JP5316235B2 - Welding method and apparatus - Google Patents

Description

  The present invention relates to a cutting method and a cutting apparatus for removing a surface defect of a steel piece after continuous casting by melting.

  If rolling is performed with defects present on the surface of the steel slab after continuous casting, there may be product defects after rolling. For this reason, after preheating the surface of the steel slab with combustion gas, the scarfing that blows off the surface defects formed on the steel slab surface layer by spraying oxygen jet and utilizing the oxidation exothermic reaction of iron-oxygen is performed. Done.

  3 (A) to 3 (C) are cross-sectional views for explaining a method of cutting a steel piece using a conventional scarfing device. FIG. 4 shows a state (hereinafter, referred to as “cutting fins”) where the cutting noble (melted metal or slag) generated by scarfing is attached to the side surface of the steel piece after the cutting shown in FIG. 3 (C) is completed. FIG. In addition, a scarfing apparatus (not shown) blows combustible gas and oxygen gas on a steel piece from a crater, and melts a steel piece surface.

  FIG. 3 (A) shows the steel piece 1 before the cutting. By blowing flammable gas and oxygen gas onto the upper surface 7b of the steel piece 1 from the crater of the scarfing device, the surface of the steel piece 1 is melted as shown in FIG. Generate. After this, the steel piece 1 is moved toward the scarfing device to continuously perform the cutting of the steel piece surface. At this time, high pressure water (not shown) is sprayed from the upper side surface of the steel slab 1 to blow off the generated cuttings on the upper surface 7 b of the steel slab 1. However, a part of the cutting blade is dripped and fused to the side surface of the steel piece as shown in FIG. If rolling is performed with the stencil 11 generated, it becomes a product defect. Therefore, it is necessary to remove it manually as a secondary maintenance.

  As a method for solving this problem, in Patent Document 1, a high-pressure water nozzle is disposed toward the side surface of the steel material, and the high-pressure water is jetted toward the scarfing sag (melting fin) generated on the side surface. A method for removing shavings is disclosed.

JP-A-62-101378 (right column on page 1)

  However, once the cutting swarf sticks to the side of the steel slab, it becomes difficult to completely remove even if high-pressure water is sprayed, and it is necessary to remove the scouring fin by performing a secondary maintenance procedure. It was.

  Then, this invention makes it a subject to provide the welding method and the welding apparatus which can suppress generation | occurrence | production of a welding fin when scarfing a steel piece.

The present inventors have observed and investigated in detail how the welding scrap generated during scarfing adheres to the side of the steel piece, and does not remove the welding scrap attached once, Various studies were conducted from the viewpoint of preventing the steel piece from adhering to the side surface of the steel piece, and the present invention was completed.
That is, according to one aspect of the present invention , a lubricating oil having a flash point of 200 ° C. or higher is sprayed or applied to the upper end portion of the side surface of the steel slab, and the upper surface of the steel slab is melted and cut by a scarfing device. It is a welding method characterized by spraying high-pressure water onto a cutting blade and removing it from the side surface of the steel piece.

Also, in the scarfing method according to an embodiment of the present invention, the upper end of spraying or applying the lubricating oil can also be a moiety that includes a range of from the top to 30mm at the side surface of the steel strip .

In the method of cutting according to one aspect of the present invention, the amount of the lubricating oil sprayed or applied is preferably at least 0.02 ml / cm ² .

One aspect of the present invention includes a transport roll for transporting a steel slab, a nozzle for spraying lubricating oil having a flash point of 200 ° C. or more on the upper end of the side surface of the steel slab transported by the transport roll, and the nozzle a source for supplying oil to the lubricating oil is sprayed by the nozzle to the upper end of the side surface of the steel strip, a scarfing apparatus for scarfing the upper surface of the steel strip being conveyed by the conveying rolls to produce A high-pressure water injection nozzle that injects high-pressure water onto the cutting surface and removes it from the side surface of the steel slab.

  By applying one embodiment of the present invention, the occurrence of filing fins can be suppressed even if the steel piece is scarfed, and secondary care of the steel piece becomes unnecessary.

It is a schematic diagram for demonstrating the welding method by embodiment of this invention. (A)-(C) are sectional drawings which cut | disconnected the steel piece part which each arrow A-C shown in FIG. 1 points out. (A)-(C) are sectional drawings for demonstrating the method of cutting a steel piece using the conventional scarfing apparatus. FIG. 4 is a perspective view showing a steel slab in which a cutting fin is generated after the cutting shown in FIG. 3 (C) is completed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

  FIG. 1 is a schematic diagram for explaining a cutting apparatus according to an embodiment of the present invention. 2A is a cross-sectional view of a steel piece at a portion indicated by an arrow A shown in FIG. 1, and FIG. 2B is a cross-sectional view at a portion of a steel piece indicated by an arrow B shown in FIG. FIG. 2C is a cross-sectional view of a steel piece at a portion indicated by an arrow C shown in FIG. 2A illustrates the pre-processing, FIG. 2B illustrates the state of the welding start, and FIG. 2C illustrates the state of the completion of the cutting. Explain.

  1 has a transport roll 2 that is rotated by a drive mechanism (not shown). This conveyance roll 2 conveys the steel piece (slab) mounted on it in the direction of the arrow 5 by rotating the conveyance roll 2. A scarfing device 3 is disposed above the transport roll 2. Further, a lubricating oil spray nozzle 4 is disposed above the transport roll 2, and the lubricating oil spray nozzle 4 is connected to a lubricating oil supply source (not shown). The lubricating oil spray nozzle 4 is a nozzle for spraying lubricating oil on the side surface of the steel slab 1 and on the non-machined side surface 7a. The lubricant spray nozzle 4 is located upstream of the scarfing device 3 in the direction of travel of the steel piece 1. Moreover, the welding apparatus has a high-pressure water injection nozzle (not shown).

  A method of cutting the steel slab 1 using the above-described cutting apparatus will be described.

The steel slab 1 is placed on the transport roll 2, and the steel slab 1 transported by the transport roll 2 is pretreated. That is, the lubricating oil 4a having a flash point of 200 ° C. or higher is sprayed on the upper end portion of the side surface 7a of the steel piece 1 with a spraying amount of 0.02 ml / cm ² or more. As a result, a lubricating oil film 4b having a thickness of about 0.2 mm is formed on the upper end of the side surface 7a of the steel piece 1. The steel piece 1 at this time is in the state shown in FIG.

In addition, it is preferable that the upper end part of the side surface 7a of the steel piece 1 in which the lubricating oil film 4b is formed is a part including the range from the upper surface 7b in the side surface 7a of the steel piece 1 to at least 30 mm, and the range exceeding 30 mm It may be a part including That is, the lubricating oil film 4b is preferably formed in a strip shape having a width of 30 mm or more along the upper surface 7b of the side surface 7a of the steel piece 1. Moreover, in this embodiment, although the lubricating oil 4a is sprayed on the upper end part of the side surface 7a of the steel piece 1 by the lubricating oil spraying nozzle 4, it is not limited to the method by a spraying nozzle, It lubricates by another method. It is also possible to spray or apply oil 4a.
Further, as the lubricating oil 4a, for example, mineral oils such as motor oil and cutting oil, vegetable oils such as olive oil and rapeseed oil, and waste oils thereof can be used.

  Next, flammable gas is ejected from the flammable gas ejection holes of the scarfing device 3, and oxygen gas is ejected from the oxygen gas ejection holes for cutting and the preheating oxygen gas ejection holes to ignite to form a heating flame. After sufficiently heating the steel slab 1, the pressure of the oxygen gas ejected from the oxygen gas ejection hole for cutting is increased to start the cutting. As the combustible gas, CO gas, natural gas, propane gas, or the like can be used.

  Next, when the melted noro (mainly iron oxide) 1a is generated on the upper surface 7b of the steel piece 1 and the cutting is confirmed (corresponding to the state shown in FIG. 2B), the scarfing device 3 is fixed. The steel slab 1 is moved by the transport roll 2 in a direction opposite to the gas ejected from the scarfing device 3 at a predetermined speed, that is, in the direction of the arrow 5 shown in FIG. Sharpen. This corresponds to the state shown in FIG.

  That is, as shown in FIG. 1, the upper surface 7 b of the steel piece 1 is scraped by the scarfing device 3 while the lubricating oil 4 a is applied to the upper end portion of the side surface 7 a of the steel piece 1 by the lubricating oil application nozzle 4. At that time, in order to prevent the cutting from being hindered by depositing the cutting scrap 1a generated by melting the steel piece 1 on the upper surface 7b of the steel piece 1, it is injected from a high pressure water injection nozzle (not shown). The high-pressure water is removed in a direction perpendicular to the traveling direction 5 of the steel slab 1. As shown in FIG. 2 (B), even if the cutting edge 1a generated on the upper surface 7b of the steel slab 1 hangs down on the side surface 7a of the steel slab 1 as shown by the arrow 6, the lubricating oil film 4b remains. It acts as an interference material, and can prevent the cutting surface from adhering to the side surface 7a of the steel slab 1 due to the lubricating oil film 4b and forming a cutting fin. As a result, as shown in FIG. 2 (C), the steel slab 1 after completion of the cutting, in which the cutting fins are not attached to the upper corner portion 7 of the side surface 7a, can be obtained. This eliminates the need for secondary maintenance work as in the prior art, eliminates equipment for secondary maintenance, and makes the equipment more compact.

  The flash point of the lubricating oil 4A used in the present embodiment is preferably 200 ° C. or higher. The reason why the lubricating oil 4a having a flash point of 200 ° C. or higher is used is that when a lubricating oil having a flash point of less than 200 ° C. is used, the lubricating oil is ignited by the heat of the lathe cutting laver 1a and obstructs the adhesion of the lathe. This is because there is a case where the effect to be obtained cannot be obtained sufficiently. In other words, if the lubricating oil has a flash point of 200 ° C. or higher, there is no fear of ignition with respect to the sensible heat of the cutting edge la.

  Moreover, it is preferable that the range which sprays lubricating oil and forms the lubricating oil film 4b is a part including the range from the upper surface 7b in the side surface 7a of the steel slab 1 to at least 30 mm. The reason why the lubricating oil film 4b is formed in this range is that there is a possibility that the cutting nodule adheres to this portion, resulting in a hot cutting fin. In other words, if the lubricating oil film 4b is formed in a portion including a range up to at least 30 mm, it is possible to suppress the adhesion of the cutting surface to the side surface 7a of the steel piece 1.

Moreover, it is preferable that the spraying amount of lubricating oil shall be 0.02 ml / cm < ² > or more. The reason is that the film thickness of the lubricating oil film 4 is about 0.2 mm, and the lubricating oil film 4 having a film thickness of 0.2 mm (that is, a film thickness of 0.2 mm or more) is formed even if it is thin. This is because the effect of inhibiting the adhesion of the welding fins can be sufficiently exhibited.

  In the present embodiment, the lubricating oil 4a is sprayed by the lubricating oil spray nozzle 4 on the side surface located parallel to the cutting direction of the steel slab 1, but perpendicular to the cutting direction of the steel slab 1. Lubricating oil may be sprayed on the rear side surface located on the side surface or on the side surface located parallel to the direction of the cutting of the steel piece 1 together with the rear side surface.

  In this embodiment, the upper surface 7b of the steel piece 1 is cut by the scarfing device 3 while the lubricating oil 4a is applied to the upper end portion of the non-cut-cut side surface 7a of the steel piece 1 by the lubricating oil application nozzle 4. However, the surface to be cut by the scarfing device may be changed as follows. For example, the upper surface and one of the side surfaces of the steel slab 1 may be cut by a scarfing device, and lubricating oil may be sprayed on the upper end of the other side of the non-machined surface, or the upper surface of the steel slab 1 may be scarfed. Lubrication oil may be sprayed on the upper end portions of both side surfaces of both sides that are not cut by the apparatus. Also, lubricating oil may be sprayed on the rear side surface located perpendicular to the direction of cutting of the steel slab 1, and the upper surface, the lower surface, and both side surfaces of the steel slab 1 may be subjected to welding with a scarfing device. The upper surface and both side surfaces of 1 may be scraped by a scarfing device.

DESCRIPTION OF SYMBOLS 1 Steel slab 1a Welding machine 2 Conveying roll 3 Scarfing device 4 Lubricating oil spray nozzle 4a Lubricating oil 4b Lubricating oil film 5 Arrow of a steel piece advancing direction 6 Arrow 7 Upper corner part 7a Side surface of a steel piece 7b Upper surface 11 of a steel piece Welding fins

Claims (4)

Spread or apply a lubricating oil having a flash point of 200 ° C. or higher to the upper end of the side surface of the steel slab,
A method of cutting , wherein an upper surface of the steel slab is cut by a scarfing device, and high pressure water is sprayed onto the generated cutting blade to remove it from the side of the steel slab. 2. The cutting method according to claim 1, wherein the upper end portion to which the lubricating oil is sprayed or applied is a portion including a range of 30 mm from the upper surface on the side surface of the steel piece. In scarfing method according to claim 1 or 2, the amount of spraying or applying the lubricant, scarfing wherein the at least 0.02 ml / cm ^2. A transport roll for transporting a steel piece;
A nozzle for spraying a lubricating oil having a flash point of 200 ° C. or more on the upper end of the side surface of the steel piece conveyed by the conveyance roll;
A supply for supplying oil to the nozzle;
Lubricating oil is sprayed by the nozzle on the upper end of the side surface of the steel slab, and a scarfing device that scrapes the upper surface of the steel slab conveyed by the conveying roll;
A high-pressure water injection nozzle that injects high-pressure water into the generated cutting blade and removes it from the steel piece side surface;
A fusing device characterized by comprising:

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