JP3103260B2 - Continuous hot rolling mill for billets - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous hot rolling equipment which is advantageous for continuously rolling several to several tens of billets.

[0002]

2. Description of the Related Art Conventionally, in a hot rolling line for a billet, a billet to be rolled has been heated, rough-rolled, and finish-rolled one by one to finish a hot-rolled sheet having a desired thickness. Such a rolling method inevitably causes a stop of the line due to poor biting of the rolled material in the finish rolling, and also has a significant inconvenience that the yield is reduced due to a defective shape of the leading and trailing ends of the rolled material.

[0003] For this reason, a rolling method has recently been adopted in which the rear end and the front end of a steel slab to be rolled are joined prior to finish rolling, and this is continuously supplied to a hot rolling mill for rolling. In this regard, in this regard, along the downstream from the rough rolling mill, a winding and rewinding device,
A facility disclosed in Japanese Patent Application Laid-Open No. 58-112601 has been known in which a shear, a welding machine (fixed type), a looper, and a finishing mill group are sequentially arranged.

[0004]

In the equipment disclosed herein, as shown in FIG. 6, since a welding machine for connecting a preceding slab and a following slab is fixed, the rolling speed is reduced. And the feeding speed of the slab occurs, and the installation of a looper for adjusting the time is indispensable, but the local temperature decrease caused by the looper in the longitudinal direction of the slab is There was a disadvantage that it was difficult to achieve uniform quality.

In order to solve such a problem, as disclosed in Japanese Patent Application Laid-Open No. 4-89120, a device for joining billets is made movable, and a looper which causes a local temperature drop of the billets is used. Facilities that omit installation have been proposed.

However, this equipment has the following drawbacks and leaves room for some improvement.

[0007] 1) Since the plate material is warped with a curl remaining as a result of winding by the winding / rewinding device, the plate material may not smoothly enter the shear for forming the joint end surface. . 2) When shaping the shape of the joint end face with a shear, if there is a shift in the billet width direction as shown in FIG. 7, there may be a diagonal cut, and as a result of joining, this is incomplete as shown in FIG. Become a joint. 3) The joined slab has a ridge at the joint as shown in FIG. 9 and is fed directly to a finish rolling mill to be rolled, as shown in FIG. As the number of passes increases, the base material portion of the slab becomes extremely thin, and eventually the plate may break, and stable rolling cannot be performed. 4) Since the induction-heat-bonded part is hotter than the other parts even after bonding, it is fed to a finish rolling mill as it is, and is subjected to finish rolling. When the stretched portion is stretched more than in the portion shown in FIG. In addition, the temperature history of the finish rolling process and the hot line cooling process in the high temperature part is different from that in other parts, and the mechanical strength and ductility of the product are not uniform as compared with other parts.

The present invention has been made to solve the above problems.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a winding and rewinding device for winding and rewinding a steel piece after rough rolling, and a method for rewinding and rewinding the steel piece by the winding and rewinding device. A leveler that corrects curling and warping, a crop shear that removes defective shapes at the leading and trailing ends of the billet, a guide that prevents displacement of the billet in the width direction, and a rear end and leading end of the billet A mobile joining device that joins by heating, heating and pressing, a ridge removing device that removes the ridge of the slab that has been joined, and a steel slab that has finished removing the ridge is continuously rolled. A hot finishing mill group is sequentially arranged, and at least one of the exit side and the entrance side of the ridge removing device, a cooling nozzle for cooling a ridge generated at the time of joining is arranged, Continuous hot rolling equipment.

FIG. 1 shows a configuration of a continuous hot rolling facility according to the present invention. In the figure, reference numeral 1 denotes a winding / rewinding device, 2 denotes a leveling device for correcting the warpage of the billet S, and a warp, 3 denotes a guide for preventing displacement of the billet in the width direction, and 4 denotes a tip of the billet S and a rear end thereof. A crop shear (a drum shear equipped with a straight blade, a curved blade, or a trapezoidal blade, etc.) for removing a defective shape portion at an end portion. Reference numeral 5 denotes heating, heating, and pressing of the rear end and the front end of the billet S. The joining device 5 has guides on its entry side and exit side for regulating the movement of the billet in the up, down, left and right directions, and its frame itself is laid in the longitudinal direction of the billet S. It can move along L.

Reference numeral 6 denotes a raised portion r generated at the time of joining.
Nozzle for advantageously cooling the steel piece S after joining is completed
2 is a device for removing a bulge (a swelled portion at a joint portion) of the device. As shown in FIG.
A rotary drum 7b having a plurality of blades 7a extending in the width direction of the slab is incorporated, and the ridge r of the slab S is cut and removed by rotating the drum 7b. It should be noted that the protruding portion removing device does not need to be limited to a rotary blade, and may be a whetstone.

8 shows the steel pieces S ₁ and S from which the protrusions r have been removed.
₂ --- is a group of hot finishing mills that roll continuously.
The joining device 5 stops heating when the portion reaches the target temperature regardless of whether or not the portion to be joined, which is the end surface of the billet S, is in contact, and then presses or heats the portion. With a function that can press the steel slabs from the beginning and simultaneously heat them at the same time, or press and heat until a predetermined joining margin is obtained. It is particularly advantageous to adapt.

[0013]

As shown in FIG. 1, a winding and rewinding device 1
Leveler 2 to correct the curl when winding with
Is installed, the shape of the front and rear ends of the billet S entering the shear 4 becomes straight without warpage,
There is no line stop due to bumping, and molding with the shear 4 can be performed smoothly. In addition, the provision of the guide 3 for preventing the displacement in the width direction of the slab does not obliquely cut the slab, so that incomplete joining in the width direction can be prevented.

As shown in FIG. 3, the carriage equipped with the joining device is moved in synchronism with the moving speed of the steel slab.
Induction heating coil c (a method in which an alternating magnetic field is applied in the thickness direction of the slab and the end of the slab is heated by the induced current induced by this, see JP-A-4-89120). When the ends of the pieces S ₁ and S ₂ are heated and heated, and the two pieces are pressed and joined in a manner as shown in FIGS. 4A and 4B, the joint between the pieces rises as shown in FIG. That is, in the present invention, the ridge removing device 7 is provided on the exit side of the joining device 5 so as to remove the ridge r before rolling the joined steel pieces S ₁ and S ₂ . In addition, rolling could be performed in a stable condition, and breakage of the plate due to the collapse of the ridge was eliminated.

In the equipment shown in FIG. 1, the cooling nozzle 6 is arranged on the exit side of the ridge removing device 7,
It is extremely advantageous to make the temperature and material uniform in the longitudinal direction of the slab (the temperature of the joint of the slab is higher than that of other areas and the temperature difference is 120 ° C or more. , 3
0 ° C. or less). In addition, the ridge removing device 7
The cooling nozzle 6 is provided on the entry side of the
Is cooled, not only the temperature and the material can be made uniform, but also the device 7 can be removed when removing the ridge r.
There is also an effect that the molten metal does not adhere to the blade 7a to shorten its life. Further, the cooling nozzles may be provided on the outlet side and the inlet side of the ridge removing device.

In the above example, as shown in FIGS. 4A and 4B, the shapes of the billets are cut so that the ends of the billets S ₁ and S ₂ are linear in the width direction. Although the case has been shown, this is merely an example, and one of the ends of the billets S ₁ and S ₂ may be cut into a concave shape and joined as shown in FIG. In this case, the billet is heated and joined at both ends in the width direction, and the center in the width direction is not heated or joined, so that the pressing force can be relatively small, the joining time can be shortened, and the power consumption can be reduced. In addition, there is an advantage that the degree of bulge which cannot be avoided when pressing the billet can be reduced.

[0017]

EXAMPLE A low-carbon steel slab having a width of 1000 mm and a thickness of 260 mm was rolled to a thickness of 30 mm by rough rolling, and then passed through leveler guides 2 and 3 as shown in FIG. Cutting the end (using a drum shear with a straight blade to cut it into a planar shape as shown in Fig. 4 above)
Then, it is guided into the joining device under the guidance of a guide capable of restraining in both the sheet thickness and the sheet width directions to heat and raise the end of the steel slab (input power: 800 Kw, frequency: 500 Hz, heating time:
15 seconds), the two billets were joined by pressing, and after removing the protruding part, the temperature difference of the joined part was 30 times lower than that of the other parts.
Cool down to within ° C and apply to finishing mill
Finished to a board that is 1.2mm. As a result, the leading and succeeding slabs can be joined reliably, and no breakage of the plate due to the ridges generated during joining can be seen, and the joints become loose in the finishing mill. No, it was confirmed that stable continuous hot rolling can be performed.

[0018]

According to the present invention, at the time of butt joining of steel slabs, the dimensional accuracy relating to butting can be improved and uniform joining properties can be ensured in the sheet thickness direction and the sheet width direction. In addition, continuous hot rolling with high productivity can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a facility according to the present invention.

FIG. 2 is a diagram showing a cutting state of a raised portion.

FIG. 3 is an explanatory diagram of a heating / heating device for a billet.

FIGS. 4A and 4B are views showing a joining procedure of a steel slab.

FIGS. 5A and 5B are diagrams showing a joining procedure of a steel slab.

FIG. 6 is a diagram showing a configuration of a conventional continuous hot rolling facility.

FIG. 7 is a view showing a shear cutting state at a tip of a billet in a conventional continuous hot rolling facility.

FIG. 8 is a view showing a state of incomplete bonding in the width direction.

FIG. 9 is an explanatory diagram of a generation state of a raised portion.

FIG. 10 is a diagram showing a situation where a plate is broken.

FIG. 11 is a view showing a situation in which a strip being rolled hangs during finish rolling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Winding / rewinding device 2 Leveler 3 Guide 4 Crop shear 5 Joining device 6 Cooling nozzle 7 Ridge removing device 8 Finishing rolling mill group

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideyuki Nikaido 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Chiba Works (72) Inventor Shigeru Isoyama 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Inside Chiba Works (72) Inventor Toshiaki Amagasa 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Inside Chiba Works (72) Inventor Toru Kondo 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Inside Chiba Works (72) Inventor Kunio Miyamoto 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd.Hiroshima Works (72) Inventor Kazuo Morimoto 4-6-22 Kanon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-4-89120 (JP, A) JP-A-4 351210 (JP, A) JP flat 6-47406 (JP, A) JP Akira 63-160707 (JP, A) JP flat 6-106203 (JP, A) (58) investigated the field (Int.Cl. ⁷ , DB name) B21B 1/26 B21B 15/00

Claims (1)

(57) [Claims] 1. A winding and rewinding device for winding and rewinding a steel slab after rough rolling, and a leveler for correcting winding and warping of the steel slab unwound by the winding and rewinding device. And, a guide for preventing the displacement of the billet in the width direction, a tip of the billet, a crop shear for removing a defective shape portion at a rear end, and heating and raising the temperature of the rear end and the tip of the billet, pressing. A mobile joining device that joins, a ridge removal device that removes the ridge of the slab that has been joined, and a hot finishing rolling mill group that continuously rolls the slab after the removal of the ridge is completed Arranged on at least one of the exit side and the entrance side of the ridge removing device,
A continuous hot rolling mill for billets, wherein a cooling nozzle for cooling a ridge formed at the time of joining is arranged.