JP2781860B2 - How to cut steel bars - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of cutting a long steel material such as a steel bar into a predetermined product length, and more particularly to a billet shearing and rolling method in a direct-feed rolling facility in which a continuous billet casting machine and a steel bar rolling machine are continuously arranged. The present invention relates to a method of obtaining a final steel bar product having a predetermined length by being cut by a material dividing shear and a cold shear in a cooling yard.

[0002]

2. Description of the Related Art In the production of steel bars in this type of rolling equipment, a rolled material is divided and cut at the exit side of a rolling mill in consideration of the length of a cooling floor of a succeeding equipment, and a plurality of rolled materials are arranged side by side on the cooling floor. After that, each divided material is cut to the final product length by a cold shear. In order to determine the cut length of the divided material, it is necessary to first detect the speed at which the rolled material is sent from the rolling mill. In general, as shown in FIG. 1, a pulse transmitter 2 for generating a pulse proportional to the number of rotations of a roll is installed in a final stand 1 of a rolling mill, and a pulse number corresponding to a determined division length is obtained. When the leading end of the rolled material 4 is detected by the hot steel detector 3 before the split shear on the exit side of the rolling mill, integration of the pulses of the pulse transmitter 2 is started, and the first split is performed by the hot steel detector 3
The distance l ₁ between the _first and second split shears 5 is converted into the number of pulses of the pulse transmitter of the last stand.
After the second time, division is performed with the number of pulses corresponding to the cutting length l ₂ on the rolling line. The cutting is performed a preset number of times, or the cutting is continued until the hot steel detector 3 provided in front of the final stand detects the tail end of the rolled material 4. In this case, the cutting length L _D is determined as follows. _{L D = n × l L min} <L D <L max L min <L T where l; final constant length product length, n; integer, L _min; minimum division length determined from the cycle time of the cooling bed capture device It is, L _max; maximum division length determined by the length of the cooling bed, L _T; final division length, various methods conventionally about how to determine the cutting length L _D has been proposed.

For example, in the method disclosed in Japanese Patent Application Laid-Open No. 55-137825, a surplus portion obtained by dividing the length of a divided material by the final fixed product length is collected into one of the divided rolled materials, and a fixed length shorter than the fixed product length is collected. It is intended to cut the short-length product at the cutting position and obtain a fixed-length product accompanying the fixed-length product.
Also in the method for cutting bars and the like according to Japanese Patent Application Laid-Open No. 55-24815, the length of the divided material is intended to be optimally cut in order to reduce crop loss, increase work efficiency, and work safety. Japanese Unexamined Patent Publication (Kokai) No. 58-171215 discloses a method in which a long material is divided on the basis of length, but is cut on a weight basis. Measure the weight with two weighing devices provided in front and back,
Based on the measurement result, a position equivalent to the weight is obtained, and the long material is moved in the longitudinal direction so as to be cut so that the position becomes the cutting position.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No.
The method of cutting steel bars described in Japanese Patent No. 137825 can prevent the occurrence of irregularly-sized material less than the length of a fixed-short product, and improve the yield and work efficiency in that a fixed-short product can be obtained with a normal online cold shear. However, the length of the surplus portion of the divided rolled material to be a fixed-short product does not always match the fixed-short product length, and the tip of the surplus material needs to be cut.
Accordingly, the number of operations of the cold shear increases, and the work efficiency in the cold shear decreases. Japanese Patent Application Laid-Open No. 58-171215 discloses a method of dividing the weight of a long material by changing the cutting position by measuring the weight each time so that the weight after division becomes a certain weight. It is not intended to optimize the processing in the process. Furthermore, in all of the above-mentioned conventional methods, the weight of the billet before rolling is determined in advance, and it is intended to improve the work efficiency and the yield by changing the dividing position under the conditions, and the like. However, it is not sufficient in terms of generation of work and work efficiency.

According to the present invention, the weight of the billet obtained by the continuous casting machine is controlled in accordance with the diameter and length of the final product before entering the bar mill, so that the work efficiency is increased and the optimum cutting without waste is achieved. It is in.

[0006]

According to the present invention, a billet cast from a continuous casting machine is rolled into a bar by a bar rolling mill, divided into required lengths, and further cut into final product lengths. In the cutting method, the division length of the rolled material on the exit side of the bar rolling mill is an integral multiple of the length of the final product and the maximum division length determined by the length of the cooling bed, and an integer of the weight of the rolled material having this length. There is provided a method for cutting a steel bar for cutting a billet obtained by the continuous casting machine so as to be equal to double the weight.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is an overall schematic view showing a flow of a steel bar from a billet to a final product according to an embodiment of the present invention.
First, the billet 7 taken out from the continuous billet casting machine 6
Is detected by a length detector 8 using a measuring roll, cut by a billet shear (hydraulic shear) 9, and weighed by a weighing machine 10 to check whether or not the billet weight is described later. When the weight of the weighed billet does not match the predetermined billet weight, the cutting position at the billet shear 9 is changed according to the deviation. The billet whose weighing is completed is sequentially fed to the bar rolling mill 12 to be rolled into a bar having a predetermined cross-sectional shape, and the divided shear 13 on the subsequent rolling line is formed.
And cut laterally on the cooling floor 14. The divided material 15 on the cooling floor 14 is cut into equal length product lengths by a cold shear 16 on the cooling floor exit side to obtain a final product 17. When a problem occurs in the bar rolling mill and the billet cannot be fed from the continuous casting machine 6, a billet yard (not shown) for storing the billet may be provided.

In the present invention, when the rolled size of the bar to be manufactured is determined, the weight of the bar per unit length can be determined under the rolled size. On the other hand, the length of the divided material cut by the dividing shear 13 at the latter stage of the rolling mill is set to a maximum division length that is an integral multiple of the length of the final product and is regulated by the length of the cooling floor 14, and is further placed on the cooling floor. The number of divided members that can be placed is set, and the total weight in terms of the billet before rolling is determined from the length and number of the divided members and the unit length weight of the steel bar. The billet length corresponding to this converted total weight is determined. Using a billet cutting length control system, the billet is cut by a billet shear on the exit side of the continuous casting machine so as to be equal to the billet length. Weigh the cut billet to the target (target) weight with a weighing machine to confirm. If a deviation occurs, change the cutting position in the billet shear and feedback control so that the target weight is achieved. I do. In the above example, the number of divided members on the continuous floor was arbitrary, but the billet weight and length calculated based on this were close to the standard billet length of the continuous casting machine so that the billet weight and length would not be extreme. Determine the number of divided materials on the cooling floor so that

[0009] If the billet cutting length is determined by the above-described method and the rolled material is divided and cut by the above-described division length, a fixed-length product can be obtained without generating an excess portion in each divided material. Here, in the actual continuous rolling, the total length of the rolled material during rolling is monitored, and if a deviation occurs beyond a certain range between the monitored total length and the total length calculated in the initial calculation, continuous casting is performed. A signal is sent to the cutting length control system of the billet shear of the machine to increase or decrease the billet weight. In monitoring the full length, l ₂ is used as the final finishing stand 1
(See Figure 1) the distance between the heat steel detector 3, the total number of pulses occurring during billet rolling at a final finishing stand 1 P _1, P
_{If 2} is the number of pulses generated by the final stand before the rolled material exits the final finishing stand 1 and reaches the hot steel detector 3, the total length L of the rolled material is L = l ₂ × P ₁ / P ₂ Is detected by Further, when actually determining the billet weight, the calculated billet weight described above includes (a) the weight of the scale lost between the billet shear of the continuous casting machine and the final stand of the rolling mill, and (b) the rolled material division on the rolling line. It is necessary to add the weight of the front and rear crop pieces (cut with a cold shear) of the rolled material cut by the shear.

Next, the method of the present invention will be described in more detail with reference to specific examples. As shown in FIG. 3, when a final fixed length product of 6 m is obtained, assuming that the length of the cooling floor 14 is 102 m, the length of the divided material divided by the rolled material dividing shear of the rolling line is an integral multiple of 6 m. 90 m as close as possible to the length of the cooling bed. As described above, the billet weight may be calculated by determining the total number of the divided members 15 accommodated in the cooling floor, but usually, for example, a 150 mm square, 1 ton standard unit of the billet shear is used to cut the billet. A home position is determined, and the position of the shear is adjusted by the cutting length control system based on the home position. Therefore, a method of obtaining the required number of 90 m divided members 15 in a range as close as possible to 1 ton of billet is adopted.
Specifically, assuming that the predetermined rolling size is D13, D13
Has a unit length weight of 0.995 Kg / m. At this time, the total length of the 1-ton billet after rolling was 1000 / 0.9.
95 is calculated as 1005 m. 90 from this billet
1005/90 = 11.167 m-dividers are obtained. From now on, the number of divided materials on the cooling floor 14 will be 11
The divided material for 0.167 pieces is set to 18 for the extra length. The weight of this extra length is 90 x 0.167 x for 11 billets
Since 0.995 = 15 Kg (estimated), 15 Kg is subtracted from 1 ton billet to obtain a calculated billet weight of 985 Kg. From this, the billet length is calculated, the actual billet length is detected by a measuring roll, the position of the billet shear is adjusted, and the billet is cut at this length. The billet after cutting is measured by a weighing machine, and the position of the billet shear is controlled by known feedback control. Also in this case, it is needless to say that the weight of the scale in the rolling line and the weight of the front and rear end crop pieces are corrected.

[0011]

As described above, according to the present invention, the billet weight of the continuous casting machine is determined according to the outer diameter and length of the final product, and the billet is cut to a length corresponding to the billet weight. And the rolled material is further divided by an integral multiple of the length of the final product.Therefore, there is no surplus part in the final product cutting, and the yield is improved. This eliminates the need for cutting, so the cutting cycle in the cold shear is shortened, and the work efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining a method of detecting a length of a rolled material and a cutting method using a hot steel detector and a split shear on a rolling line.

FIG. 2 is a schematic diagram showing the overall equipment configuration when performing the method according to the present invention.

FIG. 3 is a plan view showing an arrangement of divided materials on a cooling floor and a cutting position of a final product according to an embodiment of the present invention. Reference Signs List 6 continuous casting machine 7 billet 8 length detector 9 billet shear 10 weighing machine 12 steel bar rolling machine 13 rolled material dividing shear 14 cooling floor 15 divided material 16 cold shear 17 final fixed length product

Claims (1)

(57) [Claims] 1. A method of cutting a bar from a continuous casting machine, wherein the billet is rolled into a bar by a bar rolling machine, divided into required lengths, and further cut into a final product length. The division length of the material is an integral multiple of the length of the final product and the maximum division length determined by the length of the cooling bed, and the continuous casting machine is designed to be equal to an integral multiple of the weight of the rolled material of this length. A method for cutting a steel bar, comprising cutting a billet obtained in step (a).