JPH0688048B2 - Billet joining device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to continuous hot rolling of steel slabs (slabs, blooms, billets, and their semi-finished product stages), and in particular, continuous slabs are joined together. The present invention relates to a steel slab joining device that enables joining of steel slabs with excellent quality when the steel is turned into an alloy.

[Conventional technology]

Japanese Patent Application Laid-Open No. 48-67159 discloses a technique for joining hot materials as a continuous hot rolling method, and Japanese Patent Application Laid-Open No. 61- It is known in Japanese Patent No. 216905 and Japanese Patent Application Laid-Open No. 60-216916, but no consideration is given to the problem that the hot work material is cooled by the steel slab holding device which is indispensable when joining steel slabs. Nakatsuta.

[Problems to be solved by the invention]

Among the hot rolling lines for billets, the background of the joining method for billets will be explained by taking a hot strip mill facility as an example.
A general hot strip mill facility is composed of a rough rolling mill and a finish rolling mill, and this rough rolling mill is composed of a reversible rough rolling mill and a one-way rough rolling mill. Then, the billet supplied from the heating furnace or continuous casting equipment is first rolled by the reversible rolling mill to the required strip width and strip thickness, and then further rolled by the unidirectional rough rolling mill to the predetermined strip width. And rolled to plate thickness.

After this, the process proceeds to the finish rolling mill, but the shape of the front and rear ends of the steel slab that has been rolled by the rough rolling before that is no longer rectangular, so the front and rear ends are cut by a crop shear to adjust the shape. Then, this steel slab is rolled by a finishing rolling mill to a final plate thickness and then wound up to manufacture a hot strip coil. However, since this series of rolling is performed for each steel piece or each steel piece divided by the crop shear,
On the output side of the finish rolling mill, each coil is intermittently rolled. Therefore, in each rolling mill, a leading strip and trailing edge trailing work are required for each rolling mill, which requires extremely complicated rolling work. Therefore, if a large number of steel pieces are joined to one long steel piece and rolled, the above-mentioned problems of the rolling work can be eliminated, but the reason why this has not been realized is as follows.

1) When slabs of steel slabs are manufactured by a slab mill, the slabs have a plate thickness of around 200mm, so it is necessary to economically join slabs of this thickness in a short time. It is difficult yet and it has not been realized yet.

2) The production amount of continuous casting nostrand is 1/3 to 1/4 of the production amount of hot strip mill. Therefore, from a continuous casting facility of 3 to 4 strands to one hot strip mill, a slab is produced. Therefore, the continuous slab with a sharp corner must be cut into an appropriate length and supplied to the hot strip mill.

Therefore, if the trailing edge of the preceding slab material and the leading edge of the trailing slab material are joined and the slab material of infinite length can be supplied to the hot strip mill, the following effects can be expected.

(A) Miniaturization of rolling equipment and realization of energy saving a) Continuity reduces rolling biting and rolling out of the mill into the mill, so there is no need to increase the work roll diameter for biting performance.

b) Since the impact torque generated on the roll during biting and tail removal is eliminated, the roll drive system and work roll diameter can be reduced.

Due to the reasons a) and b) described above, the work roll diameter can be greatly reduced, and the reinforcing roll diameter can also be reduced due to the reduction of the rolling load by itself and the rolling load reduction effect of oil lubrication, and the overall rolling mill is small. Can be

(B) Improvement of quality and yield In the conventional rolling method, tension is not applied to the strip when removing the trailing edge of the finishing rolling mill, and tension is applied to other parts, resulting in changes in strip thickness and strip width. Since the front and rear ends of the strip are tensionless, plate bending is likely to occur, which deteriorates the yield quality. This can be solved by sequentially joining the slabs and making them infinite. In addition, in order to reduce the difference between tensionlessness when passing the strip and tailing as much as possible, it was inevitable to keep the tension as low as possible during normal rolling. By applying high pressure, it is possible to reduce the rolling load, to reduce the rolling force, and to roll more thin material.

For the reasons described above, continuous strip steel joining is currently performed in cold strip mills (cold strip mills), and its great economic effect is well recognized.

[Means for Solving the Invention]

In the field of cold rolling equipment, it has already been mentioned that continuous strip joining has already been realized.However, since the strip thickness is thin and the strip is at room temperature, it is best to cover the strip with a looper. It is easy, and the reason for the success is that the strips can be joined by a normal welding device in a stopped state at the joining part while supplying the strips covered by the looper to the rolling mill. On the other hand, in hot rolling equipment,
Slab plate thickness is around 200mm, 30m even on the entry side of finishing mill
Since the plate thickness is about m to 50 mm, it is difficult to form a slab loop like the cold rolling equipment described above. Even if it is possible, the rolling time is 1 to 2 per coil.
Since it is short, the conventional welding method has difficulty in welding with a joining strength that can withstand rolling. Therefore, if the slab is to be made continuous by the welding method, the hot rolling equipment cannot be made continuous unless welding is completed in a few seconds in a running welder.

However, as in the prior art described above as the continuous hot rolling method, the welding method of joining the steel pieces by approaching the entrance of the rough rolling mill, other flash welding method, electric welding method, gas welding method, induction heating method, etc. Regardless of which joining method is adopted, these steel slab joining methods require a holding device for holding and pressing both steel slabs, but when holding and pressing a slab that is a heating material. There was a problem that non-uniform temperature was generated in the contact part due to thermal outflow caused by contact with the surface of the steel slab, and the vicinity of the joint of the rolled product became an ob gauge.

An object of the present invention is to reduce the temperature and non-uniformity due to thermal outflow through a contact portion between a holding device and a steel piece for holding the steel piece when joining the steel pieces, and the joined steel pieces are joined together. It is another object of the present invention to provide a steel slab joining apparatus that suppresses the occurrence of obgage caused by uneven temperature distribution.

[Means for solving problems]

In order to achieve the above object, in the present invention, in a line of hot rolling equipment, a steel strip that joins a trailing end portion of a steel strip that travels in advance and a leading end portion of a steel strip that travels behind. In the joining apparatus, the rail is laid along the traveling direction of the steel slab, and a traveling carriage that is movable on the rail is provided. A first member that is provided in a direction and fixed to the traveling carriage, and a second member that is provided in the up-and-down direction of the trailing steel slab and is movable on the traveling carriage. The member is provided with means for operating the movement of the second member, which is connected to the first member, and further, the first and second members respectively have a first pressing means for pressing a steel piece and the first pressing means. A second pressing means, which is connected to the first pressing means and is operated to move up and down, is provided, and the steel piece of the first pressing means is provided. The billet contact member made of a low heat conductivity material on the side in which was mounted.

[Action]

In the present invention, the trailing end of the steel piece that travels in advance,
Both of the steel pieces can be held in a state where the tip of the subsequently traveling steel piece is in close contact with or in the vicinity of the traveling direction of the steel piece, and the side of the holding member facing the steel piece. Since a steel slab contact member made of a material with low post-conductivity is attached to the steel slab, heat transfer from the steel slab to the holding device is reduced between the sandwiching member and the high temperature steel slab to reduce the temperature distribution of the steel slab. This prevents unevenness from occurring.

In addition, a member having excellent heat resistance is used as the billet contact member,
In the case where the holding device is provided with the heating device, the heating device is used to heat the steel slab to prevent uneven temperature from occurring in the steel slab.

Further, since the temperature of the joint portion of the steel pieces to be joined is uniform, it is possible to surely join the steel joints, and thus it is possible to suppress the problem that the vicinity of the joint portion becomes off-gauge also in the subsequent rolling process.

[Embodiment] Next, a steel piece joining apparatus according to an embodiment of the present invention will be described with reference to FIG. The trolley 1 is provided with wheels 1a traveling on the rails 2 below the frame 1b so that the trolley 1 can travel in accordance with the moving speed of the steel slab.

In this carriage 1, the preceding steel piece holding device 5A, so as to fix and hold the leading steel piece 3 near the rear end 3a and the succeeding steel piece 4 near the tip end and 4a respectively from above and below the steel pieces 3 and 4, respectively. 5B and trailing billet holders 5C and 5D are installed.

Hydraulic cylinders 6A to 6D for operating the lifting and lowering of the holding devices are connected to the holding devices 5A to 5D, respectively. Of these, the hydraulic cylinders 6C and 6D are mounted in the frame 1a of the carriage 1 and are respectively installed on block members 1c and 1d having wheels 1e so as to be movable in the path direction of the steel pieces 3 and 4.

Then, when the preceding steel piece 3 advances to a predetermined position in the apparatus and the rear end 3a of the steel piece 3 reaches, the holding devices 5A, 5B are moved up and down by the hydraulic cylinders 6A, 6B built in the frame 1a. Then, the preceding steel slab 3 is held, and at the same time, the truck 1 travels on the rail 2 to start the translation with the preceding steel slab 3. When the tip 4a of the succeeding steel piece 4 reaches a predetermined position, the hydraulic cylinders 6C, 6D built into the block members 1c, 1d are operated to move the holding devices 5C, 5D up and down in the same manner, and the succeeding steel piece 4 is moved. Hold. And hydraulic cylinders 7a, 7b for driving pistons in the steel piece transfer direction are mounted on the upper and lower parts inside the frame 1b, and the piston rods of these hydraulic cylinders 7a, 7b are respectively blocked members 1c, 1b. In succession, the block members 1c, 1d are configured to be able to approach or separate from the frame 1b by operating the hydraulic cylinders 7a, 7b.

Further, the holding devices 5A to 5D are respectively provided with heating devices 11 for heating the sandwiched steel pieces 3 or 4 to near the melting point. Therefore, first, the hydraulic cylinders 6A and 6B built in the frame 1b are driven to operate the holding devices 5A and 5B to clamp the rear end portion 3a of the preceding steel slab 3 from above and below. The joint surface at the rear end of the steel slab 3 is heated to near the melting point by the heating device 11 incorporated in the 5B. Similarly, the hydraulic cylinders 6C and 6D built in the block members 1c and 1d are operated to operate the holding devices 5C and 5D to clamp the tip 4a of the following steel piece 4 from above and below. The joint surface at the tip of the steel slab 4 is heated to near the melting point by the heating device 11 with a built-in 5D. Moreover, since the block members 1c, 1d are moved to the preceding steel slab 3 side by operating the hydraulic cylinders 7a, 7b in this state, the joining surface A of the ends of both steel slabs 3, 4 has a melting point. They are pressed against each other while they are heated to the vicinity to join them. Next, the structure of the holding devices 5A to 5D will be described. 2 to 4 are cross-sectional views of the holding device 5B in the BB direction as a typical example. FIGS. 2 and 4 show examples in which the heating device 11 is incorporated, and FIG. 3 shows heating. Each of the examples does not include a device. In the figure, on the side of the holding device 5B facing the steel slab 3, a steel slab contact member 10 made of a heat-resistant alloy steel having excellent heat resistance is provided.
a is installed, and a heating device 11 including an electric heater and a combustion heater is installed inside the holding device 5B, and a heat insulating material is connected to a connecting portion with a hydraulic cylinder 6B that operates the holding device 5B up and down. 8 is interposed so that the influence of heat from the steel billet and the heating device 11 on the hydraulic cylinder 6B can be prevented. In the holding device 5B having the above configuration, the heating device 11
Therefore, if the temperature of the steel slab contact member 10a that is in direct contact with the steel slab 3 is raised to at least 700 ° C to 1000 ° C, the temperature difference between the hot steel slab and 900 ° C to 1200 ° C can be reduced. The temperature drop of the billet is reduced, and therefore the joining of the billet is facilitated.

FIG. 3 shows another application example of the holding device 5B. Here, as the billet contact member 10b, a ceramics material that is resistant to high temperatures and has good heat insulating properties and is strong against surface pressure and shearing is used. In this example, the heat retained by the hot steel slab 3 itself is pressed and held from above and below without being reduced, and is pressed against the joining surface of the subsequent steel slab 4 to join.

FIG. 4 shows still another application example of the holding device 5B. Here, an induction heating coil type heating device 11b is used in the holding device 5B. In this case, the temperature of the steel slab 3 is positively increased by heating to maintain the temperature of the steel slab, so that heating energy is not consumed for heating the steel slab contact member 10 and the holding device main body. In addition, it is important to select a metal member that has excellent heat resistance as well as magnetic permeability and electric conductivity in consideration of the billet contact member 10c.

According to the present embodiment described above, the hydraulic cylinders 6A to 6D and 7a
~ 7b is heat protected. In addition, the billet contact members 10a-1
By making 0c separate from the holding device body, it is possible to repair wear and damage by replacing only the contact members 10a to 10c.

Next, the operation of the steel piece joining apparatus according to the above-described embodiment will be described. In FIGS. 1 to 4, the rear end 3a of the preceding hot steel billet 3 and the tip 4a of the subsequent hot steel billet 4 are respectively holding devices 5A, 5B and 5C via the billet contact members 10a to 10c. ,
After being held in 5D, it is positioned with respect to the rear end of the preceding steel slab, and the end surfaces of both steel slabs 3 and 4 to be joined to the heating devices 11 and 11b built into the holding devices 5A to 5D. And heating the internal heating in a short time, and then the upper and lower two sets of holding devices 5A and 5B on both sides.
The members 5C and 5D are moved in the path direction of the steel pieces, and the steel pieces 3 and 4 are pressed against each other to join them. Therefore, it is necessary to hold the steel piece with a holding pressure that can generate a pressing force for the holding device. Here, the pressing force P is 1.7
If it is set to 3 kg / mm ² , the holding devices 5A to 5D need a holding force P of (1.7 to 3 kg / mm ² ) × A = μP in relation to the friction coefficient μ with the steel pieces 3 and 4. (A: cross-sectional area of pressed part, P: holding force) Here, as described above, the temperature of the steel slab during hot rolling is usually 900 ° C to 1200 ° C, although it varies depending on the type of steel and rolling conditions. Therefore, it is necessary for the holding devices 5A to 5D to have heat resistance and to prevent heat from flowing out of the steel pieces 3 and 4 to the holding device main body. Therefore, in the embodiment of the present invention, the billet contact member of the holding device
What is shown as 10a is that which adopts a heat-resistant alloy that withstands temperature rise, and what is shown as 10b is that ceramics or ceramic wool is used to prevent the temperature decrease of the steel slab. Furthermore, if a steel slab heating device 11a as represented by induction heating is incorporated in the holding device, not only the temperature decrease at the contact portion with the steel slab holding device is further reduced, but also the same as other parts. It is possible to keep the temperature at.

In addition, holding device without using expensive equipment such as induction heating
It is also possible to raise the contact part between 5A to 5D and the steel slabs 3 and 4 to 700 to 900 ° C. to reduce the heat transfer part from the steel slab to the holding device. A heat-resistant alloy may be used for the heater, and a resistance type electric heater, a combustion heater using gas or heavy oil, etc. may be used for the heating device as indicated by 11.

In this way, it is possible to reduce or prevent the temperature drop of the steel slab contact portion from the start of holding to the end of holding and releasing, and it is possible to reduce the uneven temperature distribution of the steel slab accompanying the welding operation.

As an effect of the above-mentioned embodiment, for example, when the steel piece thickness is 50 mm and the holding portion length is 150 mm at two places, if the product thickness after rolling is 2.5 mm, a strip with a length of about 6000 mm is an off gauge. There is an effect that is not necessary. That is, as shown in FIG. 5, the temperature drop indicated by the solid line due to the holding device, which is unavoidable in the conventional holding device, is prevented, and the temperature before and after the contact portion of the steel piece with the holding device is shown in other parts as shown by the dotted line. Since the temperature can be made almost equal to the temperature of, the length of the off gauge part is reduced.

〔The invention's effect〕

According to the present invention, since it is possible to hold the preceding steel piece and the following steel piece to be joined without changing the temperature distribution of the steel piece, the steel piece joined in the subsequent step is rolled by a rolling mill. When rolled into a product by rolling, the effect of preventing off gauge due to temperature unevenness is achieved, and the yield of products is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a steel slab joining apparatus according to an embodiment of the present invention, and FIG. 2 is a BB of the steel slab joining apparatus shown in FIG.
3 and 4 are partial sectional views in the BB direction of the steel slab joining apparatus shown in FIG. 1, and are sectional views showing another example of the steel slab holding apparatus, and FIG. It is a temperature distribution figure of the longitudinal direction of a steel piece. 1 ... Bogie, 2 ... Rail, 3 ... Leading steel strip, 4 ...
… Succeeding billet, 5A to 5D …… Holding device, 6A to 6D …… Hydraulic cylinder, 7A to 7D …… Hydraulic cylinder, 8 …… Heat insulation member,
10 …… Steel contact member, 11 …… Heating device.

Claims (5)

[Claims] 1. A steel slab joining apparatus for joining a trailing end of a steel slab that travels first and a leading end of a steel slab that travels backward in a line of a hot rolling facility, Laying a rail extending along the traveling direction of the billet,
A traveling carriage that is movable on the rail is provided, and inside the traveling carriage, a first member fixed to the traveling carriage that is provided in the vertical direction of the preceding steel slab and the trailing steel are provided. A second member provided in the vertical direction of the piece and movable on the traveling carriage, and means for operating the movement of the second member, which is connected to the first member on the second member Further, each of the first and second members is provided with a first pressing means for pressing the steel slab and a second pressing means connected to the first pressing means and operated to move up and down. A steel piece joining device, wherein a steel piece contact member made of a material having a low heat transfer property is attached to a side of the first pressing means facing the steel piece. 2. The steel piece joining apparatus according to claim 1, wherein a ceramic material is used as the steel piece contact member. 3. The steel slab joining apparatus according to claim 1, wherein the steel slab contacting member is provided with a steel slab contacting member made of a metal material having high heat resistance, and the steel slab contacting member and its vicinity are provided. 2. A steel piece joining device, wherein a heating device is provided in the holding member. 4. The steel piece joining device according to claim 1, wherein the steel piece contact member is made of a metal material having high heat resistance and high magnetic permeability and electric conductivity, and the heating device is a conductive heating device. An apparatus for joining steel slabs, characterized by using. 5. The joining of steel pieces according to claim 1, wherein the first pressing member is connected to the first pressing hydraulic cylinder device via a heat insulating member. apparatus.