JPH0489120A - Device for joining steel ingot - Google Patents

Abstract

PURPOSE:To provide an extremely compact construction and to allow the easy adaptation of the above device to existing equipment as well by disposing an alternate magnetic field generating coil which can be moved forward and backward discretely in the transporting direction of steel ingot and the direction orthogonal therewith between two sets of stationary type pinch rolls on the inlet side of a finishing mill. CONSTITUTION:The joining device S is moved in accompaniment with the movement of the sheet bars 2, 3 in such a manner that the magnetic poles of the alternate magnetic field generating coil 7 are positioned at the transverse center of the sheet bars in the area proximate to or in contact with the sheet bars and the alternate magnetic fields penetrating the sheet bars in the thickness direction are impressed to the sheet bars while this state is maintained. An eddy current is induced in the region where the alternate magnetic fields are impressed. The sheet bars are heated by the heat generated at this time in the short time before the arrival of the joining device S at the pinch rolls 3. In succession, the preceding sheet bars 1, 2 are pressed to each other by controlling the rotational driving speed of at least either of the pinch rolls 3, 4 or while the pressed state is maintained, the sheet bars are tightly adhered to each other by the above-mentioned heating.

Description

Detailed Description of the Invention (Industrial Application Field) This invention connects several to dozens of steel pieces such as sheet bars, slabs, or Vilent, and connects them to hot rolling equipment, especially finish rolling lines. This invention relates to a copper piece joining device suitable for continuously supplying copper pieces.

(Prior art) Conventionally, in a hot rolling line, steel billets such as slabs were heated one by one, roughly rolled, and then finished rolled to produce a hot rolled plate with a desired thickness. If this method is followed, it is inevitable that the line will stop due to poor biting of the rolled material and the yield will drop due to cutting off the leading and trailing ends of the rolled material, especially on the finish rolling line. In order to solve this problem, a rolling method was adopted in which the trailing end of the steel billet being conveyed in advance is connected to the tip of the following steel billet in advance, and this is continuously fed to the rolling line. It has become.

Documents related to this include, for example, Japanese Patent Application Laid-Open No. 63-9030
Reference is made to Publication No. 2.

(Problems to be Solved by the Invention) The technology disclosed in the above publication rapidly heats the rear end of the preceding steel piece and the tip of the following steel piece with an induction heating coil, and presses the steel pieces together. If this technique is followed, steel billets can be joined in a relatively short time on the entry side of the finish rolling line, and therefore, the steel billets that are rolled one by one can be joined together. This eliminates problems such as poor biting, improves the yield of steel billets, and significantly improves productivity on the rolling line.

However, the device proposed here has problems in that it is difficult to apply to existing lines because the device itself inevitably increases in size, and the structure is complicated, resulting in poor maintainability. In addition, in the case of such equipment, since the position where the steel pieces are clamped is far from the joint, it is difficult to match the horizontal levels at each end of the steel pieces, and if the steel pieces are joined with mismatched levels, there will be insufficient joint Because of the lack of strength, there was a risk that the joint would break and separate during rolling.

We propose a welding device that has a compact mechanism that allows easy and accurate joining of steel pieces, facilitates retraction from the conveyor line, and ease of maintenance, and can be easily applied to existing equipment. This is the purpose of this invention.

(Means for Solving the Problems) The present invention provides a method for connecting the rear end portion of a steel billet that is previously conveyed and the tip end portion of a succeeding steel billet that is conveyed subsequently at the entry side of a hot rolling facility. It is a joining device that heats and presses the steel billets while moving them in synchronization with the conveyance of each billet to bring them into close contact with each other. Equipped with fixed pinch rolls, and between these pinch rolls, there is a main truck that can move along the conveyance direction of the steel billet, and a main truck that is placed on this main truck and can move forward and backward along the width direction of the steel billet. A steel billet welding device (first method) characterized in that a sub-truck and a transverse-type alternating magnetic field generating coil having a C-shaped core fixedly held on the sub-bogie and sandwiching the steel billet in the thickness direction are installed. invention), and the welding device having the above configuration is such that in order to correct the misalignment of the joint ends of each steel billet and to prevent fluctuations in the horizontal level during pressing, the area near each end of the steel billet is sandwiched between the upper and lower sides, respectively. It shall have a clamp (second invention) which serves to keep its horizontal level approximately the same during joining.

Now, FIGS. 1(a) and 1(b) show an example of a joining device for steel billets according to the present invention, and the number 1 in the figures indicates a steel billet (hereinafter referred to as , 2 is a subsequent steel piece (hereinafter referred to as a succeeding sheet bar) L3,
4 is a pair of upper and lower pinch rolls that press the preceding sheet bar 1 and the following sheet bar 2, and also serve as conveyance (here, two sets of fixed type pinch rolls installed on the conveyance line are shown as an example, but (Two sets may be installed at the front and rear). The pinch rolls 3 and 4 also serve to press the sheet bars together. Further, 5 is a main bogie that can be moved on, for example, a track laid along the conveyance direction of the seat bars 1 and 2 (the drive system is omitted), 6 is a sub-bogie, and this sub-bogie 6 is the main bogie. 5, and moves forward and backward along a track 6a installed on the main truck 5, for example, parallel to the width direction of the seat bar (the drive system is omitted). Also, 7 is seat bar 1
A C-shaped core 7a sandwiching 2 in the thickness direction, and this core 7
The alternating magnetic field generating coil 7 is made up of a coil 7b wound around a coil 7a and a power source 7c, and the alternating magnetic field generating coil 7 is fixedly held on the subcarriage 6.

The alternating magnetic field generating coil 7 is configured to apply an alternating magnetic field that penetrates the thickness direction of each steel piece at the portion to be joined. Hereinafter, such an application method will be referred to as a transverse method.

Here, in this example, the transverse type alternating magnetic field generating coil is shown as a single unit, but the number of units installed can be increased as necessary.

FIG. 2 clearly illustrates the welding apparatus having the above structure, and FIG. 3 shows an example in which the welding apparatus according to the present invention is applied to hot rolling equipment. In addition, in FIG. 3, number 8 is a coil box, 9 is a pinch roll for unwinding the sheet bar of the coil box 8, 10 is a straightener for straightening the rewound sheet bar, and 11 is a sheet bar to form a predetermined joining shape. A shear for cutting, and 12 a group of finishing rolling mills arranged in tandem along the downstream side of the sheet bar conveyance line.

(Function) In joining the rear end of the preceding sheet bar 1 unwound from the coil box 8 and the leading end of the succeeding sheet bar 2 at the entry side of the finishing rolling mill group 12 in particular in the hot rolling equipment. First, the rear end portion of the preceding sheet bar 1 and the leading end portion of the succeeding sheet bar 2 are each cut by a shear 11 into, for example, a flat shape or a shape as shown in FIGS. 4(a) to 4(d).

The sheet bars 2 and 3 whose leading and trailing ends have been cut are continuously conveyed. In the installation area of the pinch rolls 3 and 4, the rear end of the preceding sheet bar 1 and the tip of the following sheet bar 2 are placed close to each other with a very small gap, or the tip and rear end of each sheet bar 2 and 3 are placed close to each other with a very small gap. The rotational drive speed of at least one of the pinch rolls 2.3 is controlled so as to maintain the state in which the sheet bars are in contact with each other. The sheet bar 2.3 is moved so as to be located at the widthwise center of the sheet bar, and while maintaining this state, an alternating magnetic field d penetrating the sheet bar in the thickness direction is applied. In the area where the alternating magnetic field is applied, an eddy current e is induced, and the heat generated at that time heats up the bonding device S for a short time before it reaches the pinch rolls 3 (
(See Figure 5). Following this, the rotational drive speed of the pinch rolls 3 and 4 (both of which are controlled) and the leading seat bar 1 is
．． Either the two are pressed together, or they are brought into close contact with each other by heating as described above while maintaining the pressed state.

Here, in order to perform the heating as described above more advantageously, it is particularly preferable to leave both ends of the steel piece in the width direction in contact with each other. This is because when a piece of steel is heated with both ends in contact, eddy currents as shown in Figure 5 circulate in the width direction of the piece, and there is electrical resistance at the joint surface. This is because the temperature of the joint surface increases preferentially due to Joule heat generation, and the heating time can be shortened.

(a) of FIG. 4 above, which shows suitable cutting shapes at the leading and trailing ends of the steel piece, shows that the trailing end of the preceding sheet bar 1 and the leading end of the trailing sheet bar 2 are concave with the same curvature. Figure (b) shows the case where the tip and rear end of each sheet bar 1.2 are both concave, but their curvatures are different, and Figure (C) shows the case where one of the sheet bars has a flat planar shape. state,
When only the other side is concave, Figure (d) shows the case where one side is convex and the other is concave, and the curvature of the concave side is made somewhat larger than the curvature of the convex side. The seat bar is shown with only both ends in the width direction in contact with each other, with a gap in the center area.

When such a joint shape is applied, when the joint part of each sheet bar is heated and pressed, the joint area expands from both ends in the width direction to the center, as shown in Figure 6 (a) and (b). This has the advantage that it is possible to reliably join with a relatively small pressing force, and that it can be heated to the target joining temperature in an extremely short time. As a cutting method for forming the above shape, a shear, gas cutting, laser cutting, or a drum shear having two curved blades capable of cutting into a concave shape with a specific curvature can be used.

Welding methods for joining steel pieces include heating and raising the temperature of the part to be joined to the target joining temperature, and pressing after stopping the heating, and joining method that continues heating and raising the temperature (however, the part to be joined is not heated). There are various joining methods that can be considered, such as pressing when the target temperature is reached (not exceeding the melting temperature), or heating the steel pieces after pressing them in advance, but usually the joining process The temperature of the steel piece at is 10
The temperature is about 00 to 1100°C, and the joining of the steel pieces progresses to some extent even by mere pressing. Therefore, when joining steel pieces, it is particularly desirable to heat the steel pieces while being pressed in order to shorten the joining time and reduce the input power required for heating and temperature raising.

In this invention, a C-shaped core 7a is used as the transverse-type alternating magnetic field generating coil 7 which is responsible for heating steel pieces such as sheet bars, and between the pinch rolls 3 and 4 that control the conveyance of the steel pieces. By moving the main truck 5 and the sub-truck 6 individually, the alternating magnetic field generating coil 7 is moved synchronously in the conveyance direction of the steel billet or moved forward and backward along the width direction of the steel billet, so that the steel billet is heated.・Joining operation by pressing can be performed easily and reliably, especially when it is necessary to evacuate the joining device from the conveyance line.
You can respond quickly by moving backwards. Furthermore, the structure of the device itself is very simple and compact, and maintenance is easy, and it can be easily applied to existing equipment.

In the joining apparatus having the above configuration, pinch rolls 3.
4 has been explained as a type in which the pinch rolls are fixed to the conveyor line of the sheet bar, but if this installation interval is too large, there is a risk that good joining may not be possible due to deformation of the sheet bar by its own weight, so the installation interval of the pinch rolls 3.4 is ! (See Figure 3) is preferably about 5 to 8 m.

Also, the installation interval above! Even if it is adjusted within the allowable range, depending on the operating conditions or the conveyance status of the sheet bar, the joint may shift vertically and the horizontal levels at the ends of each sheet bar may not match.

In order to cope with such a situation, in this invention, as a second invention, as shown in Section 7F (a) and (b), a hydraulic device is installed in the sub-truck 6 to sandwich the ends of each seat bar vertically. A frame 14 equipped with a clamp 13 (which may be integrated with the sub-truck or may have a separate structure) is installed, and the clamp 13 restrains the end of each seat par to prevent misalignment of the joint. We decided to adopt a configuration that allows heating and pressing treatment to be performed while preventing fluctuations in the horizontal level during straightening and pressing. Here, it is desirable that the clamp 13 be connected to the frame 14 via, for example, a ball joint j so that the clamp 13 can clamp the sheet bar in the conveying process and move in the pressing direction. Further, it is desirable to arrange a position changing means that is movable along the width direction of the sheet bar so as to be able to cope with changes in the size of the steel pieces to be joined.

(Example) In the rolling equipment shown in Fig. 3 above, which is equipped with a 7-stand tandem finishing rolling mill, the installation interval! In the mechanism shown in FIG. 1 according to the present invention, the pinch rolls 3 and 4 are arranged with the distance adjusted to 6 m, the moving distance of the sheet bar in the transport direction is 4 rrI, and the retracting distance from the transport line is 5 m. A welding device is installed, and a sheet bar (low carbon steel) with a width of 1000 mm and a thickness of 30 mm is heated under the following conditions (heating conditions): Input electricity to 2000 mm. Heating time = 2.4 seconds. Frequency: 500 Hz. Pressing force. : Surface pressure 3kg/mm2 (pinch roll)
Pressing time = 3 seconds Finish rolling speed (inlet speed of rolling mill): 60mp
m, the sheets were heated and joined while being pressed, and then fed to a finishing mill to finish a hot-rolled sheet with a thickness of 3M. As a result of investigating the rolling conditions at that time, it was confirmed that the sheet bars joined during rolling did not break and that good continuous rolling was possible.

In particular, when joining the steel pieces using clamps, a good joint shape was obtained with no discrepancy between the steel pieces at the joint.

(Effects of the Invention) Thus, according to the first invention, an alternating magnetic field is provided between the two sets of fixed pinch rolls on the entry side of the finishing rolling mill, which can move forward and backward individually in the conveying direction of the steel billet and in a direction perpendicular thereto. Since the generating coil is arranged, the structure of the bonding device is very compact, it can be easily adapted to existing equipment, and maintenance can be easily performed.

In addition, even if the width dimension of the steel slab changes, the alternating magnetic field generating coil can be moved quickly, so the alternating magnetic field can be quickly and accurately applied to the desired position while being moved by the movement of the steel slab. There is no need for extra equipment such as a looper to absorb the time required to join the pieces, and the line can be simplified.

Furthermore, according to the second aspect of the invention, when joining the ends of each steel piece, the clamps can be used to securely fix the ends, so that there is no possibility that the ends will be joined out of alignment.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are configuration explanatory diagrams of a joining device according to the present invention, Part 2 is a perspective view of a joining device according to the present invention, and FIG. 3 is a diagram showing a preferred example of hot rolling equipment. , Fig. 4(a)-(
d) is a diagram showing the planar shape of the front and rear ends of the sheet bar, Figure 5 is an explanatory diagram of the heating situation of the steel pieces, and Figures 6 (a) and (b) are illustrations of the procedure for joining the copper pieces. Figure, 7th
Figures (a) and (b) are diagrams illustrating the configuration of a clamp according to the present invention. 1... Leading seat bar 2... Following seat bar 3
．． 4... Pinch roll 5... Main bogie 6... Sub bogie 6a... Track 7... Alternating magnetic field generating coil 7a... Core 7b... Coil 7C... Power supply 8... Coil box 9...pinch roll 1
0... Reherer 11... Shear 12... Finish rolling mill group 13... Clamp 14... Frame k...
・Trajectory! ...Installation interval of pinch rolls Fig. 1 (a) Fig. 4 (b) Fig. 6 (a) (b) ?

Claims (1)

[Claims] 1. At the entry side of the hot rolling equipment, the rear end of the previously conveyed steel billet and the tip end of the subsequent steel billet are separated from each other. A joining device that heats and presses the steel pieces while moving them in synchronization with the conveyance of the steel pieces to bring them into close contact with each other, and is equipped with at least two sets of fixed pinch rolls that sandwich the steel pieces above and below and press the steel pieces by rotational drive. , between the pinch rolls, there is a main truck that is movable along the conveyance direction of the steel billet, a sub-bogie that is placed on this main bogie and that is movable forward and backward along the width direction of the steel billet, and a top of the sub-bogie. A steel billet welding device characterized in that a transverse type alternating magnetic field generating coil having a C-shaped core that is fixedly held on a steel billet and sandwiches the steel billet in its thickness direction is installed. 2. Claim 1, further comprising a clamp having the function of vertically holding the area near the rear end of the preceding steel piece and the area near the tip of the succeeding steel piece, respectively, and maintaining the horizontal level of each steel piece at substantially the same level. The device described.