WO2023190823A1

WO2023190823A1 - Powder cutting method, powder supply nozzle, and powder cutting nozzle

Info

Publication number: WO2023190823A1
Application number: PCT/JP2023/013076
Authority: WO
Inventors: 宗夫鈴置; 隆志武田; 隆加藤
Original assignee: 日酸Ｔａｎａｋａ株式会社
Priority date: 2022-03-31
Filing date: 2023-03-30
Publication date: 2023-10-05
Also published as: JP2023151007A

Abstract

Provided is a piercing method which is for performing piercing, by using a gas cutting torch, with respect to a cutting workpiece composed of general mild steel, the method having: a step for ejecting cutting oxygen and preheating gas from the gas cutting torch; and a step for supplying powder toward a preheating flame gas flow composed of the cutting oxygen and preheating gas which have been ejected from the gas cutting torch, wherein the powder is supplied in the direction along the preheating flame gas flow.

Description

Powder cutting method, powder supply nozzle, and powder cutting nozzle

The present invention relates to a powder cutting method, a powder supply nozzle, and a powder cutting nozzle.
This application claims priority to Japanese Patent Application No. 2022-060392 filed in Japan on March 31, 2022, the contents of which are incorporated herein.

Conventionally, when cutting a workpiece made of general mild steel using a gas cutting nozzle, as shown in Patent Document 1, the workpiece is generally cut for a long time, for example, 1 to 5 minutes. Piercing is performed after preheating.

Japanese Unexamined Patent Publication No. 48-41957

However, the conventional method for cutting a workpiece made of general mild steel has the problem that the piercing operation requires a lot of preheating time, which increases the total cutting time.

By the way, when cutting non-ferrous metals, the ferrous material is fed into a preheated flame stream ejected from a gas cutting nozzle to burn the powder made of iron powder, thereby strengthening the oxidation reaction and raising the temperature to a high temperature, which melts the base material. A method of cutting is known. When such a method of supplying iron material to a preheating flame stream is adopted for cutting general mild steel, fumes are generated. Furthermore, in this case, cutting costs also increase, so it is currently difficult to apply this method to cutting general mild steel.
Furthermore, conventionally, iron wire such as a steel wire is used as the iron material supplied to the preheating flame air flow. In this case, a skilled worker is required to determine the timing of supplying the iron material, and the quality is not stable. Moreover, when the worker supplies the wire to the cutting oxygen stream being blown out into the preheating flame stream over the material to be cut, slag with a high temperature of over 1500° C. is scattered near the worker. Therefore, there has been a need to further improve safety in terms of workability.

The present invention has been made in consideration of these circumstances, and is a powder cutting method that can significantly shorten the cutting time of general mild steel, thereby increasing work efficiency and improving safety. A method, a powder feeding nozzle, and a powder cutting nozzle are provided.

In order to solve the above problems, the present invention proposes the following means.
(1) Embodiment 1 of the powder cutting method according to the present invention is a powder cutting method in which a material to be cut made of general mild steel is supplied with powder made of iron powder and cut using a gas cutting nozzle. The gas cutting nozzle is provided so as to be able to eject cutting oxygen, preheating gas containing a mixture of preheating oxygen and combustible gas toward the material to be cut. The gas cutting nozzle supplies the powder toward a preheated flame air stream made of the preheated gas ejected from the gas cutting nozzle.

(2) Aspect 2 of the present invention is the powder cutting method of Aspect 1, in which the powder is supplied from the outer periphery of the jet port of the gas cutting nozzle toward the preheating flame airflow, and is supplied so as to surround the preheating flame airflow. Forms a powder stream. The powder flow formed by the powder extends in a slit shape in the direction in which the powder is ejected, and forms a non-supply area where the powder is not supplied.

(3) Aspect 3 of the present invention is the powder cutting method of Aspect 1 or Aspect 2, in which the preheated gas is ejected from the gas cutting nozzle, and the preheated flame airflow is made of the preheated gas ejected from the gas cutting nozzle. Red-hot powder is generated in the preheating flame air stream by supplying powder toward the preheating flame, and the red-hot powder is placed around the jetting fixed point of the cutting oxygen air flow, and the red-hot powder around the jetting fixed point is The cutting oxygen is supplied to the powder, and the material to be cut is pierced.

(4) Aspect 4 of the present invention is the powder cutting method of Aspect 3, by continuing from the step of performing the piercing with the through hole processed by the piercing as a cutting start point and moving the gas cutting nozzle. The method includes a gas cutting step of cutting the material to be cut. Before the gas cutting step, the powder is continued to be supplied until it passes through the blow-up slag attached to the upper surface of the workpiece due to the piercing, and after passing the powder, the supply of the powder is stopped, and then the gas cutting step is performed. Start.

(5) Aspect 5 of the powder supply nozzle according to the present invention is configured to be able to spray cutting oxygen, preheating gas containing a mixture of preheating oxygen and combustible gas toward a workpiece made of general mild steel. The cutter is installed in a gas cutting nozzle to perform powder cutting on the material to be cut. The powder supply nozzle is directed toward a powder supply path extending circumferentially along the outer periphery of the gas cutting nozzle and supplying powder made of iron powder, and a preheating flame air stream consisting of the preheated gas ejected from the gas cutting nozzle. and a powder spout for spouting the powder.

(6) Aspect 6 of the present invention is the powder supply nozzle of Aspect 5, which includes an inner cylinder that fits onto the gas cutting nozzle, and an outer cylinder that is disposed on the outer peripheral side of the inner cylinder, and The jet nozzle is disposed between the inner cylinder and the outer cylinder, and is formed in a ring shape when viewed from the nozzle axial direction.

(7) Aspect 7 of the present invention is the powder supply nozzle according to aspect 6, wherein the powder jetting port includes a partition portion that circumferentially partitions the powder jetting port around the nozzle axis, and the partition portion is arranged around the outer circumference of the inner cylinder. The surface and the inner circumferential surface of the outer cylinder are connected.

(8) Aspect 8 of the present invention is the powder supply nozzle according to aspect 7, in which the circumferential width dimension of the partition portion is smaller than the distance between the circumferentially adjacent partition portions.

(9) A ninth aspect of the present invention is the powder supply nozzle according to the seventh aspect, wherein the partition portions are provided at four locations at intervals of 90 degrees in the circumferential direction.

(10) Aspect 10 of the present invention is the powder supply nozzle of Aspect 5, which includes a first control for controlling start and stop of the supply of the cutting oxygen and the preheating gas ejected from the gas cutting nozzle, and the powder supply nozzle. The second control for controlling the start and stop of the supply of the powder spouted from the powder is controlled separately.

(11) Aspect 11 of the powder cutting nozzle according to the present invention includes the powder supply nozzle according to any one of aspects 5 to 10, and the gas cutting nozzle to which the powder supply nozzle can be attached.

According to the powder cutting method, powder supply nozzle, and powder cutting nozzle according to the present invention, it is possible to significantly shorten the cutting time for general mild steel, thereby increasing work efficiency and improving safety. .

FIG. 1 is a half-longitudinal cross-sectional view showing the overall configuration of a cutting nozzle according to an embodiment of the present invention. FIG. 2 is a view taken along the line X1-X1 shown in FIG. 1, and is a front view of the cutting nozzle seen from the tip side. FIG. 3 is a view taken along the line X2-X2 shown in FIG. 1, and is a rear view of the cutting nozzle seen from behind. FIG. 4 is a diagram showing a state of piercing using a cutting nozzle. FIG. 5 is a cross-sectional view taken along the line X3-X3 shown in FIG. 4, showing a powder flow region. FIG. 6A is an explanatory diagram of powder piercing operation. FIG. 6B is an explanatory diagram of powder piercing operation. FIG. 6C is an explanatory diagram of powder piercing operation. FIG. 6D is an explanatory diagram of powder piercing operation. FIG. 7A is a schematic diagram showing a test method according to an example, and is a diagram of a case in which no powder is supplied in a comparative example. FIG. 7B is a schematic diagram showing a test method according to an example, and is a diagram of a case with powder supply in the example. FIG. 7 is a front view of a cutting nozzle according to a modified example, viewed from the tip side.

An embodiment of the present invention will be described with reference to FIGS. 1 to 6. Note that the dimensions of each component have been adjusted as appropriate to make the drawings easier to read.

FIG. 1 is a half-longitudinal cross-sectional view showing the overall configuration of a cutting nozzle 1 of this embodiment. FIG. 2 is a view along the line X1-X1 shown in FIG. 1, and is a front view of the cutting nozzle 1 viewed from the tip side. FIG. 3 is a view taken along the line X2-X2 shown in FIG. 1, and is a rear view of the cutting nozzle 1 seen from the rear. FIG. 4 is a diagram showing a state of piercing using the cutting nozzle 1. FIG. 5 is a cross-sectional view taken along the line X3-X3 shown in FIG. 4, and is a diagram showing a region of powder flow Ta. FIG. 6 is an explanatory diagram of the powder piercing operation. In FIGS. 1 and 3, the gas cutting nozzle 2 is omitted for clarity.

The gas cutting method according to the present embodiment uses a powder cutting method performed using the cutting nozzle 1 (powder cutting nozzle) shown in FIG. This is a method for cutting. That is, the cutting nozzle 1 can be used when piercing the material W to be cut or making a cut from the end of the material W to be cut. In the cutting nozzle 1 of the present embodiment, for example, a workpiece to be cut W placed on a mounting table (not shown) on a substantially horizontal plane is pierced, and then, following the piercing, cutting is performed using the piercing as a cutting start point. show.

As shown in FIGS. 1 to 3, the cutting nozzle 1 includes a gas cutting nozzle 2 and a powder supply nozzle 3. In the cutting nozzle 1, a powder supply nozzle 3 is removably attached to the outer peripheral side of the gas cutting nozzle 2.
Here, in the cutting nozzle 1, the downstream side from which cutting oxygen and preheating gas are ejected along the nozzle axis O is called the tip side, and the side opposite to the tip side is called the proximal side.

The gas cutting nozzle 2 is provided so that cutting oxygen, preheating gas in which preheating oxygen and combustible gas are mixed can be ejected toward the material W to be cut. The gas cutting tip 2 is a tip used when cutting the material W to be cut.
Here, the combustible gas includes LPG, acetylene, propylene, LNG, hydrogen, etc., and one type of these may be used, or a preheating gas that is a mixture of these and preheating oxygen may be used. is also possible.

The gas cutting nozzle 2 includes an internal core rod 2A having a cutting oxygen supply path 21, an external nozzle 2B into which the internal core rod 2A is inserted, and a cap (not shown).
The internal core rod 2A has an elongated cylindrical shape, and has a shape that becomes thinner toward the tip side. The internal core rod 2A is screwed onto the above-mentioned cap at the base end side in the direction of the nozzle axis O. As a result, the internal core rods 2A are fitted into the base and are integral with each other. The material of the internal core rod 2A is, for example, brass, which has high thermal conductivity and heat resistance, and is also highly economical in terms of manufacturing cost.

The internal core rod 2A has a cut oxygen supply path 21 extending along the nozzle axis O in the longitudinal direction. The cut oxygen supply path 21 communicates with the external space at its tip. At the tip of the cutting oxygen supply path 21 and on the tip end surface 2a of the internal core rod 2A, a cutting oxygen spout 22 for spewing out cutting oxygen is formed. The cutting oxygen that has passed through the cutting oxygen supply path 21 is ejected forward from the cutting oxygen outlet 22.

Furthermore, the internal core rod 2A has a preheated gas supply path 23 extending along the nozzle axis O outside the cutting oxygen supply path 21. The preheating gas supply path 23 communicates with the external space at its tip. A plurality of slit-shaped preheating gas outlets 24 are formed on the tip end surface 2a of the internal core rod 2A at the tip of the preheating gas supply path 23, extending radially from the cutting oxygen outlet 22 when viewed from the nozzle axis O direction. has been done. The preheated gas that has passed through the preheated gas supply path 23 is ejected from the preheated gas outlet 24 toward the front.

The external nozzle 2B has an elongated cylindrical shape, and is fitted into the internal core rod 2A concentrically when viewed in the nozzle axial direction. The external crater 2B forms a preheated gas supply path 23 through which preheated gas, which is a mixture of preheated oxygen and combustion gas, passes between the inner surface 2c of the external crater 2B and the outer surface 2b of the internal core rod 2A. A powder supply nozzle 3 to be attached is arranged on the outer surface of the external nozzle 2B.

Next, the configuration of the powder supply nozzle 3 will be explained in detail. As shown in FIGS. 1 to 3, the powder supply nozzle 3 is provided separately from the gas cutting nozzle 2. As shown in FIGS. The powder supply nozzle 3 forms a powder supply path 31 for supplying the powder T to the outer circumference of the gas cutting nozzle 2, and has a powder spout 32 for spouting the powder T.

The powder supply nozzle 3 includes an inner cylinder 35 that fits over the gas cutting nozzle 2, an outer cylinder 36 (outer peripheral wall) arranged on the outer peripheral side of the inner cylinder 35, and a gas cutting nozzle that is inserted inside the inner cylinder 35. 2 is provided. The spout stopper nut 34, the inner tube 35, and the outer tube 36 are each formed to have a circular cross section. The

inner surfaces

34a and 35b of the connecting portions of the nozzle stopper nut 34 and the inner cylinder 35 that are continuous in the nozzle axial direction are formed to be substantially flush with each other. The gas cutting nozzle 2 is inserted and fitted into the inside of the nozzle stopper nut 34 and the inner cylinder 35 from the base end side. A female screw portion 3a is formed at the tip of the nozzle stopper nut 34 and at the base end of the inner cylinder 35 and outer cylinder 36, which coaxially communicate with each other. The spout stopper nut 34, the inner tube 35, and the outer tube 36 are integrally assembled by tightening the screw 3b shown in FIG. 3 into the female threaded portion 3a.

As shown in FIG. 1, the shape of the inner surface 35b of the inner cylinder 35 matches the outer circumferential surface 2d of the gas cutting nozzle 2, and the diameter decreases toward the tip side. A tip tapered portion 351 whose outer diameter decreases toward the tip is formed on the tip side of the outer circumferential surface 35a of the inner cylinder 35.

The outer cylinder 36 has the same length as the inner cylinder 35 in the nozzle axial direction. The outer cylinder 36 has a cylindrical base end 361 arranged on the base end side and extending concentrically in the nozzle axis direction, and a conical taper part 362 connected to the distal end side of the base end 361. The tapered portion 362 has a shape that becomes thinner toward the distal end side.

The above-mentioned powder supply path 31 through which the powder T is supplied is formed between the inner cylinder 35 and the outer cylinder 36. A closing flange 35c that protrudes radially outward is provided on the base end side of the inner cylinder 35 over the entire circumference. The closing flange 35c is in liquid-tight contact with the inner circumferential surface 36a of the outer cylinder 36 on the proximal end side. Thereby, the powder T supplied into the powder supply path 31 is ejected from the powder ejection port 32 on the tip side.

A plurality of (here, two) powder introduction joints 37 communicating with the powder supply path 31 are attached to the base end portion 361 by screw fastening. The powder introduction joint 37 is connected to a powder supply device (not shown), and powder is supplied into the powder supply path 31 from this powder supply device. As shown in FIG. 3, the mounting angle θ between the two powder introduction joints 37 when viewed from the nozzle axis direction is set to 60°.
Note that the mounting angle θ of the powder introduction joint 37 is preferably arranged so that the powder is uniformly supplied to the powder supply path 31. Therefore, the best mounting angle θ is, for example, two locations at a 180° pitch, or three locations at a 120° pitch. However, in consideration of the arrangement of the piping (not shown) connecting the powder introduction joint 37 and the powder supply device, the two locations may be placed closer to one side as in this embodiment.

As shown in FIG. 2, the powder spout 32 is arranged between the outer circumferential surface 35a of the inner cylinder 35 and the inner circumferential surface 36a of the outer cylinder 36, and is formed in a ring shape when viewed from the nozzle axial direction. Further, the powder spout 32 includes a plurality of (four in this embodiment) partition ribs 33 (partition portions) that circumferentially circumferentially circulate around the nozzle axis. That is, the partition ribs 33 are provided at intervals of 90° in the circumferential direction.

A plurality of partition ribs 33 are arranged at regular intervals in the circumferential direction of the powder spout 32 and connect the outer circumferential surface 35 a of the inner cylinder 35 and the inner circumferential surface 36 a of the outer cylinder 36 . The partition ribs 33 are provided at four locations at intervals of 90° in the circumferential direction. As shown in FIG. 1, the partition rib 33 extends from the distal end of the inner tube 35 and the outer tube 36 toward the base end side. The region where the partition rib 33 is arranged is a range that faces the tapered tip portion 351 of the inner cylinder 35 in the radial direction. Here, the width dimension of the partition rib 33 in the circumferential direction is smaller than the distance between the partition ribs 33 adjacent to each other in the circumferential direction.

The powder T ejected from the powder outlet 32 of the powder supply nozzle 3 is supplied from the outer periphery of the outlet of the gas cutting nozzle 2 toward the preheating flame stream R, forming a powder stream Ta surrounding the preheating flame stream R. do. By providing the partition rib 33 on the powder spout 32, as shown in FIG. A region Tb is formed.

Next, a piercing method for piercing a workpiece W made of general mild steel using the cutting nozzle 1, and a gas cutting method for cutting the workpiece W using this piercing method. The operation during implementation and the functions of the powder cutting method, powder supply nozzle, and powder cutting nozzle of the present embodiment described above will be described.

First, as shown in FIG. 2, the cutting nozzle 1 is used in a state in which a powder supply nozzle 3 is assembled and integrated with a gas cutting nozzle 2.
As shown in FIGS. 2 and 4, preheating gas in which preheating oxygen and combustible gas are mixed is supplied to the preheating gas supply path 23 of the gas cutting nozzle 2 of the cutting nozzle 1, and this preheating gas is supplied to the preheating gas outlet. 24 to the outside to generate a preheating flame. At the same time, cutting oxygen is supplied to the cutting oxygen supply path 21 and ejected from the cutting oxygen outlet 22. Further, in the powder supply nozzle 3, the powder T is supplied to the powder supply path 31 and ejected from the powder spout 32. At this time, the powder T ejected from the powder ejection port 32 is supplied toward the preheated flame stream R consisting of the preheated gas.
In addition, in FIG. 4, the powder T (powder flow Ta) is shown to be ejected along the outer periphery of the preheating flame flow R for ease of viewing, but it is shown that the powder T (powder flow Ta) is ejected along the outer periphery of the preheating flame flow R. Powder T is supplied.

In this embodiment, the powder jet nozzle 32 is arranged on the outer peripheral side of the cutting oxygen jet nozzle 22 and the preheating gas jet nozzle 24 of the gas cutting nozzle 2, so that the powder T jetted from the powder jet nozzle 32 flows into the preheated flame air stream. It is supplied along the outer circumferential side of R. That is, the preheating flame flow R is covered with the powder flow Ta of the powder T.
Note that, as described above, the non-supply area Tb is formed in the powder flow Ta. The preheating flame flow R is not completely covered by the powder flow Ta, but a part of the powder flow Ta is opened in the form of a slit.

The ejected powder T is supplied to the preheated flame flow R inside the powder flow Ta, is sufficiently heated and melted, and is ejected toward the workpiece W made of general mild steel. Moreover, most of the powder T can be efficiently burned without causing the powder T to be scattered outward and lost.

More specifically, as shown in FIGS. 6A to 6D, preheated gas is ejected from the gas cutting nozzle 2, and powder T is supplied toward the preheated flame stream R made of the preheated gas ejected from the gas cutting nozzle 2. As a result, red-hot powder T3 is generated in the preheating flame air flow R. Here, in FIGS. 6A to 6D, the symbol T1 indicates the powder immediately after being ejected, the symbol T2 indicates the powder that is in the process of becoming red-hot, and the symbol T3 indicates the powder that has become red-hot. Then, the red-hot powder T3 is placed around the ejection fixed point Va of the cutting oxygen stream V. By supplying cutting oxygen to the red-hot powder T3 around the ejection fixed point Va, an oxidation reaction is caused at once, and the workpiece W can be pierced or cut in an extremely short preheating time.

In this way, in this embodiment, it is possible to apply the powder cutting method to the workpiece W of general mild steel, and it is possible to improve work efficiency by significantly shortening the cutting time, and to improve safety. It is possible to improve sexual performance.
Therefore, the combustion ratio of powder T becomes high, the exothermic reaction becomes strong, and the combustion efficiency increases. Then, at the same time as melting the base material of the workpiece W, the combustion products are blown away by the mechanical energy of the preheated flame stream R, and the workpiece W can be easily pierced or cut.

By supplying the powder T to the preheating flame flow R made of the preheating gas in which preheating oxygen and combustible gas are mixed in this way, the material to be cut W is pierced to form the through hole P.
Further, in this embodiment, only piercing can be started immediately. Therefore, there is no need to perform preheating for a long time, for example, for 1 to 5 minutes, before piercing as in the conventional case. Furthermore, as described above, by supplying the powder T to the preheating flame stream R during piercing, the combustion efficiency increases. Therefore, piercing can be performed in a short time (for example, about 10 seconds or less), and the operation time can be significantly shortened.

Subsequently, after piercing the workpiece W by supplying powder T to the preheating flame flow R and forming the through hole P, and before the gas cutting step, the upper surface of the workpiece W is pierced by piercing. Continue to supply the powder T until it passes through the attached blow-up slag G. Then, after the blow-up slag G is blown off and removed by the powder T, the supply of the powder is stopped and the gas cutting process is started.
In this manner, in this embodiment, the process of peeling off the blow-up slag G can be performed simultaneously during the piercing process. Therefore, in a normal process, there is a preheating process, a piercing process, a peeling process of the blow-up slag G, a preheating process, and a cutting process, but in this embodiment, the preheating process, the piercing process (including the process of peeling the blow-up slag G) ), the cutting process can be omitted.

Furthermore, in this embodiment, the powder T can be automatically ejected by the cutting nozzle 1. Therefore, it is no longer necessary to manually supply the iron wire to the preheating flame stream R as in the past. That is, it is possible to eliminate the work performed by the worker on the material W to be cut, and it is possible to improve the safety of the work. Moreover, since the cutting nozzle 1 of this embodiment can be incorporated into a cutting device and automated, work efficiency and quality are improved.

The cutting nozzle 1 used at this time also includes a cutting oxygen outlet 22 that forms a cutting oxygen supply path 21 and blows out cutting oxygen, and a preheating gas blowout 24 that forms a preheating gas supply path 23 and blows out preheating gas. The present invention includes a gas cutting nozzle 2 having a gas cutting nozzle 2 and a powder supply nozzle 3. The powder supply nozzle 3 has a powder supply path 31 that extends in the circumferential direction along the outer periphery of the gas cutting nozzle 2 and supplies the powder T, and a preheating flame flow R that is made up of preheated gas ejected from the gas cutting nozzle 2. A powder spout 32 that spouts powder T is provided. It has an inner cylinder 35 that fits onto the gas cutting nozzle 2, and an outer cylinder 36 that is disposed on the outer peripheral side of the inner cylinder 35. The powder spout 32 is arranged between the inner cylinder 35 and the outer cylinder 36, and is formed in a ring shape when viewed from the nozzle axial direction. In this case, the powder spout 32 of the powder supply nozzle 3 has a concentric ring shape, so that the supply of the powder T is stabilized.

After piercing is completed, only the supply of powder T ejected from the powder supply nozzle 3 is stopped.
Thereafter, gas cutting is performed on the workpiece W using the through hole P of the workpiece W processed by piercing as a cutting start point using the preheated flame air flow R that is continuously ejected from the piercing process. In this way, in this embodiment, by simply stopping the ejection of the powder T after piercing, the preheating flame air flow R can continue to be ejected and a predetermined-shaped cut can be made in the workpiece W. . In other words, there is no need to stop the gas cutting tip 2 by switching between piercing and cutting operations, and the cutting operation can be performed efficiently and in a short time.

In this way, in this embodiment, incisions can be made continuously after piercing. Therefore, there is no need to temporarily stop the cutter, it is possible to prevent damage to the cut portion, and it is possible to reduce the number of places where the material to be cut W is discarded.

In addition, in this embodiment, an example of the powder cutting method was shown in which cutting is performed using the through hole P formed by piercing as the cutting starting point, but the above-mentioned cutting method in which cutting is performed directly from the end surface of the workpiece W without piercing is shown. Powder cutting method can be applied.

Note that the cutting nozzle 1 may be connected to a control section (not shown). In this case, the control section includes a first control for controlling the start and stop of the supply of cutting oxygen and preheating gas ejected from the gas cutting nozzle 2, and a first control for controlling the start and stop of the supply of the powder T ejected from the powder ejection port 32. and a second control for controlling are separately controlled. Thereby, the timing and supply time of supplying the powder T can be adjusted as appropriate in accordance with conditions such as the cutting method and the thickness and material of the material W to be cut.

Furthermore, in the piercing method of this embodiment, the preheating flame flow R is covered with the supplied powder T in the form of a film. Therefore, the powder T can be supplied from the outer periphery of the preheating flame flow R in a state in which it is evenly contacted in the circumferential direction, and when viewed in cross section, there is no unevenness in the combustion area of the powder T, and the powder T can be burned evenly over the entire cross section. I can do it.

In addition, in the piercing method of this embodiment, as shown in FIG. It forms Ta. The powder flow Ta of the powder T extends like a slit in the jetting direction of the powder T, and forms a non-supply region Tb where the powder T is not supplied. As a result, the entire preheating flame flow R is not completely covered from the outside by the powder flow Ta of the powder T, and a gap of the non-supply region Tb is formed in a part of the powder flow Ta. That is, as shown in FIG. 4, the blow-up slag G that scatters toward the cutting nozzle 1 side during piercing is diffused to the outside of the powder flow Ta from the slit-shaped gap in the non-supply area Tb. Therefore, it is possible to suppress the blow-up slag G from adhering to the gas cutting nozzle 2 of the cutting nozzle 1, and it is possible to prevent the gas cutting nozzle 2 from backfiring.

Furthermore, in the cutting nozzle 1 of the present embodiment, the powder spout 32 is equipped with a partition rib 33 that circumferentially circumferentially circumferentially surrounds the nozzle axis. The partition rib 33 connects the outer peripheral surface 35a of the inner cylinder 35 and the inner peripheral surface 36a of the outer cylinder 36. As a result, the entire preheating flame flow R is not completely covered from the outside by the powder flow Ta of the powder T, and a gap of the non-supply region Tb is formed in a part of the powder flow Ta. That is, as shown in FIG. 4, the blow-up slag G that scatters toward the cutting nozzle 1 side during piercing is diffused to the outside of the powder flow Ta from the gap in the non-supply area Tb. Therefore, it is possible to suppress the blow-up slag G from adhering to the gas cutting nozzle 2 of the cutting nozzle 1, to prevent the gas cutting nozzle 2 from backfiring, and to maintain the stability of piercing.

Furthermore, the cutting nozzle 1 of this embodiment is arranged such that the circumferential width dimension of the partition ribs 33 is smaller than the distance between the partition ribs 33 adjacent to each other in the circumferential direction. In this case, a sufficient amount of powder T can be supplied toward the preheating flame flow R.

Further, in the cutting nozzle 1 of this embodiment, partition ribs 33 are provided at four locations at intervals of 90 degrees in the circumferential direction. Therefore, the blown-up slag G can be uniformly diffused from the gap in the non-supply area Tb toward the outer four directions of the powder flow Ta.

Further, the cutting nozzle 1 of the present embodiment has a first control for controlling the start and stop of the supply of cutting oxygen and preheating gas ejected from the gas cutting nozzle 2, and a start control for controlling the supply of the powder T ejected from the powder ejection port 32. and a second control that controls stopping are separately controlled. Therefore, by stopping only the spouting of the powder T by the second control after piercing, the preheating flame flow R can continue to be jetted out as it is, and an operation can be performed to create a cut of a predetermined shape in the workpiece W. .

Next, examples conducted to prove the effects of the powder cutting method, powder supply nozzle, and powder cutting nozzle according to the above-described embodiment will be described below.

(Example)
In this example, using the cutting nozzle 1 of the above embodiment, a piercing test was conducted on a workpiece W having a predetermined thickness, and the piercing time was evaluated depending on the presence or absence of powder. FIG. 7A is a schematic diagram showing the test method, and shows a comparative example without powder supply. FIG. 7B is a schematic diagram showing the test method, and shows a case with powder supply in the example. Table 1 shows the test conditions and test results.

Two types of fuel gas (combustible gas) were used in the test: hydrocarbon gas (LPG) and hydrogen mixed gas. Hydrocarbon gas (LPG) and hydrogen mixed gas were used to perform piercing on general mild steel workpieces W with plate thicknesses of 25 mm and 50 mm, respectively, in an example with powder supply and a comparative example without powder supply. The preheating time (seconds) and the diameter of the through hole formed by piercing (piercing hole diameter (mm)) were confirmed.
Here, the symbol P2 (P) in FIG. 7A indicates the pierced hole according to the comparative example (without powder supply), and the symbol P1 (P) in FIG. 7B indicates the pierced hole according to the example (with powder supply).

The test conditions, which are powder supply amount (g/min), aperture ratio (powder supply port (corresponding to the powder spout described above)), and crater height H (mm), are as shown in Table 1. The crater height H from the top surface of the workpiece W to the crater is 100 mm in the example (with powder supply) and 10 mm in the comparative example (without powder supply).

As shown in Table 1, the test results showed that the piercing preheating time (seconds) in the example (with powder supply) was 4 to 8 seconds for a plate thickness of 25 mm and 10 seconds for a plate thickness of 50 mm. On the other hand, the piercing preheating time (seconds) in the comparative example (no powder supply) is 40 to 60 seconds (hydrocarbon gas) for a plate thickness of 25 mm, 20 to 30 seconds (hydrogen preheating gas), and 70 seconds for a plate thickness of 50 mm. -90 seconds (hydrocarbon-based hydrogen gas) and 60-80 seconds (hydrogen preheating gas). As described above, it can be seen that in the example, the piercing preheating time can be significantly shortened compared to the comparative example. Further, in the embodiment, even if the thickness of the material to be cut W is increased, the piercing preheating time increases slightly by several seconds. On the other hand, in the comparative example, as the thickness of the material to be cut W increases, the piercing time also increases nearly twice.

Furthermore, the diameter of the piercing hole in the example (with powder supply) is smaller than that in the comparative example (without powder supply). When the plate thickness of the material to be cut W was 25 mm, the thickness was 8 mm in the example, whereas it was 12 mm in the comparative example. Further, when the plate thickness of the material to be cut W is 50 mm, the thickness in the example is 12 mm, whereas in the comparative example, the thickness is doubled to 24 mm. From this, it was found that by supplying powder, the diameter of the pierced hole can be reduced and it is efficient.

Furthermore, in the case of the example, no variation was observed depending on the type of gas in both the piercing preheating time and the piercing hole diameter. Therefore, the same effect can be obtained even if a low-cost gas is used, for example.

Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like may be made without departing from the gist of the present invention. Furthermore, the components shown in the embodiments described above and the modified examples shown below can be configured by appropriately combining them.

For example, in the embodiment described above, the powder cutting method using the cutting nozzle 1 including the gas cutting nozzle 2 and the powder supply nozzle 3 was exemplified, but the powder cutting method using the cutting nozzle 1 to supply powder It is not limited to one thing. For example, instead of the cutting nozzle 1 of this embodiment, a powder supply means having the same function as the powder supply nozzle 3 may be provided separately from the gas cutting nozzle 2, and the preheating flame air flow R ejected from the gas cutting nozzle 2 may be provided. It is also possible to supply the powder from the powder supply means.

Further, in this embodiment, the powder spout 32 of the powder supply nozzle 3 is provided with a partition rib 33 (partition portion), but the partition rib 33 may be omitted. Alternatively, it is also possible to change the number and position of the partition ribs 33.
For example, a partition rib 33 (partition portion) is provided like a powder spout 32A between the outer peripheral surface 35a of the inner cylinder 35 and the inner peripheral surface 36a of the outer cylinder 36 of the modified powder supply nozzle 3A shown in FIG. It is also possible to have a ring-shaped opening over the entire circumference.

Further, the shape and quantity of each component of the gas cutting nozzle 2 (the cutting oxygen supply path 21, the cutting oxygen outlet 22, the preheating gas supply path 23, the preheating gas outlet 24, etc.) are not limited to the above embodiments.

1 Cutting nozzle 2

Gas cutting nozzle

3, 3A Powder supply nozzle 21 Cutting oxygen supply path 22 Cutting oxygen nozzle 23 Preheating gas supply path 24 Preheating gas nozzle 31

Powder supply path

32, 32A Powder nozzle 33 Partition rib (partition part)
34 Nut 35 Inner cylinder 35a Outer peripheral surface 36 Outer cylinder (outer peripheral wall)
36a Inner peripheral surface O Nozzle axis P Through hole R Preheating flame air flow T Powder T3 Red-hot powder Ta Powder flow Tb Non-supply area W Material to be cut

Claims

A powder cutting method for cutting a material made of general mild steel by supplying powder made of iron powder to the material to be cut using a gas cutting nozzle, the method comprising:
The gas cutting nozzle is provided to be able to eject cutting oxygen, preheating gas containing a mixture of preheating oxygen and combustible gas toward the material to be cut,
A powder cutting method, wherein the powder is supplied toward a preheated flame air stream made of the preheated gas ejected from the gas cutting nozzle.
The powder is supplied from the outer periphery of the ejection port of the gas cutting nozzle toward the preheating flame stream to form a powder stream surrounding the preheating flame stream,
The powder flow caused by the powder extends in a slit shape in the jetting direction of the powder, and forms a non-supply area where the powder is not supplied.
The powder cutting method according to claim 1.
The preheated gas is ejected from the gas cutting nozzle, and the powder is red-hot in the preheated flame airflow by supplying powder toward the preheated flame airflow made of the preheated gas ejected from the gas cutting nozzle. is generated, the red-hot powder is placed around a fixed jetting point of the cutting oxygen stream, and the cutting oxygen is supplied to the red-hot powder around the jetting fixed point to perform piercing on the material to be cut. ,
The powder cutting method according to claim 1 or 2.
Continuing from the step of performing piercing, using the through hole processed by the piercing as a cutting start point, a gas cutting step of cutting the material to be cut by moving the gas cutting nozzle,
Before the gas cutting step, the powder is continued to be supplied until it passes through the blow-up slag attached to the upper surface of the workpiece due to the piercing, and after passing the powder, the supply of the powder is stopped, and then the gas cutting step is performed. 4. A powder cutting method according to claim 3, wherein the powder cutting method starts with:
Cutting oxygen, preheating gas that is a mixture of preheating oxygen and combustible gas are attached to a gas cutting nozzle that is installed so that it can be ejected toward the workpiece made of general mild steel, and the workpiece is then heated. A powder supply nozzle for performing powder cutting,
a powder supply path extending circumferentially along the outer periphery of the gas cutting nozzle and supplying powder made of iron powder;
A powder supply nozzle comprising: a powder spouting port that spouts the powder toward a preheated flame air stream made of the preheated gas spouted from the gas cutting nozzle.
an inner cylinder that fits over the gas cutting nozzle; and an outer cylinder that is disposed on the outer peripheral side of the inner cylinder,
The powder supply nozzle according to claim 5, wherein the powder spout is arranged between the inner tube and the outer tube and has a ring shape when viewed from the nozzle axis direction.
The powder spout includes a partition section that circumferentially circumferentially circulates around the nozzle axis,
The partition portion connects the outer circumferential surface of the inner cylinder and the inner circumferential surface of the outer cylinder.
The powder supply nozzle according to claim 6.
The circumferential width dimension of the partition portion is smaller than the distance between the circumferentially adjacent partition portions.
The powder supply nozzle according to claim 7.
The partition portions are provided at four locations at intervals of 90 degrees in the circumferential direction,
The powder supply nozzle according to claim 7.
a first control for controlling start and stop of the supply of the cutting oxygen and the preheating gas ejected from the gas cutting nozzle; and a second control for controlling start and stop of the supply of the powder ejected from the powder ejection port. , are controlled separately,
The powder supply nozzle according to claim 5.
The powder supply nozzle according to any one of claims 5 to 10,
the gas cutting nozzle to which the powder supply nozzle can be attached;
Powder cutting nozzle.