JPH04270044A - Method for removing flash in cast slab - Google Patents

Abstract

PURPOSE:To improve flash removal efficiency and to obtain a cast slab having good quality by controlling the rotational speed of a hammer or a relative position between the hammer and the cast slab with the component, temp. and shape of the cast slab. CONSTITUTION:The rotational speed or hitting depth of the suitable hammer 1 corresponding to the condition of the cast slab, i.e., component, temp., size, etc., is set and by hitting with the hammer 1 attached to a rotor 13, the flash 41 at the lower part of the cast slab 30 is removed.

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for removing burrs generated at the lower part of a cut surface when a slab cast by continuous casting is gas-cut. [0002] When cutting slabs, blooms, beam blanks, or billets, which are slabs cast by continuous casting, into predetermined lengths by gas cutting, a gas jet is applied to the slabs from the torch of a gas cutting device. Spray at right angles to the surface. Most of the metal melt melted at the cut surface falls downward along the cut surface, but some of it adheres to the bottom of the slab as burrs. This burr may interfere with the subsequent rolling process, so it is necessary to remove it. [0003] In order to remove this burr, for example,
The method for removing burrs using a rotor incorporating a hammer described in Japanese Patent No. 1-236412 is as follows. Below the slab, a rotor having a rotation axis parallel to the bottom surface of the slab and perpendicular to the running direction of the slab is provided with a plurality of support plates that rotate together with the rotor, and pins are installed on the outer edges of the support plates. A burr removal device is used in which a plurality of hammers are rotatably supported. Hereinafter, this will be referred to as a hammer type burr removal device. When the slab with burrs attached to the lower part of the gas-cut surface of the slab travels on the roller table and reaches a predetermined position, the rotor is rotated and raised. As the rotor rotates, the hammer is swung out to the outer periphery of the rotor by centrifugal force and hits the lower surface of the slab to remove burrs. Burrs are removed from the slab while it is running. [0004] However, the conventional method for removing burrs depends on the conditions of the slab, ie, the type, composition,
Even if the temperature, size, etc. change from slab to slab, burrs are removed by keeping the rotational speed of the rotor constant. Therefore, if the conditions of the slab change, the success rate of burr removal will decrease or the hammer will not work properly. There is a possibility that the damage caused by contact will increase. For example, in the case of hard slabs (high carbon content, low temperature), a low rotation speed will reduce the success rate of burr removal, and conversely, in the case of soft slabs (low carbon content, high temperature), When the rotation speed is high, the contact flaws in the slab become large, and the possibility of defects occurring during rolling increases. Furthermore, even if the hardness of the slab and the rotational speed of the rotor are the same, the size of flaws or the rate of occurrence of flaws during rolling may differ depending on the type of slab. Furthermore, even if the hardness and type of slab are the same, if the width of the slab changes, the resistance when the rotating hammer hits the slab will change, reducing the rotation speed and reducing the success rate of burr removal. changes. For example, if the width of the slab is small, the success rate of removing burrs is high, but as the width increases, the success rate of removing burrs may decrease. [0006]Also, the height at which the hammer is swung up during rotation when removing burrs is usually higher than the lower edge of the cut surface of the slab, but the height from the lower edge (this is called the hitting depth)
needs to be adjusted depending on the conditions of the slab. This adjustment is necessary to reduce contact scratches and to sufficiently remove burrs. Further, it is necessary to adjust the height of the hammer swing, that is, the height of the rotor, depending on the amount of warpage of the end of the cut surface from which burrs are removed. If this adjustment is not appropriate, the above-mentioned contact depth adjustment cannot be performed appropriately. [0007] If the error in the above-mentioned contact depth is large, there is a possibility that the large contact depth will result in large contact defects on the slab, which may further lead to failure of the burr removal device. Furthermore, if the height is too low, burr removal may not be sufficient, and in extreme cases, the hammer may fail. [0008] In the conventional technology, the height of the rotor when removing burrs is mechanically fixed, so the height of the rotor cannot be changed depending on the amount of warpage at the end of the slab or the hardness of burrs depending on the product type. . The present invention was made in view of the above circumstances, and maintains a high burr removal rate regardless of the conditions of the slab.
Furthermore, the present invention provides a method for removing burrs from a cast slab, which can reduce hammer hit flaws to the extent that they do not affect rolling or products. Means for Solving the Problems The present invention provides a method for removing burrs from a slab using a hammer-type burr removal device, in which the rotational speed of the hammer is adjusted depending on the composition, temperature, and shape of the slab. and controlling the relative position between the hammer and the slab. [Operation] We investigated the correlation with the burr removal rate when the properties of the slab, such as the type, composition, temperature, or width of ordinary steel, stainless steel, high Mn steel, etc., changed, and found that The rotational speed of the rotor can be found. The relationship between the properties of the slab and the rotational speed of the rotor studied here is input to an information processing device, such as a computer, processor, or sequencer, related to the operation of the burr removal device. Other data necessary for deburring, i.e.
The cutting length of the slab, the temperature, the traveling speed, and the relative position between the traveling slab and the burr removal device are input to the information processing device, and the operation of the burr removal device is performed based on such information. controlled. The above-mentioned information is measured during conveyance of the slab as necessary and is input into the above-mentioned information processing device. [0012] According to the information input in this way, the appropriate rotational speed or depth of impact of the hammer is set according to the conditions of the slab to be deburred, and the rotor starts rotating, rises, and descends at the appropriate timing. , the rotation is stopped, and the burrs at the bottom of the cut surface are removed by the blow of a hammer attached to the rotor. DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a side view showing a hammer type burr removal device 10 used in the method of the present invention. In the figure, 30
is a slab slab to be deburred, and is conveyed to the deburring device 10 by the rollers 32 of the slab conveying device 31. Reference numerals 11 and 12 are a support stand and a roller of the burr removing device, respectively. 13 is a rotor, and a plurality of support plates 14, which will be described later, are provided in parallel in the axial direction of the rotor 13 (see FIGS. 2 and 3). 15 is a bearing block that supports the rotor 13; 16 is a frame that holds the bearing block 15; and 17 is a hydraulic cylinder that moves the bearing block 15 up and down. Further, arrow A indicates the direction in which the slab 30 moves. Although not particularly shown, a hydraulic circuit 58 (see FIG. 5) is provided attached to the hydraulic cylinder 17 to control the lifting and lowering of the bearing block. FIG. 4 shows the hammer type burr removing device 10 of FIG.
Optical sensor P that detects the position of the slab installed in
It is a figure showing H1-PH4. In this example, optical sensors are installed at four locations.In one optical sensor, a light emitter and a light receiver form a pair and are installed on both sides of the path through which the slab passes. When the light passes or passes through, the optical path between the light receiver and the light emitter is blocked or opened, and OFF and ON signals are output, respectively. Figure 4
PH1 and PH2 are fixed to the stand 33 or the support stand 11 shown in FIG. 1, and PH3 and PH4 are fixed to the bearing block 1.
5 and moves up and down together with the rotor 13. PH3
The optical path is inclined to the level and the slab cutting surface. 56 is a radiation thermometer that measures the temperature of the slab 30. Moreover, the dotted line L indicates the conveying roller 1 of the slab 30.
2, 32 roller levels are shown. FIG. 2 is a side view of the rotor 13 and the support plate 14 fixed thereto, and FIG. 3 is a front view of the rotor 13 shown in FIG. 2 viewed from the direction in which the slab 30 moves. In FIG. 2, arrow B indicates the rotation direction of the rotor. In the case of removing burrs from the rear end of the slab, the direction of rotation is opposite to arrow B. In the figure, 1 is a hammer, 2 is a head of the hammer, and 21 is a pin that rotatably supports the hammer 1. Hammer 1 on the left in Figure 3
shows a longitudinal section, showing the pin hole 22 and pin 21 drilled in the hammer. It should be noted that the hammer 1 is shown only in the uppermost raised position for the sake of clarity. The hammer 1, which is rotatably supported on the support plate 14 by a pin 21, is swung outward by centrifugal force as the support plate 14 rotates, and the support plate 14 is moved along with the rotor 13 in the direction of slab movement (arrow). Rotating in the direction of arrow B with respect to A), the head 2 of the hammer 1 strikes the burr 41 fixed to the lower part of the cut surface of the slab 30, thereby peeling and removing it from the slab 30. The inner diameter of the pin hole 22 is larger than the outer diameter of the pin 21 to reduce the impact when the hammer head removes the burr. FIG. 5 is a block diagram of the control used in the method of this embodiment. In the figure, numeral 51 is a business computer used for process control, and the conditions of the slab, ie, the type, composition, [C] equivalent, and size are input here. 5
Reference numeral 2 denotes a process computer that issues instructions for producing slabs, and manages tracking of slabs. Also,
Here, the properties of the slab mentioned above and the rotor 1 of the burr removal device are shown.
3, the relationship between the rotation speed and the relationship between the properties of the slab and the depth of hammer contact are input. The contact depth will be explained in detail later. Further, the temperature of the slab, which is measured by a thermometer provided in the conveying device, is also input into this process computer. Reference numeral 53 denotes a table sequencer that controls the operation of the conveying device 31 for conveying the slab, and controls the operation of the roller 32.
Controls the forward rotation, reverse rotation, stop, and rotation speed of the slab to manage the movement of the slab. In order to improve the working efficiency of the slab 30, the table sequencer 53 increases the traveling speed of the slab during transportation compared to the speed during the operation time of the burr removal device. Reference numeral 54 denotes a burr removal sequencer that controls the operation of the burr removal device 10, controls the forward rotation, reverse rotation, stop, rise, fall, and rotational speed of the rotor 13, and controls the burr removal by the hammer 1. It will be done. The ON/OFF signal from the optical sensor is also input here. 58
is a hydraulic circuit that receives a signal from the burr removal sequencer 54 and controls the lifting and lowering of the rotor 13 using the hydraulic cylinder 17. The signals input to the blocks 51 to 54 of the computer and sequencer shown in FIG. 5 depend on the type of signal and the characteristics of the installed computer and sequencer, and are limited to the input method described above. isn't it. Next, the operation of the burr removing apparatus 10 constructed as above will be explained. In FIG. 1, a slab 30 is conveyed by a conveying device 31 from a continuous casting device (not shown) and advances to a burr removing device 10 in the direction of arrow A. While the slab 30 is being removed by the burr removal device 10, the speed is slowed down, but the slab 30 does not stop. Further, the temperature of the slab 30 is measured by a thermometer 56 shown in FIG.
That value is entered into the process computer. The optical sensors PH1 to PH4 shown in FIG.
Slab 3 for controlling the operation of the hammer type burr removal device 10
Detect the zero position or the amount of warpage at the end of the slab and send these signals to the deburr sequencer. When the slab 30 is transported and the front end reaches PH1, the light is blocked and the OF
F, and based on this OFF signal, the rotation of the rotor 13 is started and the conveyance speed of the slab 30 is decelerated. [Table 1] Table 1 shows the optical sensor signal, timer and rotor 13 for removing burrs from the tip of the slab 30.
This shows the relationship with the operation of The burr removal operation will be explained with reference to this table together with FIG. 4. The rotor 13 starts rotating in response to a signal from PH1, and at this time, the rotational speed of the rotor 13 is set to an appropriate rotational speed corresponding to the properties of the slab, which has been input in advance to the process computer 52 shown in FIG. 5. . Among the properties of the slab 30, regarding temperature, the measured value of the thermometer 56 is input into the process computer 52. In FIG. 4, when the slab 30 advances and reaches PH2 from PH1, an OFF signal is output from PH2.
The rotor 13 begins to rise. PH3 is fixed to a bearing block 15 and rises together with the rotor 13. Also, at this time, the timer provided in the burr removal sequencer starts operating. The rising time of the rotor 13 is controlled in advance by a timer built into the burr removal sequencer 54 to be an appropriate time corresponding to the advancing speed of the slab 30. [0026] Then, when the tip of the slab reaches PH3, the PH
3, the lower edge of the slab tip is detected. Since the optical path of PH3 is inclined with respect to the level L and the slab cut surface, PH3 is OF
Since the F signal is transmitted, the position of the lower edge of the slab can be detected accurately. The transmission time of the 0FF signal is the time T after the timer is activated (see Table 1). The swinging height of the hammer (referring to the maximum height of the tip when the rotor 13 rotates and the hammer 1 is swung up in a free state; the same applies hereinafter) is input to the burr removal sequencer 54 while the rotor 13 is rising. There is. Therefore, the timer can be activated to stop the rotor so that the swing height is equal to the height plus the hit depth. Next, the depth of contact will be explained. FIG. 6 is an enlarged view of FIG. 2 for explaining the relative positions of the rotor 13 or the hammer 11 and the slab 30 during burr removal. In the figure, numerals 42 and 43 are loci of rotation as the pin 21 and the rotor 13 of the hammer head rotate, respectively. 45 and 45' are the heights at which the hammer 1 is swung up, 45 and 45' are the heights during lifting and burr removal, respectively. 30' in Figure 6
, 30'' indicates a slab with a curvature, 30' is an upward curvature, and 30'' is a slab with a downward curvature. 47 above
, 48 are the lower edge levels corresponding to the slabs 30', 30''. 47, 48 are the lower edge levels of the cut surfaces, and the strength of the aforementioned blow is the difference between the lower edge levels 47 or 48 and 45'. This difference is the above-mentioned contact depth, hereinafter written as ΔL. As mentioned above, this ΔL is determined depending on the properties of the slab and is input in advance to the burr removal sequencer 54. Therefore, If the level of the lower edge of the cut surface of the slab is detected, the height at which the hammer is swung up when removing burrs is determined. When the height at which the hammer is swung up is determined as described above, the burr removal sequencer 53 The timer installed in the rotor 13 is activated, and the rotor 13 is raised for a predetermined rising time, and the rise stops at a predetermined swing-up height of 45'.The time at this time is T+Δt (see Table 1).
. Δt is the time from when the PH3 turns off the signal until the rotor stops rising. The burr removal time (denoted as ΔtS) after the swing-up height reaches a predetermined height depends on the slab conditions.
The timer is set. This time ΔtS is
The timer is set according to slab conditions. If this time is too short, the burrs will not be removed sufficiently, and if it is too long, the damage caused by the hammer on the bottom surface of the slab will become large, so an appropriate time can be set based on operational experience. rotor 1
3 is raised or lowered by the cylinder 17 controlled by a hydraulic circuit 58. As described above, when the burr removal time set on the timer has elapsed, the burr removal from the cut surface of the tip of the slab 30 is completed, and the rotor 13 begins to descend and stops rotating. Next, by the PH4 OFF signal,
The lowering of the rotor is stopped. Next, burrs can be removed from the rear end of the slab in substantially the same manner as the front end; however, the same operations will not be described here. Optical sensor PH1
When the optical path reaches the point where the optical path is opened, the rotor 13 starts rotating due to the ON signal. The direction of rotation at this time is opposite to arrow B in FIG. Furthermore, in the same way as when removing the burr from the tip,
The rotor starts to rise with the ON signal of PH2. When detecting the lower edge of the rear end, the slope of the optical path is different from that of the tip, and it is difficult to use the same PH3 as the tip.
It is desirable to provide '. Once the lower edge is detected, the burr removal work is completed in the same way as for the tip. Next, this embodiment will be explained by citing specific numerical values. Table 2 shows the rotational speed of the rotor when the slab conditions, ie, carbon content, temperature, and width of the slab, are determined for the case where the type is carbon steel. Regarding the slab passing through the burr removal device, the relationship between the condition of the slab and the rotational speed of the rotor is input into the process computer 52 in advance, so it corresponds to the casting conditions of the slab conveyed to the hammer type burr removal device 10. The rotational speed of the rotor 13 thus determined is instructed to the burr removing device. The relationship may be input into a table sequencer or a burr removal sequencer. In addition, in Table 2, 99 is entered in the Max column.
9 or 9999 is a numerical value set that does not exceed this value, and this value itself has no meaning. Moreover, C equivalent is represented by the following formula. C equivalent = C + Mn /6 + (Cr
+Mo+V)/5+(Cu
+Ni)/15 [Table 2] Figure 7 is a graph showing the results obtained based on the rotational speed in Table 2, and shows the C equivalent corresponding to the hardness of the slab at three levels ( Low carbon steel; <0.20, medium carbon steel; 0.2
0 to 0.40, high carbon steel > 0.40, all units are w
t%) and rotor rotational speed at three levels (730, 6
50, 550 rpm) and shows the success rate of burr removal. The burr removal success rate is the ratio of the number of cut surfaces from which burrs have been completely removed to the total number of cut surfaces from which burrs have been removed using the method of this example, for cut surfaces with burrs attached to the lower edges. It is. In this graph, the total number of cut surfaces from which burrs were removed is approximately 1000. Graphs A, B, and C in the same figure each have a rotation speed of 730 rpm.
m, 650 rpm, and 550 rpm. The burr removal success rate is almost 100% for low carbon steel, but this rate decreases for medium and high carbon steel. For medium carbon steel, the success rate of removing burrs can be improved by increasing the rotation speed of the rotor, but for high carbon steel, even if the rotation speed is increased, the burr removal rate remains at about 50%. The reason for this is as follows. As shown in FIG. 3, since the hammer 1 is not provided above the support plate 14 provided on the rotor 13, the hammer does not hit the lower surface of the slab in this area. In the case of low carbon steel or medium carbon steel, it is torn off by the burr removed by the hammer blow of the neighboring steel, but in the case of high carbon steel, the burr removed is hard and brittle, so the burr is torn off until it tears off the neighboring burr. This is because there is no strength. To solve this problem, the hammer heads on both sides of the support plate 14 are enlarged toward the support plate side.
The shape of the hammer was improved so that the burrs above were also struck by the hammer head 2, and a burr removal rate of almost 100% was obtained. FIG. 8 is a sectional view of the improved hammer shape as described above, and for the sake of clarity, only two hammers on each side of the support plate 14 are shown, and the others are omitted. Support plate 1
The support plate 1 serves as the hammer 1 corresponding to the burr above 4.
The shape of the hammer head 2 on both sides of the hammer head 4 is improved to make the hammer head 4 wider in width. The results shown in Table 2 and FIG. 7 were obtained for carbon steel, and the slab conditions can be applied within the range shown in Table 3. For other types of steel such as stainless steel, burrs can be removed by determining the relationship between slab conditions and rotational speed in the same manner as for carbon steel. [Table 3] Table 4 shows operational data of the burr removal equipment used in this example. [Table 4] [0042] According to the present invention, the rotational speed of the hammer is controlled depending on the properties and shape of the slab, and the relative position between the hammer and the cut surface of the slab is adjusted according to the properties and shape of the slab. The system detects when the hammer is running and controls the operations of starting, raising, lowering, and stopping the rotation of the hammer, improving burr removal efficiency and reducing hammer flaws regardless of the condition of the slab, resulting in good quality. You can get slabs.

[Brief explanation of the drawing]

FIG. 1 is a side view of a hammer type burr removal device.

FIG. 2 is a longitudinal sectional view showing a rotor and a slab.

FIG. 3 is a front view showing a rotor and a hammer.

FIG. 4 is an explanatory diagram of relative position detection between a slab and a hammer.

FIG. 5 is a control block diagram of the hammer type burr removal device.

FIG. 6 is an explanatory diagram illustrating the relative positions of a hammer and a slab.

FIG. 7 is a graph showing the relationship between the carbon equivalent range of the slab and the burr removal success rate.

FIG. 8 is a diagram showing a hammer with an improved head shape.

[Explanation of symbols]

1 Hammer 2 Hammer head 10 Hammer type burr removal device 11 Support stand 12, 32 Roller 13 Rotor 14 Support plate 15 Bearing block 16 Frame 17 Hydraulic cylinder 30 Slab 31 Conveying device 41 Burr 51 Business computer 52 Process computer 53 Table sequencer 54 Burr Removal sequencer 56 Thermometer A Arrow indicating the advancing direction of the slab, B Arrow indicating the rotating direction of the rotor, L Roller level PH1 to PH4 Optical sensor

Claims (5)

[Claims] 1. A method for removing burrs from a slab using a hammer-type burr removing device, characterized in that the rotational speed of the hammer or the relative position between the hammer and the end of the slab is controlled depending on the composition, temperature, and shape of the slab. How to remove burrs from cast slabs. [Claim 2] The rotational speed of the hammer is C of the slab.
amount, or the following formula: C equivalent = C + Mn /6 + (Cr
+Mo+V)/5+(Cu
2. The method for removing burrs from a slab according to claim 1, characterized in that the C equivalent of the slab determined by +Ni)/15 is changed for each layer. 3. The rotational speed of the hammer or the relative position between the hammer and the slab is changed by detecting the warpage of the end of the slab and depending on the difference between the height of the lower edge of the end of the slab and the height at which the hammer is swung up. Claims 1 and 2 are characterized in that:
A method for removing burrs from a slab according to any one of the following. 4. The method is characterized in that the degree of warpage of the end of the slab is detected using an optical sensor in which the optical path connecting the light emitter and the receiver of the optical sensor is inclined with respect to the bottom surface and the cut surface of the slab. A method for removing burrs from a slab according to any one of claims 1, 2 and 3. 5. The burr above the support plate is directly struck using a burr removing device having a hammer having a horizontally projecting head adjacent to the support plate. The method for removing burrs from a slab according to any one of claims 2, 3 and 4.