechanism that allows billets to be sent out in accordance with the rolling speed without changing the height level of the billet during rolling.

The present invention will be explained below with reference to an illustrated embodiment.

FIG. 2 shows an equipment layout diagram of the heating furnace and rolling process in the present invention.

Further, details of each facility according to the present invention are shown in FIGS. 3 to 5.

These will be explained below.

The process from when the cold steel billet or hot steel billet S1 is carried by the charging roller table 13 until it is conveyed while being heated to the extraction side of the heating furnace 1 is the same as the conventional method.

The heating furnace according to the present invention includes a first drive device for transporting the steel billet from the charging side to the extraction side in the furnace length direction, and a soaking zone for sending the heated steel billet to the rolling mill. A second drive is provided for movement in the orthogonal direction.

The first driving device is the same as that of the conventional system, and is composed of a moving skid 5, a fixed skid 6, driving devices 7, 8, etc., and is installed in a part of the preheating zone, heating zone, and soaking zone.

The second drive device not only sends out the steel billet to the rolling mill, but also transports the billet while keeping it in a heat-retaining state in the heating furnace, with the top side being engaged with the rolling mill, so it is similar to the first drive device. It must be possible to carry out the conveyance at almost the same level without changing the level in the height direction (approximately 100 m) every time it is conveyed, and it must be able to be fed out in accordance with the rolling speed.

To do this, drive devices with a double walking mechanism have already been used. These components include a first moving beam 20, a second moving beam 21, drive devices 22, 23, etc., and are installed on the extraction side of the soaking zone. The skid 6 is fixed by the first drive device 20 while being heated inside the furnace.
The billets that have been sent to the extraction side end are moved onto the first moving beam 20 and second moving beam 21 of the second drive device by a transfer device, that is, a billet changing device 1C provided outside the furnace. Ru.

For this purpose, a state in which the steel pieces are scooped up from the fixed skid 6 using a steel piece changing device is shown in FIG. Immediately after this state, the steel piece changing device 1C retreats to the second drive device side and tilts to change the steel pieces onto 20 and 21. After the replacement is completed, it will move further backwards and out of the furnace, and the opening of the furnace will be door 1.
It is sealed by closing 0. The steel pieces transferred onto the second drive device are the first moving beam 20 and the second moving beam 2.
1 mutually move as shown in FIG. 6, and in the forward movement process, the steel pieces are transferred to each other, thereby moving toward the rolling mill side while always keeping the height level constant.

The second drive device sends the steel billet at any suitable speed until the top of the billet transferred to the upper part has not yet been bitten by the rolling mill 19, but once the top has been bitten by the rolling mill, the second drive device sends the billet at any suitable speed. It is controlled to send out at a speed that matches the speed.

These moving beams 20, 21 are driven by drive devices 22, 23. Needless to say, each beam 5, 6, 20, and 21 has an ice-cooled steel vibe structure whose outer surface is lined with a heat insulating material, and the amount of heat loss from the beam is (5 to 12) per surface area x 103 kCa11 Wth.
The heat loss from the in-furnace rollers (150 to 250) x 103kca11 h in a conventional heat retention furnace has been reduced to 1125 to 1120.

The first moving beam 20 and the second moving beam 21 constituting the second driving device are provided in multiple rows independently in the furnace length direction for convenience in bringing the billet changer 1' into the furnace. ing.

The ram of the billet changer is inserted between these beams. By doing so, the contact position on the back surface of the steel billet can be selected at random, so that skid marks that occur during transportation by the first drive device can also be erased while being transported by the second drive device.

Since the heating furnace of the present invention has the above-described configuration, it exhibits the following excellent effects.

(a) It is possible to eliminate the conventional heat retention furnace that has water-cooled furnace rollers that cause extremely high heat loss and makes it difficult to effectively utilize high-temperature combustion exhaust gas, resulting in a furnace with high thermal efficiency.

(b) When sending a steel billet into a rolling mill, in the conventional method, the billet was taken out of the furnace, but with the present invention, the steel billet can be rolled while remaining inside the furnace, so most of the heat is dissipated into the atmosphere. It becomes less.

(C) While the second drive device is sending the steel billet to the rolling mill, the contact locations between the moving beam and the steel billet are random, making it possible to reduce skid marks.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the layout of billet heating and rolling equipment according to the conventional method, FIG. 2 is a diagram showing a layout example of billet heating and rolling equipment based on the present invention, and FIG. A-A cross section in Figure 2 (However, the steel billet replacement machine 1C
Figure 4 is a sectional view taken along line BB in Figure 2, Figure 5 is a sectional view taken along line CC in Figure 2, and Figure 6 is a diagram showing the movement cycle of the moving beam. It is. 1... Steel billet heating furnace, 2... Preheating zone of the steel billet heating furnace, 3... Soaking zone of the steel billet heating furnace, 4...
...Exhaust gas discharge port, 5...Moving skid for transfer in the furnace length direction, 6...Fixed skid for transfer in the furnace length direction, 7...For transfer in the furnace length direction Drive device for moving skid (vertical movement), 8... Drive device for moving skid for transfer in the furnace length direction (horizontal movement), 9... Charging side door, 10...・Door for steel billet changing machine, 11...
... Burner, 12... Steel billet charging machine, 13...
...Charging roller table, 14...Billette extraction machine, 1C...Billage changing machine, 15...
... Extraction door, 16 ... Heat retention furnace, 17 ...
・Furnace roller of heat retention furnace, 18...Extraction side roller table, 19...Rolling machine, 20...
First moving beam for transfer to the rolling mill, 21... Second moving beam for transfer to the rolling mill, 22... Moving beam drive device for transfer to the rolling mill, 23... ...Moving beam drive device (synchronized drive unit) for transfer to the rolling mill, S
1... Steel billet on charging roller table, S2...
... Steel billet charged to the heating furnace charging side, S3...
... Steel billet heated in the heating furnace and transferred to the extraction side, Se
...A steel billet caught in a rolling mill and being transported through a heating furnace in accordance with the rolling speed.

Claims (1)

[Claims] 1. A walking-type first conveyance device that sends material in the furnace length direction and a double-walking-type second conveyance device that sends material in the furnace width direction to the in-furnace extraction section are arranged in the same heating furnace, and the heating furnace A rolling mill is installed near the side wall of the material extraction section, and
A material transfer device is installed outside the furnace on the longitudinal side of the material extraction section,
A heating furnace characterized in that the transfer device can be moved forward and backward into the furnace.