CN101175596B - Plasma cutting device and method - Google Patents
Plasma cutting device and method Download PDFInfo
- Publication number
- CN101175596B CN101175596B CN2006800168966A CN200680016896A CN101175596B CN 101175596 B CN101175596 B CN 101175596B CN 2006800168966 A CN2006800168966 A CN 2006800168966A CN 200680016896 A CN200680016896 A CN 200680016896A CN 101175596 B CN101175596 B CN 101175596B
- Authority
- CN
- China
- Prior art keywords
- oxygen
- plasma
- assist gas
- gas
- oxygen concentration
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000005520 cutting process Methods 0.000 title claims abstract description 74
- 238000000034 method Methods 0.000 title claims description 66
- 239000007789 gas Substances 0.000 claims abstract description 220
- 239000001301 oxygen Substances 0.000 claims abstract description 168
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 168
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 167
- 229910001209 Low-carbon steel Inorganic materials 0.000 claims abstract description 24
- 230000009471 action Effects 0.000 claims description 61
- 230000008569 process Effects 0.000 claims description 59
- 238000012423 maintenance Methods 0.000 claims description 47
- 229910000851 Alloy steel Inorganic materials 0.000 claims description 11
- 230000008859 change Effects 0.000 claims description 6
- 238000005507 spraying Methods 0.000 claims description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 61
- 239000003570 air Substances 0.000 abstract description 51
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 31
- 238000002485 combustion reaction Methods 0.000 abstract 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 40
- 239000000377 silicon dioxide Substances 0.000 description 20
- 239000000203 mixture Substances 0.000 description 18
- 229910000831 Steel Inorganic materials 0.000 description 10
- 239000007921 spray Substances 0.000 description 10
- 239000010959 steel Substances 0.000 description 10
- 230000001590 oxidative effect Effects 0.000 description 9
- 239000003595 mist Substances 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 230000001681 protective effect Effects 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 230000006378 damage Effects 0.000 description 5
- 238000011144 upstream manufacturing Methods 0.000 description 5
- 239000000498 cooling water Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 238000010891 electric arc Methods 0.000 description 3
- 239000011261 inert gas Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 230000002045 lasting effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000006396 nitration reaction Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 150000002926 oxygen Chemical class 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K10/00—Welding or cutting by means of a plasma
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K10/00—Welding or cutting by means of a plasma
- B23K10/006—Control circuits therefor
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/32—Plasma torches using an arc
- H05H1/34—Details, e.g. electrodes, nozzles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/38—Selection of media, e.g. special atmospheres for surrounding the working area
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K37/00—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups
- B23K37/02—Carriages for supporting the welding or cutting element
- B23K37/0288—Carriages forming part of a cutting unit
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/32—Plasma torches using an arc
- H05H1/34—Details, e.g. electrodes, nozzles
- H05H1/341—Arrangements for providing coaxial protecting fluids
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/32—Plasma torches using an arc
- H05H1/34—Details, e.g. electrodes, nozzles
- H05H1/3494—Means for controlling discharge parameters
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/32—Plasma torches using an arc
- H05H1/34—Details, e.g. electrodes, nozzles
- H05H1/36—Circuit arrangements
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H1/00—Generating plasma; Handling plasma
- H05H1/24—Generating plasma
- H05H1/26—Plasma torches
- H05H1/32—Plasma torches using an arc
- H05H1/42—Plasma torches using an arc with provisions for introducing materials into the plasma, e.g. powder, liquid
Abstract
In plasma cutting of mild steel or mild steel, it is necessary to control the oxygen concentration of the assist gas in order to reduce adhesion of dross around the hole during piercing. Oxygen, air, or a mixed gas of oxygen and nitrogen, or the like is used as the plasma gas. Nitrogen, oxygen, air, or a mixed gas of oxygen and air, or the like is used as the assist gas. In the piercing step, the oxygen concentration of the assist gas is controlled to be higher than that in the cutting step. In the piercing step, the oxygen concentration of the assist gas is 20 mol% or more, preferably 100 mol% or a high concentration close to this value; in the cutting step, the oxygen concentration of the assist gas is 20 mol% or more and lower than the combustion concentration, for example, 40 mol% to 80 mol%.
Description
Technical field
The present invention relates to plasma cutter and method, particularly to the improvement of the gas composition that offers plasma gun.
Background technology
As everyone knows, in the plasma cutting that the mist that uses oxygen, air or oxygen and nitrogen etc. cuts mild steel, low-alloy steel or mild steel as plasma gas (being also referred to as working gas, main gas or a gas), by containing the assist gas (being also referred to as secondary air) of sizable ratio oxygen to supply around the plasma arc of spray gun ejection, can improve cut quality, especially can reduce scum silica frost (motlten metal is not blown away and adheres to and is set on the workpiece) attached to back of work.Disclose the document that uses oxygen containing assist gas following document has for example been arranged.
Patent documentation 2 discloses around with the plasma arc of oxygen as plasma gas and has supplied with oxygen curtain (secondary air of pure oxygen).Then, the secondary air by oxygen increases molten metal flow, reduces the scum silica frost attached to back of work, promotes the oxidation of motlten metal simultaneously and improves the fissility of scum silica frost.
Patent documentation 3 discloses the mist of use non-oxidizing gas and oxidizing gas as secondary air, and the ratio of oxidizing gas is at least more than 40%, and wherein non-oxidizing gas is nitrogen or argon, and oxidizing gas is oxygen or air.
Patent documentation 5 discloses and has used oxygen containing gas respectively as plasma gas (gas), secondary air and three gases.If the oxygen concentration of plasma gas is the oxygen concentration of Np, secondary air is that the oxygen concentration of N2, three gases is N3, then Np＞N2 and N2＜N3.
In addition, the plasma cutting is from the operation (being also referred to as perforation process) of perforate on steel plate.In perforation process, plasma arc fusing steel plate, molten metal liquid spray to the steel plate top by plasma jet plasma gun is run through (such motlten metal be called splash) until the hole.The scaling loss of splashing that the nozzle of spray gun front end or the protective cover of covering nozzles might be gushed out from the hole.The part of the motlten metal that gushes out from the hole in addition, is adhered to as scum silica frost around in the hole and is solidified and pile up.When the cutting of product finishes, when spray gun is got back to the cutting starting position, thereby the scum silica frost that might the spray gun end can contact around the hole that is deposited in the cutting starting position makes the cutting action interruption.For fear of this phenomenon takes place, can make punch position away from product, if but do like this, just prolonged cutting path.For example known have a following technology relevant with this problem.
Patent documentation 6 discloses the secondary air flow that makes in the perforation process greater than the secondary air flow in the cutting action, protects spray gun not to be subjected to the scaling loss of splashing that sprays from the hole by the secondary air of big flow.
Patent documentation 7 discloses before perforation process begins, and prevents agent by adhering at the precalculated position of perforation injection coating scum silica frost from spray gun, to reduce the scum silica frost that adheres to around the hole.
In addition, in the perforation process and follow-up cutting action in the plasma cutting, form plasma arc (being also referred to as main arc) by the arc discharge between electrode in the plasma gun (negative pole) and the steel plate (positive pole).Thereby plasma arc is reined in the plasma jet that carefully becomes high temperature and high speed by nozzle and is blowed to steel plate, and steel plate is melted.Before perforation process begins, at first light the operation (being also referred to as the arc maintenance operation) of electric arc.In the arc maintenance operation, electrode is a negative pole, and nozzle is anodal, forms the arc discharge that is called arc maintenance between electrode and nozzle.Arc maintenance moves to steel plate.Arc maintenance arrives steel plate and is converted to after the main arc, and the circuit that links to each other with nozzle is disconnected, and has only steel plate to become positive pole, and perforation process begins.
In the arc maintenance operation, the hole exits of nozzle can be by the arc maintenance scaling loss.Because the life period of arc maintenance is short, be several milliseconds to tens of milliseconds, the nozzle damage of the operation of therefore lighting a fire each time is less.But the scaling loss degree of the hole exits of nozzle develops along with the increase of igniting number of times.After hundreds of repeatedly times the igniting, the damage of the hole exits of nozzle is very big, thereby the state of plasma arc changes, and causes cut quality to descend.Arrive this, the life-span of nozzle has arrived the end.
About this situation, patent documentation 8 discloses and has made non-oxidizing gas flow through plasma gas and secondary air simultaneously when arc maintenance is lighted, and forms non-oxidizing gas atmosphere gas near the hole exits of nozzle.Then, side by side plasma gas is converted to oxygen or oxygen containing gas to enter cutting action from non-oxidizing gas with arc maintenance basically to main arc conversion.By the non-oxidizing gas atmosphere gas in the igniting operation, can reduce the damage of the nozzle bore outlet that causes by arc maintenance.
Patent documentation 1: the spy opens clear 53-123349 communique
Patent documentation 2: the spy opens clear 59-229282 communique
Patent documentation 3: the flat 6-508793 communique of special table
Patent documentation 4: the spy opens flat No. 7051861 communiques
Patent documentation 5: the spy opens the 2000-31293 communique
Patent documentation 6: the flat 2-504603 communique of special table
Patent documentation 7: the spy opens the 2004-188485 communique
Patent documentation 8: the spy opens flat 8-215856 communique
Summary of the invention
The problem that invention will solve
According to cutting relevant above-mentioned prior art with plasma that the mist that uses oxygen or air or oxygen and nitrogen etc. cuts mild steel, low-alloy steel or mild steel as plasma gas, the gas that contains sizable ratio oxygen by use in cutting action can reduce the scum silica frost that the steel plate back side is adhered to as secondary air.But, in perforation process, will produce scum silica frost and adhere to the hole problem on every side that is deposited in.In order to address this problem, according to prior art, in perforation process, increase the flow of secondary air or before perforation process begins the coating scum silica frost adhere to and prevent agent.
Thereby, the objective of the invention is to, utilize with the prior art diverse ways reduce scum silica frost in perforation process attached to the phenomenon around the hole.
Solve the method for problem
According to an aspect of the present invention, a kind of plasma cutter, to mild steel, when low-alloy steel or mild steel cut, from plasma gun ejection plasma air-flow and when spraying assist gas around the plasma air-flow, carry out the arc maintenance operation successively, perforation process and cutting action, wherein, this device comprises the assist gas apparatus for controlling of supply, it is that oxygen-containing gas more than the airborne oxygen concentration offers plasma gun as assist gas that this control device is controlled to use oxygen concentration in cutting action, in all or part of time of perforation process with oxygen or oxygen concentration 80 moles more than the % and oxygen concentration during than cutting action high oxygen-containing gas offer plasma gun as assist gas.
According to this plasma cutter sweep, height when being controlled in all or part of time of perforation process than cutting action by oxygen concentration with assist gas, can reduce thus scum silica frost in perforation process attached to the phenomenon around the hole.
In preferred embodiment, in the arc maintenance operation, use inert gas such as oxygen-free nitrogen or oxygen containing gas as assist gas, and the oxygen concentration of the assist gas during with the arc maintenance operation low value when being controlled to be than perforation process, thus, can reduce the damage of the nozzle that arc maintenance causes.
In preferred embodiment, the oxygen concentration of the assist gas during perforation process is controlled in the scope of 80 moles of %～100 mole %, is controlled at when cutting action in the scope of 20 moles of %～80 mole %.Thus, in perforation process, can reduce scum silica frost and around the hole, adhere to, in addition, in cutting action, can prevent the burning of workpiece, but also can reduce scum silica frost adhering to surface of the work.
According to a further aspect in the invention, a kind of plasma cutter, to mild steel, when low-alloy steel or mild steel cut, from plasma gun ejection plasma air-flow and when spraying assist gas around the plasma air-flow, after producing arc maintenance, change arc maintenance into main arc, this plasma cutter sweep comprises the assist gas apparatus for controlling of supply, it is that oxygen-containing gas more than the airborne oxygen concentration offers plasma gun as assist gas to use oxygen concentration during keeping main arc that this control device has carried out control, provide in the predetermined amount of time after main arc is established oxygen or oxygen concentration 80 moles more than the % and the high oxygen-containing gas of the cutting action of oxygen concentration after than this predetermined amount of time of process as assist gas.
According to this plasma cutter sweep, oxygen concentration by the assist gas in the predetermined amount of time after main arc has just been established is controlled to the oxygen concentration that is higher than the assist gas after this time period finishes, can reduce in the perforation process that scum silica frost will carry out after main arc is just established usually attached to the hole thus around.
The invention effect
According to the present invention, can reduce scum silica frost attached to around the hole in the perforation process.
Description of drawings
Fig. 1 is the summary structure chart of wanting portion of the plasma cutter of an embodiment of the invention;
Fig. 2 is the sequential chart of the control method of arc current, plasma gas 112 and the assist gas of explanation when cutting mild steel, low-alloy steel or mild steel workpiece.
Fig. 3 is the piping diagram of the formation example of expression assist gas feed system 104.
Fig. 4 is the sequential chart of the action of expression assist gas feed system 104 shown in Figure 3.
Fig. 5 is the piping diagram of other formation examples of expression assist gas feed system 104.
Fig. 6 is the sequential chart of the action of expression assist gas feed system 104 shown in Figure 5.
Description of reference numerals
100 plasma cutters
102 plasma gunes
112 plasma gas, 114 assist gas
103 plasma gas feed systems, 104 assist gas feed systems
106 power circuits, 108 cooling water recirculation systems
109 control device, 140 workpiece
Followingly embodiments of the present invention are described with reference to accompanying drawing.
Fig. 1 is the summary structure chart that the described plasma cutter of embodiment of the present invention is wanted portion.
As shown in Figure 1, this plasma cutter sweep 100 comprises: plasma gun 102, plasma gas 112, assist gas 114, arc current and cooling water 110 are offered the plasma gas feed system 103 of plasma gun 102 respectively, assist gas feed system 104, power circuit 106, cooling water recirculation system 108, and the control device 109 that their action is controlled.
The specific embodiment
Electrode 120 has for example electrode tip (insert) 126 made such as hafnium, zirconium or their alloy of heat proof material at its leading section, has cooling water path 128 in electrode interior.Between electrode 120 and nozzle 122, there is plasma gas path 130.In plasma gas path 130, be provided with the plasma gas cyclone 132 that is used to form the plasma gas bumpy flow.Between nozzle 122 and protective cover 124, there is assist gas path 134.The outlet of assist gas path 134 is a ring-type, and round the place ahead in the hole of nozzle 122.In assist gas path 134, be provided with the assist gas cyclone 136 that is used to form the assist gas bumpy flow.
When carrying out the cutting of sheet material (workpiece) 140, plasma gun 102 is become the below of workpiece 140 near plasma gun 102 with location arrangements between the workpiece 140.Before the processing beginning, the operation of supplying gas in advance, section ejection plasma gas 112 and assist gas 114 are until its stability of flow at the fixed time.After the operation of supplying gas in advance, carry out the arc maintenance operation.So power circuit 106 applies high voltage between electrode 120 and nozzle 122, between the inner face of the leading section of electrode 120 and near the nozzle it 122, produce arc maintenance.Under the effect of arc maintenance, near the plasma gas 112 electrode 120 leading sections is sprayed with pattern at a high speed downwards from the hole of nozzle 122 by plasma.Under the guiding of this plasma jet, arc maintenance passes the hole of nozzle 122 and moves the upper surface that arrives workpiece 140 downwards.Like this, established between electrode 120 and the workpiece 140 and the incorporate main arc of plasma jet (plasma arc) 138.When the establishment of main arc was detected, power circuit 106 cut off the circuit that leads to nozzle 122, replaces, and connects the circuit that leads to workpiece 140.Thus, between electrode 120 and workpiece 140, form the arc current road.Afterwards, main arc 138 is maintained to this arc current road disconnection.
After main arc 138 is established, most advanced eleven punch 11 operation.So, on workpiece 140, leave hole 142 by main arc 138.Motlten metal from hole 142 the mouth the ejection and solidification-stack in the hole 142 around form scum silica frost 144, run through until hole 142.After hole 142 is run through, begin to carry out cutting action.In cutting action, while plasma gun 102 moves cut workpiece 140.When cutting action finished, power circuit 106 cut off the current circuit of main arc 138, and main arc 138 disappears.Then continue the operation of supplying gas, make plasma gas 112 and assist gas 114 mobile preset times.
Above-mentioned be in a succession of manufacturing procedure of order with the operation of supplying gas in advance, arc maintenance operation, perforation process, cutting action and the continuous operation of supplying gas, control device 109 is controlled so that each composition, pressure and the flow of the size of arc current and plasma gas 112 and assist gas 114 are optimum.Below more specific description is carried out in this control.Control during the workpiece 140 especially material such as cutting mild steel, low-alloy steel or mild steel etc. made describes.
Fig. 2 shows arc current, plasma gas 112 and the assist gas when how to control cutting mild steel, low-alloy steel or mild steel workpiece 140.Fig. 2 (A) shows the variation of the size of arc current, Fig. 2 (B) shows the variation of the pressure and the composition of plasma gas 112, Fig. 2 (C) shows the variation of the flow and the composition of assist gas 114, and Fig. 2 (D) shows the variation of the oxygen concentration that comprises in the assist gas 114.
Shown in Fig. 2 (A), flow from the arc maintenance operation to the cutting action arc current always.Arc current flows with predetermined little back ground current value in the arc maintenance operation, and increases gradually in perforation process, reaches predetermined cutting current value, is controlled at this cutting current value then in cutting action consistently.Then, arc current stops when cutting action finishes.
Shown in Fig. 2 (B), to the continuous operation of supplying gas, plasma gas 112 continues to flow from the operation of supplying gas in advance.The pressure of plasma gas 112 is controlled as predetermined low pre-aspirated pressure from operation to the arc maintenance operation of supplying gas in advance, when entering perforation process, increase sharply to predetermined high cutting pressure, during cutting action, be controlled at this cutting pressure at perforation process consistently, continuous die-off when supplying gas operation and be controlled as predetermined low continuous aspirated pressure entering afterwards.
Can change the composition of nitrogen (inert gas), oxygen, air or their mist etc. according to different operations, use as plasma gas 112.In this embodiment, consisting of of plasma gas 112: the operation of supplying gas in advance is the nitrogen of 100 moles of % to the arc maintenance operation, it is that 80 moles of %, nitrogen are the composition of the oxygen enrichment of 20 moles of % that the mist that is transformed into oxygen and nitrogen when entering perforation process for example has according to volumetric concentration meter oxygen, be controlled to be the composition of this oxygen enrichment during the cutting action consistently at perforation process, then, when entering the continuous nitrogen that becomes 100 moles of % when supplying gas operation once more.Perhaps as variant embodiment, consisting of of plasma gas 112: supply gas in advance operation to the arc maintenance operation and the continuous operation of supplying gas can be respectively air (promptly, contain the oxygen of the 20 moles of % that have an appointment and the nitrogen of about 80 moles of % according to volumetric concentration), in addition, during cutting action, also can be the oxygen of 100 moles of % at perforation process.
Shown in Fig. 2 (C), to lasting flowing of the initial stage of the continuous operation of supplying gas, the flow of assist gas 114 is controlled to be predetermined cutting flow to assist gas 114 consistently during this period from the operation of supplying gas in advance.Then, enter continuous when supplying gas operation assist gas 114 stop.Can change the composition of nitrogen (inert gas), oxygen, air or their mist etc. as assist gas 114 uses according to different operations.In this embodiment, consisting of of assist gas 114: from the operation of supplying gas in advance is the nitrogen of 100 moles of % to the arc maintenance operation, be converted to the oxygen of 100 moles of % when entering perforation process, during perforation process, keep this composition, change the composition that contains aerobic and nitrogen, the oxygen concentration composition lower as the mist of air and oxygen for example when entering cutting action into, and during perforation process, keep this composition than perforation process.Perhaps as variant embodiment, consisting of of assist gas 114: from the operation of supplying gas in advance to the arc maintenance operation with the continuous operation of supplying gas can be respectively air (promptly, contain the oxygen of the 20 moles of % that have an appointment and the nitrogen of about 80 moles of % according to volumetric concentration), can the oxygen of 100 moles of % during from perforation process to cutting action, in addition, in the continuous operation of supplying gas, also can be air.
At this, it should be noted the variation of the volumetric concentration (hereinafter referred to as " oxygen concentration of assist gas ") of the oxygen in the assist gas 114.Promptly, shown in Fig. 2 (D), if the oxygen concentration of the assist gas in the operation of will supplying gas in advance and the arc maintenance operation is made as D1, the oxygen concentration of assist gas in the perforation process is made as D2, the oxygen concentration of assist gas in the cutting action is made as D3, between oxygen concentration D1, the D2 of the assist gas of these different operations and D3, has the relation of D1＜D3＜D2 so.Oxygen concentration to the assist gas of every operation specifies as follows.
The oxygen concentration D1 of the assist gas in the operation of supplying gas in advance and the arc maintenance operation is the low value of 20 moles of % following (being that airborne oxygen concentration is following).Particularly, the oxygen concentration D1 of assist gas is more near 0 mole of % in the arc maintenance operation, and the degree of injury of the nozzle 122 that arc maintenance causes is more little.
The oxygen concentration D2 of assist gas is the high value of 20 moles of % above (being more than the airborne oxygen concentration) in the perforation process, for example can be 80 moles of concentration that can cause burning (oxidation reaction of the surplus of workpiece 140 cut surfaces) more than the %, also can be 100 moles of %.The oxygen concentration D2 of this assist gas just can improve the perforation ability more more near 100 moles of %, and can reduce the amount of the scum silica frost 144 that adheres to around the hole more.Can bring by this effect: thus the scaling loss degree that alleviates nozzle 122 and protective cover 124 prolong they life-span, enhance productivity and improve the advantages such as maximum thickness of slab that can cut.The value of the oxygen concentration D2 of the assist gas in this perforation process is higher than the oxygen concentration D3 of the assist gas in the cutting action.
The oxygen concentration D3 of the assist gas in the cutting action is the above and moderate values below the oxygen concentration (for example 80 moles of %) that produces burning of 20 moles of %.In cutting action, different with perforation process, oxygen concentration is that the assist gas of 100 moles of % does not adopt owing to can produce burning.In order to reach the purpose that does not produce burning and reduce the scum silica frost that adheres at workpiece 140 back sides, the oxygen concentration D3 of assist gas is in the scope of 40 moles of %～80 mole % in the cutting action, is suitable about 50 moles of % for example.
Fig. 3 shows and is used to provide oxygen concentration that the as above formation example of the assist gas feed system 104 of the assist gas 114 of variation takes place.
As shown in Figure 3, assist gas feed system 104 comprises: for from the nitrogen supply pipe 160 of the flow of nitrogen gas of nitrogenous source, for from the air flow air supply pipe 162 in air source and for two the oxygen supply pipes 164,166 from the flow of oxygen of oxygen source.The oxygen flow that two oxygen supply pipes 164,166 are designed to flow through wherein is different, and below that flow is big oxygen supply pipe 164 is called " big oxygen supply pipe ", and the oxygen supply pipe 166 that flow is little is called " little oxygen supply pipe ".Be connected with an assist gas supply pipe 188 after these four gas supply pipes 160,162,164,166 conflux, assist gas supply pipe 188 is connected with the assist gas path 134 of plasma gun 102 then.In above-mentioned four gas supply pipes 160,162,164,166, be respectively arranged with and be used to open and close the magnetic valve 172,176,182,186 of gas supply pipe separately.Magnetic valve 172 with nitrogen supply pipe 160 is called " nitrogen valve " below, the magnetic valve 176 of air supply pipe 162 is called " air valve ", the magnetic valve 182 of big oxygen supply pipe 164 is called " big oxygen supply valve ", the magnetic valve 186 of little oxygen supply pipe 166 is called " little oxygen supply valve ".
In nitrogen supply pipe 160, the provided upstream of nitrogen valve 172 is equipped with the flow control valve 170 that nitrogen flow is controlled at consistently predetermined assist gas flow value.In big oxygen supply pipe 164, the provided upstream of big oxygen supply valve 182 is equipped with the flow control valve 180 that oxygen flow is controlled at consistently the predetermined first oxygen flow value.In little oxygen supply pipe 166, the provided upstream of little oxygen supply valve 186 is equipped with the flow control valve 184 that oxygen flow is controlled at consistently the predetermined second Oxygen Flow value littler than the above-mentioned first oxygen flow value.The summation of the first oxygen flow value and the second oxygen flow value is than above-mentioned assist gas flow value smaller (perhaps, also can equate with above-mentioned assist gas flow value as variant embodiment).In addition, in air supply pipe 162, the provided upstream of air valve 176 is equipped with the pressure-reducing valve 174 that is used to set assist gas pressure, so that the stability of flow of the assist gas 114 under air valve 176 open modes is at above-mentioned assist gas flow value, and be provided with non-return valve 178 in the downstream of air valve 176.
Preferably, the confluence of four gas supply pipes 160,162,164,166 is arranged on the position of as close as possible plasma gun 102, shortens assist gas supply pipe 188 as far as possible.Thus, when the inclined to one side upstream side in above-mentioned confluence carried out the control action of air-flow, the result who has shortened this control was reflected to the time delay of plasma gun 102, had improved the precision of gas control.
Fig. 4 shows the action of assist gas feed system 104 shown in Figure 3 in above-mentioned a succession of manufacturing procedure.The arc current that Fig. 4 (A) shows in a succession of manufacturing procedure changes, Fig. 4 (B) shows the on-off action of nitrogen valve 172, Fig. 4 (C) shows the on-off action of air valve 176, Fig. 4 (D) shows the on-off action of big oxygen supply valve 182, Fig. 4 (E) shows the on-off action of little oxygen supply valve 186, and Fig. 4 (F) shows the variation of the flow of nitrogen, oxygen and air that assist gas 114 contained in addition.
As shown in Figure 4, in supply gas in advance operation and arc maintenance operation, have only nitrogen valve 172 to open, other gas trap 176,182,186 cuts out, and therefore has only nitrogen to flow as assist gas 114 shown in Fig. 4 (F).In perforation process, nitrogen valve 172 cuts out, and replaces, air valve 176, big oxygen supply valve 182 and little oxygen supply valve 186 are opened, therefore shown in Fig. 4 (F), the oxygen of oxygen enrichment and Air mixing gas (perhaps, also can have only oxygen as variant embodiment) flow as assist gas 114.In cutting action, air valve 176 and little oxygen supply valve 186 are opened, nitrogen valve 172 and big oxygen supply valve 182 are closed, therefore shown in Fig. 4 (F), oxygen concentration during than perforation process low oxygen and Air mixing gas (perhaps, also can have only air) as variant embodiment flow as assist gas 114.
Fig. 5 shows other formation examples of assist gas feed system 104.Formation example shown in Figure 5 is to remove nitrogen supply pipe 160 from formation example shown in Figure 3.
Fig. 6 shows the action of assist gas feed system 104 shown in Figure 5 in above-mentioned a succession of manufacturing procedure.The arc current that Fig. 6 (A) shows in a succession of manufacturing procedure changes, Fig. 6 (B) shows the on-off action of air valve 176, Fig. 6 (C) shows the on-off action of big oxygen supply valve 182, Fig. 6 (D) shows the on-off action of little oxygen supply valve 186, and Fig. 6 (E) shows the variation of the flow of air that assist gas 114 contained and oxygen in addition.
As shown in Figure 6, in supply gas in advance operation and arc maintenance operation, air valve 176 is opened, and big oxygen supply valve 182 and little oxygen supply valve 186 are closed, and therefore shown in Fig. 6 (E), has only air to flow as assist gas 114.In perforation process, air valve 176, big oxygen supply valve 182 and little oxygen supply valve 186 are opened entirely, and therefore shown in Fig. 6 (E), the oxygen of oxygen enrichment and Air mixing gas (perhaps, also can have only oxygen as variant embodiment) flow as assist gas 114.In cutting action, air valve 176 and little oxygen supply valve 186 are opened, and big oxygen supply valve 182 is closed, therefore shown in Fig. 6 (E), oxygen concentration during than perforation process low oxygen and Air mixing gas (perhaps, also can have only air) as variant embodiment flow as assist gas 114.
According to above-mentioned embodiment, the composition of assist gas 114 is optimised to the composition that has nothing in common with each other in arc maintenance operation, perforation process and cutting action.Like this, can improve the ability of perforation, and can reduce scum silica frost in perforation process attached to the phenomenon around the hole.Its result has improved the life-span as the protective cover and the nozzle of plasma gun consumable part.In addition, can shorten the Cutting Length of the position in formed hole from perforation process, improve production efficiency to product.In addition, because the raising of perforation ability can also increase the maximum cutting thickness of slab as one of cutter sweep key property.
Yet, in the above-described embodiment, almost switch the composition of plasma gas 112 and assist gas 114 synchronously with the switching of arc maintenance operation, perforation process and cutting action, but between operation switching and gas composition switching, also can have the some time deviation in certain permissible range.For example, the oxygen concentration of assist gas can be set to above-mentioned low concentration value D1 in the arc maintenance operation, switch to the above-mentioned high concentration value D2 that is fit to perforation process in the moment that arc maintenance changes main arc into and established main arc, after time period of predetermined length keep this high concentration value D2, through switching to the above-mentioned intermediate concentration value D3 that is fit to cutting action after this time period.At this moment, the oxygen concentration of assist gas switches to moment of intermediate concentration value D3 from high concentration value D2 also can be identical to the moment of the actual switching of cutting action from perforation process with manufacturing procedure, for example, can be earlier than it, also can be a little later.That is to say, also can in the overall process of perforation process, not continue to keep high concentration value D1, if at least a portion process, provide high concentration value D2 (perhaps than cutting action time high assist gas concentration value), then than can improve perforation process in the past.In addition, when beginning, cutting action also can not carry out the switching to intermediate concentration value D3 from high concentration value D2, even during cutting off hole to the path of from perforation process, digging of finished product, carry out the switching of this gas composition, perhaps switch, also can carry out cutting action well at the composition that carries out this gas than perforation process the finish time when summary is Zao.
More than embodiments of the present invention are illustrated, but above-mentioned embodiment only is used to illustrate example of the present invention, do not mean scope of the present invention only is defined as these embodiments.Do not breaking away under the situation of its main points, the present invention also can implement with other variety of ways.
Claims (7)
1. plasma cutter, when mild steel, low-alloy steel or mild steel are cut, from plasma gun (102) ejection plasma air-flow and when spraying secondary air around the described plasma air-flow, carry out arc maintenance operation, perforation process, cutting action successively, described plasma cutter (100) comprising:
Assist gas apparatus for controlling of supply (104,109), described control device is controlled in described cutting action being that oxygen-containing gas more than the airborne oxygen concentration offers described plasma gun as described assist gas with oxygen concentration, and in all or part of time of described perforation process with oxygen or oxygen concentration 80 moles more than the % and oxygen concentration during than described cutting action high oxygen-containing gas offer described plasma gun as described assist gas.
2. plasma cutter according to claim 1, wherein,
Described assist gas apparatus for controlling of supply (104,109) offers described plasma gun with oxygen-free or oxygen containing gas as described assist gas in described arc maintenance operation, and low value when being controlled to be the oxygen concentration of described assist gas than described perforation process when described arc maintenance operation.
3. plasma cutter according to claim 1, wherein,
Described assist gas apparatus for controlling of supply (104,109) is controlled at the oxygen concentration of described assist gas in the scope of 80 moles of %～100 mole % in all or part of time of described perforation process, be controlled at when described cutting action in the scope of 20 moles of %～80 mole %.
4. method for plasma cutting, when mild steel, low-alloy steel or mild steel are cut,, carry out arc maintenance operation, perforation process, cutting action successively from plasma gun (102) ejection plasma air-flow and when spraying secondary air around the described plasma air-flow, wherein
In described cutting action, use oxygen concentration be oxygen-containing gas more than the airborne oxygen concentration as described assist gas, when described perforation process, provide oxygen or oxygen concentration 80 moles more than the % and oxygen concentration during than described cutting action high oxygen-containing gas as assist gas.
5. plasma cutter, when mild steel, low-alloy steel or mild steel are cut, from plasma gun (102) ejection plasma air-flow and when spraying secondary air around the described plasma air-flow, change described arc maintenance into main arc after producing arc maintenance, described plasma cutter (100) comprising:
Assist gas apparatus for controlling of supply (104,109), described control device is controlled with during keeping described main arc, with oxygen concentration is that oxygen-containing gas more than the airborne oxygen concentration offers described plasma gun as described assist gas, in the predetermined amount of time after described main arc is established with oxygen or oxygen concentration 80 moles more than the % and oxygen concentration offer plasma gun than the high oxygen-containing gas of cutting action after passing through described predetermined amount of time as assist gas.
6. plasma cutter according to claim 5, wherein,
Be controlled in the scope of 80 moles of %～100 mole % in the predetermined amount of time of oxygen concentration after described main arc is established of described assist gas apparatus for controlling of supply (104,109) with described assist gas, through the cutting action behind the described predetermined amount of time time, be controlled in the scope of 20 moles of %～80 mole %.
7. method for plasma cutting, when mild steel, low-alloy steel or mild steel are cut,, after producing arc maintenance, change described arc maintenance into main arc from plasma gun (102) ejection plasma air-flow and when spraying secondary air around the described plasma air-flow, wherein
During keeping described main arc, use oxygen concentration be oxygen-containing gas more than the airborne oxygen concentration as described assist gas, provide in the predetermined amount of time after described main arc is established oxygen or oxygen concentration 80 moles more than the % and oxygen concentration than the high oxygen-containing gas of the cutting action after passing through described predetermined amount of time as assist gas.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005153411A JP4623727B2 (en) | 2005-05-26 | 2005-05-26 | Plasma cutting apparatus and method |
| JP153411/2005 | 2005-05-26 | ||
| PCT/JP2006/307732 WO2006126339A1 (en) | 2005-05-26 | 2006-04-12 | Apparatus and method for cutting with plasma |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101175596A CN101175596A (en) | 2008-05-07 |
| CN101175596B true CN101175596B (en) | 2010-09-08 |
Family
ID=37451770
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2006800168966A Active CN101175596B (en) | 2005-05-26 | 2006-04-12 | Plasma cutting device and method |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP4623727B2 (en) |
| KR (1) | KR100960845B1 (en) |
| CN (1) | CN101175596B (en) |
| WO (1) | WO2006126339A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2910360A1 (en) * | 2006-12-20 | 2008-06-27 | Air Liquide | Process for cutting a metallic part by plasma jet, comprises implementing a plasma torch for generating the plasma jet and cutting the part by plasma jet, where the metallic part comprises high alloy steel containing alloying elements |
| US8338739B2 (en) | 2008-12-22 | 2012-12-25 | Hypertherm, Inc. | Method and apparatus for cutting high quality internal features and contours |
| US8354609B2 (en) * | 2008-12-22 | 2013-01-15 | Hypertherm, Inc. | High quality hole cutting using variable shield gas compositions |
| CN103433607B (en) * | 2013-08-12 | 2016-01-13 | 华中科技大学 | A kind of digitlization CUT control system |
| JP6816260B2 (en) | 2017-03-31 | 2021-01-20 | 株式会社Ｆｕｊｉ | Plasma generator |
| JP7109350B2 (en) * | 2018-12-05 | 2022-07-29 | 小池酸素工業株式会社 | plasma torch |
| US20210204387A1 (en) * | 2019-12-31 | 2021-07-01 | The Esab Group Inc. | Methods for operating a plasma torch |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1148355A (en) * | 1994-05-25 | 1997-04-23 | 株式会社小松制作所 | Method and apparatus for plasma cutting |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3285174B2 (en) * | 1993-10-14 | 2002-05-27 | 株式会社小松製作所 | Plasma cutting method and apparatus |
| US5414237A (en) * | 1993-10-14 | 1995-05-09 | The Esab Group, Inc. | Plasma arc torch with integral gas exchange |
-
2005
- 2005-05-26 JP JP2005153411A patent/JP4623727B2/en active Active
-
2006
- 2006-04-12 KR KR1020077027354A patent/KR100960845B1/en active IP Right Grant
- 2006-04-12 CN CN2006800168966A patent/CN101175596B/en active Active
- 2006-04-12 WO PCT/JP2006/307732 patent/WO2006126339A1/en active Application Filing
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1148355A (en) * | 1994-05-25 | 1997-04-23 | 株式会社小松制作所 | Method and apparatus for plasma cutting |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2006326636A (en) | 2006-12-07 |
| KR100960845B1 (en) | 2010-06-07 |
| KR20070121062A (en) | 2007-12-26 |
| JP4623727B2 (en) | 2011-02-02 |
| WO2006126339A1 (en) | 2006-11-30 |
| CN101175596A (en) | 2008-05-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101175596B (en) | Plasma cutting device and method | |
| US6236013B1 (en) | Combined process and automatic installation for plasma-jet marking and cutting or welding, in particular of metals | |
| EP1893004B1 (en) | Contoured shield orifice for a plasma arc torch | |
| KR101626312B1 (en) | Laser cutting method and laser cutting device | |
| CN106583943A (en) | Laser micro-connecting cutting technology | |
| JPH05329635A (en) | Method and device for melting and cutting | |
| CA2109772A1 (en) | Cutting Nozzle Assembly for a Postmixed Oxy-Fuel Gas Torch | |
| CN203875486U (en) | Laser cutting machine | |
| CN1019956C (en) | Improved scarfing nozzle | |
| CA2234741C (en) | Method of controlling a plasma arc cutting torch | |
| US10517165B2 (en) | Plasma cutting apparatus | |
| AU1508600A (en) | Oxygen arc cutting with plasma pre-heating of ferrous materials, such as structural steel workpieces | |
| JP2003053548A (en) | Discharge regulator and processing equipment | |
| US20080093045A1 (en) | Method for Producing Metal Products | |
| US20230064501A1 (en) | Edge shaping using material processing systems | |
| JP5749112B2 (en) | Combustion apparatus and runner cleaning method for molten metal container | |
| JP2001232473A (en) | Method and unit for performing plasma arc machining | |
| CN113770480B (en) | Cutting method of carbon steel and stainless steel composite material | |
| JP2011212709A (en) | Piercing method and piercing device | |
| KR20190035839A (en) | Plasma torch | |
| CN212239543U (en) | Cutting nozzle | |
| JP4442970B2 (en) | Plasma marking method | |
| JP2021016867A (en) | Scarfing device for steel material, and scarfing method for steel material | |
| JP2002273593A (en) | Laser cutter | |
| CN102066033B (en) | Plasma cutting torch |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |