JPH05253737A - Cutting of bar steel - Google Patents

Abstract

PURPOSE:To improve yield by determining the billet weight of a continuous casting machine in correspondence with the outside diameter and length of a final product, cutting the billet to the length corresponding to the billet weight, supplying the billet to a bar steel rolling mill and dividing the rolled member to the length in an integer times of the length of a final product. CONSTITUTION:When the rolling size of a bar steel to be manufactured is determined, the weight of a bar steel per length under this rolling size is obtained. While, the length of a divided member 15 which is cut by a dividing shear 13 in the rear stage of a rolling mill 12 is determined to an integer times of the length of a final product 17 and to the max. dividing length which is regulated from the length of a cooling floor 14. Further, the number of divided members placed on the cooling floor is set, and the total weight after the reduction calculation to the billet before rolling is obtained from the length of the divided member, number of pieces, and the weight per length of the bar steel. Then, the billet length corresponding to the total reduction weight is obtained. Then, the billet is cut by a billet shear 9 on the outgoing side of a continuous casting machine 6 so as to obtain the equal length to the billet length by using a billet cutting length control system.

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 particularly to a billet shearing and rolling in a direct rolling mill in which a billet continuous 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 cutting with 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, the rolled material is divided and cut on the outlet side of the rolling mill in consideration of the length space of the cooling floor of the subsequent equipment, and a plurality of the rolled materials are arranged side by side on the cooling floor. Then, each divided material is cut into a final product length with a cold shear. In order to determine the cut length of the divided material, it is first necessary to detect the feed rate of the rolled material from the rolling mill. In general, as shown in FIG. 1, a pulse oscillator 2 that emits pulses proportional to the roll rotation speed is installed on the final stand 1 of the rolling mill, and the number of pulses corresponding to the determined division length is obtained. When the front end of the rolled material 4 is detected by the hot steel detector 3 in front of the split shear on the delivery side of the rolling mill, the pulse integration of the pulse transmitter 2 is started, and the hot steel detector 3 is used for the first division.
The distance l ₁ between the dividing shear 5 and the divided shear 5 is converted into the number of pulses of the pulse generator of the last stand.
From the second time onward, division is performed with the number of pulses corresponding to the cutting length l ₂ on the rolling line. The number of times of cutting is set a predetermined number of times, or the cutting is continued until the hot steel detector 3 provided before 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 is the final standard length of the product, n is an integer, and L _min is the minimum division length determined from the cycle time of the cooling bed intake 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 according to Japanese Patent Laid-Open No. 55-137825, a surplus portion obtained by dividing the length of the divided material by the final length of the fixed length product is collected in one of the divided rolled materials, and a fixed length shorter than the length of the fixed length product. It is intended to obtain a fixed short product along with the fixed product by cutting the short product at the cutting position.
Also in the method of split cutting of steel bars according to Japanese Patent Laid-Open No. 55-24815, the length of the split material is reduced to reduce crop loss, work efficiency is improved, and work safety is attempted for optimum cutting. In Japanese Patent Laid-Open No. 58-171215, a long material is divided on a length basis, but is cut on a weight basis. Weigh the weight with two weighing machines installed at the front and rear,
Based on this measurement result, a weight equal position is obtained, and the long material is moved in the longitudinal direction so that the cutting position is the cutting position.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The steel bar cutting method disclosed in Japanese Patent No. 137825 can prevent the generation of irregular length material that is shorter than the length of the fixed short product, and improves the yield and the work efficiency in that the fixed short product can be obtained by a normal online cold shear. However, the length of the surplus portion of the divided rolled material to be the constant short length product does not always match the length of the constant short length product, and it becomes necessary to cut the tip of this surplus material.
The number of operations of the cold shear increases correspondingly, and the work efficiency in the cold shear decreases. Further, in the weight division method for a long material disclosed in JP-A-58-171215, the cutting position is changed by measuring the weight each time so that the weight after division becomes a certain weight. It is not intended to optimize the process in the process. Further, in any of the conventional methods described above, the weight of the billet before rolling is predetermined, and the dividing position is changed under such conditions to improve the work efficiency and the yield. Is not yet sufficient in terms of occurrence and work efficiency.

According to the present invention, the weight of the billet obtained by the continuous casting machine is controlled according to the diameter and length of the final product before entering the bar rolling mill to improve the working efficiency and achieve the optimum cutting without waste. Especially.

[0006]

According to the present invention, a billet cast from a continuous casting machine is rolled into a steel bar by a steel 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 delivery side of the steel bar rolling mill is an integral multiple of the final product length and the maximum division length determined from the length of the cooling bed, and an integer of the weight of the rolled material of this length. A method for cutting steel bar is provided, in which the billet obtained by the continuous casting machine is cut so as to have a weight equal to double the weight.

[0007]

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 billet continuous casting machine 6
Is detected by a length detector 8 using a measuring roll, cut by a billet shear (hydraulic shear) 9, and the weight of the billet described later is weighed by a weigher 10. 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 that has been weighed is sequentially fed to the steel bar rolling mill 12 to be rolled into bar steel having a predetermined cross-sectional shape, and the split shear 13 on the subsequent rolling line is used.
Is cut into a predetermined length and placed horizontally on the cooling floor 14. The divided material 15 on the cooling floor 14 is cut into equal length product lengths at equal intervals by a cold shear 16 on the cooling floor outlet side to obtain a final product 17. When a trouble 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 steel bar to be manufactured is determined, the weight of the steel bar per unit length is known under this rolled size. On the other hand, the length of the split material cut by the split shear 13 at the latter stage of the rolling mill is set to an integral multiple of the final product length and the maximum split length regulated by the length of the cooling bed 14, and further placed on the cooling bed. The number of divided materials that can be placed is set, and the total weight of the billet before rolling is calculated from the length and the number of divided materials and the unit length weight of the steel bar. The billet length corresponding to this converted total weight is obtained. Using a billet cutting length control system, the billet is cut by a billet shear on the outlet side of the continuous casting machine so as to have the same billet length. The cut billet is weighed with a weigher to determine if it has the target weight, and if deviation occurs, the cutting position on the billet shear is changed and feedback control is performed to obtain the target weight. I do. In the above example, the number of dividing materials on the continuous floor was set arbitrarily, but the billet weight and length calculated based on this number should be as close as possible to the standard billet length of the continuous casting machine so that it does not become extreme. Determine the number of split materials on the cooling floor so that

If the billet cutting length is determined by the above-mentioned method and the rolled material is divided and cut by the above-mentioned divided length, a standard length product can be obtained without producing an excess portion in each divided material. Here, in actual continuous rolling, the total length of the rolled material being rolled 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 addition, for the monitoring of the total length, 1 ₂ is the final finishing stand 1
Between the hot steel detector 3 and the hot steel detector 3 (see Fig. 1), P ₁ is the total number of pulses generated during billet rolling in the final finishing stand 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 Detected in. Further, when actually determining the billet weight, in addition to the above-described calculated billet weight, (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 rolling material division on the rolling line. It is necessary to add the weight of the cut pieces (cut in the cold shear) at the leading and trailing ends 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, in the case of obtaining a final standard length product of 6 m, if the length of the cooling floor 14 is 102 m, the length of the divided material divided by the rolling material dividing shear of the rolling line is an integral multiple of 6 m. And the length is 90 m, which is as close as possible to the length of the cooling bed. As described above, the billet weight may be calculated from the total number of the split members 15 accommodated in this cooling floor, but normally, for example, the billet shear of the billet shear is cut so that the billet is cut in a standard unit of 150 mm square and 1 ton. A home position is defined, and the position of the shear is adjusted by the cutting length control system based on this position. Therefore, a method of obtaining the required number of dividing members 15 of 90 m in a range as close as possible to 1 ton of the billet is adopted.
Specifically, if the predetermined rolling size is D13, D13
The unit length weight of is 0.995 Kg / m. At this time, the total length of the 1-ton billet after rolling is 1000 / 0.9.
It is calculated as 95 = 1005 m. 90 from this billet
1005/90 = 11.167 division materials of m are obtained. From now on, the number of divisional materials on the cooling floor 14 will be 11,
The split material for 0.167 pieces is made to have an extra length of 18. The weight of this extra length is 90 × 0.167 × for 11 billets.
Since 0.995 = 15 kg (approximate), 15 kg is subtracted from the 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 the 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. In this case as well, the weight of the scale and the weight of the leading and trailing edge crop pieces in the rolling line are of course 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 the length of the final product, and the billet is cut into the length corresponding to this billet weight. Since it is supplied to a steel bar rolling mill and all rolled material is divided by an integral multiple of the length of the final product, there is no surplus portion at the last product cutting, yield is improved, and surplus portion Since the cutting is not required, the cutting cycle in the cold shear is shortened and the work efficiency is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining a method for 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 carrying out the method according to the present invention.

FIG. 3 is a plan view showing an arrangement of dividing members on a cooling floor and a cutting position of a final product according to an embodiment of the present invention. 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 Dividing material 16 Cold shear 17 Final standard size product

Claims (1)

[Claims] 1. A method for cutting a steel bar, comprising rolling a billet from a continuous casting machine into a steel bar using a steel bar rolling mill, dividing the billet into required lengths, and further cutting into a final product length. The continuous length of the continuous casting machine is set so that the division length of the material is an integral multiple of the final product length and the maximum division length determined from the length of the cooling bed, and is equal to the integral multiple of the weight of the rolled material of this length. A method for cutting steel bars, which comprises cutting the billet obtained in.