JP2002263704A - Method and equipment for continuously rolling metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and equipment for continuously rolling a metallic material, in which the stable operation of continuous rolling is executed and the manufacture of products having excellent quality of a joined part can be attained. SOLUTION: After a metallic rough shape material is successively rolled with a rolling mill train on the upstream side of a rolling line on which a plurality of rolling mill trains are arranged in series and after the shapes of an end faces of metallic base stocks are measured between the rolling mill trains on the upstream and the downstream sides with a joining device on which an image pickup unit for end-part shapes is mounted and which is preferably moved back and forth. The material is positioned by striking the rear end of a preceding metallic base stock against the tip of the succeeding metallic base stock, they are joined together after adjusting joining conditions in accordance with the measured value of the shape of the end face of the metallic base stock and, by continuously rolling the metallic base stocks with the rolling mill train, they are made into a metallic finished material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of rolling a metal blank such as a billet into a metal blank having a predetermined size, and joining a preceding metal blank and a subsequent metal blank in a rolling line. In addition, the present invention relates to a method and equipment for continuously rolling a metal material to be continuously rolled, and more particularly to improving the quality of a joint. In the present invention, the term “metal coarse material” means a material at a so-called intermediate stage after a metal raw material is subjected to rolling such as rough rolling.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a long metal material having a predetermined cross-sectional area and shape such as a wire, a rod, or a strip from a metal material such as a bloom or a billet, the metal material is subjected to hot working. Rolling is performed. The hot rolling is a method of rolling a metal element heated to a high temperature or a metal element having a high temperature obtained by continuous casting to obtain a metal material having a desired size and shape.

By the way, in such hot rolling, a metal material having a finite length is sequentially rolled one by one.
In so-called batch rolling, a time interval occurs between the rolling of one metal raw material and the rolling of the next metal raw material. There was a case where it had to stand on the floor and wait. For this reason, there has been a problem that the temperature of the metal base material and the metal rough material is inevitably reduced, and when they are rolled, reheating is required.

To solve such a problem, for example, Japanese Patent Laid-Open No.
Japanese Patent No. -5803 discloses a so-called continuous rolling method. The technique described in Japanese Patent Application Laid-Open No. 10-5803 discloses a process of sequentially rolling a plurality of materials (formed materials) in a first rolling mill row, and moving a traveling welding machine in synchronization with the movement of the materials. Meanwhile, a step of connecting the rear end of the preceding material and the front end of the following material by flash butt welding to form a continuous material, a grinding process of removing burrs at a weld of the continuous material, and further downstream of the continuous material. And a step of continuously rolling in a second rolling mill row arranged in the rolling mill.

[0005]

In the technique described in Japanese Patent Application Laid-Open No. 10-5803, as described above, the traveling type welding machine is moved while being synchronized with the preceding movement of the material.
A step of connecting the rear end of the preceding material and the front end of the following material by flash butt welding is an essential requirement.
However, when the inventor repeated various trials, it was found that there was a serious problem in such a synchronous transfer method for synchronizing with the movement of the material.

That is, it is difficult to measure the accurate moving speed of a material moving hot, or requires extremely expensive measuring equipment, and even if the accurate moving speed of the material can be measured. However, it is difficult to accurately and quickly follow a heavy truck carrying a welding machine on the moving speed of the preceding material, or a complicated and expensive control mechanism is required.

[0007] If the synchronization is insufficient, the joining point does not fall within the optimal position range between the electrode for gripping the preceding material and the electrode for gripping the following material, so that joining is performed under inappropriate joining conditions. As a result, it has been found that problems such as insufficient strength and poor shape of the joint portion occur, and in extreme cases, the joint cannot be performed. Using the technique described in Japanese Patent Application Laid-Open No. 10-5803, in order to ensure that the strength of the joint is sufficiently strong so that it does not break during rolling, the current at the time of welding is increased to secure the amount of fusion. It was necessary to press the trailing edge of the preceding material and the leading edge of the following material sufficiently strongly. Therefore, the generation of so-called burrs, in which molten metal or softened metal protrudes outside the joint, is inevitable, and a grinding step of removing burrs at a welded portion (joined portion) of a continuous material has been an essential step.

However, a joint (welded portion) is formed in a continuous material.
When a grinding step for removing burrs is performed, the temperature of the continuous material decreases during grinding. For this reason, during continuous rolling downstream, the joint may not be sufficiently rolled, or the rolled structure of the joint may be different from the other parts, and the homogeneity of the obtained product may be impaired. In addition, the cost increase due to the installation of the grinding device and the frequent replacement of the grindstone is inevitable.

Further, if the operation is continued without noticing the wear of the grindstone, the metal oxide inside the burr is pushed into the continuous material due to insufficient removal of the burr at the joint (this is referred to as slagging). ), And there is a problem that the quality of that part is deteriorated. The present invention solves the above-mentioned problems of the prior art, and prevents or suppresses the occurrence of burrs at the joint,
Burr grinding process is unnecessary or the load of burr grinding can be remarkably reduced, continuous rolling operation can be performed stably, and it is possible to manufacture products with excellent joint quality. An object is to propose a continuous rolling method and a continuous rolling facility.

[0010]

Means for Solving the Problems The inventor of the present invention has conducted intensive studies in order to achieve the above-mentioned object, and as a result, the shape of the front end or the rear end of the material to be joined has been changed to the joint strength of the joint, and furthermore, It was concluded that it had a significant effect on the outbreak. The present inventor has also concluded that the positioning of the materials to be joined also has a significant effect on the joining strength of the joint, and thus on the occurrence of burrs.

The present invention has been made based on the above-mentioned findings,
It was completed after further consideration. That is,
According to a first aspect of the present invention, a metal raw material is sequentially rolled in a rolling mill row upstream of a rolling line in which a plurality of rolling mill rows are arranged in series to form a metal coarse material. The rear end of the rough metal material to be joined to the leading end of the subsequent rough metal material, and then continuously rolled in a downstream rolling mill row to form a metal finish material.
In the method for continuously rolling a metal material, before the joining, a shape of a rear end of the preceding metal rough material and / or a shape of a front end of the subsequent metal rough material is measured, and based on a measured value of the shape. A method for continuously rolling a metal material, characterized in that the joining condition is adjusted. In the first aspect of the present invention, the measured value of the shape is such that the leading end of the subsequent metal coarse material is Obtained by imaging and processing the shape of the rear end of the preceding metal rough material and / or the shape of the front end of the subsequent metal rough material before hitting the rear end of the rough metal material. In the first aspect of the present invention, it is preferable that the joining is joining by flash butt welding.

According to a second aspect of the present invention, there is provided an upstream rolling mill row which sequentially rolls a metal blank into a metal coarse material, and is disposed between the upstream rolling mill row and the downstream rolling mill row. For joining a rear end of a metal coarse material to be formed and a front end of a subsequent metal coarse material to form a continuous metal coarse material, and a downstream rolling mill for continuously rolling the continuous metal rough material to obtain a metal finished material In a continuous rolling equipment for metal materials in which columns are sequentially arranged in series, the joining device captures an image of the shape of the rear end of the preceding metal rough material and / or the shape of the front end of the following metal rough material. And a joining condition control means for controlling joining conditions by a signal from the imaging device.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. FIG. 1 shows an example of a continuous rolling equipment for metal materials suitable for carrying out the method of the present invention. In the present invention, the metal blank is rolled using a plurality of rolling mill rows to form a metal finish (product). Directly sent from a continuous casting machine not shown,
Alternatively, the metal blank (billet) 1 heated by the heating furnace 2 is roughly rolled in an upstream rolling mill row (rough rolling mill row) 3 of a plurality of rolling mill rolling rows to form a metal coarse material 5. You. The metal blank is then rolled by a downstream rolling mill row (intermediate rolling mill row) 13 and then, if necessary, further finished rolled by a further downstream rolling mill row (finish rolling mill row) 14 to finish the metal finishing material of the product. It is said.

In the present invention, a joining device 12 is disposed between the upstream rolling mill row 3 and the downstream rolling mill row 13. This joining device 12 joins the leading end of the following metal rough material 10 to the rear end of the preceding metal rough material 11, and continuously in the downstream rolling mill row 13 and, if necessary, in the downstream rolling mill row 14. Roll it.
It is preferable that the leading and trailing ends of the metal blanks 10 and 11 to be joined leave the upstream rolling mill line 3 and be cut by a cutter 4 so that the end faces are adjusted to a shape suitable for joining. As the cutting machine 4, a crop shear or a traveling sawing machine can be preferably used.

The rear end of the preceding metal rough 11 and the subsequent metal rough 10
The joining device 12 for joining the tips is an upstream rolling mill train 3
The mobile joining device 12 is disposed between the upstream rolling mill row 3 and the downstream rolling mill row 13 and is preferably disposed between the upstream rolling mill row 3 and the downstream rolling mill row 13. Although FIG. 1 shows an example in which the mobile joining device is provided, it goes without saying that the present invention is not limited to this.

The movable joining device 12 is preferably a cart, and the moving means (not shown) drives wheels or pinions by a motor mounted on the movable joining device 12 (in this case, a rack and pinion). Method) self-propelled method,
Alternatively, any method such as a passive method using an externally provided cylinder may be used. The reciprocation between the upstream rolling mill row 3 and the downstream rolling mill row 13 in the mobile joining apparatus 12 does not necessarily mean only linear motion,
For example, at the time of joining, it moves along the conveying direction of the preceding metal coarse material and the following metal coarse material in the rolling line, but may return and move out of the rolling line.

The joining in the present invention is not limited to a particular method if a strong joining can be obtained in a short time. The joining method meeting this purpose is flash butt welding, heat welding, induction heating using a coil. A welding method or the like can be used. Note that flash butt welding is particularly preferable because inclusions are hardly involved in the joint. When the above-mentioned mobile joining apparatus 12 is running on a rolling line, the support rolls 91 constituting the roller table 9 for transporting and supporting the metal rough material are sequentially moved to positions not interfering with the mobile joining apparatus 12. It is preferable to be able to retreat.

In the mobile joining apparatus 12 of the present invention, the joining means
Along with 16, a gripping device 15 for gripping the subsequent metal rough material 10
It is preferable to have Gripping device for mobile joining device 12
15 preferably has a moving means (not shown) together with the gripping means. The gripping means grips the subsequent metal rough material 10, and the gripping means moves backward in the direction of the arrow in FIG. Can be moved to a predetermined position optimal for joining in the rolling line 19.

The joining in the present invention is performed by abutting the leading end of the following metal rough material and the trailing end of the preceding metal rough material. Preferably, the moving metal joining device described above is used to join the following metal rough material. The metal material is gripped, and then advanced at a speed at which the combined speed of the moving speed of the gripping device 15 and the advance speed of the movable joining device 12 exceeds the advance speed of the preceding metal coarse material, and the rear end of the preceding metal coarse material 11 It is preferable to perform the positioning by abutting the leading end of the metal rough material 10 to be followed. As a result, the rear end of the preceding metal coarse material 11 and the front end of the subsequent metal rough material 10 are brought into contact with an optimal position for joining.

The most characteristic point of the present invention is that before joining the rear end of the preceding metal rough material 11 and the front end of the subsequent metal rough material 10, the rear end of the preceding metal rough material 11 is joined. Shape and /
Or measure the shape of the tip of the subsequent metal rough material 10,
It is to adjust the joining conditions based on the measured value of the shape. Therefore, the joining device 12 includes the preceding metal rough material 11.
An imaging device 40 that captures the image of the shape of the rear end of the metal rough material 10 and / or the shape of the front end of the following metal rough material 10 and performs image analysis;
And a joining condition control means 16c for controlling the joining condition based on the signal from 40.

FIG. 2 shows an outline of the shape measurement when the mobile bonding apparatus 12 is used. In the figure, 15 is a gripping device, 16 is a joining means, 10 is a subsequent metal rough, 11 is a preceding metal rough,
19 is a rolling line, 40 is an imaging device, 41 is an imaging unit, 42 is a signal storage unit, 43 is an image processing / analysis unit, and 16c is a joining condition control unit. FIG. 2 shows a case where the joining method is flash butt welding, and the joining gripping means 16a and 16b in the joining means 16 are clamp-type electrodes which also serve as electrodes. In the present invention, the joining method is not limited to this, and there is no problem even with the induction heating welding method. In the case of the induction heating welding method, the holding means 16a for joining is used.
, 16b need only be a clamp mechanism, and it is necessary to arrange a coil at the joint position.

FIG. 2 shows a state in which the leading end of the subsequent metal coarse material 10 which is gripped by the gripping device 15 disposed and mounted on the movable joining device 12 and is moving forward together with the movable joining device 12 is still in contact with the preceding metal. This shows a state in which it does not follow the rear end of the coarse material 11.
In this state, the imaging section 41 of the imaging device 40 mounted on the mobile bonding apparatus captures the rear end shape of the preceding metal rough 11 and the front end shape of the subsequent metal rough 10. As the imaging unit 41, for example, a CCD camera can be preferably used, but it is not particularly limited to this.

An image taken by the image pickup section 41 of the image pickup apparatus 40
The end face of the metal coarse material has a shape as shown in FIG. 4, for example.
You. The captured image is sent to the signal storage unit 42 and digitized.
After that, it is sent to the image processing / analysis unit 43. Image processing·
In the analysis unit 43, for example, from the image illustrated in FIG.
Projection length X₁₁, X_TenOr the protruding area S₁₁, S
_TenCalculate and so on. The overhang sought in this way
Length X₁₁, X_TenAnd projected area S₁₁, S_TenThe data for
It is input to the welding condition controller 16c of the welding device 12 and
Matching conditions are set.

Incidentally, in the configuration shown in FIG.
The base is provided so that the rear end of the preceding metal rough material 11 and the front end of the subsequent metal rough material 10 are individually photographed. There is no problem at all. Alternatively, the shape of only one end may be measured and used for controlling the joining device. This is because the shape of the cut surface by the cutting machine is often not significantly different from the cut shape in the previous cut and the cut shape in the next cut.In such a case, the preceding metal rough material or the subsequent metal This is because it is sufficient to grasp only one end shape of the coarse material.

FIG. 3 shows a state in which the preceding metal blank 11 and the subsequent metal blank 10 are butt-joined. These metal rough materials 11 and 10 are joined by joining means 16a and 16 which also serve as electrodes of the joining device.
b. After the clamp is completed, a current is applied between the trailing end of the preceding material and the leading end of the following material to perform flash butt welding. At this time, the gripping device 15 releases the subsequent metal rough material 10,
It has moved to the standby position. In the case of high-frequency induction heating, the joint is heated and fused by a coil (not shown).

The joining is performed based on the joining conditions set by the joining condition control section 16c. When the welding method is flash butt welding, the welding conditions that can be set include the welding current value, flash time, welding time, pressing force between the preceding metal coarse material and the following metal rough material, pressing distance, and the like. However, it is not always necessary to control all of them at once, and any one or two or more conditions may be set.

Here, the measured protrusion of the end of the metal coarse material
Length X₁₁, X_TenAnd projected area S ₁₁, S_TenAgainst
How to determine the setting conditions described in
Off-line preliminary experiments using a sample of the shape
Therefore, the burr of the joint is minimum and the strength of the joint,
Find out in advance the conditions under which quality falls within an acceptable range, and
It is better to use and decide.

In the above description, the flash butt welding has been described as an example of the joining method. However, in the other joining methods, for example, induction heating welding (or pressure welding) and the like, the optimum conditions were found in the same manner, and the actual end of the metal rough material was found. What is necessary is just to control the condition at the time of joining to the optimal condition based on the measured value of the shape of the part. After joining is completed and it becomes a continuous metal rough,
The gripping by the joining means 16 is released, and the rolling is performed by a downstream rolling mill row to obtain a finished metal material.

As the metal base material, blooms, billets, etc., which are used as raw materials for processing wires, rods, molds, etc., are suitable. The metal material produced by this continuous rolling method is a wire, a bar, a mold, or the like, and particularly preferably a wire or a bar. Steel is most commonly used as a metal, but is not particularly limited to this. Hot rolling of a wire or a bar made of a copper alloy or an aluminum alloy may be used.

[0030]

EXAMPLE Using the continuous rolling equipment shown in FIG. 1, continuous rolling of deformed steel bars was performed. A billet (120 mmφ) of SD24 steel was used as a metal base material, and a rough metal rolling material 5 (a round bar having a diameter of 45 mm) was formed by a rough rolling mill row (upstream rolling mill row 3). The metal blank 5 (also referred to as a coarse bar) was cut by 200 mm at each of its front and rear ends by a cutting machine 4 (crop shear) provided on the exit side of the rough rolling mill. Then, the preceding and following 50 coarse bars (metal rough material 5) are
As a succeeding material, continuous flash butt welding was performed by the movable joining device 12 to obtain a continuous metal coarse material.

The continuous metal blank is subjected to an intermediate rolling mill row (downstream rolling mill row 13) and a finishing rolling mill row (downstream rolling mill row).
According to 14), it was rolled into a concrete bar (metal finish) having a diameter of 15 mm to obtain an example of the present invention. At the time of joining, the end shape of the metal rough material before joining is photographed by a CCD camera (imaging unit 41) loaded on the movable joining device 12 shown in FIG. 2 and sent to a signal storage unit 42, which then processes the image. Analysis was performed by the analysis unit 43, and the protruding areas S ₁₁ and S ₁₀ were obtained. According to the measured value of this shape, the optimal joining conditions (flash butt welding conditions) were selected from the setting condition table of the joining condition control unit 43 and flash butt welding was performed.

It should be noted that the optimum flash butt welding conditions such that the height of the burrs after joining is within 5 mm with respect to the various cut portions obtained by the preliminary experiment are grasped in advance.
This was stored in the setting condition table of the joining condition control unit 16c of the joining device. As a result, it was possible to perform rolling without breakage of the joined portion during intermediate rolling and finish rolling. In addition, the strength, shape, and quality of the joints were examined for the final product, but none of the joints had insufficient strength, poor shape, and no bite.

On the other hand, as Comparative Example 1, welding was carried out with the flash butt welding conditions at the time of joining constant, a continuous metal rough was formed, and the joining (welding) location was deburred with a grinding device. It was rolled by a row and a finishing mill row. The conditions other than the joining were the same as in the example of the present invention, and 50 rough bars were continuously joined. In Comparative Example 1, in the rolling of the intermediate rolling mill row and the rolling of the finishing rolling mill row, three cases occurred in which the joint was broken during the rolling,
Five defects occurred at the joint of the final product (metal finish).

Further, as Comparative Example 2, welding was performed with the flash butt welding conditions at the time of welding constant, and continuous rolling was performed by an intermediate rolling mill row and a finishing rolling mill row without performing deburring at the welding point. Was. In this case, in the rolling of the intermediate rolling mill row and the rolling of the finishing rolling mill row, two cases occurred in which the joint was broken during the rolling. Also,
8 shape defects at the joint of the final product (metal finish)
There were five cases each, five times each of slap biting and insufficient strength.

[0035]

As described above in detail, according to the present invention, a final rolled product having excellent joint quality can be obtained without deburring the joint, and can be used in intermediate rolling and finish rolling. Operation troubles due to joint breakage can be eliminated, and industrially remarkable effects such as improved yield and improved production efficiency can be achieved.

[Brief description of the drawings]

FIG. 1 is an overall view schematically showing an example of a continuous rolling facility suitable for carrying out the method of the present invention.

FIG. 2 is a schematic explanatory view showing an example of a configuration of a mobile bonding apparatus suitable for carrying out the method of the present invention and a state at the time of shape measurement.

FIG. 3 is a schematic explanatory view showing an example of a configuration of a mobile joining apparatus suitable for carrying out the method of the present invention and a state at the time of joining.

FIG. 4 is an explanatory view showing an example of an end shape of a coarse metal material cut by a crop shear.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal raw material 2 simple heating furnace 3 upstream rolling mill row (rough rolling mill row) 4 cutting machine 5 metal rough material 9 table roll 91 support roll 10 subsequent metal rough material 11 preceding metal rough material 12 joining device (Movable joining device) 13 Downstream rolling mill row (intermediate rolling mill row) 14 Downstream rolling mill row (finishing rolling mill row) 15 Gripping device 16 Joining means 16a Joining means for preceding metal coarse material 16b Following metal coarse material Joining means 16c Joining condition control means 17 Moving speed control means 18 Measure roll 19 Rolling line 40 Imaging device 41 Imaging unit 42 Signal storage unit 43 Image processing analysis unit

Claims (4)

[Claims] 1. A metal raw material is sequentially rolled by a rolling mill row upstream of a rolling line in which a plurality of rolling mill rows are arranged in series to form a metal coarse material, and then, the metal rough material of the preceding metal coarse material In the continuous rolling method of the metal material, the rear end of the rough material is joined to the leading end of the following metal rough material, and then continuously rolled in a downstream rolling mill row to obtain a metal finish material. Measuring the shape of the rear end of the preceding metal rough material and / or the shape of the front end of the following metal rough material, and adjusting the joining condition based on the measured value of the shape. A continuous rolling method for metal materials. 2. The measured value of the shape is determined by the shape and / or the shape of the rear end of the preceding metal coarse material before the leading end of the subsequent metal rough material strikes the rear end of the preceding metal rough material. The method according to claim 1, wherein the method is obtained by imaging a shape of a tip of the subsequent metal rough material and performing image processing. 3. The method according to claim 1, wherein the joining is performed by flash butt welding. 4. An upstream rolling mill row, which is sequentially rolled to form a metal coarse material by rolling metal blanks, and is disposed between the upstream rolling mill row and the downstream rolling mill row, and is provided with A joining device that joins the rear end and the leading end of the following metal rough material to form a continuous metal rough material, and a downstream rolling mill row that continuously rolls the continuous metal rough material and obtains a metal finish material, In the continuous rolling equipment for metal materials arranged in series, the joining device captures the shape of the rear end of the preceding metal coarse material and / or the shape of the front end of the following metal coarse material, and performs image analysis for image analysis. A continuous rolling equipment for metal materials, comprising: an apparatus; and a joining condition control means for controlling joining conditions by a signal from the imaging device.