JP5601866B2 - Piercing method and apparatus - Google Patents

Description

  The present invention relates to a piercing method and a piercing device for smoothly starting a cutting operation by removing slag generated when piercing (drilling) a material to be cut in a certain direction.

  2. Description of the Related Art Thermochemical cutting methods are widely practiced in which a part of a material to be cut such as a steel plate or non-ferrous plate material is oxidized and / or melted and removed from the base material. As this thermochemical cutting method, a gas cutting method that mainly cuts a steel plate using a gas cutting crater, a plasma cutting method that cuts a steel plate and a stainless steel plate using a plasma cutting crater, a metal material and a non-cutting method using a laser cutting crater. A laser cutting method for cutting a metal material has been put into practical use.

  When the above-mentioned cutting methods are used to cut a material to be cut made of a metal material, the material to be cut is generally pierced, and the target die cutting is started using the formed hole as a starting point. It is.

  When piercing the material to be cut, slag composed of an oxidation product or a molten base material is generated as the hole grows, and this slag blows up and adheres to the surface of the material to be cut. And when starting the cutting | disconnection with respect to a to-be-cut material, there exists a problem that the slag adhering to the surface inhibits the oxidation and fusion | melting of a base material, and cannot start a cutting | disconnection smoothly.

  In order to solve the above-mentioned problem, some methods such as a method of moving a crater with the growth of a hole and a method of blowing off a slag blown up in a certain direction can eliminate the influence of slag and start cutting. Proposals have been made. In addition, the present applicant has proposed a technique for removing slag generated by injecting slag exhaust gas from the injection hole around the piercing when piercing is performed on a nozzle attached to a cutting torch (Patent Document). 1).

Japanese Patent No. 3751728

  However, even the technique of Patent Document 1 does not disclose handling of the slag exhaust gas before starting cutting after piercing, and a response has been desired.

  The object of the present invention is to provide a new proposal for processing slag generated during piercing and starting cutting continuously, and is common to any of the gas cutting method, plasma cutting method and laser cutting method. It is an object of the present invention to provide a piercing method and a piercing apparatus that can be applied to the above.

In order to achieve the above object, a first configuration of a piercing method according to the present invention is a piercing method in which a part of a material to be cut is oxidized and / or melted and excluded from a base material to cut slag generated when cutting. A plurality of axes having an axis that coincides with a processing center line of a cutting torch selected from a gas cutting torch, a plasma cutting torch, or a laser cutting torch, and a circle that is set around the axis and that passes through the axis. Forming a jet port for injecting slag exhaust gas for blowing off the slag generated during piercing on the straight line, and performing piercing on the material to be cut by the nozzle attached to the cutting torch, the piercing portion from the jet port the slag exclusion gas injected around, the slag exclusion gas during pre Symbol piercing before starting the cut after piercing Than the flow rate or pressure, characterized in that to eliminate the slag generated by reducing the flow rate or pressure of the slag exclusion gas.

  Further, the second configuration of the piercing method according to the present invention is that, in the first configuration, when the material to be cut is iron or an iron alloy, air is used as slag exhaust gas injected from the injection port at the time of piercing. Alternatively, a mixed gas of oxygen gas, nitrogen gas, and argon gas and a mixed ratio of the oxygen gas with respect to the entire mixed gas is injected by 50% or less in terms of molar ratio.

  Further, a third configuration of the piercing method according to the present invention is that, in the first configuration, when the material to be cut is stainless steel or a non-ferrous alloy, oxygen is used as a slag exhaust gas injected from the injection port at the time of piercing. A mixed gas of gas, nitrogen gas, and argon gas, and a mixed gas having a molar ratio of oxygen gas to the entire mixed gas of 55% or more is injected.

The first configuration of the piercing apparatus according to the present invention is a piercing apparatus that oxidizes and / or melts a part of a material to be cut and eliminates slag generated when the material is cut from the base material and cut. A cutting torch selected from a cutting torch, a plasma cutting torch, or a laser cutting torch, and an axis that coincides with the machining center line of the cutting torch, and a plurality that passes through the axis on a circumference set around the axis An injection port for injecting slag exhaust gas for blowing off slag generated during piercing is formed on the straight line of the nozzle, and a nozzle attached to the cutting torch and the piercing for the material to be cut from the injection port injecting the slag exclusion gas around the piercing part, the slag exclusion gas during pre Symbol piercing before starting the cut after piercing Than the flow rate or pressure and having a gas supply control means for reducing the flow rate or pressure of the slag exclusion gas.

  A second configuration of the piercing apparatus according to the present invention is the first configuration, wherein the gas supply control means is configured to inject from the injection port during piercing when the material to be cut is iron or an iron alloy. As the slag exhaust gas, air or a mixed gas of oxygen gas, nitrogen gas, and argon gas, and a mixed gas having a molar ratio of oxygen gas to the whole mixed gas of 50% or less is injected from the injection port. It is characterized by that.

  According to a third configuration of the piercing apparatus according to the present invention, in the first configuration, the gas supply control unit is configured to inject from the injection port during piercing when the material to be cut is stainless steel or a non-ferrous alloy. As the slag exhaust gas, a mixed gas of oxygen gas, nitrogen gas, and argon gas, and a mixed gas having a molar ratio of oxygen gas to the whole mixed gas of 55% or more is injected from the injection port. And

According to each first configuration of the piercing method and the piercing apparatus according to the present invention, the slag generated at the time of piercing adheres radially around the piercing hole, and starts from the end of the hole to which no slag is attached. Smooth cutting can be started. Moreover, by reducing the flow rate or pressure of the slag eliminating gas than the flow rate or pressure of the slag exclusion gas during peak aliasing before starting the cut after piercing, it is less susceptible to slag exclusion gas during cutting I can do it.

  Further, according to the second to third configurations of the piercing method and the piercing apparatus according to the present invention, when the oxygen gas concentration contained in the slag exhaust gas is high, the piercing hole becomes larger and the slag discharged by that amount. Therefore, when the material to be cut is iron or an iron alloy, the mixing ratio of oxygen gas to the entire mixed gas is 50% or less in molar ratio, so that it is included in the slag exhaust gas. By controlling the oxygen gas concentration to be low, the piercing hole is reduced, and the amount of slag discharged and adhering to the material to be cut can be suppressed, and the yield is improved. When the material to be cut is stainless steel or a non-ferrous alloy, the oxygen gas concentration contained in the slag exhaust gas is increased by setting the mixing ratio of the oxygen gas to the whole mixed gas to 55% or more in terms of molar ratio. The slag adhering to the material to be cut can be easily peeled off.

It is a schematic explanatory drawing which shows the structure at the time of applying the piercing apparatus which concerns on this invention to a laser cutting device. It is a section explanatory view showing the composition of a nozzle. FIG. 3 is a front view of FIG. 2. It is a schematic diagram explaining the hole formed in the to-be-cut material by piercing, and the generated slag. It is a section explanatory view explaining other composition of a nozzle. (A) is a figure which shows the mode of the slag which generate | occur | produces on the surface of a to-be-cut material by the conventional piercing method, (b) shows the mode of slag which generate | occur | produces on the to-be-cut material surface when piercing by the piercing apparatus which concerns on this invention. FIG. The graph which shows the weight of the slag which generate | occur | produced when changing the mixing ratio (molar ratio) of the oxygen gas with respect to the whole mixed gas of a slag exclusion gas to the steel plate material and stainless steel material of thickness 25mm by the piercing apparatus based on this invention, respectively. It is.

  An embodiment of a piercing method and a piercing apparatus according to the present invention will be specifically described with reference to the drawings.

  In FIG. 1, reference numeral 15 denotes a piercing device that oxidizes and / or melts a part of a material to be cut D and eliminates slag 25 that is generated when the material D is cut from the base material. As shown in FIGS. 2 and 3, the piercing device 15 includes a cutting torch 16 appropriately selected from a gas cutting torch, a plasma cutting torch, or a laser cutting torch, and an axis 3 that coincides with the machining center line of the cutting torch 16. And an injection port 2 for injecting slag exhaust gas for blowing off the slag 25 generated at the time of piercing on a plurality of straight lines 4 passing through the axis 3 on a circumference set around the axis 3. When piercing the nozzle A attached to the cutting torch 16 and the material D to be cut, the slag exhaust gas is injected from the injection port 2 to the periphery of the piercing portion, and before the cutting is started after the piercing. A gas supply control means for stopping the slag exhaust gas or reducing the flow rate or pressure of the slag exhaust gas at the time of piercing. It is configured to have a gas supply device E.

  As shown in FIG. 1, the gas supply device E has a gas cylinder 21a containing nitrogen gas, a gas cylinder 21b containing oxygen gas, a gas cylinder 21c containing argon gas, and an air compressor 21d for compressing air in the atmosphere. The pressure regulators 22a to 22d are connected to the gas cylinders 21a to 21c and the air compressor 21d, and the flow rate adjusting valves 23a to 23d including electromagnetic valves are connected to the downstream side of the gas cylinders 21a to 21c. A flow rate control unit 17 that is connected to the mixer 14 and further controls the flow rate of the mixed gas mixed by the mixer 14 is provided downstream thereof. The mixed gas whose flow rate is controlled by the flow rate control unit 17 is supplied from the gas pipe 24 to the supply hole 8 of the nozzle A.

  As the configuration of the flow rate control unit 17, for example, two gas pipes having large and small diameters are connected in parallel in the middle of the gas pipe 24 through which the mixed gas mixed by the mixer 14 flows, and the diameter is large at the time of piercing. Open the gas pipe and close the gas pipe with a small diameter, close the gas pipe with a large diameter before starting cutting after piercing, and open the gas pipe with a small diameter, or close both large and small pipes. By doing so, the slag exhaust gas can be stopped before the cutting is started after piercing, or the flow rate or pressure of the slag exhaust gas can be reduced more than the flow rate or pressure of the slag exhaust gas at the time of piercing.

  Other configurations of the flow control unit 17 include, for example, flow control by a constant flow element that measures mass flow of a fluid and performs flow control, and an electropneumatic regulator (electropneumatic) that converts an electric signal into a gas pressure signal. The pressure control by a transformer) is performed to stop the slag exhaust gas before starting cutting after piercing, or the flow rate or pressure of the slag exhaust gas rather than the flow rate or pressure of the slag exhaust gas at the time of piercing. Can be reduced.

  Here, the constant flow element is a device that controls the flow rate by measuring the flow rate of the granule, and converts the command (setting) electrical signal set in advance and the actual flow rate actually flowing in the pipe into an electrical signal. The flow rate output signal is compared, and the valve opening is automatically adjusted so that the signal levels coincide with each other.

  The electropneumatic regulator (electropneumatic converter) is a device that continuously controls the gas pressure by an electrical command signal from a computer or the like.

  In this embodiment, when the material D to be cut is iron or an iron alloy, the gas supply device E uses air or oxygen gas, nitrogen gas, and argon gas as slag exhaust gas that is injected from the injection port 2 during piercing. And a mixed gas having a molar ratio of oxygen gas to the whole mixed gas of 50% or less is injected from the injection port 2.

  The air in the atmosphere has a mixing ratio of a molar ratio of 78% nitrogen gas, 21% oxygen gas, and a small amount of carbon dioxide, water vapor, argon, etc. When the material to be cut D is iron or an iron alloy Can supply only the air compressed by the air compressor 21d to the gas pipe 24 and inject it from the injection port 2 as the slag exhaust gas injected from the injection port 2 at the time of piercing.

  On the other hand, when the material D to be cut is stainless steel or a non-ferrous alloy, the slag exhaust gas injected from the injection port 2 at the time of piercing is a mixed gas of oxygen gas, nitrogen gas, and argon gas, and oxygen gas for the entire mixed gas A mixed gas having a molar ratio of 55% or more is injected from the injection port 2. After piercing, after stopping the injection of the mixed gas of oxygen gas, nitrogen gas and argon gas as the slag exhaust gas from the injection port 2, nitrogen gas or argon gas is injected from the injection port 2 as the inert gas. Then, the cutting of the workpiece D is started.

  The mixing ratio of oxygen gas to the whole mixed gas is set to 50% or less or 55% or more in terms of molar ratio by controlling the flow rate adjusting valves 23a to 23d by a control device (not shown). I can do it. As another example, a mixed gas in which the mixing ratio of oxygen gas to the whole mixed gas is set to 50% or less or 55% or more in advance is generated and accommodated in each gas cylinder. It may be connected to the gas pipe 24 via the regulating valve and supplied to the supply hole 8 of the nozzle A via the flow rate control unit 17.

  As shown in FIGS. 2 and 3, the nozzle A is configured such that a fitting hole 1 for fitting the crater B is formed at the center, and a plurality of injection holes 2 are formed around the fitting hole 1. ing. When the crater B is fitted into the fitting hole 1 of the nozzle A, one injection port 2 is formed on each of a plurality of straight lines 4 passing through the axis 3 that coincides with the machining center line of the crater B. That is, no other injection port 2 exists on the extended line of the straight line 4 connecting the injection port 2 and the axis 3.

  In the present embodiment, the nozzle A has a main body member 5 having a fitting hole 1 into which a crater B can be fitted at the center, and a plurality of nozzles that are fixed to the main body member 5 and inject a slag-excluding gas at a preset position. And a nozzle member 6 having an injection port 2.

  The nozzle A needs to be firmly integrated with the crater B when the crater B is fitted. For this reason, screw parts 7a and 7b are formed in the main body member 5 and the crater B, and the nozzle A and the crater B can be integrated by fastening these screw parts 7a and 7b. .

  The main body member 5 of the nozzle A is provided with a supply hole 8 through which the slag exhaust gas injected from the injection port 2 is supplied. The supply hole 8 is a ring-shaped member formed by the main body member 5 and the nozzle member 6. It is connected to the groove 9. An injection port 2 connected to the groove 9 is formed at a preset position of the nozzle member 6.

  Therefore, the supplied slag exhaust gas is injected from the injection port 2 to the outside by supplying the supply hole 8 with the slag exhaust gas selected from the oxidizing gas or the inert gas according to the material of the material D to be cut. Is possible.

  In this embodiment, when the crater B is fitted into the fitting hole 1 of the nozzle A, a ring-shaped slit 10 is formed along the outer peripheral surface of the crater B. This slit 10 is for injecting an oxidizing gas or an inert gas according to the material of the material D to be cut, and is formed only when a laser cutting crater is used as the crater B. For this reason, the main body member 5 is provided with a supply hole 11 communicating with the slit 10.

  When the selected gas is supplied to the supply hole 11, this gas is injected from the slit 10, wraps the laser beam irradiated from the crater B toward the material D to be cut in a sheath shape, and is heated by the laser beam. The combustion of the cutting material D is promoted, or the generated melt is excluded from the material D to be cut to form a kerf. Therefore, it is possible to cut the material D by irradiating the laser beam from the crater B toward the material D while injecting gas from the slit 10 and moving the crater B while maintaining this state. It is.

  Therefore, when a gas cutting crater or a plasma cutting crater is used as the crater B, it is not necessary to form the slit 10, and the fitting hole 1 formed in the body member 5 has an inner diameter equal to the outer diameter of these cutting craters. In addition, it is not necessary to form the supply hole 11 in the main body member 5.

  The laser cutting crater B has a torch body 16a (see FIG. 1) held by a torch holder (not shown), and the crater B is detachably attached to the tip of the torch body 16a. For this reason, a detachable screw 12 is formed at the end of the crater B on the torch body 16a side. The nozzle A is held by a torch holder (not shown) by being attached to the crater B attached to the torch body 16a by screwing the screw portions 7a and 7b.

  Even when the crater B is a gas cutting crater or a plasma cutting crater, these craters B are detachably attached to the torch body 16a as in the case of the laser cutting crater.

  Next, the procedure for piercing the workpiece D with the nozzle A configured as described above will be described with reference to FIGS. In FIG. 1, a gas supply device E is connected to a nozzle A fitted with a crater B. The gas supply device E includes gas cylinders 21a to 21c and an air compressor 21d, pressure adjusting devices 22a to 22d, flow rate adjusting valves 23a to 23d made of electromagnetic valves, a mixer 14, and a flow rate control unit 17. It is connected to the supply hole 8 of the nozzle A via the gas pipe 24.

  The gas cylinders 21a to 21c and the air compressor 21d are filled with a gas selected according to the material of the material D to be cut, and the selected gas is supplied to the nozzle A as a slag exhaust gas during piercing. That is, when the material to be cut D is mild steel, an inert gas such as nitrogen gas or argon gas, or a gas such as air or a gas obtained by slightly mixing oxygen gas with nitrogen gas is selected. When is a non-ferrous metal, an oxidizing gas typified by oxygen gas is selected.

  The pressure adjusting devices 22a to 22d have a function of adjusting the pressure of the slag exhaust gas supplied to the nozzle A, and the flow rate adjusting valves 23a to 23d, which are electromagnetic valves, and the flow rate control unit 17 are provided for the slag exhaust gas to the nozzle A. It has a function to control supply and shutoff.

  When the gas supply device E is connected to the nozzle A as described above, and the crater B is operated with the nozzle A facing the material D, the melt (slag) in which the material D is oxidized or melted. Blows up to the surface of the material D to be cut. At this time, when the slag exhaust gas is injected from the injection port 2 of the nozzle A, the slag is blown off by the injected slag exhaust gas.

  As shown in FIG. 4, the slag 25 is blown off to the opposite side of the injection port 2 around the piercing hole 26, and adheres radially around the piercing hole 26. That is, the slag 25 does not adhere to the nozzle A at a position corresponding to the injection port 2. Therefore, while maintaining the operating state of the crater B fitted to the nozzle A, the crater B is moved in the direction in which the slag 25 is not attached (direction of the injection port 2), thereby cutting the workpiece D. It is possible to start smoothly.

  Operate the flow control valves 23a to 23d to stop the slag exhaust gas before starting cutting after piercing, or reduce the flow or pressure of the slag exhaust gas from the flow or pressure of the slag exhaust gas during piercing. Then, the slag removal gas is injected from the injection port 2 of the nozzle A, and the generated slag 25 can be excluded.

In the experiments by the inventors of the present application, it has been found that it is more effective to intermittently inject the slag exclusion gas injected from the nozzle A toward the workpiece D during piercing rather than continuous injection. The term “intermittent” includes temporal intermittentness, pressure level, and time / pressure mixing. For example, when the time is intermittent, the range of 0.3 seconds to 1 second is preferable, and when the pressure is changed, the range of 0.1 MPa to 0.3 MPa (1 kg / cm ^{2 to} 3 kg / cm ² ) is preferable, When both are mixed, it is preferable that the value in the above range is appropriately selected and varied. Further, the slag 25 may be injected before the piercing is completed and solidified.

  According to the above configuration, the slag 25 generated during piercing adheres radially around the piercing hole 26, and smooth cutting can be started from the end of the piercing hole 26 where the slag 25 is not attached. I can do it. Also, stop slag exhaust gas before starting cutting after piercing, or reduce slag exhaust gas flow rate or pressure at the time of piercing to reduce slag exhaust gas flow rate or pressure. It can be made less susceptible to gas.

  Further, when the concentration of oxygen gas contained in the slag exhaust gas is high, the piercing hole 26 becomes large, and the slag 25 discharged by that amount cannot be suppressed, resulting in poor yield. For this reason, when the material D to be cut is iron or an iron alloy, the oxygen gas concentration contained in the slag exhaust gas is kept low by setting the mixing ratio of the oxygen gas to the entire mixed gas to 50% or less in terms of molar ratio. As a result, the piercing hole 26 is reduced, and the amount of the slag 25 that is discharged by that amount and adheres to the material D to be cut can be suppressed, and the yield is improved. When the material to be cut D is stainless steel or a non-ferrous alloy, or when the material to be cut D is iron or an iron alloy and the plate thickness exceeds about 25 mm, the mixing ratio of oxygen gas to the total mixed gas is 55 in molar ratio. By setting the ratio to at least%, it is possible to increase the concentration of oxygen gas contained in the slag removal gas to promote oxidation of the slag 25 and to easily peel off the slag 25 that has melted and adhered to the material D to be cut. Note that a pipe connected to a liquid supply device (not shown) may be connected to the supply hole 8 of the nozzle A to inject either the surfactant or water from the injection port 2.

  Next, another nozzle F will be described with reference to FIG. In FIG. 5, the same parts as those in the first embodiment described above and the parts having the same functions are denoted by the same reference numerals, and description thereof is omitted.

  In the nozzle F shown in FIG. 5, when the torch body 16a is fitted in the fitting hole 1 for fitting the torch body 16a, the axis 3 coincides with the center line of the crater B which is the processing center of the torch body 16a. A single injection port 2 is formed on the circumference around the axis 3 and on a straight line 4 passing through the axis 3.

  A screw 31 is formed in the fitting hole 1 of the nozzle F, and a screw 32 to be screwed with the screw 31 is formed in the torch body 16a. Therefore, the torch body 16a and the nozzle F can be integrated by inserting the torch body 16a through the fitting hole 1 and screwing the screws 31 and 32 together.

  Even with the nozzle F configured as described above, it is possible to blow off the slag 25 in the same manner as the nozzle A described above, and it is possible to start cutting smoothly after piercing.

  Further, in the nozzle F of the present embodiment, as shown by a broken line in FIG. 5, the entire nozzle F may be incorporated in the torch body 16a. Thus, even when the nozzle F is configured inside the torch main body 16a, it is possible to obtain the same effect as in the first embodiment.

  6A is a view showing a state of the slag 25 generated on the surface of the workpiece D by the conventional piercing method, and FIG. 6B is a diagram showing the surface of the workpiece D when piercing is performed by the piercing device 15. It is a figure which shows the mode of the slag 25 which generate | occur | produces. FIG. 7 shows the slag 25 generated when piercing is performed by changing the mixing ratio (molar ratio) of oxygen gas to the total mixed gas of slag exclusion gas into a steel plate material and a stainless steel material having a thickness of 25 mm by the piercing device 15. 4 is a graph showing the weight of the slag 25 attached to the surface of the material D to be cut. As the piercing device 15, a plasma cutting torch with an output of 400A manufactured by Koike Oxygen Co., Ltd. was used. As shown in FIG. 7, in the case where the material to be cut D is a steel plate material as an example of iron or an iron alloy, the material to be cut if the mixing ratio of oxygen gas to the total mixed gas of slag exhaust gas is 50% or less in molar ratio. The weight of the slag 25 adhering to the surface of the material D is kept as low as about 30 g, and when the material D to be cut is stainless steel or stainless steel as an example of the non-ferrous alloy, the mixing ratio of oxygen gas to the whole mixed gas of slag exhaust gas If the molar ratio is 55% or more, it can be seen that the weight of the slag 25 adhering to the surface of the material D to be cut is kept as low as about 25 g.

  As an application example of the present invention, the present invention can be applied to a piercing method and a piercing device for smoothly starting a cutting operation by eliminating slag generated when piercing (drilling) a material to be cut in a certain direction.

A ... Nozzle B ... Tinder D ... Material to be cut E ... Gas supply device (gas supply control means)
F ... Nozzle 1 ... Fitting hole 2 ... Injection port 3 ... Axis 4 ... Line 5 ... Main body member 6 ... Nozzle members 7a, 7b ... Threaded portion 8 ... Supply hole 9 ... Groove
10… Slit
11… Supply hole
12 ... Screw
13a to 13d ... Gas piping
14 ... Mixer
15… Piercing device
16… cutting torch
16a ... torch body
17… Flow control unit
21a-21c ... gas cylinder
21d Air compressor
22a to 22d ... pressure adjusting device
23a-23d ... Flow rate adjustment valve
24… Gas piping
25… slug
26… Piercing hole
31, 32 ... Screw

Claims (6)

A piercing method that eliminates slag generated when a part of a material to be cut is oxidized and / or melted and removed from a base material and cut.
An axis that coincides with the machining center line of a cutting torch selected from a gas cutting torch, a plasma cutting torch, or a laser cutting torch, and on a plurality of straight lines passing through the axis on a circumference set around the axis. An injection port for injecting slag exhaust gas for blowing off the slag generated at the time of piercing is formed, and the piercing is performed from the injection port to the periphery of the piercing portion when piercing the workpiece with the nozzle attached to the cutting torch. injecting slag exclusion gas, eliminating the slag generated by reducing the flow rate or pressure of the slag eliminating gas than the flow rate or pressure of the slag exclusion gas during pre Symbol piercing before starting the cut after piercing A piercing method characterized by the above. When the material to be cut is iron or an iron alloy, air or a mixed gas of oxygen gas, nitrogen gas, and argon gas as the slag exhaust gas injected from the injection port at the time of piercing and oxygen with respect to the entire mixed gas The piercing method according to claim 1, wherein a mixed gas having a gas mixing ratio of 50% or less in terms of molar ratio is injected. When the material to be cut is stainless steel or a non-ferrous alloy, a mixed gas of oxygen gas, nitrogen gas, and argon gas as a slag exhaust gas injected from the injection port at the time of piercing and mixing of oxygen gas with respect to the whole mixed gas 2. The piercing method according to claim 1, wherein a mixed gas having a molar ratio of 55% or more is injected. A piercing device that oxidizes and / or melts a part of a material to be cut and eliminates slag that is generated when the material is cut out of a base material.
A cutting torch selected from a gas cutting torch or a plasma cutting torch or a laser cutting torch;
Injecting slag exhaust gas for blowing off slag generated at the time of piercing on the circumference set around the axis and on a plurality of straight lines passing through the axis, the axis having the same axis as the machining center line of the cutting torch Forming a nozzle to be attached to the cutting torch;
Wherein injecting the slag exclusion gas around the piercing part from the injection port in the practice of the piercing for workpiece, the flow rate or pressure of the slag exclusion gas during pre Symbol piercing before starting the cut after piercing Gas supply control means for reducing the flow rate or pressure of the slag exhaust gas than
A piercing device comprising: When the material to be cut is iron or an iron alloy, the gas supply control means is air or a mixed gas of oxygen gas, nitrogen gas and argon gas as slag exhaust gas injected from the injection port during piercing. 5. The piercing apparatus according to claim 4, wherein a mixed gas having a molar ratio of oxygen gas to the entire mixed gas of 50% or less is injected from the injection port. When the material to be cut is stainless steel or a non-ferrous alloy, the gas supply control means is a mixed gas of oxygen gas, nitrogen gas and argon gas as the slag exhaust gas injected from the injection port at the time of piercing, and the mixture The piercing device according to claim 4, wherein a mixed gas having a molar ratio of oxygen gas to the whole gas of 55% or more is injected from the injection port.