JPH09295001A - Continuous rolling method and equipment - Google Patents

Abstract

(57) [Abstract] [Problem] To shorten the billet processing time cycle. SOLUTION: The fixed welding in which the billet 10 extracted from the heating furnace 1 is connected at least twice as long by flash butt welding from the upstream side of a continuous rolling mill 8 for continuously rolling continuously connected billets. A machine 3, a traveling welding machine 5 that flash-butt welds this double-sized billet with a preceding continuous billet, a traveling grinder 6 that grinds burrs at each weld, and an induction heating device 7 that heats the continuous billet. Are arranged in series, and the stationary welding machine 3 and the traveling welding machine 5 are arranged in tandem.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a billet continuous rolling method and apparatus in which a stationary welding machine and a traveling welding machine are arranged in tandem.

[0002]

2. Description of the Related Art In the conventional continuous rolling method for producing wire rods, steel bars or shaped steels with high energy efficiency and high efficiency, billets are extracted one by one from a heating furnace,
Weld the trailing edge of the leading billet and the leading edge of the trailing billet with a single traveling flash butt welding machine, then remove the burrs at the weld with a scarf, etc., and use an induction heating device to remove this continuous billet. After the temperature is raised to the temperature required for rolling, continuous rolling is performed in a rolling mill train (for example, JP-A-52-43754). In addition, a direct rolling method (H
Similarly, in DR and Hot Direct Rolling), one rolling flash butt welding machine is used for continuous rolling (for example, Japanese Examined Patent Publication No. 57-11722).

In continuous rolling of billets, it is important to shorten the processing time cycle of one billet, but the weight of one billet that has been generally used in the past is 0.5 ton to 2 ton. 70-80ton /
The processing time cycle of one billet needs to be 1 minute or less in order to increase the production capacity of more than hr. However, in the conventional continuous rolling method, since only one traveling welding machine is arranged online, it is difficult to shorten the welding time inherent in the traveling welding machine. It was impossible to achieve a time cycle.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to shorten the billet processing time cycle.
It is an object of the present invention to provide a continuous rolling method and apparatus capable of performing a time cycle of 1 minute or less without significantly changing the billet size of existing equipment.

[0005]

In order to solve the above problems, the continuous rolling method according to the present invention uses a flash butt welding process for connecting the trailing end of a leading billet and the leading end of a trailing billet, and a burr at the welded portion. In the method of continuously rolling the continuous billet in the rolling mill row after the grinding process to remove and the heating process to heat the continuously connected continuous billet, the welding machine used for the flash butt welding process is arranged in tandem. The first step of connecting the billet to at least twice the length by the fixed welding machine and then the traveling welding machine of the double-sized billet. And a second step of connecting by.

In the fixed welding machine, since the billet of unit weight is connected to at least twice the length, it is sufficient to connect the billet of the double scale in the traveling welding machine, which is sufficient for the flash butt welding time. You can have a margin. Therefore, the billet processing time cycle can be shortened.

Further, in the second step by the traveling type welding machine, the feeding speed of the billet is set to be the same as the biting speed of the first stand of the rolling mill train, and the trailing double-scale billet becomes a continuous billet at the start of welding. The feed is controlled so as to catch up. This prevents the billet from being subjected to excessive force, while at the same time allowing continuous welding and rolling of the billet.

The present invention can be applied to a continuous rolling method using a heating furnace or a direct rolling method using a continuous casting machine. In the former method, the heating furnace is arranged upstream of the fixed welding machine. , The billet is extracted from the heating furnace at a substantially constant time pitch shorter than the welding time of the second step. In the latter method, a continuous casting machine that casts a billet with a plurality of strands is arranged upstream of the fixed welding machine, and the billet cut into a relatively short length is welded in the second step through a line connecting machine. Directly sent to a fixed welder at an almost constant time pitch shorter than the time. Here, the line connecting machine connects the casting line of the continuous casting machine and the billet continuous line intermittently or intermittently, and includes, for example, a turntable, a transfer conveyor, and a shift carriage. The method of the present invention is applied when a continuous casting machine for multiple casting is installed so that the billet must be cut relatively short due to restrictions such as a building, and when the time cycle takes 1 minute or more. Especially effective.

In the case of the above-mentioned direct feed rolling method, since the heating furnace is not required and the heat possessed by the billet can be effectively utilized, the induction heating apparatus can reduce the temperature at the outlet side of the continuous casting machine from about 920 ° C. Rolling temperature up to approx. 1020 ° C approx. 100
Since it is sufficient to raise the temperature by only ° C, the heating unit consumption becomes extremely low.

The continuous rolling apparatus of the present invention used in the above continuous rolling method is a flash butt welding method in which the billet is at least double in length from the upstream side of the rolling mill train for continuously rolling the continuously connected billets. Fixed welder connected with, a traveling welder that flash-butt welds this double-scale billet with the preceding continuous billet, a traveling grinder that grinds burrs at each weld, and induction heating that heats the continuous billet. The apparatus is arranged in series, and the fixed welding machine and the traveling welding machine are arranged in tandem.

In the continuous rolling apparatus of the present invention, a billet heating furnace is arranged upstream of the fixed welding machine, or continuous casting is performed to continuously cast the billet in a plurality of strands on the upstream side of the fixed welding machine. And a line connecting machine for intermittently connecting a billet cut into a relatively short length to a fixed welding machine.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 is a schematic diagram showing a continuous rolling production line according to the first embodiment of the present invention. In FIG.
1 is a heating furnace, 2 is a descaler, 3 is a fixed type flash butt welding machine (hereinafter, referred to as a fixed type welding machine), 4 is a descaler, 5 is a traveling type flash butt welding machine (hereinafter,
6 is a traveling grinder, 7 is an induction heating device, 8 is a continuous rolling mill, and 8a is its first stand. The continuous line 12 of the billet 10 and the rolling line 13 of the continuous rolling mill 8 coincide with each other, and the continuous rolling mill 8 is arranged in series from the descaler 2 on this one linear production line 11 and fixed. Type welding machine 3 and traveling type welding machine 5 are arranged in tandem.

First, an outline of a billet connecting method in the continuous rolling apparatus configured as described above will be described.

The fixed-sized billet 10 is heated while being fed horizontally in the heating furnace 1, and is extracted from the heating furnace 1 one by one. The first billet 10 is sent to the fixed welder 3 after removing the scales at the leading end and the trailing end by the descaler 2, and is stopped by aligning the position of the trailing end of the billet 10 with the center position thereof. This positioning stop may be performed by tracking control of the feed table, or by using a disapearing stopper. Next, the second extracted billet 10 is similarly sent to the fixed welding machine 3 via the descaler 2, and the rear end of the first billet and the front end of the second billet are flash butt welded. Here, a double-sized billet with double the length is made. This is the first double-sized billet.

Next, the first double-scale billet, after removing the scales at the leading end and the trailing end by the descaler 4, is sent to the traveling type welding machine 5, is temporarily stopped, and is similarly processed in the fixed type welding machine 3. The second double-scale billet connected in the above manner is controlled so as to catch up with the first double-scale billet at the time of welding start, thereby performing flash butt welding between the first and second double-scale billets. Here, the billet is four times as long. That is, a 4L billet (L is the length of one billet) is produced. After that, in the traveling welding machine 5, 2L is added to this 4L billet.
The billets are continuously connected one after another, and the billets are continuously connected.

The billet thus made continuous is
After the burr of each welded portion is ground and removed by the traveling grinder 6, the temperature required for rolling (about 102
The temperature is raised to 0 ° C.) and continuously rolled by the continuous rolling mill 8.

The above operation will be described in more detail with reference to the time chart of FIG. In this time chart, the horizontal axis is the time axis, and the vertical axis is the distance and arrangement between the main machines. In this example, the billet extraction time pitch t is set to 30 sec. Code ...
Represents the extraction order of the billet 10. The length of L represented along the vertical axis is the length of one billet.

Now, the first billet is extracted from the heating furnace 1 and sent to the fixed welding machine 3 (feed time t1), and the billet is stopped at its center position (waiting time t2). . Then the second billet is 3
It is extracted after 0 sec and is flash butt welded with the first. This double-scale (2L) billet 10a becomes the first and is sent to the traveling welding machine 5 after a predetermined waiting time t3 (feed time T1) and stopped until the trailing double-scale billet 10b arrives (standby). Time T2).

When the first double billet 10a is started to be fed to the traveling welding machine 5, the third billet is extracted almost at the same time, and the third and fourth billets 10a are extracted.
The second double-sized billet 10 connected during the waiting time T2 of
b is sent to the traveling welding machine 5 after the waiting time t2. At this time, the feed of the double-sized billet 10b is controlled so that the tip of the second double-sized billet 10b catches up with the rear end of the waiting first double-sized billet 10a at the welding start time of the point Ws. When the double-sized billet 10b catches up, the traveling welding machine 5 starts running, and at the point We, welding of the first double-sized billet 10a and the second double-sized billet 10b is completed. After that, the traveling welding machine 5 retracts to the original position. The actual welding time WT1 of the traveling welder 5 is about 24 seconds, and the total welding time W including the return time WT2 is W.
The time chart is organized so that T is completed within 60 seconds. Here, the first 4L billet 10A is produced. The feed rate of the 4L billet 10A is the same as the biting rate of the first stand of the continuous rolling mill, and at the point P, the tip of the 4L billet 10A is bitten into the first stand. The traveling welding machine 5 and traveling grinding machine 6 are arranged so that the speeds thereof are synchronized with the biting speed. Moreover, since the grinding time GT of the weld burr is extremely short, it is possible to perform grinding with a sufficient margin during the welding time.

The fifth billet is assembled to delay the extraction a little (with an extraction delay time t4), and its waiting time t5 is shortened to prevent cooling. And the third double-sized billet 10c connected to the sixth billet
Are connected to the preceding 4L billet 10A by the traveling type welding machine 5 and added for 2L. That is, 6L billet 1
It becomes 0B. In this way, 2L of each is successively added (8L billet 10C, 10L billet, ...), and the continuous rolling of the billet is performed by the continuous rolling mill 8.

Therefore, in the traveling type welding machine 5, it is only necessary to connect the 2L portions, so that there is a sufficient margin in the welding time originally possessed by the traveling type welding machine. Therefore, one conventional traveling type welding machine is used. It is possible to carry out in 1/2 time cycle as compared with the time cycle in which is used. The reason why such a time cycle can be shortened is that the fixed welding machine 3 is connected to the double-sized billet having at least twice the length.

Embodiment 2 FIG. FIG. 3 is a schematic diagram showing a continuous rolling production line according to the second embodiment of the present invention. The present invention is also applicable to the direct feed rolling method using a continuous casting machine as described above. This example shows the case of the direct feed rolling method, in which a continuous casting machine 20 for multiple casting is installed so as to be orthogonal to the rolling line 13 due to the restrictions of the building 30, etc., and the billet 10 has a short length. This is the case when you have no choice but to cut with. Even in such a case, the present invention can be applied only by arranging the fixed welding machine 3 and the traveling welding machine 5 in tandem. In FIG. 3, 21 is a casting line, 22 is a cutting machine, and 23 is a chain conveyor that laterally feeds the cut billets 10 one by one to a turntable 24. Billet 1 with this turntable 24
0 is intermittently or intermittently directly sent to the fixed welding machine 3, and the cutting time of the billet 10 can be set to t = 30 sec as in the time chart of FIG. The continuous processing of the billet by the fixed welding machine 3 and the traveling welding machine 5 can also be performed as described above. The turntable 24 is shown as an example of the line connecting device, but the present invention is not limited to this.

When the billet is cast by two strands, the turntable 24 can be constructed as shown in FIG. In FIG. 4, 25 is a turntable 2
Reference numeral 27 denotes a cylinder device that laterally pushes the billet 10 carried onto the carriage 4 onto the rotation center line 26 while the turntable 24 rotates by a predetermined angle (for example, 90 °), and 27 is a disapearing stopper.

[0024]

As described above, according to the present invention, the fixed welding machine and the traveling welding machine are arranged in tandem, and first, the billet is at least twice as long as the flash butt welding by the fixed welding machine. , And then the double-sized billet is connected by flash butt welding by double the length by a traveling type welding machine to make the billet continuous, so welding with the traveling type welding machine Since the time can be afforded, the billet processing time cycle can be shortened to 1 minute or less. Moreover, since it is only necessary to install a fixed welding machine, it is not necessary to make a large change in the billet size of the existing equipment.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a continuous rolling production line according to a first embodiment of the present invention.

FIG. 2 is a time chart according to the first embodiment.

FIG. 3 is a schematic diagram showing a continuous rolling production line according to a second embodiment of the present invention.

FIG. 4 is a diagram showing another configuration example of the turntable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Disscaler 3 Fixed welding machine 4 Disscaler 5 Traveling welding machine 6 Traveling grinder 7 Induction heating device 8 Continuous rolling machine 10 Billet 11 Manufacturing line 12 Continuous line 13 Rolling line 20 Continuous casting machine 21 Casting line 22 Cutting machine 23 Chain conveyor 24 Turntable

Claims (7)

[Claims] 1. A flash butt welding process for connecting a trailing end of a leading billet and a leading end of a trailing billet, a grinding process for removing burrs in the welded portion, and a heating process for heating continuously connected billets. After that, in the method of continuously rolling the continuous billet in the rolling mill train, the welding machine used in the flash butt welding process consists of a fixed welding machine and a traveling welding machine arranged in tandem, and first the fixed type At least 2 billets by welding machine
A continuous rolling method comprising: a first step of connecting to a double length, and a second step of connecting the double-sized billet with the traveling welding machine. 2. The billet feed rate in the second step is set to be the same as the biting rate of the first stand of the rolling mill train, and the trailing double-scale billet is continuously fed at the start of welding in the second step. The continuous rolling method according to claim 1, wherein the feed is controlled so as to catch up with the billet. 3. A heating furnace is arranged on the upstream side of the fixed welding machine, and the billet is extracted from the heating furnace at a substantially constant time pitch shorter than the welding time of the second step. The continuous rolling method according to claim 1 or 2. 4. A continuous casting machine for casting a billet in a plurality of strands is arranged on the upstream side of the fixed welding machine, and the billet cut into a relatively short length is subjected to the second step through a line connecting machine. 3. The continuous rolling method according to claim 1 or claim 2, wherein the continuous rolling method is carried directly to the fixed type welding machine at a substantially constant time pitch shorter than the welding time. 5. A fixed welding machine for connecting billets at least twice as long by flash butt welding from the upstream side of a rolling mill train for continuously rolling continuously connected billets, and this double-scale billet. A traveling welding machine that performs flash butt welding with the preceding continuous billet, a traveling grinding machine that grinds burrs of each weld, and an induction heating device that heats the continuous billet are arranged in series, and the fixed welding is performed. A continuous rolling mill characterized in that the rolling mill and the traveling welding machine are arranged in tandem. 6. The continuous rolling mill according to claim 5, wherein a billet heating furnace is arranged upstream of the fixed welding machine. 7. A continuous casting machine for casting a billet in a plurality of strands on the upstream side of the fixed welding machine, and a line for intermittently connecting the billet cut into a relatively short length to the fixed welding machine. The continuous rolling mill according to claim 5, further comprising a connecting machine.