JP2013027906A - Method of conditioning billet surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of conditioning a surface which can remove securely the surface defect portion due to crest-like protrusions without inputting the surface defect portion due to the crest-like protrusions generated when in flame-scarfing to a grinding device, on the occasion that a surface defect portion is comprehended by a billet surface inspection after flame scarfing processing, the billet surface is cleaned by removing the comprehended surface defect portion by a partial conditioning with the grinding device.SOLUTION: In the method of conditioning a surface, the surface of a billet 7 is flame-scarfed by a flame scarfing equipment 1, then, surface defects remaining in the billet surface after flame-scarfing and each portion of crest-like protrusions in the portion where the flame scarfing is not yet performed and those generated when in flame scarfing are ground by a grinding device 2, the generated position of the crest-like protrusions is estimated on the basis of the mechanical dimension of the flame scarfing equipment and the latest past result of flame scarfing, the estimated generated position of the crest-like protrusions is automatically input to the grinding machine, and at the same time, each generated position of the surface defect comprehended by the surface inspection of the billet after flame scarfing and the portion where the flame scarfing is not yet performed are input to the grinding device, each generated position of the input surface defect, the portion where the flame scarfing is not yet performed, and the crest-like protrusions are ground by the automatic operation of the grinding device.

Description

  The present invention relates to surface flaws such as cracks and non-metallic inclusions present on the surface of steel slabs such as continuously cast steel slabs and steel slabs produced by split rolling, and the surface of steel slabs generated during welding The present invention relates to a surface care method for removing uncut parts and defective parts that protrude in a mountain shape.

  Since the surface of the steel slab or steel ingot produced by continuous casting has a surface defect such as cracks and non-metallic inclusions on the surface of the steel slab produced by split-rolling, such as hot and cold scurfers It has been practiced that the entire surface of the steel slab surface is subjected to a scouring treatment with a thickness of about 2 mm, for example, by spraying oxygen gas for cutting onto the steel slab surface using a welding machine. In particular, for steel slabs for thin steel sheets that require surface cleanliness in products, full surface cutting is generally performed.

  However, even when the entire surface is cut, if the surface flaws such as cracks and non-metallic inclusions generated in the steel slab are deeper than the cutting depth, they remain without being removed. Moreover, due to troubles and malfunctions of the welding equipment, the thickness of the cutting may be uneven in the width direction of the steel slab or in the longitudinal direction of the steel slab, and uncut parts may occur. Furthermore, in the hot-cutting equipment such as hot scurfer and cold scurfer for cutting slab steel slab, several torch units are arranged in the width direction because the steel slab to be welded is wide. It is an arrayed structure, and there may be a case where defective welding occurs at the joint portion of the torch unit (see, for example, Patent Document 1). This defective cutting occurs due to non-uniform supply of the oxygen gas for cutting at the joint portion of the torch unit, and has a cross-sectional shape protruding in a mountain shape from the surrounding portion. In the present invention, this poorly-cut portion is referred to as “mountain protrusion” because of its cross-sectional shape. These ridges may also fall down during hot rolling, and may cause scale-like surface defects in the rolled steel sheet product.

  Therefore, when the entire surface of a steel slab is cut using a hot scurfer or cold scurfer, the surface of the slab is inspected after the entire surface of the slab is welded. Using another grinding device such as a grinder, the remaining surface flaws such as objects, uncut parts, and ridged parts (collectively referred to as “surface defect parts”) The removal is generally performed (see, for example, Patent Document 2). In the present invention, this surface cleaning method using the grinding apparatus is referred to as “partial maintenance” in order to distinguish it from “entire surface cleaning” by means of hot cutting.

  In this case, based on the result of steel slab surface inspection after cutting, the surface defect part is partially cleaned using a grinding device such as a grinder, but the result of the steel slab surface inspection is applied to the grinding device for performing partial cleaning. In general, a grinding apparatus that performs input and performs partial maintenance automatically discriminates and grinds a surface defect portion to be ground based on input data. The method of inputting the inspection result of the surface of the steel slab into the grinding machine is to shoot the steel slab with surface defects marked with paint etc. with a camera, process the captured image into electronic data, and grind the processed electronic data. (For example, refer to Patent Document 3), the surface of the steel slab is displayed in two dimensions of the X axis and the Y axis, and the surface defect portion is displayed on the two dimensional coordinate axis. A manual input method is used.

JP 2005-52867 A JP-A-8-90226 JP 7-290353 A

  After grasping the surface defect part by the surface inspection of the steel piece after the cutting process in the welding equipment, for example, the surface defect part is displayed on a two-dimensional coordinate axis composed of the X axis and the Y axis, and the position is ground. In the case of manual input, the accuracy of input data is extremely important, and input mistakes and omissions are directly related to poor maintenance, that is, poor quality. In addition, there is a problem that a lot of time is spent on the input work itself and the maintenance time is prolonged. In particular, the surface defect portion due to the mountain-shaped protrusion has a large area, which causes a long time for input work for specifying the position. Also, when photographing the surface of a steel slab with a camera, it is necessary to display a surface defect portion due to a mountain-shaped projection by marking or the like, and this also causes a delay in the surface maintenance work of the steel slab.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to grasp the surface defect site by the surface inspection of the steel slab after the cutting process in the welding equipment, and then identify the recognized surface defect site. When cleaning the steel slab surface by removing it by partial maintenance with a grinding device, the surface defect site due to the chevron can be reliably detected without inputting the surface defect site due to the chevron that occurs during the cutting process to the grinding machine. It is an object of the present invention to provide a method for cleaning the surface of a steel slab, which can be removed at the same time, and as a result, can speed up the surface cleaning work of the steel slab.

The gist of the present invention for solving the above problems is as follows.
(1) The surface of the steel slab is hot-cut by a hot scurfer or cold scurfer, and then the surface flaws remaining on the surface of the steel slab after the hot-scraping, uncut parts, and ridges generated at the time of the hot-scraping In a surface treatment method for a steel slab where the surface is removed from the surface of the steel slab by grinding the part with a grinding device, a ridge-shaped projection based on the mechanical dimensions of the hot or cold scurfer and the latest past cutting results The generation position of the estimated ridges was automatically input to the grinding device before grinding the steel slab by the grinding device, and was grasped by surface inspection of the steel slab after cutting The surface flaws remaining on the surface of the steel slab and the occurrence positions of the uncut parts are input to the grinding device before grinding the steel slab by the grinding device. Protrusion Characterized by ground by automatic operation of each the grinding apparatus occurrence point, surface care method of billet.

  According to the present invention, by utilizing the fact that the position of occurrence of the ridge-shaped projections after the cutting in the welding equipment can be specified by the machine dimensions of the welding equipment and the characteristic (癖) specific to the welding equipment, Since the position of occurrence of the ridge-shaped protrusion is estimated and the estimated position of the ridge-shaped protrusion is automatically input in advance to a grinding device for grinding and removing this ridge-shaped protrusion, the operator inputs the position where the ridge-shaped protrusion is generated. Mistakes and missing input are prevented in advance, and it is possible to reliably remove the ridges by grinding. In addition, this greatly reduces the number of input data, and also eliminates the need for marking on the surface of the steel slab at the surface defect portion due to the ridge-like projections, greatly speeding up the surface maintenance of the steel slab. .

It is a plane schematic diagram of the care line of a steel piece. It is the schematic which shows the positional relationship of a cold scarfer and a steel piece. It is a figure which contrasts and shows the cross-sectional shape of the steel piece by which it was cut, and the arrangement position of a torch unit. It is the schematic of the generation | occurrence | production position of the mountain-shaped protrusion in the long side surface of the steel pieces from which a shape differs.

  Hereinafter, the present invention will be described in detail.

  As a method for removing surface defects from the surface of a steel slab, first, the entire surface of the steel slab is subjected to hot cutting with a hot scurfer or cold scurfer, and then the surface inspection of the slab surface of the steel slab (inspection using equipment and Visual inspection) and grasped by this surface inspection, surface defects such as cracks and non-metallic inclusions remaining on the surface of the steel slab after cutting, uncut parts on the surface of the steel slab, and ridges generated during welding Each occurrence position of the surface defect portion of the protrusion is input to the control unit of the grinding device, and the grinding device automatically identifies and repairs the surface defect portion to be ground based on the input data. A method of grinding and removing is performed.

  In the method for removing the surface defect of the steel slab thus performed, the mountain-shaped protrusions are generated almost constantly and the generation area is large, so that the marking operation or the mountain-shaped display for indicating the position where the mountain-shaped protrusions are generated The operation of manually inputting the protrusion generation position into the control unit of the grinding apparatus using the two-dimensional coordinates of the steel slab surface indicated by the X-axis and the Y-axis is a cause of delaying the surface maintenance work of the steel slab. . Therefore, the present inventors mark the occurrence position of the ridge-shaped projections every time the surface inspection of each steel slab, or manually input the two-dimensional coordinates of the steel slab surface indicated by the X axis and the Y axis. Considered to omit the work to do.

  From this point of view, the structure of the scarf machine installed in the steel piece maintenance line shown in FIG. 1 was observed. FIG. 1 is a schematic plan view of a billet care line. In FIG. 1, reference numeral 1 is a cold kerfur, 2 is a grinding device, 3 is a grinder installed in the grinding device 2, 4 is a billet. The roller table for conveyance for conveying to the cold scarfer 1, 5 is the roller table for inspection for performing the surface inspection of the steel piece, 6 is the roller table for grinding for conveying the steel piece to be ground, 7 Is a billet. In FIG. 1, the steel slab 7 moves from the right side to the left side of the paper surface, and is subjected to a thermal cutting process (entire care) by the cold scarfer 1, a surface inspection by the inspection roller table 5, and a surface grinding (partial maintenance) by the grinding device 2. ) Is performed. Note that the grinder 3 is movable in the width direction of the steel slab 7 in the grinding device 2 and configured to grind any part of the steel slab 7. Moreover, in each roller table 4, 5, 6, the roll is not shown and is omitted.

  A schematic diagram of the positional relationship between the cold scurfer 1 and the steel piece 7 is shown in FIG. FIG. 2 is a schematic view taken along the line XX ′ in FIG. 1, that is, a schematic view seen from the longitudinal direction of the steel slab 7. A plurality of torch units 8 each having a frame 9 and a lower back frame 10 and having a width W (= 270 mm) on the back frames 9 and 10 (four on each side in FIG. 2 up to a width of 1050 mm) Corresponding to slab steel slabs). The upper surface side of the steel slab 7 is preheated by the preheating gas injected from the torch unit 8 disposed on the back frame 9 and is also cut by the oxygen gas for cutting injected from the torch unit 8. The lower surface side of the steel slab 7 is cut by the preheating gas and the oxygen gas for cutting that are injected from the torch unit 8 arranged at 10.

In FIG. 2, W ₀ is the lateral width of the slab-shaped steel piece 7. The cold scurfer 1 is a type in which the upper surface and the lower surface of the steel slab 7 are simultaneously welded. The torch unit 8 is disposed only on the back frame 9 on the upper surface side, and only one surface of the steel slab 7 is welded. The model to be used may be used. In this case, the steel piece 7 after the cutting is reversed, and the uncut surface is separately cut.

  FIG. 3 shows the cross-sectional shape of the steel piece 7 cut by the cold kerfur 1 and the arrangement position of the torch unit 8 of the cold kerfur 1 in comparison with each other. Reference numeral 11 in FIG. 3 is a mountain-shaped protrusion generated at the time of cutting. The ridge-shaped protrusions 11 have a maximum height of about 3.0 mm and a maximum width of about 5 mm. As shown in FIG. 3, it has been found that the mountain-shaped protrusion 11 is generated at the joint portion of the torch unit 8. In addition, it has been found that the mountain-shaped protrusions 11 are greatly influenced by the “mechanical wrinkles” of the cold scarf 1, and the generation of the mountain-shaped protrusions 11 is very reproducible. In other words, the generation position of the mountain-shaped protrusions 11 having a height and width that must be ground is determined unless the position of the torch unit 8 (position in the height direction and the lateral direction) is corrected, or the torch unit 8 itself. It has been found that unless it is replaced, it occurs at a specific location on the surface of the billet. In FIG. 3, the heights and widths of the respective mountain-shaped protrusions 11 are displayed equally, but actually the heights and widths are different at the respective positions.

  Normally, one side of the short side surface of the steel slab 7 (the short side surface on the left side of the steel slab 7 in FIGS. 2 and 3) is the reference position of the cold kerfur 1 (the torch unit 8 on the left side in FIGS. 2 and 3). Therefore, the position where the ridge-shaped protrusions 11 are generated can be specified. That is, since the width W of the torch unit 8 is 270 mm, it can be specified in FIG. 3 that the protrusions 11 are generated at intervals of 270 mm from the left end portion toward the steel piece 7. Among the mountain-shaped protrusions 11, the mountain-shaped protrusions 11 having a height and a width that need to be ground are grasped in the past surface inspection on the inspection roller table 5 performed before the cutting process. Thus, each time the individual steel pieces 7 are cut off, the ridges 11 to be ground can be identified without inspecting the ridges 11 to be ground by the grinding device 2. Here, as described above, the past surface inspection is performed immediately after correction of the arrangement position of the torch unit 8 or replacement of the torch unit 8 itself because the occurrence of the mountain-shaped projections 11 is very reproducible. However, it is preferable to perform a surface inspection of the steel slab 7 every week or every day and make a determination based on the result.

  Then, by automatically inputting the position of the mountain-shaped protrusion 11 specified to be ground to the control unit of the grinding apparatus 2, the position of the mountain-shaped protrusion 11 specified to be ground is marked, or the grinding apparatus It is not necessary to manually input to the second control unit. Among the surface defect portions of the steel slab 7 after the cutting, the remaining surface flaws and the generation positions of the uncut parts are different every time the individual steel slab 7 is cut. The position is grasped by the surface inspection, and marking for specifying the position and input to the control unit of the grinding apparatus 2 are performed each time.

  The present invention has been made on the basis of the above findings, and the method of surface treatment of a steel slab according to the present invention is based on the machine dimensions of a hot scurfer or cold scurfer and the latest past cutting results. Estimate the occurrence position of protrusions, and automatically input the estimated generation position of mountain-shaped protrusions to the grinding device before grinding it with the grinding device and grasp it by surface inspection of the steel slab after cutting The surface flaws remaining on the steel slab surface and the occurrence positions of the uncut parts are input to the grinding device before grinding the steel slab by the grinding device, and the input surface flaws, uncut parts and Each occurrence portion of the mountain-shaped protrusions is ground by automatic operation of the grinding apparatus.

  In FIG. 4, the schematic of the generating position of the mountain-shaped protrusion 11 in the long side surface of the steel piece 7 from which a shape differs is shown. FIG. 4A is a view showing the generation position of the mountain-shaped protrusion 11 in the normal steel piece having the same slab width at both ends of the steel piece 7, and FIG. FIG. 4 (C) is a diagram showing the position where the ridge-like protrusions 11 are generated when a taper steel slab having different slab widths is subjected to a thermal cutting process from a narrower slab width. FIG. 4 (C) shows the slab widths at both ends of the steel slab 7. It is a figure which shows the generation | occurrence | production position of the mountain-shaped protrusion 11 when a different taper steel slab is heat-cut from the one where a slab width is wide. In any case, the mountain-shaped protrusion 11 is generated at every interval of the width W of the torch unit 8.

  As described above, according to the present invention, the position of the ridge-shaped protrusion 11 after the cutting can be specified by the machine dimension of the cutting equipment and the characteristics unique to the cutting equipment. The generation position is estimated, and the estimated generation position of the mountain-shaped protrusion 11 is automatically input in advance to the control unit of the grinding device 2 for grinding and removing the mountain-shaped protrusion 11. Thus, it is possible to prevent an input error or an input omission at the occurrence point of the occurrence, and to reliably remove the mountain-shaped protrusion 11 by grinding. In addition, this greatly reduces the number of input data and further eliminates the need for marking on the surface of the steel slab for the ridge-like protrusions 11, thereby greatly speeding up the surface maintenance work of the steel slab 7.

  In the above description, the cutting equipment is the cold scurfer 1, but the present invention can be applied along the above even if the cutting equipment is a hot scurfer. By the way, by applying the present invention, it has been confirmed that the time spent on the surface maintenance of the steel slab 7 can be shortened for 5 minutes per steel slab, and a significant productivity improvement is realized.

DESCRIPTION OF SYMBOLS 1 Cold scarfer 2 Grinding device 3 Grinder 4 Roller table for conveyance 5 Roller table for inspection 6 Roller table for grinding 7 Steel piece 8 Torch unit 9 Back frame 10 Back frame 11 Mountain protrusion

Claims (1)

  The surface of the steel slab is cut by hot or cold scurfers, and then the surface flaws remaining on the surface of the steel slab after cutting, the uncut parts, and the ridges generated during the cutting are ground. In the method of surface treatment of the steel slab, where surface defects are removed from the surface of the steel slab by grinding with an apparatus, the position where the ridges are generated based on the machine dimensions of the hot or cold scurfer and the latest past cutting results The steel slab was automatically input into the grinding device before grinding the steel slab by the grinding device, and the surface position of the steel slab after the welding was grasped. Each occurrence position of surface flaws and uncut parts remaining on the surface is input to the grinding device before grinding the steel slab by the grinding device, and the input surface flaws, uncut parts and chevron projections are input. That Characterized by grinding the automatic operation of the record the grinding apparatus occurrence location, surface care method of billet.

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