Component such as a wearing part for an arc torch, in particular a plasma burner or plasma cutting torch, arc torch comprising same, and method of plasma cutting

Abstract

The invention relates to a component for an electrically operated arc torch, in particular a plasma burner or plasma cutting torch, characterised in that the component or at least a part or a region of the component consists of a material comprising aluminium oxide and at least one of the chemical elements silver and copper.

Description

[0001] Component, such as a wear part, for an arc torch, in particular a plasma torch or plasma cutting torch, arc torch with the same and method for plasma cutting

[0002] The present invention relates to a component, such as a holder and a receptacle for wearing parts, as well as a wearing part, such as an electrode, a nozzle, a nozzle cap and a nozzle protection cap, for an arc torch, in particular a plasma torch or a plasma cutting torch, an arc torch, in particular a plasma torch or a plasma cutting torch, comprising the same and a method for plasma cutting.

[0003] Arc torches and plasma torches (plasma arc torches) in particular are typically used for the thermal processing of a wide variety of materials, such as metallic and non-metallic materials, for example for cutting, welding, marking or, more generally, for heating.

[0004] For example, a TIG torch can be an arc torch. However, it doesn't have a nozzle like a plasma torch. Nevertheless, the electrodes of an arc torch and a plasma torch can be identical in design.

[0005] Plasma torches typically consist essentially of a torch body, an electrode, a nozzle, and a nozzle holder. Modern plasma torches also feature a nozzle protection cap mounted over the nozzle. A nozzle is often secured by a nozzle cap. Depending on the plasma torch type, the components subject to wear during operation of the plasma torch due to the high thermal stress caused by the arc include, in particular, the electrode, the nozzle, the nozzle cap, the nozzle protection cap, the nozzle protection cap holder, and the plasma gas guide and secondary gas guide components. These components can be easily replaced by an operator and are therefore considered wearing parts (components with a limited service life).

[0006] The plasma torches are connected via cables to a power source and a gas supply that feeds the plasma torch. Furthermore, the plasma torch can be connected to a cooling device for a cooling medium, such as a coolant.

[0007] Plasma cutting torches, in particular, are subject to high thermal loads. This is caused by the strong constriction of the plasma jet by the nozzle bore. Small bores are used here to allow high current densities of 50 to 150 A / mm 2 in the nozzle bore, high energy densities of approx. 2xio 6 W / cm 2and high temperatures of up to 30,000 K are generated. Furthermore, higher gas pressures, typically up to 12 bar, are used in plasma cutting torches. The combination of high temperature and high kinetic energy of the plasma gas flowing through the nozzle bore leads to the melting of the workpiece and the expulsion of the molten material. A kerf is created, and the workpiece is severed. In plasma cutting, oxidizing gases are often used to cut unalloyed or low-alloy steels, and non-oxidizing gases are used to cut high-alloy steels or non-ferrous metals.

[0008] A plasma gas flows between the electrode and the nozzle. The plasma gas is guided through a gas guide. This allows the plasma gas to be directed in a targeted manner. It is often set in rotation around the electrode by a radial and / or axial offset of the openings in the plasma gas guide. The plasma gas guide is made of electrically insulating material because the electrode and nozzle must be electrically insulated from one another. This is necessary because the electrode and nozzle have different electrical potentials during operation of the plasma cutting torch. To operate the plasma cutting torch, an arc is created between the electrode and the nozzle and / or the workpiece, which ionizes the plasma gas. To ignite the arc, a high voltage can be applied between the electrode and nozzle. This pre-ionizes the path between the electrode and nozzle and thus forms an arc.The arc burning between the electrode and the nozzle is also called the pilot arc.

[0009] The pilot arc exits through the nozzle bore and strikes the workpiece, ionizing the path to the workpiece. This allows the arc to form between the electrode and the workpiece. This arc is also called the main arc. The pilot arc can be switched off during the main arc. However, it can also continue to operate. In plasma cutting, this is often switched off to avoid placing additional strain on the nozzle.

[0010] The electrode and nozzle, in particular, are subject to high thermal stress and require cooling. At the same time, they must also conduct the electrical current required to form the arc. Therefore, materials with good thermal and electrical conductivity are used, usually metals such as copper, silver, aluminum, tin, zinc, iron, or alloys containing at least one of these metals.

[0011] The electrode often consists of an electrode holder and an emissive insert made of a material with a high melting temperature (> 2000°C) and a lower electron work function than the electrode holder. Tungsten is used as the material for the emissive insert when non-oxidizing plasma gases such as argon, hydrogen, nitrogen, helium, and mixtures thereof are used. Hafnium or zirconium is used when oxidizing gases such as oxygen, air, and mixtures thereof, nitrogen-oxygen mixtures, and mixtures with other gases are used. The high-temperature material can be fitted, for example, by pressing it with a positive and / or friction fit, into an electrode holder made of a material with good thermal and electrical conductivity.

[0012] The electrode and nozzle can be cooled by gas, such as plasma gas or a secondary gas flowing along the outside of the nozzle. However, cooling with a liquid, such as water, is more effective. In this case, the electrode and / or nozzle are often cooled directly with the liquid, meaning the liquid is in direct contact with the electrode and / or nozzle. To guide the cooling liquid around the nozzle, a nozzle cap is located around the nozzle. Its inner surface, together with the outer surface of the nozzle, forms a coolant chamber through which the coolant flows.

[0013] Modern plasma cutting torches also feature a nozzle protection cap outside the nozzle and / or nozzle cap. The inner surface of the nozzle protection cap and the outer surface of the nozzle or nozzle cap form a space through which a secondary or shielding gas flows. The secondary or shielding gas exits the bore of the nozzle protection cap and envelops the plasma jet, creating a defined atmosphere around it. The secondary gas also protects the nozzle and nozzle protection cap from arcs that can form between the nozzle and the workpiece. These are known as double arcs and can damage the nozzle. The nozzle and nozzle protection cap are subjected to significant stress from hot material spraying up, particularly when piercing the workpiece.The secondary gas, whose volume flow during piercing may be higher than that during cutting, keeps the splashing material away from the nozzle and the nozzle protection cap and thus protects it from damage.

[0014] The nozzle protection cap is also subject to high thermal stress and must be cooled. For this reason, materials with good heat and electrical conductivity are used for this purpose. These are usually metals such as copper, silver, aluminum, tin, zinc, iron or alloys containing at least one of these metals. The electrode and nozzle can also be cooled indirectly. In this case, they are in contact with a component made of a material with good heat and electrical conductivity, usually a metal such as copper, silver, aluminum, tin, zinc, iron or alloys containing at least one of these metals. This component is in turn cooled directly, meaning that it is in direct contact with the coolant, which is usually flowing. These components can simultaneously serve as a holder or receptacle for the electrode, the nozzle, the nozzle cap or the nozzle protection cap and dissipate the heat and supply the current.

[0015] It is also possible for only the electrode or only the nozzle to be cooled with liquid.

[0016] The nozzle cap is usually cooled solely by the secondary gas. Arrangements are also known in which the secondary gas cap is cooled directly or indirectly by a cooling liquid.

[0017] Plasma torches, and especially plasma cutting torches, are subject to high levels of wear and tear due to the high energy density and high temperatures. This particularly applies to the electrode, nozzle, and nozzle protection cap.

[0018] Previously known solutions for the electrode, which consist of inserting the emission insert made of a high-melting material such as tungsten or hafnium into a material with good thermal conductivity, such as copper or silver, often do not achieve satisfactory results. Particularly with high electrical currents, e.g., greater than 300 A, and when using oxygen-containing gases or gas mixtures as plasma gas, the lifetimes are often too short. Furthermore, there are often large fluctuations in lifetime. The emission insert wears out during operation, i.e., when a burning arc or plasma jet is present. It gradually burns back. If it has burned back more than 1 mm, the use of copper as the material for the electrode holder often leads to sudden failure of the entire electrode. The arc or plasma jet then transfers from the emission insert to the holder and destroys it. This also destroys the nozzle. The entire torch can even be destroyed.

[0019] When using copper as the material for the electrode holder, the electrode can burn back a maximum of 1 mm before failure occurs.

[0020] By using silver as the material for the electrode holder, the electrode can often burn back to 1.5 mm before failure occurs.

[0021] Since this failure also occurs suddenly, the cutting process is abruptly terminated in the cases described. The material being cut is often then unusable.

[0022] In particular, when using oxygen-rich secondary gas, i.e. the proportion of oxygen is at least 25 percent by volume of the secondary gas, arcs, so-called double arcs, can form, which burn between the nozzle, the protective cap and the workpiece.

[0023] Oxygen-rich secondary gas has a positive effect on the cut quality of the workpiece, especially when cutting structural steel. Dredging is reduced and the cut surfaces are smoother. Cutting speeds can often be achieved at higher speeds than with secondary gas without oxygen or with a lower oxygen content.

[0024] Particularly when using argon-rich secondary gas, i.e. the proportion of argon is at least 25 percent by volume of the secondary gas, arcs, so-called double arcs, can form, which burn between the nozzle, the protective cap and the workpiece.

[0025] Argon-rich secondary gas has a positive influence on the cutting quality of the workpiece to be cut, especially when cutting high-alloy steels, because the oxygen present in the ambient air is kept away from the cutting edges and thus a reaction, e.g. oxidation, of these gases with the hot plasma-cut surface of the workpiece is avoided.

[0026] The described double arcs damage the nozzle, the nozzle cap and the nozzle protection cap.

[0027] The aim of the invention is to improve the service life of components, such as holders and receptacles for wearing parts, as well as of wearing parts, such as electrodes, nozzles, nozzle caps and nozzle protection caps, for an arc torch, in particular a plasma torch or a plasma cutting torch.

[0028] According to the invention, this object is achieved according to a first aspect by a component for an electrically operated arc torch, in particular a plasma torch or plasma cutting torch, characterized in that the component or at least a part or a region of the component consists of a material which comprises aluminum oxide and at least one of the chemical elements silver and copper.

[0029] In addition, this object is achieved by an arc torch having at least one component according to one of claims 1 to 23.

[0030] Furthermore, this object is achieved by a method for plasma cutting using an arc torch, wherein the plasma cutting torch is operated with oxygen, an oxygen-containing gas or gas mixture and / or reducing gas or gas mixture and / or inert gas or gas mixture as plasma gas (PG) and / or secondary gas (SG).

[0031] Furthermore, this object is achieved by a method for plasma cutting using an arc torch, wherein the plasma cutting torch is operated with oxygen or an acidic gas mixture in which the proportion of oxygen is at least 25 volume percent of the gas mixture, as plasma gas (PG) and / or secondary gas (SG).

[0032] Furthermore, this object is achieved by a method for plasma cutting using a plasma cutting torch, wherein the plasma cutting torch is operated with argon or an argon-containing gas mixture in which the proportion of argon is at least 25 volume percent of the gas mixture, as plasma gas (PG) and / or secondary gas (SG).

[0033] With regard to the component, it can be provided that at least one component or at least one of the components is cooled with a liquid medium.

[0034] Alternatively, it can be provided that the proportion of aluminum oxide is at least 0.15%, better at least 0.3%, most preferably at least 0.5% of the volume or mass of the material.

[0035] The proportion of aluminium oxide should preferably be a maximum of 2.0%, preferably a maximum of 1.5%, and most preferably a maximum of 1.0% of the volume or mass of the material.

[0036] In a particular embodiment, the component is a wear part for an arc torch.

[0037] In particular, the consumable part can be an electrode for an arc torch.

[0038] According to another particular embodiment, the electrode has a front end and a rear end, extends along a longitudinal axis M, and has at least one emission insert at the front end, as well as an electrode holder and, if appropriate, a holding element for the emission insert. In particular, it can be provided that at least a portion of an inner surface of the electrode holder or an inner surface of the holding element, which is in contact with the emission insert by contact, consists of said material.

[0039] Furthermore, it can be provided that the material extends at least 0.5 mm, better at least 1 mm radially and most preferably at least 1.3 mm outwards from at least the partial section of the inner surface of the electrode holder or the inner surface of the holding element.

[0040] Advantageously, at least a portion of a front surface immediately adjacent to the front surface of the emission insert comprises said material.

[0041] In particular, it can be provided that said partial section of the front surface extends radially outwards by at least 0.5 mm, better at least 1 mm and most preferably at least 1.3 mm.

[0042] Advantageously, the emission insert consists of at least 90% of the volume or mass of hafnium or zirconium or tungsten.

[0043] In a further particular embodiment, it can be provided that the wearing part is a nozzle with at least one nozzle opening.

[0044] In particular, it can be provided that at least a partial section of an inner surface of the nozzle opening comprises said material.

[0045] Advantageously, the material extends radially outward at least 0.5 mm, more preferably at least 1 mm, and most preferably at least 1.3 mm, from at least the partial section of the inner surface of the nozzle opening. According to a further particular embodiment of the present invention, the wear part can be a nozzle protection cap with at least one nozzle protection cap opening.

[0046] Advantageously, at least a portion of an inner surface of the nozzle protection cap opening comprises said material.

[0047] Advantageously, the material extends at least 0.5 mm, better at least 1 mm and most preferably at least 1.3 mm radially outwards from at least the partial section of the inner surface of the nozzle protection cap opening.

[0048] According to a further particular embodiment, it can be provided that the wearing part is a nozzle cap with at least one nozzle cap opening.

[0049] Advantageously, at least a portion of an inner surface of the nozzle cap opening comprises said material.

[0050] In particular, it can be provided that the material extends radially outwards at least from the partial section of the inner surface of the nozzle cap opening by at least 0.5 mm, better at least 1 mm and most preferably at least 1.3 mm.

[0051] According to a further particular embodiment, it can be provided that the component is a receptacle or a holder for at least one wear part for an arc torch.

[0052] In particular, it can be provided that the receptacle or holder is a nozzle receptacle, a nozzle cap receptacle or an electrode receptacle or a nozzle protection cap receptacle.

[0053] According to a particular embodiment, the arc torch can be a plasma torch or plasma cutting torch. Finally, the method can provide for the at least one component or at least one of the components to be cooled with a liquid medium. The invention extends the service life of the components, such as wearing parts, in particular the electrode, of the arc, plasma, and plasma cutting torch. The emission insert can burn back further to approximately 2 mm without destroying the electrode.

[0054] In particular, the service life of electrodes, nozzles and nozzle protection caps as well as their holders can be extended.

[0055] The invention reduces the effects of a double arc.

[0056] Further features and advantages of the invention will become apparent from the appended claims and the following description of several embodiments based on the schematic drawings. In the drawings:

[0057] Figure 1: a sectional view of a plasma torch according to a particular embodiment of the present invention;

[0058] Figure 2: a sectional view of an electrode of the plasma torch of Figure

[0059] 1 according to a particular embodiment of the present invention;

[0060] Figure 2.1: a front view of the electrode of Figure 2;

[0061] Figure 2.2: a sectional view of an electrode holder of the electrode of

[0062] Figure 2 according to another particular embodiment of the present invention; Figure 2.3: another sectional view of the electrode of the plasma torch of

[0063] Figure 1;

[0064] Figure 2.4: a sectional view of an emission insert of the electrode of

[0065] Figure 2 according to a particular embodiment of the present invention;

[0066] Figure 3: a sectional view of an electrode according to another particular embodiment of the present invention;

[0067] Figure 3.1: a front view of the electrode of Figure 3;

[0068] Figure 3.2: a sectional view of an electrode holder of the electrode of

[0069] Figure 3 according to a particular embodiment of the present invention;

[0070] Figure 3.3: a front view of a holding element of the electrode of Figure 3 according to a particular embodiment of the present invention;

[0071] Figure 3.4: a side view of the retaining element of Figure 3.3;

[0072] Figure 4: a sectional view of an electrode according to another particular embodiment of the present invention;

[0073] Figure 4.1: a front view of the electrode of Figure 4;

[0074] Figure 4.2: a sectional view of an electrode holder of the electrode of

[0075] Figure 4 according to a particular embodiment of the present invention; Figure 4.3: a sectional view of a holding element of the electrode of Figure 4 according to a particular embodiment of the present invention;

[0076] Figure 5: a sectional view of an electrode according to another particular embodiment of the present invention;

[0077] Figure 5.1: a front view of the electrode of Figure 5;

[0078] Figure 5.2: a sectional view of an electrode holder of the electrode of

[0079] Figure 5 according to a particular embodiment of the present invention;

[0080] Figure 5.3 is a sectional view of a holding element of the electrode of Figure 5 according to a particular embodiment of the present invention;

[0081] Figure 6: a sectional view of a nozzle according to a particular

[0082] Embodiment of the present invention;

[0083] Figure 6.1: another sectional view of the nozzle of Figure 6;

[0084] Figure 7: a sectional view of a nozzle protection cap according to a particular embodiment of the present invention;

[0085] Figure 7.1: a sectional view of the nozzle protection cap of Figure 7;

[0086] Figure 8: a sectional view of a nozzle cap of the plasma torch of

[0087] Figure 1 according to a particular embodiment of the present invention; and Figure 8.1 is a sectional view of the nozzle cap of Figure 8 with a nozzle cap insert according to a particular embodiment of the present invention.

[0088] Figure 1 shows a sectional view of a plasma cutting torch 1 according to a particular embodiment of the present invention, comprising a nozzle cap 2, a plasma gas guide 3, a nozzle 4 according to a particular embodiment of the present invention with a nozzle opening 4.1, a nozzle and nozzle cap receptacle 5, an electrode receptacle 6, and an electrode 7 according to a particular embodiment of the present invention. The electrode 7 comprises an electrode holder 7.1 and an emission insert 7.3 with a length Li of, for example, 3 mm, an outer circumferential surface 7.3.2, and a front surface 7.3.1 (see Figure 2.4). In this example, the nozzle and nozzle cap receptacle 5 serves as a holder for both the nozzle and the nozzle cap. In other examples, however, there may also be a separate nozzle receptacle and a nozzle cap receptacle.

[0089] The plasma cutting torch 1 further comprises a nozzle protection cap holder 8, to which a nozzle protection cap 9 according to a particular embodiment of the present invention with a nozzle protection cap opening 9.1 is attached. In this example, the plasma cutting torch 1 also includes a secondary gas guide 10. Secondary gas SG is supplied through the secondary gas guide 10. Furthermore, a supply for plasma gas PG, coolant returns WR1 and WR2, and coolant feeds WV1 and WV2 are present on the plasma cutting torch 1. During operation, the arc or plasma jet burns between the emission insert 7.3 of the electrode 7, flows through the nozzle opening 4.1 and the nozzle cap opening 9.1, and is thereby constricted before it strikes a workpiece (not shown). The inner surface of the nozzle opening 4.1 is designated 4.2, and that of the nozzle cap opening 9.1 is designated 9.2.

[0090] Figures 2 and 2.1 show the electrode 7 of Figure 1, wherein Figure 2 is a sectional view through the electrode 7 and Figure 2.1 is view A of the front end of the electrode 7. The electrode 7 has a front end 7.1.8 with a front surface 7.1.1, a rear end 7.1.9, an outer surface 7.1.2 and a cavity 7.1.1 through which a coolant flows or can flow when installed. The electrode 7 comprises the electrode holder 7.1, which is shown by way of example in Figure 2.2, and the emission insert 7.3, which is shown by way of example in Figure 2.4. The emission insert 7.3 is pressed into a bore 7.1.5 with a diameter Di of, for example, 1.8 mm (-0.05) in the electrode holder 7.1. The bore 7.1.5 has an inner surface 7.1.3 that is in contact with the outer surface 7.3.2 of the emission insert 7.3. The mass of the emission insert 7.3 in this example preferably consists of at least 97% hafnium, the remainder being essentially zirconium.

[0091] The electrode holder 7.1 consists, for example, of a material made of silver, copper, and aluminum oxide Ä12O3. The mass proportions are distributed as follows, for example: silver 92.5%, copper 7%, and aluminum oxide Ä12O3 0.5%. The material used here is an example of the material for the entire electrode holder 7.1. It is also possible for the material to be present only in part or in an area of ​​the electrode holder 7.1. This is then preferably the case at least on the inner surface 7.1.3 of the electrode holder 7.1. This area then preferably extends at least 0.5 mm radially outwards from the inner surface. It is even better if the area extends at least 1 mm radially outwards. This can be realized, for example, by the aluminum oxide content and / or the silver content decreasing radially outwards and the copper content increasing.

[0092] Figure 2.3, which shows a cross-sectional view of electrode 7, also shows burnback L2. Burnback is defined as the difference between the surface 7.3.1 of the emission insert 7.3 in its new state and the lowest point of the surface burned back during operation. In the present example, L2 = 2 mm.

[0093] It is also possible for the electrode holder to consist only of a material consisting of copper and aluminum oxide. By way of example, a mass fraction of 99.5% copper and 0.5% aluminum oxide is specified here. Figure 3 shows an electrode 7 according to a further particular embodiment of the invention, wherein Figure 3 is a sectional view through the electrode 7 and Figure 3.1 is view A of the front end 7.1.8 of the electrode 7. The electrode 7 has a front end 7.1.8 with a front surface 7.1.1, a rear end 7.1.9, an outer surface 7.1.2 and a cavity 7.1.1 through which a coolant flows or can flow when installed. The electrode 7 comprises an electrode holder 7.1, which is shown by way of example in Figure 3.1, a holding element 7.2, which is shown by way of example in Figures 3.3 and 3.4, and an emission insert 7.3. The emission insert 7.3 is inserted into a bore 7.2.1 with a diameter D5 of the holding element 7.2. The bore 7.2.1 has an inner surface 7.2.3 which is in contact with the outer surface 7.3.2 of the emission insert 7.3.

[0094] The holding element 7.2 with an outer diameter D3 is pressed into the bore 7.1.5 with an inner diameter Di of the electrode holder 7.1. The bore has an inner surface 7.1.3 that is in contact with the outer surface 7.2.2 of the holding element.

[0095] The retaining element here, for example, consists of a material made of silver, copper, and aluminum oxide. The mass distribution is as follows: silver 92.5%, copper 7%, and aluminum oxide Δ12O 30.5%. The material used for the entire retaining element is 7.2.

[0096] The retaining element 7.2 has a diameter D3 of, for example, 4 mm, and the emission insert 7.3 has a diameter D7 (see Figure 2.4) of, for example, 1.8 mm. This results in a wall thickness of the retaining element of 1.1 mm and thus also a front circular surface 7.2.5 that extends 1.1 mm radially outward.

[0097] It is also possible for the material to be present only in a part or an area of ​​the holding element 7.2. This is then preferably the case at least on the inner surface 7.2.3 of the holding element 7.2. This area then preferably extends at least 0.5 mm radially outward from the inner surface 7.2.3. It is even better if the area extends at least 1 mm radially outward. This can be realized, for example, by the aluminum oxide content and / or the silver content decreasing radially outward and the copper content increasing.

[0098] The electrode holder 7.1 consists at least of a material with good electrical conductivity, in this example 99.9% of its mass being copper.

[0099] In this example, the mass of the emission insert preferably consists of at least 97% hafnium. The remaining component in this example is essentially zirconium.

[0100] It is also possible for the electrode holder to consist solely of copper and aluminum oxide. For example, a mass fraction of 99.5% copper and 0.5% aluminum oxide is specified here.

[0101] Figure 4 shows an electrode 7 according to a further particular embodiment of the invention, wherein Figure 4 is a sectional view through the electrode 7 and Figure 4.1 is view A of the front end 7.1.8 of the electrode 7. The electrode 7 has a front end 7.1.8 with a front surface 7.1.1, a rear end 7.1.9, an outer surface 7.1.2 and a cavity 7.1.1 through which a coolant flows or can flow when installed. The electrode 7 comprises an electrode holder 7.1, which is shown in Figure 4.2, a holding element 7.2, which is shown in Figure 4.3, and an emission insert 7.3. The emission insert 7.3 is inserted into a bore 7.2.1 with a diameter D5 of the holding element 7.2.

[0102] The bore 7.2.1 of the holding element 7.2 has an inner surface 7.2.3 which is in contact with the outer surface 7.3.2 of the emission insert 7.3.

[0103] The holding element 7.2, with an outer diameter D3, is pressed into a bore 7.1.5 with an inner diameter Di of the electrode holder 7.1. The bore 7.1.5 has an inner surface 7.1.3 that is in contact with the outer surface 7.2.2 of the holding element 7.2. The holding element 7.2 can be connected to the electrode holder 7.1, for example, by frictional engagement, positive engagement, or by a thermal joining process such as soldering, welding, in particular laser soldering, laser welding, arc soldering, arc welding, vacuum soldering, vacuum laser welding, or electron beam welding. It is particularly advantageous if the welding or soldering is performed from the rear end 7.1.9 and a seam (weld seam, solder seam) 7.4 is located in a cavity 7.1.7 extending to the rear end. Diffusion welding is also advantageous as a joining process; it uses pressure and temperature.

[0104] If a thermal joining, such as soldering or welding, of the holding element 7.2 to the electrode holder 7.1 is carried out from the direction of the cavity 7.1.7, this has the following advantages compared to a thermal joining from the front:

[0105] No seam visible from the front and no rework necessary.

[0106] The retaining element 7.2, for example, consists of a material made of copper and aluminum oxide. The mass proportions are distributed as follows: copper 99.3% and aluminum oxide 0.7%. The material used for the entire retaining element 7.2 is used as an example.

[0107] The retaining element 7.2 has a diameter D3 of, for example, 6 mm, and the emission insert 7.3 has a diameter D7 of, for example, 1.8 mm. This results in a wall thickness of the retaining element 7.2 of 2.1 mm and thus also a front circular surface 7.2.5 that extends 2.1 mm radially outward.

[0108] It is also possible for the material to be present only in a part or an area of ​​the holding element 7.2. This is then preferably the case at least on the inner surface 7.2.3 of the holding element 7.2. This area then preferably extends at least 0.5 mm radially outward from the inner surface. It is even better if the area extends at least 1 mm radially outward. This can be realized, for example, by the aluminum oxide content and / or the silver content decreasing radially outward and the copper content increasing.

[0109] The electrode holder 7.1 consists at least of a material with good electrical conductivity, in this example 99.9% of its mass being copper.

[0110] In this example, the mass of the emission feedstock preferably consists of at least 97% hafnium.

[0111] Figure 5 shows an electrode 7 according to a further particular embodiment, wherein Figure 5 is a sectional view through the electrode 7 and Figure 5.1 is view A of the front end 7.1.8 of the electrode. The electrode 7 has a front end 7.1.8, a rear end 7.1.9, an outer surface 7.1.2 and a cavity 7.1.1 through which the coolant flows or can flow when installed. The electrode 7 comprises an electrode holder 7.1, which is shown by way of example in Figure 5.2, a holding element 7.2, which is shown by way of example in Figure 5.3 and an emission insert 7.3. The emission insert 7.3 is inserted into a bore 7.2.1 with a diameter D5 of the holding element 7.2.

[0112] The bore of the holding element 7.2 has an inner surface 7.2.3 which is in contact with the outer surface 7.3.2 of the emission insert.

[0113] The holding element 7.2 is attached to the cylindrical section with its outer surface 7.2.2 on the front surface 7.1.1 of the electrode holder 7.1. The holding element 7.2 can be connected to the electrode holder 7.1, for example, by frictional engagement, positive engagement, or by a thermal joining process such as soldering, welding, in particular laser soldering, laser welding, arc soldering, vacuum soldering, vacuum laser welding, or electron beam welding. It is particularly advantageous if the welding or soldering is carried out from the rear end 7.19 and a seam (weld seam, solder seam) 7.4 is located in a cavity 7.1.7 extending to the rear end. Diffusion welding is also advantageous as a joining process; in this case, pressure and temperature are applied.

[0114] The retaining element 7.2, for example, consists of a material made of silver, copper, and aluminum oxide. The mass distribution is as follows: silver 92%, copper 7.5%, and aluminum oxide 0.5%. The material used for the entire retaining element 7.2 is used as an example.

[0115] The retaining element 7.2 has a diameter D3 of, for example, 10 mm, and the emission insert has a diameter D7 of, for example, 1.8 mm. This results in a wall thickness of the retaining element 7.2 of 4.1 mm and thus also a front circular surface 7.2.5 that extends 4.1 mm radially outward.

[0116] It is also possible for the material to be present only in a part or an area of ​​the holding element 7.2. This is then preferably the case at least on the inner surface 7.2.3 of the holding element 7.2. This area then preferably extends at least 0.5 mm radially outward from the inner surface. It is even better if the area extends at least 1 mm radially outward. This can be realized, for example, by the aluminum oxide content and / or the silver content decreasing radially outward and the copper content increasing.

[0117] The electrode holder 7.1 consists of at least a material with good electrical conductivity, in this example 99.5% of its mass being copper.

[0118] In this example, the mass of the emission feedstock preferably consists of at least 97% hafnium.

[0119] Figure 6 shows a nozzle 4 from Figure 1 being inserted. This nozzle 4 can, for example, be made entirely of a material made of copper and aluminum oxide. However, it is essential that the area of ​​the nozzle that can come into contact with the plasma jet or the arc is made of this material. This is the inner surface 4.2 of the nozzle opening 4.1. This can be achieved, for example, by attaching a nozzle insert 4.4 made of said material in a nozzle holder 4.3. This is shown as an example in Figure 6.1.

[0120] In the present example shown in Figure 6, nozzle 4 consists of a material made of copper and aluminum oxide. The mass fractions are distributed as follows: copper 99.7%, aluminum oxide 0.3%. The material used for the entire nozzle 4 has been used as an example in Figure 6.

[0121] The nozzle insert 4.4 shown in Figure 6.1 can be connected to the nozzle holder 4.3, for example, by frictional engagement, positive engagement, or by a thermal joining process such as soldering, welding, in particular laser soldering, laser welding, arc soldering, vacuum soldering, vacuum laser welding, or electron beam welding. Diffusion welding is also advantageous as a joining process, applying pressure and temperature.

[0122] Figure 7 shows the nozzle protection cap 9 according to Figure 1. This nozzle protection cap 9 can be made entirely of a material consisting of copper and aluminum oxide. However, it is essential that the area of ​​the nozzle protection cap that can come into contact with the plasma jet or the arc is made of this material. This is the inner surface 9.2 of the nozzle protection cap 9. This can be achieved, for example, by attaching a nozzle protection cap insert 9.4 made of said material into a nozzle protection cap holder 9.3. This is shown as an example in Figure 7.1.

[0123] In the present example shown in Figure 7, the nozzle protection cap 9 is made of a material consisting of copper and aluminum oxide. The mass fractions are distributed as follows: copper 99.5%, aluminum oxide 0.5%. The material used for the entire nozzle protection cap 9 has been used as an example.

[0124] The nozzle protection cap insert 9.4 shown in Figure 7.1 can be connected to the nozzle protection cap holder 9.3, for example, by frictional engagement, positive engagement, or by a thermal joining process such as soldering, welding, in particular laser soldering, laser welding, arc soldering, arc welding, vacuum soldering, vacuum laser welding, or electron beam welding. Diffusion welding is also advantageous as a joining process, applying pressure and temperature.

[0125] Figure 8 shows the nozzle cap 2 of the plasma torch according to Figure 1. This nozzle cap 2 can be made entirely of a material consisting of copper and aluminum oxide. However, it is essential that the area of ​​the nozzle cap that can come into contact with the plasma jet or the arc is made of this material. This is the inner surface 2.2 of the nozzle cap 2. This can be achieved, for example, by attaching a nozzle cap insert 2.4 made of said material to a nozzle protection cap holder 2.3. This is shown as an example in Figure 8.1.

[0126] In the present example shown in Figure 8, the nozzle cap 2 consists of a material made of copper and aluminum oxide. The mass proportions are distributed as follows: copper 99.5%, aluminum oxide 0.5%. The material used here is the same as for the entire nozzle cap 2, as an example.

[0127] The nozzle cap insert 2.4 shown in Figure 8.1 can be connected to the nozzle cap holder 2.3, for example, by frictional engagement, positive engagement, or by a thermal joining process such as soldering, welding, in particular laser soldering, laser welding, arc soldering, vacuum soldering, vacuum laser welding, or electron beam welding. Diffusion welding is also advantageous as a joining process, applying pressure and temperature.

[0128] In the foregoing description, the phrase "according to one embodiment" or "according to a particular embodiment" was used. This may refer to the same, but also to a different or further embodiment.

[0129] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential both individually and in any combination for the realization of the invention in its various embodiments.

[0130] List of reference symbols Arc torch Nozzle cap Nozzle cap opening Inner surface of the nozzle cap opening Nozzle cap holder Nozzle cap insert Plasma gas guide Nozzle Nozzle opening Inner surface of the nozzle opening Nozzle holder Nozzle insert Nozzle and nozzle cap receptacle Electrode receptacle Electrode Electrode holder Front surface Outer surface Inner surface Bore Cavity Front end Rear end Holding element Bore Outer surface Inner surface Front annular surface Emission insert Front surface Outer surface 7-4 Seam

[0131] 8 Nozzle protection cap holder

[0132] 9 Nozzle protection cap

[0133] 9.1 Nozzle protection cap opening

[0134] 9.2 Inner surface of the nozzle protection cap opening

[0135] 9.3 Nozzle cap holder

[0136] 9.4 Nozzle protection cap insert

[0137] 10 Secondary gas routing

[0138] The inner diameter

[0139] D3 outer diameter

[0140] D5 inner diameter

[0141] D7 diameter

[0142] Li length

[0143] L2 backburn

[0144] M mean longitudinal axis

[0145] PG Plasma Gas

[0146] SG secondary gas

[0147] WRi coolant return

[0148] WR2 coolant return

[0149] WVi coolant supply

[0150] WV2 coolant supply

Claims

Claims:

1. Component (2; 4; 5; 6; 7; 8; 9) for an electrically operated arc torch (1), in particular a plasma torch or plasma cutting torch, characterized in that the component or at least a part or a region of the component consists of a material which comprises aluminum oxide and at least one of the chemical elements silver and copper.

2. Component (2; 4; 5; 6; 7; 8; 9) according to claim 1, wherein the proportion of silver or copper or the sum of copper and silver is at least 98%, better at least 99%, most preferably at least 99.5% of the volume or mass of the material.

3. Component (2; 4; 5; 6; 7; 8; 9) according to claim 1, wherein the proportion of aluminum oxide is at least 0.15%, better at least 0.3%, most preferably at least 0.5% of the volume or mass of the material.

4. Component (2; 4; 5; 6; 7; 8; 9) according to one of the preceding claims, wherein the proportion of aluminum oxide is a maximum of 2.0%, better a maximum of 1.5%, most preferably a maximum of 1.0% of the volume or mass of the material.

5. Component (2; 4; 7; 9) according to one of claims 1 to 4, wherein the component is a wear part for an arc torch (1).

6. Component (7) according to one of claims 5, wherein the wearing part is an electrode (7) for an arc torch (1).

7. Component (7) according to claim 6, wherein the electrode (7) has a front end (7.1.8) and a rear end (7.1.9), extends along a longitudinal axis M and comprises at least one emission insert (7.3) at the front end (7.1.8) and a Electrode holder (7.1) and, if necessary, a holding element (7.2) for the emission insert (7.3).

8. Component (7) according to claim 7, wherein at least a portion of an inner surface (7.1.3) of the electrode holder (7.1) or an inner surface (7.2.3) of the holding element (7.2) which is in contact with the emission insert (7.3) by contact is made of said material.

9. Component (7) according to claim 8, wherein the material extends at least 0.5 mm, better at least 1 mm radially and most preferably at least 1.3 mm outwards from at least the partial section of the inner surface (7.1.3) of the electrode holder (7.1) or the inner surface (7.2.3) of the holding element (7.2).

10. Component (7) according to one of claims 7 to 9, wherein at least a portion of a front surface (7.1.1) immediately adjacent to the front surface (7.3.1) of the emission insert (7.3) comprises said material.

11. Component (7) according to claim 10, wherein said portion of the front surface (7.1.1) extends radially outwardly by at least 0.5 mm, more preferably at least 1 mm, and most preferably at least 1.3 mm.

12. Component (7) according to one of claims 7 to 11, wherein the emission insert (7.3) consists of at least 90% of the volume or mass of hafnium or zirconium or tungsten.

13. Component (4) according to claim 5, wherein the wearing part is a nozzle (4) with at least one nozzle opening (4.1).

14. Component (4) according to claim 13, wherein at least a portion of an inner surface (4.2) of the nozzle opening (4.1) comprises said material.

15. Component (4) according to claim 14, wherein the material extends radially outwards at least from the partial section of the inner surface (4.2) of the nozzle opening (4.1) by at least 0.5 mm, better at least 1 mm and most preferably at least 1.3 mm.

16. Component (9) according to claim 5, wherein the wearing part is a nozzle protection cap (9) with at least one nozzle protection cap opening (9.1).

17. Component (9) according to claim 16, wherein at least a portion of an inner surface (9.2) of the nozzle protection cap opening (9.1) comprises said material.

18. Component (9) according to claim 17, wherein the material extends radially outwardly at least 0.5 mm, better at least 1 mm and most preferably at least 1.3 mm from at least the partial section of the inner surface (9.2) of the nozzle protection cap opening (9.1).

19. Component (2) according to claim 5, wherein the wearing part is a nozzle cap (2) with at least one nozzle cap opening (2.1).

20. Component (2) according to claim 19, wherein at least a portion of an inner surface (2.2) of the nozzle cap opening (2.1) comprises said material.

21. Component (2) according to claim 20, wherein the material extends radially outwardly at least 0.5 mm, better at least 1 mm and most preferably at least 1.3 mm from at least the partial section of the inner surface (2.2) of the nozzle cap opening (2.1).

22. Component (5; 6; 8) according to one of claims 1 to 4, wherein the component is a receptacle (5; 6; 8) or a holder for at least one wearing part (2 or 4 or 7 or 9) for an arc torch (1).

23. Component (5; 6; 8) according to claim 22, wherein the receptacle (5; 6; 8) or holder is a nozzle receptacle (5), a nozzle cap receptacle (5) or an electrode receptacle (6) or a nozzle protection cap receptacle (8). 24- Arc torch comprising at least one component according to one of the preceding claims.

25. An arc torch according to claim 24, wherein it is a plasma torch or plasma cutting torch.

26. A method for plasma cutting using an arc torch according to claim 25, wherein the plasma cutting torch is operated with oxygen, an oxygen-containing gas or gas mixture and / or reducing gas or gas mixture and / or inert gas or gas mixture as plasma gas (PG) and / or secondary gas (SG).

27. A method for plasma cutting using an arc torch according to claim 25, wherein the plasma cutting torch is operated with oxygen or an acidic gas mixture in which the proportion of oxygen is at least 25 volume percent of the gas mixture, as plasma gas (PG) and / or secondary gas (SG).

28. A method for plasma cutting, using a plasma cutting torch according to claim 25, wherein the plasma cutting torch is operated with argon or an argon-containing gas mixture in which the proportion of argon is at least 25 volume percent of the gas mixture, as plasma gas (PG) and / or secondary gas (SG).

29. Method according to one of claims 26 to 28, wherein the at least one component (2; 4; 5; 6; 7; 8; 9) or at least one of the components (2; 4; 5; 6; 7; 8; 9) is cooled with a liquid medium.

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