JP2010269370A - Fusion-cutting method of plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mitigate descaling operation during gas fusion cutting by suppressing generation of Fe<SB>3</SB>0<SB>4</SB>scale or Fe<SB>2</SB>0<SB>3</SB>scale having high viscosity and bad peelability and by preventing oxidation of FeO scale having superior flowability and peelability. <P>SOLUTION: A plate is fusion-cut by using a fusion cutting nozzle whose outer cylinder is covered with a water cooled cylinder and by using a fusion-cutting gas in which vaporized flux is mixed in fuel gas. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to the prevention of adhesion of deposits called scales or dross (burrs, noro, etc.) generated when gas cutting of thick plates such as ordinary steel and special steel or gas cutting of slabs manufactured by continuous casting. In particular, the present invention relates to a fusing nozzle structure and a method of using the fusing nozzle.

The gas fusing method involves fusing slabs such as slabs that are produced by continuous casting with thick steel plates such as ordinary steel and special steel by oxidative reaction of fuel gas such as acetylene (C2H2) and propane (C3H6) with oxygen. It is utilized for such as. The gas fusing method has advantages such as fast fusing speed, efficiency, simple equipment, and low running cost. However, the biggest disadvantage of the gas fusing method is that scales or dross generated by oxidation reaction with the fusing molten iron adhere to and grow on the lower surface of the material to be cut. Such deposits are called scales or dross (burrs, noro, etc.), and removal of these deposits after fusing is a heavy labor. Hereinafter, the non-attachment is called a scale. In addition, since the slab produced by continuous casting has surface defects, the part of the defects is removed by scarfing with fuel gas and oxygen, but there is a problem that the scale reattaches to the slab surface after the removal. . The scale removal work in the conventional gas fusing work often relies on human naval tactics, and the actual situation is that a human is riding on steel with residual heat after fusing and the fusing part is maintained with a hand grinder. Yes, it's hot, dirty and hard 3K work. In steel cutting manufacturers, processes such as material removal, deployment, and fusing are computerized by NC conversion of the fusing machine, and even unskilled personnel can respond with short-term education and training, but depending on the conditions of steel type and thickness At the same time, it has not yet been possible to automate the fusing operation so that the scale does not adhere by changing the pressure, flow rate, fusing speed and fusing preheating temperature of fuel gas and oxygen. Furthermore, the automation of scale removal work has been delayed, and robotization is difficult due to differences in steel types and fusing shapes. Therefore, conventionally, various fusing methods have been proposed in which the scale does not adhere in the fusing work of the thick plate material. For example, in Japanese Laid-Open Patent Publication No. 1-133675, as a high-speed gas fusing method, a preheating mixed gas is supplied from a double concentric annular arrangement of preheating flame jet nozzles that are disposed so as to surround a fusing oxygen jet port at a shaft portion of a gas fusing crater. There has been proposed a method of injecting water. Further, in Japanese Patent Application Laid-Open No. 2003-112239, an air jet that is jetted from a nozzle to a burr generation / adherence portion caused by melting of a slab when a slab formed by a vertical caster is melted by a flame from a gas cutter torch. There has been proposed a method of removing burrs by causing a slanting collision from above. Furthermore, in Japanese Laid-Open Patent Publication No. 2000-176737, a throttling portion comprising a concave conical surface and a convex conical surface that provides a fusing oxygen flow path at the axial center of the fusing nozzle and generates a Coanda spiral flow at the tip of the fusing oxygen flow path. A fusing nozzle in which is fixedly formed has been proposed.

The inventor vaporizes the liquid flux and mixes it in the fusing gas, thereby cleaning the surface of the thick plate material and controlling the fluidity and melting point of the scale generated at the time of fusing so as not to be welded to the fusing material. Invented method, Japanese Patent Application No. 2007-287820 (vaporization flux for gas fusing) and Japanese Patent Application No. 2008-104825 (liquid flux vaporizer) and Japanese Patent Application No. 2008-178420 (method and apparatus for producing liquid flux) ) And Japanese Patent Application No. 2008-270435 (Liquid Flux and its Manufacturing Method and Manufacturing Device), the manufacturing method of the liquid flux, the liquid flux, the vaporizing device of the liquid flux, etc. were embodied. And in Japanese Patent Application No. 2007-335790 (melting nozzle for metal bodies), the primary side auxiliary combustion gas and the secondary side auxiliary combustion gas are swirled to generate a high-speed and powerful flame to increase the cutting speed of the thick plate material. A fusing nozzle (a fusing nozzle for metal bodies) that can prevent the scale from adhering to the thick plate material has been realized. When the liquid flux was vaporized by the fusing nozzle and the thick plate material was fusing with a fusing gas mixed with a combustible gas such as propane or acetylene, the adhesion of the scale could be greatly reduced.

JP-A-1-133675 JP 2003-112239 A JP 2000-176737 A Japanese Patent Application No. 2007-335790 Japanese Patent Application No. 2007-287820 Japanese Patent Application No. 2008-104825 Japanese Patent Application No. 2008-178420 Japanese Patent Application No. 2008-270435

In the method of Patent Document 1, since the fuel gas such as propane and acetylene and the oxygen pressure are increased and melted, (1) the risk of gas leakage and explosion increases, (2) the pressure of the combustible gas and oxygen is increased. Although it is possible to blow up the high-temperature scale, the pressure of the fuel gas and oxygen increases as the material to be melted increases, and the viscosity of iron oxide (FeO, Fe2O3, Fe2O4) increases as the oxygen pressure increases. As a result, the flowability of the fusing scale is reduced and the fracturing scale is liable to adhere to the molten cross section. As the amount of oxygen used increases, the basic unit of the thick plate material decreases, (4) the surface roughness of the melted surface decreases, and (5) the fusing scale is firmly gas-welded to the lower surface of the thick plate. Take time to remove the work because it wears, (6) Since the blowing nozzle is large radiant heat from the blown material is easily heated enter the nozzle body, there are problems such as flashback or explosion.

In the method of Patent Document 2, high-viscosity iron oxide (FeO, Fe2O3, Fe2O4) contained in the fusing scale is formed not only on the lower surface of the material to be melted but also on the upper surface, and generally the upper surface is steel shot. Alternatively, it was removed by the sand shot method, and the lower surface was removed by a mechanical chipping machine, but complete removal was impossible.

In the method of Patent Document 3, (1) the specific structure of the constricted portion composed of the concave conical surface and the convex conical surface is not specified, (2) the quantification that reduces the fusing width, raises the fusing temperature, and increases the fusing rate. There are problems such as unknown effects.

In the method of Patent Document 4, the secondary air was forcibly sucked from the ejector, and the fusing flame was forcibly cooled, thereby reducing the heat generated by the pinch effect and the flame, thereby increasing the length of the flame. However, when the high temperature slab is melted, Fe3O4 and Fe2O3 in the scale increase, the fluidity of the scale decreases and the scale becomes harder and the adhesion strength of the scale increases, making it difficult to remove the scale. In order to solve this problem, Japanese Patent Application No. 2007-287820 published in Japanese Patent Application No. 2007-287820 (vaporization flux for gas fusing), Japanese Patent Application No. 2008-104825 published in Japanese Patent Application No. 2008-104825 (liquid flux vaporization apparatus), and Japanese Patent Application No. 2008 issued in Japanese Patent Application No. 2007-287825. -178420 Public Information (Liquid Flux Manufacturing Method and Apparatus) and Patent Document 8 Japanese Patent Application No. 2008-270435 Public Information (Liquid Flux and Manufacturing Method and Apparatus) Even if it was used, a great effect was not obtained. That is, (1) When the tip of the fusing nozzle comes close to 100 mm or less with respect to a high temperature slab of 900 to 1100 ° C., the backfire occurs. (2) By sucking secondary air from the ejector, Fe2O3 (hematite) in the fusing scale As Fe3O4 (magnetite) increases, it has been found that the fusing scale becomes hard. That is, it has been found that when the high temperature slab is melted, the tip of the fusing nozzle and the height of the high temperature slab need to be close to about 10 to 35 mm in the same manner as when the cold material is melted. In addition, when the distance between the liquid flux vaporizer and the fusing nozzle is long, there is a problem that the vaporized flux component in the fusing gas is deposited on the pipe and the nozzle.

The problems to be solved by the present invention based on the above problems are as follows. (1) While suppressing the generation of Fe3O4 scale and Fe2O3 scale with high viscosity and low peelability, FeO scale with good fluidity and high peelability Protects and prevents oxidation by reducing the scale removal work at the time of gas fusing, (2) Drops the scale by its own weight without applying physical external force to the fusing scale, (3) Clean with few irregularities (4) Reduce the pressure of fuel gas and oxygen as much as possible to reduce the fusing width and improve the yield of the material to be melted. (5) High-temperature slab fusing at 900 to 1000 ° C at the fusing nozzle tip. In the same manner as in the cold material fusing, it can be close to about 10 to 15 mm, (6) a thick plate having a thickness of about 1000 mm can be fused, and (7) fuel gas. Provide secure fusing work together to reduce the consumption of oxygen, it is to prevent precipitation of components vaporized flux (8) pipes and the inner surface of the fusing nozzle.

The first solving means is a fusing nozzle in which the outer cylinder of the fusing nozzle is covered with a water-cooled cylinder, and the tip of the water-cooled cylinder is extended from the tip of the fusing nozzle. This is a fusing method in which the shielding property in the hood between the fusing nozzle and the material to be cut is increased to increase the internal pressure to prevent the secondary air from being caught. The length of the fusing flame can be increased by reducing the gas ejected from the periphery of the hood as much as possible and concentrating the gas flow in the direction of the fusing gas. Further, the length of the fusing flame can be secured even if the oxygen pressure is reduced to max 0.6 MPa and the fusing gas pressure is reduced to about max 0.06 MPa.

The second solving means is nozzle fusing in which at least the tip of the inner side surface of the water-cooled cylinder of the fusing nozzle has a divergent shape. Increases the shielding between the fusing nozzle and the material to be cut to increase the internal pressure to prevent the entrainment of secondary air, and widens the tip of the fusing nozzle to rectify the gas flow in the hood and blow out by gas ejection This is a fusing method that prevents gas turbulence.

A third solution is to blow a fuel gas into a vaporizer to vaporize a liquid flux to obtain a vaporized flux, and a gas fusing using a fusing gas in which the vaporized flux and the fuel gas are mixed and a fusing nozzle is used. Is the method.

In general, metal fusing can be performed by narrowing the fusing width or reducing scale adhesion by blowing off the generated scale with high-temperature and high-pressure oxygen at the same time as oxidizing and burning the metal. Narrowing the fusing width and facilitating descaling will lead to a reduction in the basic unit and labor costs, but the important point for that is (1) The temperature at which the metal oxidizes and burns is determined from the melting point of the metal. Lowering, (2) lowering the metal oxide generated by combustion below the melting point temperature of the metal and providing fluidity, and (3) increasing the length of the fusing flame. In order to embody this, (1) using a fusing gas in which vaporized flux is mixed with fuel gas; (2) providing a hood at the tip of the fusing nozzle to prevent outside air from entering, and the fusing gas is to be cut (3) The component of the vaporization flux efficiently reaches the cut surface, and the FeO scale around the fusing flame is changed to Fe3O4 scale. It is to avoid changing to the Fe2O3 scale.

Fusing of general steel materials such as mild steel and carbon steel is performed by burning and oxidizing reaction of oxygen and fuel gas such as propane (C3H6) and acetylene (C2H2) from a fusing nozzle, but it is roughly classified by analyzing the fusing scale. Then, wustite (FeO) is generated on the base material side, magnetite (Fe3O4) is generated in the middle, and hematite (Fe2O3) is generated on the outer side. When steel material at room temperature is fused, the distance between the fusing nozzle and the material to be melted can be set to about 10 to 15 mm. Therefore, the scale becomes easy to remove because FeO is thick and the intermediate Fe3O4 is thinly generated. On the other hand, when fusing a high temperature slab of 900 to 1100 ° C., if the fusing nozzle tip is too close to the high temperature slab, there is a risk of backfire due to radiant heat, so the fusing nozzle tip is set about 100 to 200 mm away from the high temperature slab. There is a need. The combustion state of the fusing gas can be distinguished by the excess oxidation flame, the fuel gas excess flame, the neutral flame, and the color of the center of the flame, but the combustion state is greatly affected by the distance between the fusing nozzle tip and the material to be cut. . For this reason, in gas cutting of a high-temperature slab, the oxygen pressure is set to 0.9 to 1.4 MPa, the cutting gas (fuel gas) pressure is set to 0.1 to 0.2 MPa, oxygen is increased to cause excessive combustion, and the flame length is increased. And was blown out. When oxygen is injected at a high pressure in this way, the phenomenon of entrapping secondary air violently in the melting surface occurs, and the oxidation of FeO is accelerated to change to Fe3O4 or Fe2O3, so the scale changes to a hard and sticky scale. It becomes difficult.

In the conventional gas fusing method, a part of excess oxygen that does not react with the fusing gas invades one after another into the melted section, so it was impossible to keep the scale generated at the time of fusing as FeO. The reasons are as follows: 1) When oxygen is excessive with respect to the cutting gas, oxygen molecules are adsorbed on the melting surface of the material to be cut. 2) Oxygen molecules undergo higher and higher temperature oxidation to generate heat of dissociation when they dissociate into oxygen atoms. 3) Oxygen atoms enter the metal. 4) Because FeO, Fe3O4, and Fe2O3 grow from oxygen that has penetrated the metal as a nucleus, and continuously grow from FeO to Fe3O4 and further from Fe3O4 to Fe2O3 by oxygen atoms that penetrate continuously. .

It has been difficult to reduce Fe3O4 and Fe2O3 even if a fusing gas obtained by mixing a vaporized flux with a fuel gas using a conventional fusing nozzle is used. That is, in order to facilitate removal of the scale after fusing, the oxide scale is brought into the state of FeO by fusing to suppress the suction of secondary air while maintaining an appropriate flame length using a fusing nozzle covered with a water-cooled cylinder. Need to hold.

For this purpose, in the present invention, for example, borate glass (B2O3 + Na + K + P2O5 + Si) is coated on the surface of FeO to prevent oxidation of FeO. Since FeO is soft and has low viscosity, gas fusing is possible because it has good peelability and is difficult to adhere to scale.

A mechanism for generating FeO scale by a fusing method using a fusing gas mixed with a fusing nozzle coated with a water-cooled cylinder and a vaporized flux will be described. In conventional fusing with a fusing gas without vaporization flux, the Fe2O3 scale or Fe3O4 scale adheres to the lower part of the fusing, and the scale grows one after another using this as a nucleus, and the molten iron at the time of fusing is covered with this Fe2O3 scale or Fe3O4 scale. In order to be firmly welded to the fusing material, it took a lot of labor to remove the scale once adhered. Therefore, the present inventor disclosed Japanese Patent Application No. 2007-287820 (vaporization flux for gas cutting) and Japanese Patent Application No. 2008-178420 (manufacturing method and apparatus for liquid flux) and Japanese Patent Application No. 2008-270435. Invented a method of fusing the vaporized flux produced by public relations (liquid flux and its production method and production equipment) with a fusing gas mixed with fuel gas. The melting point temperature of the scale generated at that time is made lower than the melting point temperature of the metal by adding the vaporizing flux component to the metal melting point of the gas melted part. As a result, it is possible to improve the fusing speed and prevent the scale from adhering, and to obtain a clean melted surface without irregularities and scale adhering. The high-temperature fusing flame of the fusing nozzle replaces hydrogen, oxygen, and other components of the vaporization flux with hydrogen in the fusing gas component, which separates hydrogen and oxygen. Produces a oxidative effect. For example, B (boron) changes from 2H3BO3 to 2B (OH) 3 in a high temperature environment. Further, 2B (OH) 3 → B2H6 (diborane) + 3O2. Further, B2H6 + 6H2O + 3O2 → B2H6 + 6H2 + 6O2. The hydrogen or oxygen generated here reacts with, for example, K or Na to change from K + OH → KOH (potassium hydroxide) and Na + OH → NaOH (caustic soda), thereby producing a strong oxidizing action. Boron has atomic number 5 and thus has 3 valence electrons in the L shell, but is stabilized by adding 5 electrons to 8 electrons. Therefore, by taking in 12 hydrogens, it is stabilized as diborane. The water-cooled cylinder provided in the fusing nozzle cuts off the oxygen supply from the outside air, so that it has the effect of suppressing the combustion of B2H6 (diborane), and B2H6 remains and has the effect of protecting the FeO scale. Na, K, etc. penetrate into the generated scale to reinforce the FeO scale secondarily to become borate glass (B2O3 + Na + K + P2O5 + Si), and a borate glass film of about 10 ppm sticks to the FeO scale surface or porous scale. . At this time, strong oxidizing groups such as KOH and NaOH become ions such as K and Na due to high temperatures, so that OH adheres to the successively generated scale side, and it is difficult to produce Fe3O4 and Fe2O3 to protect the FeO scale. . As a result, the scale is mainly composed of FeO, and the scale is soft and easily peeled off, so that the mechanical scale removal work in the subsequent process becomes easy.

Furthermore, the fusing nozzle can be brought close to the material to be cut by coating the fusing nozzle invented in Japanese Patent Application No. 2007-335790 (fusing nozzle for metal bodies) of Patent Document 5 with the water-cooled cylinder of the present invention. Therefore, the cutting width can be reduced and the peeling effect of the scale can be enhanced. The length of the fusing flame can be increased by providing a swirl flow to the oxygen gas or fusing gas by providing a fixed spiral slit channel or a rotating spiral slit channel in the fusing nozzle, and the vaporization flux on the fusing surface Can react with a wide range to produce a FeO scale with good peelability.

The dropping mechanism of the scale generated by gas fusing is classified as follows. A mechanism called blistering causes stress to concentrate where the adhesion is weak, and the film is lifted. Once lifted, the coating breaks due to thermal stress. If it breaks, it loses adhesion and falls off. If this is repeated, a small scale will appear and the scale will have many gaps. In a mechanism called flaking, a crack occurs in the initial film, and then the film in the vicinity projects outward. Flaked coatings are easy to peel off with a light impact. A mechanism called shear cracking is a phenomenon in which a part of the scale is pushed out to cause shear cracking and the scale becomes conical or concave, leading to cracking of the scale, which tends to peel off. The mechanism called rupture is that the coating film generated is stretched and contracted along the base material due to rapid thermal stress in the vicinity of the interface due to the rapid thermal stress near the interface. .

The peeling mechanism of the scale generated at the time of gas fusing is classified into the above four types, but the common thing is that the scale is oxidized by oxygen molecules becoming oxygen atoms and ionic bonds with the scale. When the scale is oxidized, the volume expands and compressive stress is generated. On the contrary, when the volume shrinks, tensile stress is generated. Na, K, Si, B, P, etc. in the vaporized flux enter the ultrafine pinholes and cracks of these scales, thereby bonding the scales. For example, borate glass or the like functions as an adhesive, and adheres to the surface of the FeO film with a thickness of max 10 ppm, so that the progress of oxidation is suppressed and the formation of the Fe3O4 scale or Fe2O3 scale is difficult to occur. Since it stays in the state, it is easy to remove the scale after fusing.

In order to promote the effect of protecting this FeO scale, it is important to increase the shielding between the nozzle tip surrounded by the water-cooled cylinder and the material to be melted, that is, the hood, by covering the fusing nozzle with the water-cooled cylinder. It is. Secondary air entrainment is suppressed by the pressure rise effect in the hood, and the fusing gas efficiently flows along the cut surface to protect the FeO scale, making the FeO scale difficult to oxidize and changing to the Fe3O4 scale or Fe2O3 scale Therefore, the scale mainly composed of FeO is generated. The amount of Na, K, Si, and B, which are components of the vaporizing flux, remains in the melted cross section of the material to be melted at a maximum of 10 ppm or less and is removed after rolling, and there is no problem as a product defect.

One factor that affects the adhesion of the scale is the difference in the thermal expansion coefficient of the oxide film. For example, FeO is 12.2 × E (−6) in the temperature range of 100 to 1000 ° C., Fe 3 O 4 is 16.6E (−6) in the range of 25 to 1000 ° C., and Fe 2 O 3 is 12. 5E (-6) and Fe are 11.7E (-6) at 0-100 degreeC. When the FeO is 100, the difference in the coefficient of thermal expansion between the scales is 136 for Fe3O4 and 102.5 for Fe2O3. Stress is generated between the scale and the metal to be cut due to the difference in thermal expansion, but if the thermal expansion is small, the scale follows the elastic deformation of the material to be cut, but if the thermal expansion increases, the scale Is prone to breakage. Since the adhesion strength between the scale and the material to be cut is proportional to the weight, the adhesion strength varies in the order of FeO <Fe3O4> Fe2O3. Since the adhesion strength of the Fe3O4 scale is maximized, when Fe3O4 is formed on the FeO scale, the FeO scale is pulled by the Fe3O4 scale and is broken off. When Fe3O4 is generated, the Fe3O4 scale drops off one after another, and the molten iron adheres directly to the surface of the material to be cut, and a new scale is generated based on this molten iron. become. Since the FeO scale has the lightest weight and the low adhesion strength, the best method for removing the scale after fusing is to protect the cut surface of the material to be cut by generating a large amount of FeO scale. Since oxygen active elements (Na, K, Si, B, P, Ba, Zn, Ce) and the like are contained in the vaporized flux in an amount of 0.01 to 0.2 mol%, the oxidation rate of the FeO scale is suppressed, so the FeO scale is The adhesion strength of the FeO scale is increased, and oxides such as borate glass in the active element are dispersed and serve as an adhesive, so that the FeO scale protects the molten surface and the fused iron directly into the molten surface. Prevent sticking. Since the FeO scale is easily peeled off, the fused iron, the Fe3O4 scale, or the Fe2O3 scale attached to the FeO scale is easily peeled off from the material to be cut.

In the fourth solution, in the method of fusing gas with the fusing gas or the fusing nozzle, a repeater incorporating permanent magnets at appropriate intervals is installed in the middle of the supply pipe from the vaporizer to the fusing nozzle. This is a gas fusing method.

The common effects of the first and second solving means are as follows: (1) Since it is water-cooled, the tip of the water-cooled cylinder can be close to a high-temperature slab of 900 to 1000 ° C. at a distance of about 10 to 15 mm similar to that of a low-temperature steel (2) Since the tip of the fusing nozzle can be brought close to the same distance as the low-temperature steel even for the high-temperature slab, the oxygen pressure can be reduced to 0.6 MPa, and the fusing gas pressure can be reduced to 0.06-0.2 MPa. (3) Since the fusing nozzle can be protected from high-temperature slabs, it does not backfire. (4) The gap between the fusing nozzle tip and the material to be cut can be covered, so it has a shielding effect against the outside air and the pressure inside the water exceptional cylinder is higher than the outside air. Therefore, the fuel gas is ejected from the lower part of the water-cooled cylinder and the outside air is not sucked in. (5) Since most of the fuel gas ejected from the periphery of the water-cooled cylinder can be discharged along the melt surface in the direction of the blowout flame, Melt length It can be lengthened in the direction.

The effect of the second solving means is that since the water-cooled cylinder has a divergent shape, the fusing gas in the hood is rectified in accordance with the divergent shape, so that the sealing effect in the hood is enhanced and it becomes difficult to suck in the outside air.

The effect of the third solving means will be described. As described in Japanese Patent Application Nos. 2007-287820 and 2008-178420, the FeO scale is prevented from being oxidized by fusing the fuel gas with a vaporized flux, and the Fe3O4 scale and Fe2O3 scale are A fusing method that makes stacking difficult is realized. Furthermore, in the present invention, it is possible to lengthen the fusing flame by coating the fusing nozzle with a water-cooled outer cylinder, and by efficiently reacting the vaporized flux with the melting section, the releasable FeO scale is protected and the viscosity is increased. The removal work of the scale was reduced by suppressing the generation of the Fe3O4 scale and the Fe2O3 scale which are highly difficult to peel off. That is, this effect is born by a fusing method that combines a fusing nozzle coated with a water-cooled cylinder and a fusing gas in which vaporized flux is mixed with fuel gas. (1) The scale generated during fusing is roughly classified as fusing Fe2O3 is formed just outside the flame, and FeO is formed just outside the material to be melted, and Fe3O4 is formed in the middle. By using a fusing gas mixed with vaporized flux and fuel gas, most of the scale is made FeO. (2) Since the majority of the fuel gas ejected from the periphery of the water-cooled cylinder can be discharged along the melt surface in the direction of blowout of the blown flame, the length of the blown flame can be set in the direction of blowout. The reaction efficiency between the vaporized flux and the fuel gas and the high-temperature molten cross section is increased, and the vaporized flux protects the molten cross section and has good peelability. Since kale (FeO) produces, that it can be easily remove scale.

The effect of the fourth solution is that the fusing gas in which the fuel gas and the vaporized flux are mixed can prevent the vaporized flux from being recrystallized in the middle of being sent from the vaporizer to the fusing nozzle and being clogged in the pipe. .

The first and second solving means will be described with reference to FIGS. 1, 2, 3, 4, and 5. FIG. FIG. 1 is a longitudinal sectional view when a water-cooled cylinder 20 is attached to an outer cylinder 11 of a fusing nozzle 10. FIG. 2 is a cross-sectional view when the water-cooled cylinder 20 is attached to the outer cylinder 11 of the fusing nozzle 10. FIG. 3 is a longitudinal sectional view when the inner side surface 22 and the outer side surface 23 of the distal end portion 21 of the water-cooled cylinder 20 are widened toward the end. FIG. 4 is a longitudinal sectional view when the inner side surface 22 of the tip 21 of the water-cooled cylinder 20 is widened toward the end. FIG. 5 is a schematic diagram when the material to be cut 30 is gas-cut by the fusing nozzle 10. The first means is that the outer cylinder 11 of the fusing nozzle 10 is covered with a water-cooled cylinder 20, and the tip 21 of the water-cooled cylinder 20 is extended from the tip 12 of the fusing nozzle 10. 10. The angle θ between the inner surface 23 of the tip 21 of the water-cooled cylinder 20 and the tip of the fusing nozzle is usually around 90 °, but in the range of 60 to 90 ° when the material to be cut is thin or the temperature is low. Appropriate points can be selected. If θ is smaller than 60 °, there is a problem that the gas flow inside the hood 15 is disturbed and becomes a hindrance to the fusing flame and the melted surface becomes rough. The water-cooled cylinder 20 can be attached to the fusing nozzle 10 by a method such as brazing, TIG welding, or bolting. FIG. 1 shows an example in which the bolt 16 is attached. A rib 17 having a long hole 18 is attached to the water-cooled cylinder 20, and the long hole 18 is tightened through a bolt 16 attached to the outer cylinder 11 of the fusing nozzle 10. If the water cooling cylinder 20 is attached with the bolt 16, the dimension H of the front-end | tip part 21 of the water-cooling cylinder 20 and the front-end | tip part 12 of the fusing nozzle 10 can be adjusted. When the dimension H of the tip 21 of the water-cooled cylinder 20 and the tip 12 of the fusing nozzle 10 is determined from the beginning, the cooling effect is great when the water-cooled cylinder 20 and the outer cylinder 11 of the fusing nozzle 10 are joined by brazing. . The dimension H from the front end portion 12 of the fusing nozzle 10 to the front end portion 21 of the water exceptional cylinder 20 is preferably 5 to 20 mm. The distance h from the front end portion 21 of the water-cooled cylinder 20 and the surface of the material to be melted 30 in the case of gas fusing is preferably 5 to 15 mm. Therefore, the distance G between the material to be cut 30 and the tip 12 of the fusing nozzle 10 is 10 to 35 mm. If the distance h between the tip 21 of the water-cooled cylinder 20 and the hot material to be melted 30 is smaller than 5 mm, backfire may occur. Further, when the surface of the material to be cut 30 is not smooth, there is a risk that the tip 21 of the water-cooled cylinder 20 contacts the convex portion of the material to be cut 30 and damages the fusing nozzle 10. Further, if h is too far from 15 mm, the blowing gas is blown out from the periphery of the tip 21 of the water-cooled cylinder 20 so that the length of the fusing flame cannot be increased, or the vaporization flux sufficiently reaches the melting section of the material to be cut. In other words, the protection of the FeO scale 31 is insufficient and the peelability of the scale is reduced. Suitable materials for the water-cooled cylinder 20 are copper, copper alloy, iron, stainless steel, titanium, and the like. The water cooling cylinder 20 has a cooling water flow path 24 through which cooling water flows through a cooling water inlet 25 and a cooling water outlet 26. Since the cooling water flow rate of 6 m / second or more is suitable, the amount of cooling water may be ensured according to the cross-sectional area of the water-cooled cylinder 20. Suitable cooling water is pure water or soft water. FIG. 2 shows a cross section of the fusing nozzle 10 and the water-cooled cylinder 20. An inner tube 13 and an outer tube 14 are incorporated in the outer cylinder 11 of the fusing nozzle 10. The inner pipe 13 includes a rib 13a and a central gas flow path 13b. The outer tube 14 includes a rib 14a. A gas flow path 13 c is formed between the inner tube 13 and the outer tube 14. A gas flow path 14 b is formed between the outer tube 14 and the outer cylinder 11. Various proposals have been made for the selection of the internal structure of the fusing nozzle 10 and the flow paths of the fuel gas and oxygen gas, and the present invention is limited by differences in the internal structure of the fusing nozzle 10 and the flow of the fusing gas and oxygen gas. It is not a thing. In addition, by attaching the water-cooled cylinder 20 of the present invention to the fusing nozzle of Japanese Patent Application No. 2007-335790 (metal fusing nozzle), the swirling gas swirling effect is added and the length of the combustion flame is further increased. Therefore, the FeO scale 31 having good peelability can be generated.

2nd means is the example which made the front-end | tip part 21 of the water-cooled cylinder 20 into the shape which spreads like FIG.3 and FIG.4. The angle θ of the tip 21 is suitably 90 to 160 °. If the angle is larger than 160 °, the outer diameter of the tip end portion 21 is increased and the circumference is expanded, so that the fuel gas is ejected more and the sealing performance is deteriorated. The tip portion 21 of the water-cooled cylinder 20 is widened when the material to be melted 30 is thick or at a high temperature, and the optimum θ is within a range of 90 to 160 ° depending on the combination of the thickness and temperature of the material to be melted 30. Can be selected. 3 shows the outer side surface 22 and the inner side surface 23 of the water-cooled cylinder 20 having a diverging shape, but FIG. 4 shows an example in which only the inner side surface 22 is diverging. FIG. 4 shows an example in which the tip 12 of the fusing nozzle 10 is protected by a receiving seat 24 provided on the inner side surface 22 of the water-cooled cylinder 20. Since the fusing nozzle 10 is exposed to a higher temperature as the fusing nozzle 10 is closer to the material 30 to be cut such as a high-temperature slab, the exposed portion of the metal is preferably protected by the water-cooled cylinder 20 as much as possible. FIG. 5 shows the flow of the fusing gas when fusing with the fusing nozzle 10 to which the water-cooled cylinder 20 is added. By adding the water-cooled cylinder 20, it is possible to suppress the blowing gas from being ejected in the horizontal direction and to guide the flow of the cutting gas in the thickness direction of the material to be cut 30, thereby increasing the length of the fusing flame.

As shown in FIG. 6, the third solution is to blow a fuel gas into the vaporizer 40 to vaporize the liquid flux 50 to obtain a vaporized flux. The fusing gas obtained by mixing the vaporized flux and the fuel gas and the fusing nozzle 10 is a gas fusing method in which fusing is performed using 10. As the vaporizer 40, for example, the vaporizer 40 proposed in Japanese Patent Application No. 2008-104825 (liquid flux vaporizer) can be used. The liquid flux 50 is disclosed in Japanese Patent Application No. 2007-287820 (vaporization flux for gas fusing) and Japanese Patent Application No. 2008-178420 (manufacturing method and apparatus for liquid flux) and Japanese Patent Application No. 2008-270435 (liquid flux and its production). The liquid flux 50 proposed in the method and manufacturing apparatus) can be used.

The scale generated during fusing is roughly classified as shown in FIG. 1. An Fe2O3 scale 33 is formed just outside the fusing flame and an FeO scale 31 is formed just outside the material to be melted 30 as shown in FIG. However, by using a fusing gas in which vaporized flux and fuel gas are mixed, the generation of the Fe2O3 scale 33 and the Fe3O4 scale 32 can be suppressed, and most of the scale can be changed to the FeO scale 31. Sexuality is improved.

As shown in FIG. 7, the fourth solution is a method in which gas is blown by the fusing gas and the fusing nozzle 10 as shown in FIG. 7. Permanent magnets are provided at appropriate intervals in the middle of the supply pipe 60 from the vaporizer 40 to the fusing nozzle 10. This is a gas fusing method in which a repeater 70 incorporating 71 is installed. One repeater 70 is provided within at least 10 m. As shown in FIG. 8, a plurality of magnets 71 are arranged in the repeater 70 so as to have a magnetic force of at least 30000 gauss. In order to increase the contact area between the magnet 71 and the fusing gas, as shown in FIG. 8, as shown in FIG. 8, many folds are provided in the repeater 70 or spirally formed so that the fusing gas flow path in the repeater 70 is as long as possible. It is good. As the magnet 71, a neodymium magnet or the like is suitable. Various internal structures of the repeater 70 are proposed depending on the strength and arrangement of the magnets 71, but the present invention is not limited by the difference in the internal structure of the repeater 70. By providing the vaporizer 40 as close to the fusing nozzle 10 as possible, the number of relays 70 can be reduced. FIG. 9 shows an example in which the material to be cut 30 is melted by mounting the fusing nozzle 10 on a fusing carriage 80 used in continuous casting or thick plate cutting. When the fusing nozzle 10 is mounted on the fusing trolley 80, the vaporizer 40 and the repeater 70 can be mounted on the fusing trolley 80, so that the number of installed repeaters 70 can be reduced. The fusing nozzle 10 can be moved in the vertical direction by the nozzle driving device 81, so that the tip G of the fusing nozzle 10 and the height G of the workpiece 30 can be optimally adjusted. The piping 60 of the fusing cart 80 and the piping 60 on the ground side are usually connected by a flexible hose 61 or the like so that the fusing cart 80 can move on the rail 82. The fusing cart 80 is generally used in continuous casting machines and gas fusing of thick plates, and the present invention is not limited by the manner and combination of the vaporizer 40 and the repeater 70.

Longitudinal section when water-cooled cylinder is attached to the fusing nozzle Cross section when water-cooled cylinder is attached to the fusing nozzle Longitudinal section when water-cooled cylinder is attached to the fusing nozzle Longitudinal section when water-cooled cylinder is attached to the fusing nozzle Gas flow during gas fusing Flow diagram of third solution Flow diagram of the fourth solution Vertical section of repeater The flow figure at the time of carrying a fusing nozzle in a fusing cart.

10: fusing nozzle, 11: outer cylinder, 12: tip, 13: inner pipe, 13a: rib, 13b: central gas flow path, 13c: gas flow path, 14: outer pipe, 14a: rib, 14b: gas flow Road: 15: Inside the hood, 16: Bolt, 17: Rib, 18: Long hole, 20: Water cooling cylinder, 21: Tip part, 22: Inner side surface, 23: Outer side surface, 24: Cooling water flow path, 25: Cooling water Inlet, 26: Cooling water outlet, 30: Material to be cut, 31: FeO scale, 32: Fe3O4 scale, 33: Fe2O3 scale, 40: Vaporizer, 50: Liquid flux, 60: Piping, 61: Flexible hose, 70: Repeater, 71: magnet, 80: fusing cart, 81: nozzle drive, 82: rail

Claims (4)

A fusing nozzle characterized in that the outer cylinder of the fusing nozzle is covered with a water-cooled cylinder, and the tip of the water-cooled cylinder is extended from the tip of the fusing nozzle. The fusing nozzle according to claim 1, wherein at least a tip end portion of the inner side surface of the water-cooled cylinder of the fusing nozzle has a divergent shape. A gas fusing method comprising blowing a combustion gas into a vaporizer to vaporize a liquid flux to obtain a vaporized flux, and fusing using a fusing gas obtained by mixing the vaporized flux and the combustion gas and the fusing nozzle. In the method of fusing gas with the fusing gas and the fusing nozzle, a repeater incorporating permanent magnets at appropriate intervals is installed in the middle of a supply pipe from the vaporizer to the fusing nozzle. 3. The gas fusing method according to 3.

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