JPH0692001B2 - Billet joining device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to several to several tens of steel pieces such as a sheet bar, a slab, or a billet, which are joined together, especially in a finishing rolling line of a hot rolling facility. The present invention relates to a steel strip joining apparatus suitable for continuous feeding to steel sheets.

(Prior Art) Conventionally, in a hot rolling line, steel pieces such as slabs are heated one by one, rough rolled, and finish rolled to finish a hot rolled sheet having a desired thickness. When the method is followed, especially in the finishing rolling line, it is inevitable that the line stop due to defective biting of the rolled material and the reduction of the yield due to the cutting of the leading and trailing edges of the rolled material are inevitable. In order to solve such a problem, a rolling method is adopted in which the trailing end of the precedingly conveyed steel strip and the leading end of the following steel strip are pre-joined and continuously fed to the rolling line. It's coming. For documents relating to this, for example, JP-A-63-90302 is referred to.

(Problems to be Solved by the Invention) In the technique disclosed in the above publication, the rear end portion of the preceding steel piece and the tip portion of the following steel piece are rapidly heated by an induction heating coil to press the steel pieces together. According to such a technique, the steel pieces can be joined to each other in a relatively short time on the entry side of the finish rolling line, and therefore the steel pieces are rolled one by one. The troubles such as the defective biting which had been caused are eliminated, the yield of the steel slab can be improved, and the productivity in the rolling line can be remarkably improved.

However, the device proposed here has a problem that it is difficult to apply it to an existing line because the device itself is inevitably increased in size, and the structure is complicated, resulting in poor maintainability. Also, in the case of such a device, it is difficult to match the horizontal level at each end of the steel slab because the position where the steel slab is clamped is far from the joint, and sufficient welding is possible when the slab is joined with the level inconsistent. Since the strength was not obtained, there was a risk that the joint portion would break and separate during rolling.

We will provide a compact joining device that is simple and accurate for joining steel pieces and has a simplified mechanism such as backward movement from the transfer line and easy maintenance, and can be easily applied to existing equipment. That is the object of the present invention.

(Means for Solving the Problem) The present invention is provided on the entrance side of a hot rolling facility with a rear end portion of a steel piece that is conveyed first and a tip end portion of a subsequent steel piece that is subsequently conveyed. Is a joining device for heating and pressing while moving in synchronism with the transportation of each steel slab to bring them into close contact with each other. It was equipped with a fixed pinch roll, and between the pinch rolls, a main carriage that was able to move along the transport direction of the steel slab, and it was possible to move forward and backward along the width direction of the steel slab placed on this main trolley. A steel slab joining apparatus, characterized in that a transversal alternating magnetic field generating coil having a C-shaped core fixedly held on the sub trolley and sandwiching the steel slab in the thickness direction is installed. The invention is the invention), and the joining device having the above-mentioned configuration is provided with a displacement of the joining end portion of each steel piece. In order to prevent fluctuations in the horizontal level during straightening and pressing, the area near each end of the steel slab is sandwiched vertically, and there is a clamp that helps keep the horizontal level almost the same during joining (second
Invention).

1 (a) and 1 (b) show an example of a steel piece joining device according to the present invention. The number 1 in the figure is a steel piece that is conveyed prior to the entrance side of the finish rolling mill (hereinafter referred to as "steel piece"). , The preceding sheet bar), 2 is a steel piece following the preceding sheet bar 1 (hereinafter referred to as the succeeding sheet bar), 3, 4
Presses the preceding sheet bar 1 and the following sheet bar 2,
Further, it is a pair of upper and lower pinch rolls that also serve as a conveyor (here, a fixed type having two pairs installed on the conveyor line is shown as an example, but two pairs may be installed before and after the joining portion). The pinch rolls 3 and 4 also serve to press the sheet bars together. Further, 5 is a main carriage (driving system is omitted) which is laid along the conveyance direction of the seat bars 1 and 2 and is movable on a track k, for example, 6 is an auxiliary carriage, and this auxiliary carriage 6 is the main carriage. It is mounted on the vehicle 5 and is moved back and forth along the track 6a (parallel to the width direction of the seat bar) installed on the main carriage 5 (the drive system is omitted). Reference numeral 7 denotes a C-shaped core 7a that sandwiches the sheet bars 1 and 2 in the thickness direction thereof, a coil 7b wound around the core 7a, and an alternating magnetic field generating coil composed of a power supply 7c. It is fixedly held by the sub-carriage 6.

The alternating magnetic field generating coil 7 is adapted to apply an alternating magnetic field that penetrates through the thickness direction of each of the steel pieces in the joining scheduled portion. Hereinafter, such an application method is referred to as a transverse method.

In this example, the above-mentioned transverse alternating magnetic field generating coil is shown as a single unit, but the number of installed coils can be increased if necessary.

FIG. 2 schematically illustrates the joining device having the above-described configuration, and FIG. 3 shows an example in which the joining device according to the present invention is applied to hot rolling equipment. In FIG. 3, numeral 8 is a coil box, 9 is a pinch roll for rewinding the sheet bar of the coil box 8, 10 is a leveler for straightening the unwound sheet bar, 11 is a predetermined joining shape of the sheet bar. Shears for cutting, and 12 are finishing rolling mill groups arranged in tandem along the downstream side of the sheet bar conveying line.

(Operation) When joining the rear end portion of the preceding sheet bar 1 unwound from the coil box 8 and the leading end portion of the succeeding sheet bar 2 especially at the entrance side of the finishing rolling mill group 12 of the hot rolling equipment. First, the rear end portion of the preceding sheet bar 1 and the succeeding sheet-
The tips of the bars 2 are cut by a shear 11 into, for example, a flat shape or a shape as shown in FIGS. Each seat bar 2,3 after cutting the front and rear edges
Will continue to be transported. In the installation area of the pinch rolls 3 and 4, the rear end portion of the preceding sheet bar 1 and the leading end portion of the succeeding sheet bar 2 are in a close state with a very small gap,
Alternatively, the rotational drive speed of at least one of the pinch rolls 2 and 3 is controlled so that the front and rear end portions of the respective sheet bars 2 and 3 are kept in contact with each other. The magnetic poles of the coil 7 are swung by the movement of the seat bars 2 and 3 so that the magnetic poles are located in the proximity area or the contact area of the seat bar and in the center of the seat bar in the width direction, and the seat bar is maintained while maintaining that state. An alternating magnetic field d penetrating in the thickness direction is applied. In the region to which the alternating magnetic field is applied, the eddy current e is induced, and the heat generated at that time heats the bonding apparatus S for a short time before reaching the pinch roll 3 (see FIG. 5). Following this, the rotational drive speed of at least one of the pinch rolls 3 and 4 is controlled to control the preceding seat bar 1,
The two are pressed together or they are brought into close contact with each other by the above heating while maintaining the pressed state.

Here, in order to perform the above-mentioned heating more advantageously, it is particularly preferable that both ends of the steel piece in the width direction are in contact with each other. This is because when the steel pieces are heated with both ends in contact with each other, an eddy current as shown in FIG. 5 circulates in the width direction of the steel pieces, and electric resistance exists at the joint surface. Therefore, the temperature of the joint surface is preferentially raised by Joule heat generation, and the heating time can be shortened.

FIG. 4 (a), which shows a suitable cutting shape at the front end and the rear end of the steel slab, shows that the rear end of the preceding sheet bar 1 and the front end of the subsequent sheet bar 2 are concave with the same curvature. A case where the sheet bars are cut is shown, and FIG.
If the rear end is also concave, but their curvatures are different,
In the same figure (c), when one planar shape is flat and the other is concave, in the same figure (d), one is convex and the other is concave, and the concave curvature is somewhat larger than the convex curvature. This is a case where the width is increased, and in any of the cases shown here, only the widthwise both ends of the seat bar are brought into contact with each other, and a gap is provided in the central region thereof. Applying such a joint shape heats the joint of each sheet bar,
When pressed, as shown in FIGS. 6 (a) and 6 (b), the joining region expands from both ends in the width direction to the central portion, so that joining can be performed reliably with a relatively small pressing force. In addition, there is an advantage that the target bonding temperature can be heated in an extremely short time. As a cutting method for forming the above-mentioned shape, a shear, gas cutting, laser fusing, or a drum shear having two curved blades capable of cutting in a concave shape with a specific curvature can be applied.

As for the joining form of the steel slab, the joining form is such that the planned joining portion is heated and heated to the target joining temperature, and after the heating is stopped, the heating is continued (however, the joining portion is maintained). There are various conceivable forms, such as joining at which the target temperature is reached when the temperature does not exceed the melting temperature) or joining in which the steel slab is heated in a pre-pressed state. The temperature of the billet at 1000
The temperature is about 1100 ° C, and the joining of the steel pieces progresses to some extent even by simple pressing. For this reason, when joining steel pieces, it is desirable to heat the steel pieces in a pressed state in order to reduce the joining time and the input power required for heating / heating.

In the present invention, in particular, a C-shaped core 7a is used as an alternating magnetic field generating coil 7 in a transverse method for heating a steel piece such as a sheet bar, and between the pinch rolls 3 and 4 that control the conveyance of the steel piece, Since the alternating magnetic field generating coil 7 is configured to move synchronously in the conveying direction of the steel slab or to move back and forth along the width direction of the steel slab by individually moving the main trolley 5 and the sub trolley 6, heating of the slab The joining operation by pressing can be performed easily and reliably, and particularly when the joining device needs to be retracted from the transport line, it can be quickly dealt with by the backward movement of the sub-carriage 6. In addition, the structure of the device itself is very simple and compact, maintenance can be performed easily, and it can be easily applied to existing equipment.

In the joining device having the above configuration, the pinch rolls 3, 4
However, if the installation interval is too large, it may not be possible to perform good joining due to deformation due to the weight of the sheet bar. Therefore, the installation interval l of the pinch rolls 3 and 4 may be (See Fig. 3)
Is preferably about 5 to 8 m.

Even if the installation interval l is adjusted within the allowable range, depending on the operating conditions or the sheet bar conveyance conditions, the joints may shift vertically and the horizontal level at the end of each sheet bar may not match. .

In order to deal with such a situation, the sub-carriage 6 according to the second invention of the present invention is shown in FIGS. 7 (a) and 7 (b) as a second invention.
The frame 14 (which may be an integral structure with the sub-carriage or may be a divided structure) equipped with a hydraulic clamp 13 for vertically sandwiching the end portions of the seat bars is installed in the By 13 the ends of each sheet bar are restrained, and the heating / pressing process is performed while correcting the displacement of the joints and preventing the horizontal level from varying during pressing. Here, the clamp 13 is preferably connected to the frame 14 via a ball joint j, for example, so that the clamp 13 can move in the pressing direction while sandwiching the sheet bar which is being conveyed.
Further, it is desirable to arrange a position changing means which is movable along the width direction of the seat bar so that the size of the steel pieces to be joined can be changed.

(Example) The pinch rolls 3 and 4 with the installation interval 1 adjusted to 6 m are arranged in the pressing equipment shown in FIG. 3 equipped with a 7-stand tandem finishing mill, and the sheet bar conveyance direction is provided between them. A sheet bar (low carbon steel with a width of 1000 mm and a thickness of 30 mm, provided with a joining device having a mechanism shown in FIG. 1 according to the present invention, which has a travel distance of 4 m along with a retreat distance from a transport line of 5 m ), Operating conditions (heating conditions) Input power: 2000kw Heating time: 2.4 seconds Frequency: 500Hz Pressing force: Surface pressure 3kg / mm ² (pinch roll) Pressing time: 3 seconds Finishing rolling speed (inlet side of rolling mill) Speed): Heated and bonded under pressure of 60 mpm and supplied to a finishing rolling mill to finish a hot rolled sheet with a plate thickness of 3 mm. As a result of investigating the rolling condition at that time, it was confirmed that the continuous sheet bar was not broken during rolling and good continuous rolling was possible.

In particular, when joining the steel pieces to which the clamps were applied, a good joint shape was obtained without observing the dislocation of the steel pieces at the joint.

(Effect of the invention) Thus, according to the first invention, an alternating magnetic field capable of individually advancing and retreating between the two sets of fixed pinch rolls on the entry side of the finish rolling mill in the conveying direction of the steel slab and in the direction orthogonal thereto. Since the generator coil is arranged, the structure of the joining device is very compact, it can be easily adapted to existing equipment, and maintenance can be performed easily.

Further, since the alternating magnetic field generating coil can be moved quickly even if the width dimension of the steel slab is changed, the alternating magnetic field can be applied to the desired position quickly and accurately in a state of being swung along with the movement of the steel slab. No extra equipment such as a looper for absorbing the joining time of the pieces is required, and the line can be simplified.

Further, according to the second aspect of the present invention, when the ends of the steel pieces are joined together, they can be securely fixed by the clamps, so that the ends are not displaced and joined together.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) and (b) are configuration explanatory views of a welding device according to the present invention, FIG. 2 is a perspective view of the welding device according to the present invention, and FIG. 3 is a hot rolling facility. 4 (a) to 4 (d) are views showing the planar shape of the front and rear ends of the seat bar, and FIG. 5 is an explanatory view of the heating state of the billet, FIG. FIGS. 7 (a) and 7 (b) are explanatory views of the procedure for joining steel pieces, and FIGS. 7 (a) and 7 (b) are explanatory views of the structure of the clamp according to the present invention. 1 ... Leading seat bar, 2 ... Subsequent seat bar 3,4 ... Pinch roll, 5 ... Main bogie 6 ... Sub bogie, 6a ... Orbit 7 ... Alternating magnetic field generating coil 7a ... Core, 7b ... … Coil, 7c …… Power supply 8 …… Coil box, 9 …… Pinch roll 10 …… Leveler, 11 …… Shear 12 …… Finishing mill group 13 …… Clamp, 14 …… Frame k …… Track l …… Pinch roll installation interval

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Hadano 1 Kawasaki-cho, Chiba City, Chiba Prefecture Inside the Kawasaki Steel Co., Ltd. (72) Inventor Hideo Takekawa 1 Kawasaki-cho, Chiba City Chiba Steel Co., Ltd. Chiba Steel In-house (72) Inventor Hiroyuki Yoshimura 1 Kawasaki-cho, Chiba-shi, Chiba In-house at Chiba Works, Kawasaki Steel Co., Ltd. (56) Reference JP-A-61-253178 (JP, A)

Claims (2)

[Claims] 1. On the entrance side of a hot rolling facility, a rear end of a steel piece that is conveyed first and a front end of a subsequent steel piece that is conveyed subsequently are referred to as the conveyance of each steel piece. A joining device for heating, pressing and closely contacting each other while moving in synchronism, comprising at least two sets of fixed pinch rolls for pressing the steel pieces by sandwiching the steel pieces up and down and rotating the steel pieces. Between the rolls, the main carriage that can move along the conveying direction of the steel slab, and the sub-carriage that is placed on this main trolley and that can move back and forth along the width direction of the steel slab, are fixedly held on the sub-carriage. An apparatus for joining steel pieces, wherein a transverse type alternating magnetic field generating coil having a C-shaped core sandwiching the steel pieces in the thickness direction is installed. 2. A clamp having a function of holding a region near the rear end of the preceding steel slab and a region near the tip end of the subsequent steel slab above and below, respectively, to keep the horizontal level of each steel slab substantially the same. The device according to claim 1.