JP7336131B2 - Gas cutting machine and gas cutting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a gas cutting machine and a gas cutting method suitable for cutting materials having curved surfaces.

In gas cutting, the surface of the steel material to be cut is heated to a high temperature with a preheating flame, and the steel material is cut by blowing oxygen gas (cutting oxygen) onto the heated portion. That is, when cutting oxygen is blown to a location heated to a high temperature by a preheating flame, the steel material burns (the steel material and oxygen react to form an oxide), and the heat melts the steel material itself. For this reason, the steel is cut by blowing off the combustion products and the molten steel with the cutting oxygen.

An example of a gas cutting machine used for such gas cutting is disclosed in Patent Document 1, for example. As shown in Patent Document 1, various gases for gas cutting are ejected from a cutting tip. The cutting nozzle includes a cutting oxygen nozzle for ejecting cutting oxygen, a curtain oxygen nozzle surrounding the cutting oxygen nozzle for ejecting oxygen gas for a curtain, and a fuel gas nozzle surrounding the curtain oxygen nozzle. and a preheating oxygen outlet surrounding the fuel gas outlet for ejecting oxygen gas for preheating.

Here, the curtain oxygen is supplied to maintain the purity of the oxygen gas for cutting and to assist the combustion of the fuel gas. It is set to a very small amount (flow rate sufficiently smaller than the flow rate of oxygen gas for preheating). Curtain oxygen may also be omitted.

JP 2018-167299 A JP-A-8-168877

The characteristic of gas cutting as described above is that the energy for melting is supplied by combustion of the material to be cut (e.g., steel). There is something you can do. However, conventionally, when trying to cut a material having a curved surface, there is a problem that the end portion (curved surface) where cutting is started is not sufficiently preheated, and cutting of the material cannot be started even after a long time.

For example, if the material to be gas cut is a slab, bloom, billet, etc. that does not have a curved surface or has a small R (curvature radius) at the corners, the preheating flame hits the edge where cutting is started perpendicularly. Therefore, sufficient preheating is applied to the end portion, and cutting slag (slag) can be easily generated by blowing oxygen for cutting. However, when the material to be gas-cut is round steel, pipe, column, etc., or when the corner radius is large such as slab, bloom, billet, etc., the curved surface where the preheating flame starts cutting the material Since the curved surface portion is obliquely hit, the curved surface portion is not sufficiently preheated, and cutting slag cannot be generated even if cutting oxygen is blown.

In order to solve such problems, conventionally, for example, as disclosed in Patent Document 2, powder (such as iron powder) is supplied to a preheating flame, and the heat of combustion of the powder is used to achieve cutting. There are some that generate cutting slag when oxygen for cutting is blown. A similar phenomenon occurs when the operator supplies wire (wire), and cutting slag can be generated when oxygen for cutting is blown.

However, the method of inserting the powder requires a mechanism for inserting the powder (powder feeder, its accessories, etc.), which causes a problem of increased cost. In addition, when the operator supplies the numbered lines, the operator's work is increased and the safety of the operator must be considered.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas cutting machine and a gas cutting method capable of cutting a material having a curved surface at low cost, safely and reliably. do.

In order to achieve the above object, the present invention provides a gas cutting machine comprising a cutting tip and a valve mechanism for controlling the ejection of gas from the cutting tip, wherein the cutting tip is arranged in the center. a first ejection port for ejecting oxygen gas for cutting; a plurality of second ejection ports for ejecting oxygen gas for preheating, which are arranged so as to surround the first ejection port; a plurality of third ejection ports arranged so as to surround the ejection port for ejecting the fuel gas; and a plurality of third ejection ports arranged so as to surround the third ejection port for ejecting the oxygen gas for preheating. 4 ejection ports, wherein the valve mechanism is capable of independently controlling the pressure and flow rate of the gas supplied from the first ejection port to each of the fourth ejection ports, and the second ejection port The gas supply line connected to is a first line that can control the supply/stop of oxygen gas at a first pressure by opening and closing a first valve, and the supply/stop of oxygen gas at a second pressure lower than the first pressure. and a second line whose stop can be controlled by opening and closing a second valve.

According to such a gas cutting machine, it is possible to preheat the curved surface portion of the material having the curved surface by supplying oxygen gas at the first pressure, which is high pressure, from the first line to the second ejection port. That is, an enhanced preheating flame can be used to preheat the curved portion so that sufficient preheating is applied to the curved portion to initiate cutting of the material. In addition, by supplying oxygen gas at a second pressure, which is a relatively low pressure, from the second line to the second ejection port, it is possible to stably continue cutting the material after cutting is started by the cutting oxygen. Become. In this way, it is possible to cut materials with curved surfaces at low cost, safely and reliably.

Further, in the present invention, there is provided a gas cutting method for cutting a material having a curved surface using the gas cutting machine, wherein oxygen gas for preheating at the first pressure is jetted from the second jet port, and 3. By ejecting the fuel gas from the ejection port, the curved surface is preheated, after the preheating, the oxygen gas for cutting is ejected from the first ejection port, and the second pressure is applied from the second ejection port. of the oxygen gas, the fuel gas is ejected from the third ejection port, and the preheating oxygen gas is ejected from the fourth ejection port to start cutting the material. A gas cutting method is provided.

According to such a gas cutting method, it is possible to preheat the curved surface portion of a material having a curved surface by first supplying oxygen gas at a first pressure, which is a high pressure, from the first line to the second ejection port. Become. That is, an enhanced preheating flame can be used to preheat the curved portion so that sufficient preheating is applied to the curved portion to initiate cutting of the material. Thereafter, oxygen gas for cutting is ejected from the first ejection port, oxygen gas at a relatively low second pressure is ejected from the second ejection port, fuel gas is ejected from the third ejection port, and the By ejecting oxygen gas for preheating from the nozzle 4, cutting of the material can be started by the cutting oxygen, and thereafter, cutting of the material can be stably continued. In this way, it is possible to cut materials with curved surfaces at low cost, safely and reliably.

After preheating the curved surface, it is preferable to once retract the position of the cutting tip and then start cutting the material from the end face of the material.

In this way, if the position of the cutting tip is retreated after preheating the curved surface and the standing start is used to start cutting from the end face of the material, regardless of the temperature of the material to be gas-cut (for example, at normal temperature ), you can certainly start cutting the material.

ADVANTAGE OF THE INVENTION According to this invention, the gas cutting machine and the gas cutting method which can cut|disconnect the material with a curved surface low-cost, safely, and reliably can be provided.

It is a figure which shows an example of the gas cutter of this invention. FIG. 2 is a diagram showing an example of the cutting tip of FIG. 1; 2 is a waveform diagram for controlling ejection/stopping of each gas by the valve mechanism of FIG. 1. FIG. It is a figure which shows an example of the gas cutting method of this invention. It is a figure which shows the gas cutter of a comparative example. FIG. 6 is a diagram showing an example of the cutting tip of FIG. 5; 6 is a waveform diagram for controlling ejection/stopping of each gas by the valve mechanism of FIG. 5. FIG. FIG. 10 is a diagram showing a comparative gas cutting method for a material that does not have curved surfaces. FIG. 5 is a diagram showing a gas cutting method of a comparative example for materials having curved surfaces; It is a figure which shows the round bar as a test material.

As mentioned above, there has been a problem in the prior art that it is not possible to start cutting a material having a curved surface. For example, when the temperature of the material to be gas-cut (e.g., steel) is high (e.g., 600° or higher), after preheating the curved surface portion where the cutting is started using a conventional preheating flame, Although it may be possible to start cutting with a standing start in which the position of the cutting tip is once retracted and then cutting is started from the end face of the material, this is not a certainty. In addition, when the temperature of the material to be gas-cut is low (for example, normal temperature), even if the curved surface portion where cutting is started is preheated over time, the temperature of the curved surface portion does not rise, and after that, Cutting slag does not occur even if the cutting operation is performed, so cutting cannot be started.

Therefore, even in these cases, a method of supplying powder and a method of supplying wire by an operator have been known as methods for reliably starting the cutting of the material. The latter has the problem that the operator's safety has to be considered as well as the operator's work increases.

For this reason, it is possible to cut materials with curved surfaces such as round steel, pipes, columns, slabs, blooms, and billets with large rounded corners at a low cost, safely, and reliably. The development of a gas cutting machine and a gas cutting method that are more efficient have been demanded.

As a result of earnestly examining the above problems, the inventor first focused on the structure of the cutting tip. When cutting a material with a curved surface, in order to start cutting, that is, to generate cutting slag (slag) on the curved surface by cutting oxygen, a preheating flame sufficient to sufficiently preheat the curved surface is generated. All you have to do is However, conventionally, the preheating oxygen nozzle for ejecting oxygen gas for preheating exists at the outermost periphery of the cutting tip, and sufficient heating capacity for the curved surface cannot be obtained only by controlling the pressure and flow rate of the oxygen gas for preheating. couldn't get.

On the other hand, in the cutting nozzle, in addition to the cutting oxygen nozzle and the preheating oxygen nozzle, there is a curtain oxygen nozzle that ejects oxygen gas for a curtain as a nozzle capable of ejecting oxygen gas. The pressure and flow rate of the oxygen gas ejected from the curtain oxygen ejection port (curtain oxygen) are set to small values for the purpose of maintaining the purity of the cutting oxygen and assisting the combustion of the fuel gas, and was fixed. Therefore, the present inventors have made further extensive studies from the viewpoint of whether the curtain oxygen outlet can be used as a preheating oxygen outlet.

As a result, the present inventor found that since the curtain oxygen nozzle exists on the innermost circumference of the cutting tip, it is possible to obtain an amazing heating capacity for curved surfaces by using this as a preheating oxygen nozzle. Found it. In addition, the present inventor believes that this amazing heating ability is effective in preheating the curved surface portion when starting to cut a material having a curved surface, but once the curved surface portion is sufficiently preheated, After starting the cutting of the material, in order to stably continue the cutting of the material, the oxygen gas for preheating is ejected from the preheating oxygen ejection port arranged at the outermost periphery of the cutting nozzle as before, and the cutting is continued. It has been found that it is preferable to jet curtain oxygen from a curtain oxygen jet arranged on the innermost circumference of the crater.

In order to realize the above, the present inventors have further studied what kind of changes should be made to the conventional gas cutting machine and gas cutting method. The supply line consists of a first line capable of controlling supply/stop of oxygen gas at a first pressure (high pressure) by opening and closing a first valve, and a supply line of oxygen gas at a second pressure (low pressure) lower than the first pressure. The present invention has been completed by finding that /stop can be configured by a second line that can be controlled by opening and closing the second valve.

That is, the present invention is a gas cutting machine comprising a cutting tip and a valve mechanism for controlling the ejection of gas from the cutting tip, wherein the cutting tip is arranged in the center and contains oxygen gas for cutting. a plurality of second ejection ports for ejecting oxygen gas for preheating disposed so as to surround the first ejection port; and the second ejection port so as to surround the a plurality of third ejection ports arranged to eject the fuel gas; and a plurality of fourth ejection ports arranged to surround the third ejection ports to eject the oxygen gas for preheating. and the valve mechanism is capable of independently controlling the pressure and flow rate of the gas supplied from the first ejection port to each of the fourth ejection ports, and is connected to the second ejection port. The lines are a first line that can control the supply/stop of oxygen gas at a first pressure by opening and closing a first valve, and a second valve that can control the supply/stop of oxygen gas at a second pressure lower than the first pressure. and a second line that can be controlled by opening and closing.

In the following description, in order to make the present invention easier to understand, the first ejection port disposed at the center of the cutting tip for ejecting oxygen gas for cutting will be referred to as a "cutting oxygen ejection port". A second ejection port arranged to surround the first ejection port for ejecting preheating oxygen gas or curtain oxygen is referred to as a "preheating oxygen (in-oxygen) ejection port", and The third ejection port for ejecting the fuel gas that is the source of the preheating flame is called the "fuel gas ejection port", and is arranged so as to surround the third ejection port and ejects the oxygen gas for preheating. The fourth outlet for heating is called a "preheated oxygen (out-oxygen) outlet".

In addition, the oxygen gas for cutting is referred to as "cutting oxygen", and the oxygen gas for preheating ejected from the preheating oxygen (in-oxygen) ejection port is referred to as "preheating oxygen (in-oxygen)", and the preheating oxygen (out-oxygen) The preheating oxygen gas ejected from the ejection port will be referred to as "preheating oxygen (out oxygen)".

According to the gas cutting machine and the gas cutting method of the present invention, it is possible to cut a material having a curved surface at a low cost, safely and reliably.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be specifically described based on the attached drawings, but the present invention is not limited to these.

FIG. 1 shows an example of the gas cutter of the present invention. FIG. 2 shows an example of the cutting tip of FIG.
The gas cutting machine 10 includes a cutting tip 11, a cutting blowpipe (torch) 12 having the cutting tip 11 attached to the tip thereof, and supplying oxygen and fuel gas to the cutting tip 11 through the cutting blowpipe 12 and cutting the cutting tip. and a valve mechanism 13 for controlling ejection of each gas from 11 .

The cutting nozzle 11 includes a cutting oxygen nozzle (first nozzle) 1 for ejecting cutting oxygen arranged in the center, and a cutting oxygen nozzle 1 surrounding the cutting oxygen nozzle 1 to supply preheated oxygen (in-oxygen). A plurality of preheated oxygen (in-oxygen) jets (second jets) 2 for jetting, and a plurality of fuel gases for jetting fuel gas arranged so as to surround the preheated oxygen (in-oxygen) jets 2 An ejection port (third ejection port) 3 and a plurality of preheated oxygen (out-oxygen) ejection ports (fourth ejection port) arranged to surround the fuel gas ejection port 3 and for ejecting preheated oxygen (out-oxygen). 4.

For example, the preheating oxygen (in-oxygen) jets 2 are arranged on the circumference of two concentric circles centered on the cutting oxygen jet 1 . The fuel gas jets 3 are also arranged on the circumference of two concentric circles centered on the cutting oxygen jets 1 . Further, the preheating oxygen (out oxygen) jets 4 are arranged on the circumference of one circle centered on the cutting oxygen jet 1 . However, the layout of the preheated oxygen (in-oxygen) ejection port 2, the fuel gas ejection port 3, and the preheated oxygen (out-oxygen) ejection port 4 is not limited to this.

The cutting oxygen jet 1 jets cutting oxygen at a high pressure and a large flow rate when starting to cut the material (at the time of cutting) and when continuing to cut the material (at the time of cutting). The high pressure and high flow rate referred to here refer to pressure and flow rate sufficient to blow off combustion products and molten steel, for example, a pressure of 0.7 MPa or more and a flow rate of 50 Nm ³ /Hr or more. be.

The preheated oxygen (in-oxygen) ejection port 2 ejects preheated oxygen (in-oxygen) at a high pressure and a large flow rate when preheating the curved surface portion of the material having a curved surface before the start of cutting (during preheating). do. In addition, the preheated oxygen (inside oxygen) ejection port 2 ejects preheated oxygen (inside oxygen) at a low pressure and a small flow rate during cutting and cutting. The high pressure and high flow rate referred to here mean a pressure and flow rate that are greater than the pressure and flow rate during cutting and cutting, and are less than the pressure and flow rate of cutting oxygen. and a flow rate of 20 Nm ³ /Hr. In addition, the low pressure and low flow rate means a pressure and flow rate smaller than the pressure and flow rate during preheating, and are the same pressure and flow rate as the curtain oxygen, for example, a pressure of 0.01 MPa, and a pressure of 1 A flow rate of 0.5 Nm ³ /Hr is set.

The fuel gas ejection port 3 ejects fuel gas (such as LPG) at a low pressure and a small flow rate during cutting and cutting. The low pressure and small flow rate referred to here means a pressure and flow rate smaller than the pressure and flow rate of the preheated oxygen (in-oxygen) ejected from the preheated oxygen (in-oxygen) ejection port 2 during preheating. A pressure of 0.07 MPa and a flow rate of 12 Nm ³ /Hr are set.

The preheated oxygen (out oxygen) jet 4 jets out preheated oxygen (out oxygen) at a low pressure and a small flow rate during cutting and cutting. The low pressure and small flow rate referred to here means a pressure and flow rate smaller than the pressure and flow rate of the preheated oxygen (in-oxygen) ejected from the preheated oxygen (in-oxygen) ejection port 2 during preheating. A pressure of 0.07 MPa and a flow rate of 13 Nm ³ /Hr are set.

The valve mechanism 13 includes a cutting oxygen supply line that supplies oxygen gas as cutting oxygen to the cutting oxygen ejection port 1, and an in-oxygen supply line that supplies oxygen gas as preheated oxygen (in-oxygen) to the preheated oxygen (in-oxygen) ejection port 2. line (portion surrounded by frame 20), fuel gas supply line for supplying fuel gas to fuel gas ejection port 3, oxygen gas supplied as preheated oxygen (out oxygen) to preheated oxygen (out oxygen) ejection port 4 and an out oxygen supply line.

The cutting oxygen supply line supplies oxygen gas at a predetermined pressure (for example, 0.9 MPa) and a predetermined flow rate (90 Nm ³ /Hr) to the cutting oxygen jet 1 as cutting oxygen through the plug valve PV1 and the electromagnetic valve EV1. . In addition, the needle valve GV1 functions as a pressure/flow control valve, and when the electromagnetic valve EV1 is closed (the supply of cutting oxygen is stopped), the pressure of bypass oxygen (bleeder oxygen) is 0.01 MPa, for example. and 1.5 Nm ³ /Hr of oxygen gas is supplied to the cutting oxygen nozzle 1 .

The in-oxygen supply line 20 includes a high-pressure line (first line) capable of controlling the supply/stop of high-pressure oxygen gas at a first pressure and a large flow rate, and the supply/stop of low-pressure oxygen gas at a second pressure and a small flow rate. and a low-pressure line (second line) capable of controlling The high-pressure line supplies oxygen gas from the plug valve PV3 as preheated oxygen (in-oxygen) to the preheated oxygen (in-oxygen) jet 2 via a pressure/flow rate regulator PA3H and an electromagnetic valve (first valve) EV3H. . Pressure/flow regulator PA3H produces preheated oxygen (in-oxygen) at high pressure (eg 0.5 MPa) and large flow (20 Nm ³ /Hr).

In the low-pressure line, oxygen gas from the plug valve PV3 is supplied to the preheated oxygen (in oxygen) jet port 2 as preheated oxygen (in oxygen) via the pressure/flow regulator PA3L and the electromagnetic valve (second valve) EV3L. supply. Pressure/flow regulator PA3L produces preheated oxygen (in-oxygen) at low pressure (eg 0.01 MPa) and small flow (1.5 Nm ³ /Hr).

A fuel gas supply line supplies fuel gas to the fuel gas outlet 3 via a plug valve PV2, a pressure/flow regulator PA2, and an electromagnetic valve EV2. The pressure/flow regulator PA2 produces fuel gas with a pressure of 0.07 MPa and a flow rate of 12 Nm ³ /Hr, for example. Further, the needle valve GV2 is used for pilot fire, and supplies a very small amount of fuel gas to the fuel gas ejection port 3, for example.

The preheated oxygen (out-oxygen) supply line supplies oxygen gas as preheated oxygen (out-oxygen) to the preheated oxygen (out-oxygen) outlet 4 via the plug valve PV4, the pressure/flow regulator PA4, and the electromagnetic valve EV4. supply. The pressure/flow rate regulator PA4 generates oxygen gas at a pressure of, for example, 0.1 MPa and a flow rate of 30 Nm ³ /Hr. Further, the needle valve GV3 is used for pilot fire, and supplies, for example, a very small amount of oxygen gas to the preheated oxygen (out-oxygen) jet port 4 .

The needle valve 14 generates oxygen gas at a low pressure and a small flow rate based on preheated oxygen (out oxygen) at the time of conventional cutting and cutting, and supplies this as curtain oxygen to the preheated oxygen (in oxygen) jet port 2. It has a role to supply. However, in the present invention, as described above, the preheated oxygen (in-oxygen) is connected to the preheated oxygen (in-oxygen) jet port 2 and selectively separates the oxygen gas at high pressure and high flow rate from the oxygen gas at low pressure and low flow rate. It has a preheated oxygen (in-oxygen) supply line that can be supplied to the ejection port 2 .

Therefore, in the present invention, the needle valve 14 may always be kept closed, or may be omitted.

FIG. 3 shows waveform diagrams for controlling ejection/stopping of each gas by the valve mechanism of FIG. FIG. 4 shows an example of the gas cutting method of the present invention.
That is, by performing the control in FIG. 3, the operation shown in FIG. 4 is actually realized. Hereinafter, the gas cutting method of the present invention will be described with reference to FIGS. 3 and 4. FIG.

First, the operation of advancing the torch 12 (cutting tip 11) to the cutting start position is started, and the fuel gas electromagnetic valve (EV2 in FIG. 1) is opened to eject the fuel gas from the fuel gas ejection port 3. At this time, bypass oxygen is ejected from the cutting oxygen nozzle 1, seed flame gas is ejected from the fuel gas nozzle 3, and pilot flame oxygen is ejected from the preheating oxygen (out-oxygen) nozzle 4, respectively. ) is output (see FIG. 4(a)).

Next, when a predetermined time (for example, 0.5 seconds) has passed since the torch 12 started moving forward, it is determined that the torch 12 has reached the cutting start position, and the preheat oxygen (in oxygen) electromagnetic valve ( EV3H and EV3L in FIG. Here, in this example, it is assumed that both EV3H and EV3L in FIG. 1 are opened, but only EV3H in FIG. 1 may be opened and EV3L in FIG. 1 may be closed. At this time, the preheated oxygen (out oxygen) electromagnetic valve (EV4 in FIG. 1) is opened to eject preheated oxygen (out oxygen) from the preheated oxygen (out oxygen) ejection port 4 . As a result, a preheating strengthening flame is output from the cutting tip 11 (see FIG. 4(b)).

Next, when a predetermined time (for example, 0.5 seconds + 0.5 seconds) has elapsed since the torch 12 started to advance, it is determined that the torch 12 has reached the preheating start position, and the advance of the torch 12 is completed. Let Then, at the preheating start position, preheating by a preheating reinforcing flame is started for the preheating location X of the curved surface R of the material (for example, steel) 16 to be gas-cut (see FIG. 4(c)).

Next, after performing preheating with preheating intensifying flame for a predetermined time (for example, about 40 seconds), preheating of the preheating point X is completed. That is, the operation of retracting the torch 12 from the preheating start position to the cutting start position is started. When a predetermined time (for example, 0.5 seconds) has elapsed since the torch 12 started to retreat, it is determined that the torch 12 has reached the cutting start position (see FIG. 4(d)). Then, the preheated oxygen (in-oxygen) electromagnetic valves (EV3H and EV3L in FIG. 1) are closed to stop the injection of preheated oxygen (in-oxygen) from the preheated oxygen (in-oxygen) injection port 2 . Instead of this, the cutting oxygen electromagnetic valve (EV1 in FIG. 1) is opened to jet the cutting oxygen from the cutting oxygen jet port 1. As a result, a cutting flame is output from the cutting tip (see FIG. 4(e)).

Next, an operation (cutting operation) for advancing the torch 12 from the cutting start position toward the preheating start position is started. After a predetermined time (for example, 0.5 seconds) has elapsed since the torch 12 started to move forward, the torch 12 reaches the preheating start position. At this time, since the material 16 is sufficiently preheated at the preheating point X, cutting slag is formed by cutting oxygen, and cutting (cutting) of the material 16 is started (FIGS. 4(h)).

As described above, according to the gas cutting method of the present invention, using a so-called standing start, first, the preheating point X of the curved surface R of the material 16 to be gas-cut is heated for a predetermined time (for example, about 40 seconds). ) is preheated. In this case, the preheating point X reaches a high temperature (red color) and is sufficiently preheated. After that, when cutting (cutting) of the material 16 is started using cutting oxygen, cutting slag easily occurs at the preheating point X. and the actual disconnection starts. That is, according to the present invention, it is possible to provide a gas cutting machine and a gas cutting method capable of cutting a material having a curved surface at low cost, safely and reliably.

The gas cutting machine and gas cutting method described above are effective when starting to cut a material at a low temperature (for example, room temperature).

Specifically, there are secondary gas cutters that cut billets such as slabs and billets produced by continuous casting gas cutters into sizes required by users, and waste steel of various shapes generated in the steel manufacturing process. The above-described gas cutting machine and gas cutting method can be applied to a scrap gas cutter or the like that cuts ingots to a predetermined size for reuse as secondary raw materials.

EXAMPLES The present invention will be described in detail below with reference to examples, but these are not intended to limit the present invention.

(Example)
An attempt was made to cut a test material having a curved surface using the gas cutting machine and the gas cutting method described in FIGS. 1 to 4 (Example), and it was verified whether the test material could actually be cut. At this time, as a comparative example, cutting of the same test material was attempted using the following gas cutting machine and gas cutting method, and it was similarly verified whether or not the test material could be cut.

FIG. 5 shows a gas cutter of a comparative example. FIG. 6 shows an example of the cutting tip of FIG.
In the comparative example, the same parts as those of the gas cutting machine 10 shown in FIGS. 1 and 2 are denoted by the same reference numerals, and descriptions thereof are omitted.

The gas cutter 10′ of the comparative example differs from the gas cutter 10 of FIGS. 1 and 2 in that the comparative example does not have an in-oxygen supply line connected to the preheated oxygen (in-oxygen) jet port 2. . That is, in the comparative example, by keeping the needle valve 14 slightly open at all times, from the preheated oxygen (in-oxygen) ejection port 2, the preheated oxygen (out-oxygen) in the preheated oxygen (out-oxygen) supply line is low pressure and A small flow of oxygen gas (curtain oxygen) is always injected. In other words, in the comparative example, preheating using a preheating intensifying flame as in the present invention cannot be performed.

FIG. 7 shows waveform diagrams for controlling ejection/stopping of each gas by the valve mechanism of FIG. FIG. 8 shows a comparative gas cutting method for materials without curved surfaces. FIG. 9 shows a comparative gas cutting method for materials with curved surfaces.

In the gas cutting method of the comparative example, as described above, before starting cutting of the materials 15 and 16, preheating using the preheating intensifying flame cannot be performed, so cutting of the materials 15 and 16 by running start I do. In a running start, in a state where the fuel gas electromagnetic valve (EV2 in FIG. 5) is opened and the pilot flame (primary flame) is output (see FIGS. 8(a) and 9(a)), the preheating oxygen electromagnetic valve ( EV4 in FIG. 5) is opened, and a cutting oxygen electromagnetic valve (EV1 in FIG. 5) is opened to generate a cutting flame (see FIGS. 8(b) and 9(b)).

Thereafter, the torch 12 (cutting tip 11) is shifted to start cutting the materials 15 and 16 (see FIGS. 8(c)-(e) and 9(c)-(e)).

In the comparative example, as shown in FIG. 8, it was possible to cut the material with a running start for a material that does not have a curved surface, or a slab, bloom, billet, or the like whose corners have a small radius. However, as shown in FIG. 9, for materials with curved surfaces, especially round steel, pipes, columns, or slabs, blooms, billets, etc. with large corner radiuses, the embodiment makes it easy to start cutting the material. However, in the comparative example, cutting of the material could not be started even though the cutting operation was repeated many times with a running start.

The results of the cutting test in the example will be described below, taking as an example the case where a round steel is used as the test material.

・ Test material (round steel)
FIG. 11 shows a round bar as a test material.
A round steel as a test material has a size of 200 mm in radius (400 mm in diameter). USG (having the same structure as the cutting tip in FIG. 2) was used as the cutting tip.

At the time of preheating before starting cutting of the material (round steel) 17, the height from the upper end of the material 17 to the cutting tip 11 is set to 115 mm, and the height from the preheating point X to the cutting tip 11 is set to 177 mm. did. Further, the fuel gas is ejected from the fuel gas ejection port at a pressure of 0.07 MPa and a flow rate of 12 Nm ^{3 /} Hr. Bypass oxygen (bleeder oxygen) with a pressure of 0.01 MPa and a flow rate of 1.5 Nm ³ /Hr was jetted from the cutting oxygen jet to generate a preheating strengthening flame. Then, the preheating point X was preheated for 30 seconds using this preheating intensifying flame.

After that, the preheated oxygen (in-oxygen) is stopped, and instead, preheated oxygen (out-oxygen) at a pressure of 0.07 MPa and a flow rate of 13 Nm ³ /Hr is ejected from the preheated oxygen (out-oxygen) outlet, and further, Cutting oxygen having a pressure of 0.80 MPa and a flow rate of 80 Nm ³ /Hr was jetted from the cutting oxygen nozzle to generate a cutting flame. At this time, it was confirmed that cutting of the material 17 can be easily started from the preheated point X using the cutting flame.

Then, the cutting tip 11 was retracted at a retraction speed of 15 mm/min, and while cutting the material 17, the cutting tip 11 was moved from the preheating point X to the cutting start end surface. After that, the cutting tip 11 was advanced at a cutting speed of 60 mm/min until the cutting of the material 17 was completed.

From the above cutting test results, it was proved that the round steel can be cut at a low cost, safely and reliably in the example.

INDUSTRIAL APPLICABILITY As described above, according to the present invention, it is possible to provide a gas cutting machine and a gas cutting method capable of cutting a material having a curved surface at low cost, safely and reliably.

In addition, this invention is not limited to the said embodiment. The above-described embodiment is an example, and any device having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect is the present invention. included in the technical scope of

DESCRIPTION OF SYMBOLS 1... Cutting oxygen outlet, 2... Preheating oxygen (in oxygen) outlet, 3... Fuel gas outlet, 4... Preheating oxygen (out oxygen) outlet, 10... Gas cutter, 11... Cutting tip, 12... Cutting Blowpipe (torch) 13 Valve mechanism 14 GV1, GV2, GV3 Needle valve 15, 16, 17 Material (steel) 20 In-oxygen supply line PV1, PV2, PV3, PV4 Plug valve PA1, PA2, PA3H, PA3L, PA4... pressure/flow regulators, EV1, EV2, EV3H, EV3L, EV4... electromagnetic valves.

Claims (3)

A gas cutting machine comprising a cutting tip and a valve mechanism for controlling the ejection of gas from the cutting tip,
The gas cutter is capable of preheating material and cutting and cutting the preheated material,
The cutting nozzle includes a first ejection port for ejecting oxygen gas for cutting, which is arranged in the center, and a plurality of nozzles for ejecting oxygen gas for preheating, which are arranged so as to surround the first ejection port. a second ejection port, a plurality of third ejection ports arranged to surround the second ejection port for ejecting fuel gas, and a plurality of third ejection ports arranged to surround the third ejection port for preheating and a plurality of fourth ejection ports for ejecting oxygen gas,
The valve mechanism can independently control the pressure and flow rate of the gas supplied from the first ejection port to each of the fourth ejection ports, and the gas supply line connected to the second ejection port is , a first line capable of controlling the supply/stop of oxygen gas at a first pressure by opening/closing a first valve, and the supply/stop of oxygen gas at a second pressure lower than the first pressure by opening/closing a second valve. and a controllable second line. A gas cutting method for cutting a material having a curved surface using the gas cutting machine according to claim 1,
preheating the curved surface by ejecting oxygen gas for preheating at the first pressure from the second ejection port and ejecting the fuel gas from the third ejection port;
After the preheating, the oxygen gas for cutting is ejected from the first ejection port, the oxygen gas at the second pressure is ejected from the second ejection port, and the fuel gas is ejected from the third ejection port, The gas cutting method is characterized in that the cutting of the material is started by ejecting the oxygen gas for preheating from the fourth ejection port. 3. The gas cutting method according to claim 2, wherein after the curved surface is preheated, the position of the cutting tip is once retracted, and then cutting of the material is started from the end surface of the material.

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