JPH09150206A - Hot rolling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity and the accuracy of quality of rolled products by enhancing the yield of rolling by eliminating the loss of a material during rolling and, simultaneously, stabilizing the size of the rolled products, that is, by improving the yield of products by remarkably reducing the loss of the rolled products that is caused at the time of cutting. SOLUTION: While clamping the rear end part of a preceding rolled stock rolled at an intermediate rolling mill 10 with a clamping member 92 on one side and also clamping the tip part of the succeeding rolled stock rolled at a roughing mill 6 with the clamping member 91 on the other side, the feed rate of the rolled stock with the roughing mill 6 and the feed rate of the rolled stock with the intermediate rolling mill 10 are adjusted. In this way, by making the tip face of the succeeding rolled stock to abut on the rear end face of the preceding rolled stock, applying voltage to the contact faces of both rolled stocks through the clamping members 91, 92 and executing contact resistance heating, both rolled stocks are welded while being moved between the roughing mill 6 and the intermediate rolling mill 10 and, by continuously rolling the welded rolled stock with the intermediate rolling mill 10 and a finishing mill 11, the rolled stock is formed into steel bars, shapes, other bar steel, wires, bars in coil, or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling method for forming a steel bar, a shaped steel or other bar steel, a wire rod, a bar-in coil or the like from a billet or a cast piece supplied from a continuous casting facility.

[0002]

BACKGROUND OF THE INVENTION Conventionally, a billet or a slab supplied from a continuous casting facility is heated in a heating facility and then rolled in a rolling facility including a rough rolling mill, an intermediate rolling mill, a finishing rolling mill, etc. Shaped steel and other steel bars, wire rods, burn-in coils, etc. (hereinafter referred to as "rolled products")
In the hot rolling method for forming, the size (weight, length) of the rolled product to be manufactured is determined by the size (weight) of the rolled material such as billet or cast slab. Therefore, in order to manufacture a rolled product of a specified size (weight, length) accurately and with little material loss, the size (weight) of the rolled material should be matched to the size of the rolled product. Is required. However, it is practically impossible to match the size (weight) of the rolled material with the size of the rolled product, and the rolled product formed from the final cut piece of the rolled product formed from one rolling material. The size (weight, length) of the will be uneven.

[0003]

As described above, in the conventional hot rolling method, the size (weight, length) of the rolled product formed from the final cut pieces is not uniform.
In addition to the loss of material, there are mixed irregularities in the rolled products and the rolling work in the rolling equipment is one
There is a problem that productivity and quality accuracy of rolled products are deteriorated due to the fact that each rolling material becomes intermittent.

The present invention solves the problems of the above-mentioned conventional hot rolling method, eliminates the loss of material during rolling to improve the rolling yield, and at the same time stabilizes the size of rolled products, that is, An object of the present invention is to provide a hot rolling method capable of improving productivity and quality accuracy of rolled products by significantly reducing loss of rolled products generated at the time of cutting and improving product yield.

[0005]

In order to achieve the above object, the hot rolling method of the present invention is such that the trailing end of the preceding rolled material rolled in the intermediate rolling mill is gripped by one gripping member. Adjusting the feed rate of the rolled material by the rough rolling mill and the feed rate of the rolled material by the intermediate rolling mill while gripping the tip of the trailing rolled material being rolled in the rough rolling mill by the other gripping member By doing so, the leading end surface of the trailing rolled material is brought closer to the trailing end surface of the preceding rolled material, and the holding member maintains the abutting state of both rolled material so that both rolled material are placed between the rough rolling mill and the intermediate rolling mill. It is characterized in that it is welded while being moved by, and the rolled material that is welded is continuously rolled by an intermediate rolling mill and a finishing rolling mill to be formed into a bar steel, a shaped steel or other bar steel, a wire rod, a bar-in coil or the like. Here, for welding the rolled materials, various welding methods such as electric welding, pressure welding using induction heating or gas heating, and flash butt welding can be used. In addition, "maintain the contact state of both rolled materials"
This means maintaining a contact state suitable for the welding method applied (including maintaining a minute interval) when welding rolled materials.

In this case, the rolling material is rolled in a rough rolling mill so that the cross section has a substantially rectangular or circular shape, the preceding rolled material and the trailing rolled material that have been rolled are welded, and the welded rolled material is intermediate. It can be continuously rolled by a rolling mill and a finish rolling mill.

Further, in the rough rolling mill, the rolled material is rolled into a substantially rectangular shape, the rolled material before and after the rolling are welded, and the thickness of the welded rolled material is increased and the width is increased. It can be shaped so as to decrease so that the cross section becomes substantially square, circular or elliptical, and the shaped rolled material can be continuously rolled by an intermediate rolling mill and a finishing rolling mill.

In this case, by the rolling caliber,
The welded rolled material can be shaped to increase the thickness of the rolled material and decrease its width.

In the hot rolling method of the present invention, the trailing end portion of the preceding rolled material rolled in the finish rolling mill is gripped by one gripping member, and the trailing end rolling in the intermediate rolling mill is performed. While gripping the leading end of the rolled material by the other gripping member, by adjusting the feed rate of the rolled material by the intermediate rolling mill and the feed rate of the rolled material by the finish rolling mill, the leading end surface of the trailing rolled material Is brought closer to the rear end surface of the preceding rolled material, and the gripping member maintains the abutting state of both rolled materials while welding them while moving them between the intermediate rolling mill and the finishing rolling mill. Is continuously rolled by a finish rolling mill to form bar steel, shaped steel and other bar steel, wire rod, burn-in coil and the like. Here, for welding the rolled materials, various welding methods such as electric welding, pressure welding using induction heating or gas heating, and flash butt welding can be used. Further, “maintaining the contact state of both rolled materials” means maintaining the contact state suitable for the welding method applied when welding the rolled materials (including maintaining a minute interval). .) Is meant.

In this case, the material to be rolled is rolled in an intermediate rolling mill so that the cross section has a substantially square or circular shape, and the rolled material that precedes the rolled material and the rolled material that follows the rolled material are welded to finish the welded rolled material. It can be continuously rolled by a rolling mill.

Further, in the above case, while applying a voltage to the contact surfaces of both rolled materials through the gripping member to heat the contact resistance, the leading end surface of the following rolled material and the trailing end surface of the preceding rolled material are Welding can be performed by pressing with the gripping member.

Further, after the leading end surface of the succeeding rolled material comes into contact with the trailing end surface of the preceding rolled material, the feed rates of both rolled materials can be set to the same speed.

Further, after the rolled material is welded, deburring of the welded portion can be performed.

According to the present invention, the preceding rolled material and the following rolled material are of a size suitable for welding the rolled material at a high temperature and the end surface area of the rolled material (the end surface of the rolled material). If it has a large area, it will be difficult to weld it uniformly in a short time.) Move it between the rough rolling mill and the intermediate rolling mill or between the intermediate rolling mill and the finishing rolling mill in the rolled state. However, since the welded and rolled material is continuously rolled by the intermediate rolling mill and finishing mill or finishing mill, it does not affect other processes, and it is easy and highly accurate. In addition to being able to weld rolled materials to each other, it improves the rolling yield by eliminating material loss during rolling, and at the same time stabilizes the size of rolled products, that is, cuts rolled products to a specified size. (Weight,
By significantly reducing the loss of rolled products that occurs when processing to length) and improving the product yield, it is possible to perform rolling operations in rolling equipment continuously, and to improve productivity and productivity. It is possible to improve the quality accuracy of rolled products.

Further, when the rolled material is rolled so that its cross section has a substantially rectangular or circular shape, and the rolled material which is rolled is welded to the rolled material which follows, the rolled material is simply rolled. The two can be welded together.

Further, in the rough rolling mill, the rolled material is rolled into a substantially rectangular shape, the rolled material before rolling and the rolled material after welding are welded, and the thickness of the welded rolled material is increased and the width is increased. When forming so as to decrease, rolled materials can be welded to each other with higher accuracy, and the quality accuracy of rolled products can be further improved.

When the rolled material welded by the rolling caliber is formed so that the thickness of the rolled material is increased and the width is reduced, the rolled material simply welded is increased in thickness and Can be shaped so that

Further, welding may be performed while pressing the front end surface of the succeeding rolled material and the rear end surface of the preceding rolled material with a gripping member, or the leading end surface of the succeeding rolled material may be after the preceding rolled material. After contacting the end faces, the rolled materials can be welded with higher accuracy by setting the feed rates of both rolled materials to the same speed.

Further, after the rolled material is welded, deburring of the welded portion can be performed to further improve the quality accuracy of the rolled product.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the hot rolling method of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of equipment used to carry out the hot rolling method of the present invention. This equipment is a continuous casting equipment 1 for supplying slabs, a cutting machine 2, a slab conveying table 3, a heating equipment 4 for uniformly heating the slabs installed subsequently, a descaler 5, a rough rolling mill. 6, Shear 7, Descaler 8, Rolling material welding device for welding the trailing end surface of the preceding rolled material rolled in the intermediate rolling mill 10 and the leading end surface of the trailing rolled material rolled in the rough rolling mill 6 9, intermediate rolling mill 10, finish rolling mill 11, rolled product transport table 1 for transporting the formed rolled product
2 and a down coiler 13 that winds the rolled product into a coil when the rolled product is a wire rod or a bar-in coil.

In this case, the slab conveyance table 3 can be provided with a billet introduction table (not shown) for introducing a rolling material such as a billet from outside the line, if necessary. Further, a deburring device such as a grinder may be installed between the welding device 9 and the intermediate rolling mill 10 to weld the rolled materials together, and then deburring can be performed.

The welding device 9 has a gripping member 91 for gripping the leading end of the trailing rolled material rolled by the rough rolling mill 6.
A gripping member 92 for gripping the trailing end of the preceding rolled material rolled in the intermediate rolling mill 10, and both gripping members 9
1 and 92, and a guide member 93 that movably supports them in the moving direction of the rolled material. This gripping member 91,
Reference numeral 92 indicates a state in which the leading end surface of the following rolled material and the trailing end surface of the preceding rolled material are in contact with each other, and a voltage can be applied to the contact surfaces of both rolled materials. The two rolled materials are welded together by the rough rolling mill 6 and the intermediate rolling mill 10. In this case, the gripping members 91, 9
By attaching a drive mechanism such as a hydraulic cylinder that can forcibly adjust the distance between both gripping members to 2, it is possible to perform welding while pressurizing the leading end surface of the following rolled material and the trailing end surface of the preceding rolled material. it can. Further, the gripping members 91, 92 may be provided with an end surface treatment mechanism for removing the scale formed on the end surface of the rolled material and shaping the end surface of the rolled material. In this case, rough rolling of the equipment shown in FIG. Shear 7 installed after machine 6
And the descaler 8 can be omitted. Further, a shield mechanism that covers the entire welding device 9 can be provided so that the rolled material can be welded in an atmosphere of an inert gas such as nitrogen gas.

Next, a hot rolling method using the above equipment will be described. The slab or billet supplied from the continuous casting facility 1 and the billet supplied from the introduction table are transported to the heating facility 4 via the slab transport table 3,
After uniformly heating with the heating equipment 4 and removing the scale formed on the surface of the cast slab or billet with the descaler 5, the rough rolling machine 6 has a predetermined diameter (for example, φ60 m).
m)), the scale formed on the surface of the rolled material is removed by the descaler 8, and the trailing end of the preceding rolled material rolled in the intermediate rolling mill 10 is connected to the welding device 9 While gripping with one gripping member 92, while gripping the leading end of the following rolled material rolled in the rough rolling mill 6 with the other gripping member 91,
By setting the feed rate of the rolled material by the rough rolling mill 6 to be higher than the feed rate of the rolled material by the intermediate rolling mill 10, the leading end surface of the trailing rolled material is brought into contact with the trailing end surface of the preceding rolled material and gripped. A voltage is applied to the contact surfaces of both rolled materials via members 91 and 92 to heat them by contact resistance heating, so that both rolled materials are welded between the rough rolling mill 6 and the intermediate rolling mill 10. Continuous rolling is performed by the rolling mill 10 and the finishing rolling mill 11 to form bar steel, shaped steel and other bar steel, wire rods, bar-in coils, etc., and the formed rolled product is transported by the rolled product transport table 12. If the rolled product is a wire rod or a burn-in coil, the rolled product is wound into a coil by the down coiler 13.

In this case, at the time of welding, the leading end surface of the following rolled material abuts the trailing end surface of the preceding rolled material so that the rolled material does not bend between the rough rolling mill 6 and the intermediate rolling mill 10. After that, the feed rate of the rolled material by the rough rolling mill 6 is set to the intermediate rolling mill 1
It is desirable to set the feed rate of the rolled material by 0 to the same rate.

Further, in this example, the rolling material is rolled by the rough rolling mill 6 so that the rolling material has a predetermined diameter, that is, a cross section of a substantially circular shape, but the rolling material is not limited to this. The rolling material is rolled by the machine 6 to have a substantially rectangular cross section, the preceding rolled material and the trailing rolled material that are rolled are welded, and the welded rolled material is processed by the intermediate rolling mill 10 and the finish rolling mill 11. It can also be rolled continuously.

Further, when the rolled materials are welded to each other, a voltage is applied to the contact surface of both rolled materials to heat them by contact resistance heating so that both rolled materials are welded between the rough rolling mill 6 and the intermediate rolling mill 10. However, the present invention is not limited to this, and various welding methods such as electric welding, pressure welding using induction heating or gas heating, and flash butt welding can be used.

In the above example, the preceding rolled material and the following rolled material are of a size (rolled material) suitable for welding the rolled material at a high temperature and the end surface area of the rolled material. If the area of the end face is large, it will be difficult to weld it uniformly in a short time.) Welding is performed between the rough rolling mill 6 and the intermediate rolling mill 10 and the welded rolled material is intermediate. Although the rolling mill 10 and the finishing rolling mill 11 are configured to continuously roll the rolling material, the rolling material is not limited to this, and as shown in FIG. Has a high temperature (at a temperature lower than the above example) and the area of the end surface of the rolled material is suitable for welding (smaller than the above example, that is, uniform welding in a short time) Intermediate rolling mill 10 in a rolled state.
And the finish rolling mill 11 are welded by the welding device 9 having the same configuration as the above example, and the rolled material welded is finished rolling mill 1.
It can also be configured to continuously roll at 1.

FIG. 3 shows another example of equipment used for carrying out the hot rolling method of the present invention. This equipment is the same as the equipment shown in FIG. 1, a continuous casting equipment 1 for supplying a slab, a cutting machine 2, a slab transfer table 3, and a heating for uniformly heating the slab installed subsequently. Equipment 4, descaler 5, rough rolling mill 6, shear 7, descaler 8, intermediate rolling mill 10 and the trailing end surface of the rolled material and the leading edge of the trailing rolled material rolled in the rough rolling mill 6 Welding device 9 for rolled material for welding surfaces, intermediate rolling mill 10, finish rolling mill 11, rolled product transport table 12 for transporting formed rolled product, and rolled product when rolled product is wire rod or burn-in coil It is composed of a down coiler 13 wound into a coil and a forming machine 14 arranged between the welding device 9 and the intermediate rolling mill 10.

After the rolled materials rolled into a substantially rectangular shape (for example, thickness: 20 to 40 mm, width: about 10 times the thickness) in the rough rolling mill 6 are welded to each other, the thickness of the rolled material is increased and the width is decreased. Is formed by the forming machine 14 so that the cross section becomes substantially rectangular, circular or elliptical. This forming machine 14 includes a plurality of rolling mills, for example, rolls in which the rolled material is laterally oriented. Multiple rolling mills equipped with a special caliber (masa caliber) that restricts the spread of
After shaping the rolled material so that its cross section is approximately rectangular, once the flat surface of the rolled material is adjusted through a rolling machine equipped with ordinary rolls, and then again passed through a rolling machine equipped with a special caliber (masa caliber). Or a continuous forging machine.

Next, a hot rolling method using the above equipment will be described. The slab or billet supplied from the continuous casting facility 1 and the billet supplied from the introduction table are transported to the heating facility 4 via the slab transport table 3,
After uniformly heating with the heating equipment 4 and removing the scale formed on the surface of the slab or billet with the descaler 5, the rough rolling mill 6 has a substantially rectangular shape (for example, thickness: 30 mm, width: 300 mm), the scale formed on the surface of the rolled material is removed by the descaler 8 from the rolled material, and the rear end of the preceding rolled material rolled by the intermediate rolling mill 10 is connected to one of the welding devices 9. While holding the leading end of the trailing rolled material being rolled in the rough rolling mill 6 by the other gripping member 91, the feed rate of the rolled material by the rough rolling mill 6 is intermediate-rolled. By setting the feeding speed of the rolled material by the machine 10, the leading end surface of the trailing rolled material is brought into contact with the trailing end surface of the preceding rolled material, and the two rolled materials are brought into contact with each other via the gripping members 91 and 92. Rough rolling mill 6 both rolled material by contact resistance heating by applying a voltage to the surface and the intermediate mill 10
The welded rolled material was welded between and formed by the forming machine 14 such that the thickness of the rolled material was increased and the width was decreased so that the cross section had a substantially rectangular, circular or elliptical shape. The rolled material is continuously rolled by the intermediate rolling mill 10 and the finishing rolling mill 11 to form a bar steel, a shaped steel or other bar steel, a wire rod, a bar-in coil, etc., and the molded rolled product is transported by the rolled product transport table 12. To do. When the rolled product is a wire rod or a burn-in coil, the rolled product is wound into a coil by the down coiler 13.

Also in the case of this example, when welding rolled materials to each other,
Both rolling materials are welded between the rough rolling mill 6 and the intermediate rolling mill 10 by applying a voltage to the contact surfaces of the two rolling materials to heat the contact resistance, but the invention is not limited to this, and for example, Various welding methods such as electric welding, pressure welding using induction heating or gas heating, and flash butt welding can be used. Further, a deburring device can be installed between the forming machine 14 and the intermediate rolling mill 10 to weld the rolled materials to each other, and then deburring can be performed. This deburring can be performed not only by grinding with a grinder, but also by mechanical cutting because the shape of the rolled material is a substantially square shape.
Deburring can be performed efficiently.

[0033]

According to the inventions of claims 1 and 5, it is possible to easily and highly accurately weld the rolled materials to each other in a short time without affecting other steps, and during rolling. It is possible to improve the rolling yield by eliminating the material loss and to stabilize the size of the rolled product, that is, when the rolled product is cut and processed into the specified size (weight, length). By significantly reducing the loss of rolled products and improving product yield, it is possible to improve productivity and quality accuracy of rolled products in combination with being able to continuously perform rolling work in rolling equipment. it can.

According to the second and sixth aspects of the invention, the rolled materials can be easily welded to each other.

According to the invention of claim 3, the rolled materials can be welded to each other with higher accuracy, and
It is possible to further improve the quality accuracy of rolled products.

According to the fourth aspect of the present invention, the rolled material that is simply welded can be formed so that the thickness of the rolled material is increased and the width thereof is decreased.

According to the seventh and eighth aspects of the invention, the rolled materials can be welded to each other with higher accuracy.

According to the invention of claim 9, it is possible to further improve the quality accuracy of the rolled product.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of equipment for carrying out a hot rolling method according to the present invention.

FIG. 2 is a side view showing a modified example of equipment for carrying out the hot rolling method according to the present invention.

FIG. 3 is a side view showing another example of equipment for carrying out the hot rolling method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Continuous casting equipment 2 Cutting machine 3 Slab transfer table 4 Heating equipment 5 Descaler 6 Rough rolling machine 7 Shear 8 Descaler 9 Welding device 91 Gripping member 92 Gripping member 93 Guide member 10 Intermediate rolling mill 11 Finish rolling mill 12 Rolled product transportation table 13 Down coiler 14 Molding machine

Claims (9)

[Claims] 1. A rear end portion of a preceding rolled material rolled in an intermediate rolling mill is held by one holding member, and a leading end portion of a following rolled material rolled in a rough rolling mill is held by the other holding member. While gripping by the gripping member, by adjusting the feed rate of the rolled material by the rough rolling mill and the feed rate of the rolled material by the intermediate rolling mill, the leading end surface of the trailing rolled material becomes the trailing end surface of the preceding rolled material. Weld them while moving them between the rough rolling mill and the intermediate rolling mill while maintaining the contact state of both rolled materials by the gripping members and moving the welded rolled material to the intermediate rolling mill and finish rolling mill. The method of hot rolling is characterized in that it is continuously rolled into a bar steel, shaped steel or other bar steel, wire rod, burn-in coil or the like. 2. A rough rolling mill rolls a material to be rolled into a substantially rectangular or circular cross section, welds a rolled material preceding and rolled, and welds the rolled material to an intermediate rolling mill. 2. The hot rolling method according to claim 1, wherein the rolling is performed continuously by a finishing rolling mill. 3. A rough rolling mill is used to roll a rolled material into a substantially rectangular shape, weld the rolled material before and after rolling, and increase the thickness of the welded rolled material so that the width is 2. The reduction rolling is performed so that the cross section has a substantially rectangular shape, a circular shape, or an elliptical shape, and the formed rolling material is continuously rolled by an intermediate rolling mill and a finishing rolling mill.
The hot rolling method described. 4. The hot rolling method according to claim 3, wherein the welded rolled material is formed by a rolling caliber so that the thickness of the rolled material is increased and the width thereof is decreased. 5. The trailing end of the preceding rolled material rolled in the finish rolling mill is held by one holding member, and the leading end of the trailing rolled material rolled in the intermediate rolling mill is held by the other holding member. By adjusting the feed rate of the rolled material by the intermediate rolling mill and the feed rate of the rolled material by the finishing rolling machine while gripping by the gripping member, the leading end surface of the trailing rolled material becomes the trailing end surface of the preceding rolled material. Weld them while moving them between the intermediate rolling mill and the finishing mill while maintaining the contact state of both rolling mills by the gripping member, and continuously welding the rolled materials with the finishing mill. Rolled steel bar,
A hot rolling method characterized by forming into a shaped steel or other bar steel, a wire rod, a burn-in coil or the like. 6. A rolling material is rolled in an intermediate rolling mill so that the cross section has a substantially square or circular shape, and the rolled material of the preceding rolling and the rolling material of the following are welded, and the rolled material thus welded is finished rolling mill. 6. Rolling continuously at
The hot rolling method described. 7. The front end surface of the rolled material following and the rear end surface of the preceding rolled material are pressed by the gripping member while applying a voltage to the contact surfaces of the two rolled materials through the gripping member to heat the contact resistance. Welding is performed by
The hot rolling method according to 3, 4, 5 or 6. 8. The feeding speed of both rolled materials is set to the same speed after the leading end surface of the trailing rolled material comes into contact with the trailing end surface of the preceding rolled material. 3, 4, 5,
The hot rolling method according to 6 or 7. 9. After welding the rolled material, deburring of the welded portion is carried out.
The hot rolling method according to 5, 6, 7 or 8.