JP2020192551A - Gas cutting device and gas cutting method - Google Patents

Abstract

To safely and surely cut a material having a curved surface at low cost.SOLUTION: A gas cutting device includes a cutting nozzle 11 and a valve mechanism 13 that controls blow out of gas from the cutting nozzle 11, in which the cutting nozzle 11 has a first blow-out port 1 for blowing out oxygen gas for cutting, a second blow-out port 2 for blowing out oxygen gas for preheating, a third blow-out port 3 for blowing out fuel gas and a fourth blow-out port 4 for blowing out oxygen gas for preheating, the valve mechanism 13 can independently control a pressure and a flow rate of gas supplied to each of the first blow-out port 1 to the fourth blow-out port 4, and the gas supply line connected to the second blow-out port 2 is composed of a first line that can control supply/stop of oxygen gas with a first pressure by opening/closing of a first valve EV3H and a second line that can control supply/stop of oxygen gas with a second pressure lower than the first pressure by opening/closing a second valve EV3L.SELECTED DRAWING: Figure 1

Description

The present invention relates to a gas cutting machine and a gas cutting method suitable for cutting a material having a curved surface.

In gas cutting, the surface of the steel material to be cut is heated to a high temperature by a preheating flame, and oxygen gas (cutting oxygen) is blown to the portion heated to the high temperature to cut the steel material. That is, when cutting oxygen is sprayed on a portion heated to a high temperature by a preheating flame, the steel material burns (the steel material reacts with oxygen to form an oxide), and the heat melts the steel material itself. Therefore, the steel material is cut by blowing off the combustion product and the molten steel material with the cutting oxygen.

As an example of a gas cutting machine used for such gas cutting, for example, there is one disclosed in Patent Document 1. As shown in Patent Document 1, various gases for gas cutting are ejected from the cutting crater. Further, the cutting crater surrounds the cutting oxygen spout that ejects cutting oxygen, the curtain oxygen spout that surrounds the cutting oxygen spout and ejects oxygen gas for a curtain, and the fuel gas that surrounds the curtain oxygen spout. A fuel gas outlet for ejecting oxygen gas is provided, and a preheated oxygen ejection outlet for ejecting oxygen gas for preheating surrounding the fuel gas outlet.

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, and as disclosed in Patent Document 1, the flow rate thereof is It is set to a small amount (a flow rate sufficiently smaller than the flow rate of oxygen gas for preheating). Also, curtain oxygen may be omitted.

JP-A-2018-167299 Japanese Unexamined Patent Publication No. 8-168877

The characteristic of gas cutting as described above is that energy for melting is supplied by combustion of a material (for example, steel) to which the energy is cut, and therefore, cutting of a thick material which is difficult to supply the energy from the outside is also possible. There is something you can do. However, conventionally, when trying to cut a material having a curved surface, there is a problem that sufficient preheating is not applied to the end portion (curved surface) at which the cutting is started, and the cutting of the material cannot be started forever.

For example, if the material to be gas cut does not have a curved surface, or if the corners have a small radius of curvature (R), such as slag, bloom, billet, etc., the preheating flame will hit the end where cutting starts. Therefore, sufficient preheating is applied to the end portion, and cutting oxygen (slag) can be easily generated by spraying 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 it hits the portion diagonally, sufficient preheating is not applied to the curved surface portion, and cutting oxygen cannot be generated even if cutting oxygen is sprayed.

In order to solve such a problem, conventionally, for example, as disclosed in Patent Document 2, powder (iron powder, etc.) is supplied to the preheating flame, and the combustion heat of the powder is used for cutting. There is one that causes cutting slag when sprayed with oxygen. Further, the same phenomenon occurs when the operator supplies the wire number (wire), and when oxygen for cutting is sprayed, a cutting glue can be generated.

However, the method of inserting powder requires a mechanism for inserting the powder (powder supply device, its accessories, etc.), which causes a problem of increased cost. In addition, when the operator supplies the track, the work of the operator must be increased and the safety of the operator must be taken into consideration.

The present invention has been made to solve the above problems, and an object of the present invention is 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 surely. To do.

In order to achieve the above object, the present invention is a gas cutting machine provided with a cutting crater and a valve mechanism for controlling gas ejection from the cutting crater, and the cutting crater is arranged in a central portion. A first spout for ejecting oxygen gas for cutting, a plurality of second spouts arranged so as to surround the first spout, and a plurality of second spouts for ejecting oxygen gas for preheating, and the second spout. A plurality of third spouts arranged so as to surround the spouts to eject fuel gas, and a plurality of first spouts arranged so as to surround the third spouts to eject oxygen gas for preheating. It has four spouts, and the valve mechanism can independently control the pressure and flow rate of the gas supplied from the first spout to each of the fourth spouts, and the second spout. The gas supply line connected to is the first line in which the supply / stop of the oxygen gas of the first pressure can be controlled by opening and closing the first valve, and the supply / stop of the oxygen gas of the second pressure lower than the first pressure. Provided is a gas cutting machine characterized in that the stop is composed of 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 a curved surface by supplying oxygen gas having a high pressure of the first pressure from the first line to the second ejection port. That is, since the curved surface portion can be preheated by using the enhanced preheating flame, sufficient preheating can be applied to the curved surface portion to start cutting the material. In addition, by supplying oxygen gas of 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 a material having a curved surface at low cost, safely, and reliably.

Further, the present invention is a gas cutting method for cutting a material having a curved surface by using the gas cutting machine, in which oxygen gas for preheating the first pressure is ejected from the second ejection port and the first. By ejecting the fuel gas from the three ejection ports, the curved surface is preheated, and after the preheating, the cutting oxygen gas is ejected from the first ejection port, and the second pressure is ejected from the second ejection port. It is characterized in that cutting of the material is started by ejecting the oxygen gas of the above, ejecting the fuel gas from the third ejection port, and ejecting the oxygen gas for preheating from the fourth ejection port. Provide a gas cutting method.

According to such a gas cutting method, it is possible to preheat the curved surface portion of the material having a curved surface by first supplying oxygen gas having a high pressure of the first pressure from the first line to the second ejection port. Become. That is, since the curved surface portion can be preheated by using the enhanced preheating flame, sufficient preheating can be applied to the curved surface portion to start cutting the material. After that, oxygen gas for cutting is ejected from the first ejection port, oxygen gas having a second pressure having a relatively low pressure is ejected from the second ejection port, fuel gas is ejected from the third ejection port, and the first 4 By ejecting oxygen gas for preheating from the ejection port, cutting of the material can be started by the cutting oxygen, and after that, cutting of the material can be stably continued. In this way, it is possible to cut a material having a curved surface at low cost, safely, and reliably.

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

In this way, by using a standing start in which the position of the cutting crater is retracted after preheating the curved surface and cutting is started from the end face of the material, regardless of the temperature of the material to be gas-cut (for example, at room temperature). You can certainly start cutting the material (if any).

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 surely.

It is a figure which shows an example of the gas cutting machine of this invention. It is a figure which shows the example of the cutting crater of FIG. It is a waveform diagram for controlling the ejection / stop of each gas by the valve mechanism of 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 cutting machine of the comparative example. It is a figure which shows the example of the cutting crater of FIG. It is a waveform diagram for controlling the ejection / stop of each gas by the valve mechanism of FIG. It is a figure which shows the gas cutting method of the comparative example with respect to the material which does not have a curved surface. It is a figure which shows the gas cutting method of the comparative example with respect to the material which has a curved surface. It is a figure which shows the round steel as a test material.

As described above, conventionally, there has been a problem that cutting of a material having a curved surface cannot be started. For example, when the temperature of the material (for example, steel) to be gas-cut is high (for example, 600 ° or more), a conventional preheating flame is used to preheat the curved surface portion where the cutting is started, and then the curved surface portion is preheated. It may be possible to start cutting with a standing start in which the position of the cutting crater is once retracted and then cutting is started from the end face of the material, but this is not certain. Further, when the temperature of the material to be gas-cut is low (for example, normal temperature), the temperature of the curved surface portion does not rise even if the curved surface portion to start cutting is preheated for a long time, and then the curved surface portion does not rise. Cutting cannot be started because the cutting surface does not occur even if the cutting operation is performed.

Therefore, even in these cases, a method of supplying powder and a method of supplying the track by the operator have been known as a method for reliably starting cutting of the material, but the former has a problem of increasing the cost. The latter has a problem that the work of the operator increases and the safety of the operator must be taken into consideration.

Therefore, it is possible to cut curved materials such as round steel, pipes, columns, and slabs, blooms, and billets with large R at the corners at low cost, safely, and reliably. There was a need to develop a new gas cutting machine and gas cutting method.

As a result of diligent studies on the above problems, the present inventor first focused on the structure of the cutting crater. When cutting a material having a curved surface, in order to start cutting, that is, to generate cutting slag at the curved surface portion by cutting oxygen, a preheating flame sufficient to sufficiently preheat the curved surface portion is generated. Just do it. However, conventionally, the preheated oxygen outlet that ejects the oxygen gas for preheating exists on the outermost periphery of the cutting crater, and the pressure and flow rate of the oxygen gas for preheating are sufficient to control the curved surface portion. I couldn't get it.

On the other hand, in the cutting crater, there is a curtain oxygen ejection port that ejects oxygen gas for a curtain as an ejection port capable of ejecting oxygen gas in addition to the cutting oxygen ejection port and the preheated oxygen ejection port. The pressure and flow rate of the oxygen gas (curtain oxygen) ejected from the curtain oxygen outlet is set to a small value for the purpose of maintaining the purity of the cutting oxygen and assisting the combustion of the fuel gas. It was fixed. Therefore, the present inventor has made further diligent studies from the viewpoint of whether the curtain oxygen outlet can be used as a preheated oxygen outlet.

As a result, the present inventor has found that the curtain oxygen ejection port exists on the innermost circumference of the cutting crater, and by using this as the preheating oxygen ejection port, it is possible to obtain an astonishing heating capacity for the curved surface portion. I found it. In addition, the present inventor is effective in preheating the curved surface portion when starting cutting of a material having a curved surface, but the curved surface portion is sufficiently preheated, and once After the cutting of the material is started, in order to continue the cutting of the material in a stable manner, the oxygen gas for preheating is ejected from the preheating oxygen outlet arranged at the outermost periphery of the cutting crater and the cutting is performed as before. We have found that it is preferable to eject curtain oxygen from the curtain oxygen outlet located on the innermost circumference of the crater.

Then, the present inventor further diligently studied what kind of changes should be made in the conventional gas cutting machine and gas cutting method in order to realize the above, and as a result, the gas connected to the curtain oxygen ejection port The supply line is the first line in which the supply / stop of the oxygen gas of the first pressure (high pressure) can be controlled by opening and closing the first valve, and the supply of the oxygen gas of the second pressure (low pressure) lower than the first pressure. The present invention has been completed by finding that the / stop may be composed of a second line that can be controlled by opening and closing the second valve.

That is, the present invention is a gas cutting machine provided with a cutting crater and a valve mechanism for controlling the ejection of gas from the cutting crater, and the cutting crater is arranged in a central portion and oxygen gas for cutting. A first spout for ejecting a gas, a plurality of second spouts arranged so as to surround the first spout, and a plurality of second spouts for ejecting oxygen gas for preheating, and a second spout so as to surround the second spout. It has a plurality of third outlets arranged to eject fuel gas, and a plurality of fourth outlets arranged so as to surround the third outlet to eject oxygen gas for preheating. However, 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 connected to the second ejection port. The lines are the first line in which the supply / stop of the oxygen gas of the first pressure can be controlled by opening and closing the first valve, and the supply / stop of the oxygen gas of the second pressure lower than the first pressure of the second valve. It is a gas cutting machine characterized by being composed of 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 outlet for ejecting oxygen gas for cutting, which is arranged at the center of the cutting crater, is referred to as a "cutting oxygen outlet". The second spout for ejecting oxygen gas for preheating or curtain oxygen, which is arranged so as to surround the first spout, is called a "preheating oxygen (in oxygen) spout" and surrounds the second spout. The third spout for ejecting the fuel gas that is the source of the preheating flame is called a "fuel gas spout", and is arranged so as to surround the third spout to eject oxygen gas for preheating. The fourth spout for this purpose will be referred to as a "preheated oxygen (out oxygen) spout".

In addition, the oxygen gas for cutting is called "cutting oxygen", and the oxygen gas for preheating ejected from the preheating oxygen (in oxygen) outlet is called "preheating oxygen (in oxygen)", and the preheating oxygen (out oxygen) The oxygen gas for preheating ejected from the spout is 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 low cost, safely and surely.

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings, but the present invention is not limited thereto.

FIG. 1 shows an example of the gas cutting machine of the present invention. FIG. 2 shows an example of the cutting crater of FIG.
The gas cutting machine 10 supplies oxygen and fuel gas to the cutting crater 11 through the cutting crater 11, the cutting crater (torch) 12 to which the cutting crater 11 is attached at the tip, and the cutting crater 11 and the cutting crater 11. A valve mechanism 13 for controlling the ejection of each gas from 11 is provided.

The cutting crater 11 is arranged at the center and is arranged so as to surround the cutting oxygen outlet (first outlet) 1 for ejecting cutting oxygen and the cutting oxygen outlet 1 to provide preheated oxygen (in oxygen). A plurality of preheated oxygen (in oxygen) outlets (second outlet) 2 for ejecting and a plurality of fuel gases for ejecting fuel gas arranged so as to surround the preheated oxygen (in oxygen) outlet 2. A plurality of preheated oxygen (out oxygen) spouts (fourth spout) arranged so as to surround the spout (third spout) 3 and the fuel gas spout 3 for ejecting preheated oxygen (out oxygen). Has 4 and.

For example, the preheated oxygen (in oxygen) spout 2 is arranged on the circumference of two concentric circles centered on the cutting oxygen spout 1. Further, the fuel gas outlet 3 is also arranged on the circumference of two concentric circles centered on the cutting oxygen outlet 1. Further, the preheated oxygen (out oxygen) outlet 4 is arranged on the circumference of one circle centered on the cutting oxygen outlet 1. However, the layout of the preheated oxygen (in oxygen) outlet 2, the fuel gas outlet 3, and the preheated oxygen (out oxygen) outlet 4 is not limited to this.

The cutting oxygen outlet 1 ejects cutting oxygen at a high pressure and a large flow rate when cutting the material is started (at the time of cutting) and when the material is being cut (at the time of cutting). The high pressure and the large flow rate referred to here are a pressure and a flow rate sufficient to blow off the combustion product and the molten steel material, for example, a pressure of 0.7 MPa or more and a flow rate of 50 Nm ³ / Hr or more. is there.

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). To do. Further, the preheated oxygen (in oxygen) ejection port 2 ejects preheated oxygen (in oxygen) at a low pressure and a small flow rate at the time of cutting and cutting. The high pressure and the large flow rate here mean a pressure and a flow rate that are larger than the pressure and the flow rate at the time of cutting and cutting and smaller than the pressure and the flow rate of the cutting oxygen, for example, a pressure of 0.5 MPa. And set to a flow rate of 20 Nm ³ / Hr. Further, the low pressure and the small flow rate mean the pressure and the flow rate smaller than the pressure and the flow rate at the time of preheating, and the same pressure and the flow rate as the pressure and the flow rate as the curtain oxygen, for example, the pressure of 0.01 MPa and 1 The flow rate is set to .5 Nm ³ / Hr.

The fuel gas outlet 3 ejects fuel gas (LPG or the like) at a low pressure and a small flow rate at the time of cutting and cutting. The low pressure and the small flow rate here mean a pressure and a flow rate smaller than the pressure and the flow rate of the preheated oxygen (in oxygen) ejected from the preheated oxygen (in oxygen) outlet 2 at the time of preheating, for example, 0. The pressure is set to .07 MPa and the flow rate is set to 12 Nm ³ / Hr.

The preheated oxygen (out oxygen) ejection port 4 ejects preheated oxygen (out oxygen) at a low pressure and a small flow rate at the time of cutting and cutting. The low pressure and the small flow rate here mean a pressure and a flow rate smaller than the pressure and the flow rate of the preheated oxygen (in oxygen) ejected from the preheated oxygen (in oxygen) outlet 2 at the time of preheating, for example, 0. The pressure is set to .07 MPa and the flow rate is set to 13 Nm ³ / Hr.

The valve mechanism 13 supplies a cutting oxygen supply line that supplies oxygen gas as cutting oxygen to the cutting oxygen ejection port 1 and an in-oxygen supply that supplies oxygen gas as preheating oxygen (in-oxygen) to the preheating oxygen (in-oxygen) ejection port 2. A line (a portion surrounded by a frame 20), a fuel gas supply line that supplies fuel gas to the fuel gas outlet 3, and oxygen gas as preheated oxygen (out oxygen) are supplied to the preheated oxygen (out oxygen) outlet 4. It is equipped with an out oxygen supply line.

The cutting oxygen supply line supplies oxygen gas having a predetermined pressure (for example, 0.9 MPa) and a predetermined flow rate (90 Nm ³ / Hr) to the cut oxygen outlet 1 as cutting oxygen via the plug valve PV1 and the solenoid valve EV1. .. Further, the needle valve GV1 functions as a pressure / flow rate adjusting valve, and when the electromagnetic valve EV1 is closed (a state in which the supply of cutting oxygen is stopped), the bypass oxygen (bleeder oxygen) is, for example, 0.01 MPa. And 1.5 Nm ³ / Hr of oxygen gas is supplied to the cutting oxygen outlet 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 supply / stop of oxygen gas at a low pressure of a second pressure and a small flow rate. It is equipped with a low-pressure line (second line) that can control. The high-pressure line supplies oxygen gas from the plug valve PV3 to the preheated oxygen (in oxygen) outlet 2 as preheated oxygen (in oxygen) via the pressure / flow rate regulator PA3H and the electromagnetic valve (first valve) EV3H. .. The pressure / flow rate regulator PA3H produces preheated oxygen (in oxygen) at high pressure (eg 0.5 MPa) and large flow rate (20 Nm ³ / Hr).

Further, in the low pressure line, oxygen gas from the plug valve PV3 is sent to the preheated oxygen (in oxygen) outlet 2 as preheated oxygen (in oxygen) via the pressure / flow rate regulator PA3L and the electromagnetic valve (second valve) EV3L. Supply. The pressure / flow rate regulator PA3L produces preheated oxygen (in oxygen) at low pressure (eg 0.01 MPa) and small flow rate (1.5 Nm ³ / Hr).

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

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

The needle valve 14 generates low-pressure and small flow rate oxygen gas based on preheated oxygen (out oxygen) at the time of conventional cutting and cutting, and uses this as curtain oxygen to the preheated oxygen (in oxygen) outlet 2. It has a role of supplying. However, in the present invention, as described above, the preheated oxygen (in-oxygen) is connected to the preheated oxygen (in-oxygen) outlet 2, and the high-pressure and large-flow oxygen gas and the low-pressure and small-flow oxygen gas are selectively preheated (in-oxygen). It has a preheated oxygen (in oxygen) supply line that can supply to the spout 2.

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

FIG. 3 shows a waveform diagram for controlling the 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 of 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.

First, the operation of advancing the torch 12 (cutting crater 11) to the cutting start position is started, and the fuel gas solenoid valve (EV2 in FIG. 1) is opened to eject the fuel gas from the fuel gas outlet 3. At this time, by ejecting bypass oxygen from the cutting oxygen outlet 1, pilot gas from the fuel gas outlet 3, and pilot oxygen from the preheating oxygen (out oxygen) outlet 4, the pilot flame (pilot) is ejected from the cutting crater. ) Is output (see FIG. 4 (a)).

Next, when a predetermined time (for example, 0.5 seconds) has elapsed from the start of advancing the torch 12, it is determined that the torch 12 has reached the cutting start position, and the preheated oxygen (in oxygen) solenoid valve ( EV3H and EV3L) in FIG. 1 are opened to eject preheated oxygen (in oxygen) from the preheated oxygen (in oxygen) outlet 2. Here, in this example, it is assumed that both EV3H and EV3L of FIG. 1 are opened, but only EV3H of FIG. 1 may be opened and EV3L of FIG. 1 may be closed. At this time, the preheated oxygen (out oxygen) solenoid valve (EV4 in FIG. 1) is opened to eject the preheated oxygen (out oxygen) from the preheated oxygen (out oxygen) outlet 4. As a result, the preheating enhanced flame is output from the cutting crater 11 (see FIG. 4B).

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

Next, after preheating with the preheating strengthening flame for a predetermined time (for example, about 40 seconds), the preheating of the preheating portion 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 from the start of the retreat of the torch 12, it is determined that the torch 12 has reached the cutting start position (see FIG. 4D). Then, the preheated oxygen (in oxygen) solenoid valves (EV3H and EV3L in FIG. 1) are closed to stop the ejection of the preheated oxygen (in oxygen) from the preheated oxygen (in oxygen) outlet 2. Instead of this, the cutting oxygen solenoid valve (EV1 in FIG. 1) is opened to eject the cutting oxygen from the cutting oxygen outlet 1. As a result, the cutting flame is output from the cutting crater (see FIG. 4 (e)).

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

As described above, according to the gas cutting method of the present invention, first, using the so-called standing start, a predetermined time (for example, about 40 seconds) with respect to the preheated portion X of the curved surface R of the material 16 to be gas cut. ) Preheat. In this case, the preheated portion X becomes high temperature (red) and sufficient preheating is performed. Therefore, when cutting (cutting) of the material 16 is started using cutting oxygen after that, a cutting slag is easily generated at the preheated portion X. Then, the cutting is actually started. 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 surely.

The gas cutting machine and the gas cutting method are effective when starting cutting of a material at a low temperature (for example, room temperature).

Specifically, secondary gas cutters that cut steel pieces such as slabs and billets generated by continuous casting gas cutters to the size required by the user, and scrap steel of various shapes generated in the steel manufacturing process. The above gas cutting machine and gas cutting method can be applied to a scrap gas cutter or the like that cuts the bullion into a certain size in order to reuse it as a secondary raw material.

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

(Example)
Using the gas cutting machine and the gas cutting method described in FIGS. 1 to 4, an attempt was made to cut a test material having a curved surface (Example), and it was verified whether or not 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 similarly, it was verified whether or not the test material could be cut.

FIG. 5 shows a gas cutting machine of a comparative example. FIG. 6 shows an example of the cutting crater of FIG.
In the comparative example, the same parts as those of the gas cutting machine 10 of FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

The difference between the gas cutting machine 10'of the comparative example and the gas cutting machine 10 of FIGS. 1 and 2 is that the in-oxygen supply line connected to the preheated oxygen (in-oxygen) ejection port 2 does not exist in the comparative example. .. That is, in the comparative example, by always opening the needle valve 14 in a small amount, the preheated oxygen (in oxygen) outlet 2 is low pressure and low pressure based on the preheated oxygen (out oxygen) of the preheated oxygen (out oxygen) supply line. A small flow of oxygen gas (curtain oxygen) is constantly ejected. In other words, in the comparative example, preheating using the preheating enhancing flame as in the present invention cannot be performed.

FIG. 7 shows a waveform diagram for controlling the ejection / stopping of each gas by the valve mechanism of FIG. FIG. 8 shows a gas cutting method of a comparative example for a material having no curved surface. FIG. 9 shows a gas cutting method of a comparative example for a material having a curved surface.

In the gas cutting method of the comparative example, as described above, it is not possible to perform preheating using the preheating strengthening flame before starting the cutting of the materials 15 and 16, so that the materials 15 and 16 are cut by the running start. I do. At the running start, in the state where the fuel gas solenoid valve (EV2 in FIG. 5) is opened and the pilot flame (separate flame) is output (see FIGS. 8A and 9A), the preheated oxygen solenoid valve (see FIG. 8A and FIG. By opening EV4) in FIG. 5 and further opening the cutting oxygen solenoid valve (EV1 in FIG. 5), a cutting flame is generated (see FIGS. 8 (b) and 9 (b)).

After that, cutting of the materials 15 and 16 is started by shifting the torch 12 (cutting crater 11) (see FIGS. 8 (c) to (e) and FIGS. 9 (c) to 9 (e)).

In the comparative example, as shown in FIG. 8, for a material having no curved surface or a slab, bloom, billet or the like having a small radius at the corner, the material could be cut at the running start. However, as shown in FIG. 9, for materials having curved surfaces, particularly round steel, pipes, columns, or slabs, blooms, billets, etc. with large R at the corners, in the examples, cutting of the material is easily started. However, in the comparative example, the cutting operation was repeated many times at the running start, but the cutting of the material could not be started.

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

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

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 crater 11 is set to 115 mm, and the height from the preheating point X to the cutting crater 11 is set to 177 mm. did. The fuel gas is ejected from the fuel gas outlet at a pressure of 0.07 MPa and a flow rate of 12 Nm ³ / Hr, and the preheated oxygen (in oxygen) is ejected from the fuel gas outlet at a pressure of 0.50 MPa and a flow rate of 20 Nm ³ / Hr. In oxygen), bypass oxygen (bleeder oxygen) with a pressure of 0.01 MPa and a flow rate of 1.5 Nm ³ / Hr was ejected from the cutting oxygen outlet to generate a preheat enhanced flame. Then, the preheating portion X was preheated for 30 seconds using this preheating strengthening flame.

After that, the preheating oxygen (in oxygen) is stopped, and instead, the preheating oxygen (out oxygen) having 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 at a pressure of 0.80 MPa and a flow rate of 80 Nm ³ / Hr was ejected from the cutting oxygen outlet to generate a cutting flame. At this time, it was confirmed that the cutting flame can be used to easily start cutting the material 17 from the preheating portion X.

Then, the cutting crater 11 was retracted at a recession speed of 15 mm / min, and the cutting crater 11 was moved from the preheating point X to the cutting start end face while cutting the material 17. After that, the cutting crater 11 was advanced at a cutting speed of 60 mm / min, and the cutting crater 11 was advanced 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 low cost, safely and surely in the examples.

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 surely.

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

1 ... cutting oxygen outlet, 2 ... preheated oxygen (in oxygen) outlet, 3 ... fuel gas outlet, 4 ... preheated oxygen (out oxygen) outlet, 10 ... gas cutting machine, 11 ... cutting crater, 12 ... cutting Blowing pipe (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 rate regulator, EV1, EV2, EV3H, EV3L, EV4 ... Solenoid valve.

Claims (3)

A gas cutting machine equipped with a cutting crater and a valve mechanism for controlling the ejection of gas from the cutting crater.
The cutting crater is arranged in a central portion to eject oxygen gas for cutting, and a plurality of cutting craters arranged so as to surround the first ejection port to eject oxygen gas for preheating. A second spout, a plurality of third spouts arranged so as to surround the second spout for ejecting fuel gas, and a plurality of third spouts arranged so as to surround the third spout for preheating. It has multiple fourth outlets for ejecting oxygen gas,
The valve mechanism can independently control the pressure and flow rate of the gas supplied from the first spout to each of the fourth spouts, and the gas supply line connected to the second spout is , The supply / stop of the oxygen gas of the first pressure can be controlled by opening / closing the first valve, and the supply / stop of the oxygen gas of the second pressure lower than the first pressure can be controlled by opening / closing the second valve. A gas cutting machine characterized in that it consists of 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.
The curved surface is preheated by ejecting oxygen gas for preheating 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 of the second pressure is ejected from the second ejection port, and the fuel gas is ejected from the third ejection port. A gas cutting method characterized in that cutting of the material is started by ejecting the oxygen gas for preheating from the fourth ejection port. The gas cutting method according to claim 2, wherein after preheating the curved surface, the position of the cutting crater is once retracted, and then cutting of the material is started from the end face of the material.

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