Abstract: The plasma spraying apparatus includes a cathode, a first gas nozzle surrounding a head of the cathode therewith to form a first gas path outside of the cathode, and a second gas nozzle surrounding the first gas nozzle therewith to form a second gas path outside of the first gas nozzle. The second gas nozzle is formed with a wire path through which a wire is inserted such that a distal end of the wire is disposed in front of a nozzle opening of the second gas nozzle. The wire path has a substantially rectangular cross-section having a longer side extending in a direction in which the plasma flame extends, the wire path causing the wire to bend within elastic limit of the wire.

Abstract: A plasma gun with two gap electrodes on opposite ends of a chamber of ablative material such as an ablative polymer. The gun ejects an ablative plasma at supersonic speed. A divergent nozzle spreads the plasma jet to fill a gap between electrodes of a main arc device, such as an arc crowbar or a high voltage power switch. The plasma triggers the main arc device by lowering the impedance of the main arc gap via the ablative plasma to provide a conductive path between the main electrodes. This provides faster triggering and requires less trigger energy than previous arc triggers. It also provides a more conductive initial main arc than previously possible. The initial properties of the main arc are controllable by the plasma properties, which are in turn controllable by design parameters of the ablative plasma gun.

Abstract: A cathode assembly and a method for generation of pulsed plasma are disclosed. The cathode assembly comprises a cathode holder connected to multiple longitudinally aligned cathodes, preferably of the same diameter, and different lengths. The method is characterized by forming an electric arc between the cathodes in the assembly and an anode by passing DC current of a predetermined magnitude. Once the arc is established the current is reduced to the magnitude sufficient to sustain an electric arc, or a slightly larger magnitude, thereby reducing the area of arc attachment to a single cathode. Once the area of attachment has been reduced, the current is raised to the operational level of the pulse, while the area of attachment does not increase significantly.

Abstract: A process for the thermal deposition coating of a workpiece is provided that comprises the steps of: thermally depositing a coating on a metallic surface of a workpiece from a deposition head wherein at least one condition selected from the group of: coating deposition rate onto said surface, relative motion between the surface and said deposition head, and cryogenic coolant application rate onto said workpiece is controllable; substantially simultaneously measuring temperatures at a plurality of locations over the metallic surface of the workpiece; determining an average temperature of the temperatures measured in step (b); comparing the average temperature to a preselected minimum temperature and a preselected maximum temperature for the workpiece; and adjusting at least one of the controllable conditions if said average temperature is not between the preselected minimum temperature and the preselected maximum temperature for the workpiece.

Abstract: A plasma spray gun comprises a nozzle, an upstream powder injector, and a downstream powder injector. The upstream powder injector is disposed outside the nozzle and axially adjacent a nozzle outlet. The downstream powder injector is disposed axially downstream of the first upstream powder injector. The downstream powder injector is operative in a first coating mode, and the upstream powder injector is operative in a second coating mode.

Abstract: A method and apparatus by which liquid feedstock suspensions containing fine particles, micron- and nano-sized, are injected, with sufficient droplet velocity, preferably axially, into a plume of a thermal spray apparatus for the production of high-quality nanostructured coatings allows complete entrainment of the droplets in the plume, while the injection orifice remains potentially blockage-free for long periods of operation. The method and apparatus permit delivery at a low flow rate and with sufficient velocity to permit effective deposition, while reducing obstructions for a suspension feedstock delivery system and permits suspension feedstock to be controlled and delivered with reduced sensitivity of the spray process on the injection conditions to enable production of nanostructured coatings.

Abstract: A method of thermally depositing metal onto a target surface using a plasma transferred wire arc thermal spray apparatus, wherein the method includes the steps of offsetting the central axis of a consumable wire with respect to an axial centerline of a constricting orifice; and establishing and operating a plasma transferred wire arc between a cathode and a free end of the consumable wire; and melting and atomizing a continually fed free end of the consumable wire into molten metal particles and projecting the particles onto said target surface.

Abstract: A method and apparatus for microplasma spray coating a portion of a turbine vane without masking any portions thereof. The apparatus includes a microplasma gun with an anode, cathode, and an arc generator for generating an electric arc between the anode and cathode. An arc gas emitter injects gas through the electric arc. The electric arc is operable for ionizing the gas to create a plasma gas stream. A powder injector injects powdered material into a plasma stream. A localized area of the turbine vane is coated with the powdered material without having to mask the turbine vane.

Abstract: The present disclosure generally relates to systems, apparatus and methods of plasma spraying and plasma treatment of materials based on high specific energy molecular plasma gases that may be used to generate a selected plasma. The present disclosure is also relates to the design of plasma torches and plasma systems to optimize such methods.

Abstract: A plasma spray nozzle is provided. Owing to their high degree of wear, previous plasma spray nozzles were not suitable for the coating of components for which long coating times were necessary. The coating times may be reduced considerably by the triple injection of powder into the inner channel through the plasma spray nozzle.

Abstract: A microplasma spray coating apparatus includes a microplasma apparatus with an anode, cathode, and an arc generator for generating an electric arc between the anode and cathode. An arc gas emitter injects inert gas through the electric arc. The electric arc is operable for ionizing the gas to create a plasma gas stream. A powder injector nozzle extends through the anode and injects powdered material into the plasma stream for transfer to the workpiece.

Abstract: The plasma poling device includes: a holding electrode 4 being disposed in a poling chamber 1 and holding a substrate to be subjected to poling 2 thereon; an opposite electrode 7 being disposed in the poling chamber and being disposed opposite to the substrate to be subjected to poling held on the holding electrode; a power source 6 being electrically connected to either the holding electrode or the opposite electrode; a gas supply mechanism supplying a gas for forming plasma to a space between the opposite electrode and the holding electrode; and a control unit controlling the power source and the gas supply mechanism, wherein the control unit controls the power source and the gas supply mechanism, so as to form a plasma at a position opposite to the substrate to be subjected to poling to thereby perform poling treatment on the substrate to be subjected to poling.

Abstract: A system and method for the automated or “robotic” application of hardfacing to a surface of a drill bit.

Abstract: The invention relates to a plasma torch, comprising: a plasma generator comprising a cathode extending along an axis X and an anode (24), the cathode and the anode being arranged so as to be capable of generating, in a chamber (26), an electric arc between the anode and the cathode due to an electrical voltage, the plasma generator also comprising a plasmagen gas injection device (30) comprising an injection pipe (72) leading, along an injection axis (Ii), to an injection opening (74) in the chamber; a means for injecting a material to be discharged into a plasma flow generated by said plasma generator, the plasma torch being characterized in that: the relationship R? between: the radial distance (yi) of said injection opening, defined as the minimum distance between the axis X and the center of said injection orifice; the largest transverse size (DC) of the cathode in the region of the chamber downstream from the position PAC, wherein PAC denotes the axial position of maximum radial mutual encroachment of th

Abstract: A method and apparatus for microplasma spray coating a portion of a turbine vane without masking any portions thereof. The apparatus includes a microplasma gun with an anode, cathode, and an arc generator for generating an electric arc between the anode and cathode. An arc gas emitter injects gas through the electric arc. The electric arc is operable for ionizing the gas to create a plasma gas stream. A powder injector injects powdered material into a plasma stream. A localized area of the turbine vane is coated with the powdered material without having to mask the turbine vane.

Abstract: Different plasma spray guns have differing current and voltage requirements for their operation. The spray guns generally fall into low voltage high current and high voltage low current types. The power requirements of the guns vary greatly in terms of overall power ranging from few tens of kilowatts to few hundreds of kilowatts. The guns also have wide ranging requirements for voltage and current. A power delivery unit is described in which the unit is capable of delivering the wide range of power as well as the wide ranges of voltage and current. A plasma spray system with such power delivery unit can universally operate both the low voltage high current and high voltage low voltage spray gun types. Such system can reduce capital and operation costs since shops need not maintain separate and incompatible plasma spray systems.

Abstract: A method of hard facing a metal substrate with a two-layer abrasion and impact resistant coating by fusing a softer inner first coat of a matrix alloy of nickel-, cobalt- or iron-base alloy with carbide particles onto the substrate and fusing a harder second outer coat of a matrix alloy of nickel-, cobalt- or iron-base alloy with angular carbide particles onto the softer inner first coat. The softer inner first coat preferably has a hardness of about 30-40 Rc and the harder outer second coat preferably has a hardness of about 50-60 Rc. The carbide particles preferably are tungsten carbide particles in the size range of about 60 to 250? and comprise about 55 to 65 wt % of each of the inner and outer coats.

Abstract: A method and apparatus for microplasma spray coating a portion of a substrate, such as a gas turbine compressor blade, without masking any portions thereof. The apparatus includes a microplasma gun with an anode, cathode, and an arc generator for generating an electric arc between the anode and cathode. An arc gas emitter injects inert gas through the electric arc. The electric arc is operable for ionizing the gas to create a plasma gas stream. A powder injector injects powdered material into a plasma stream. A localized area of the compressor blade is coated with the powdered material without having to mask the compressor blade.

Abstract: A hybrid nozzle for use in a plasma spray gun, especially for plasma spraying silicon to form semiconductor devices such as solar cell. The outlet of the gun includes a two-piece annular electrode against which the plasma is ignited and through which the plasma plume exits the gun together with entrained silicon. In one embodiment, the upstream part is composed of graphite to allow ignition of the plasma and the downstream part is composed of pure silicon. In another aspect, the silicon feedstock is injected into the plasma plume through ports formed through the silicon part.

Abstract: An adjustable plasma spray gun apparatus is disclosed. In one embodiment, an adjustable plasma spray gun apparatus includes: a plasma spray gun body having a fore portion and an aft portion; and a first coupler configured to removably attach to the plasma spray gun body at the aft portion, the coupler including: a first portion having a first axial opening configured to removably attach to the plasma spray gun body at the aft portion; and a second portion having a second axial opening configured to removably attach to one of an electrode body or a second coupler.

Abstract: A method of thermally depositing metal onto a target surface using a plasma transferred wire arc thermal spray apparatus, wherein the method includes the steps of offsetting the central axis of a consumable wire with respect to an axial centerline of a constricting orifice; and establishing and operating a plasma transferred wire arc between a cathode and a free end of the consumable wire; and melting and atomizing a continually fed free end of the consumable wire into molten metal particles and projecting the particles onto said target surface.

Abstract: A method of material treatment in which the surface of a metal substrate is converted to a composite structure of the metal and its nitride or carbide utilizing a high temperature chemically active thermal plasma stream, and the product obtained from that method. The complex thermal plasma contains controllable additions of active gas, liquid or solid substances. The surface layer obtained is functionally graded to the substrate resulting in an excellent bond that resists delamination and spalling, and provides a significant increase in hardness, wear and erosion resistance, and corrosion resistance, and a decrease in coefficient of friction.

Abstract: A plasma apparatus is provided including a cathode module, an anode module, and at least one inter-electrode insert located between the cathode module and the anode module. The cathode module includes at least one cathode, and a pilot module may be provided adjacent to the cathode module. The pilot module may assist ignition of the plasma apparatus. The inter-electrode insert may have an upstream and a downstream transverse surface. Both the upstream transverse surface and the downstream transverse surface are angled in a downstream direction.

Abstract: Different plasma spray guns have differing current and voltage requirements for their operation. The spray guns generally fall into low voltage high current and high voltage low current types. The power requirements of the guns vary greatly in terms of overall power ranging from few tens of kilowatts to few hundreds of kilowatts. The guns also have wide ranging requirements for voltage and current. A power delivery unit is described in which the unit is capable of delivering the wide range of power as well as the wide ranges of voltage and current. A plasma spray system with such power delivery unit can universally operate both the low voltage high current and high voltage low voltage spray gun types. Such system can reduce capital and operation costs since shops need not maintain separate and incompatible plasma spray systems.

Abstract: There is provided an apparatus for producing single-wall carbon nanotubes. The apparatus comprises a plasma torch having a plasma tube adapted to receive an inert gas and form an inert gas plasma; a feeder adapted to direct a carbon-containing substance and a metal catalyst towards said inert gas plasma so that the carbon-containing substance and the metal catalyst contact said inert gas plasma downstream of where said inert gas is introduced in said plasma tube, to thereby form a plasma comprising atoms or molecules of carbon and the atoms of said metal; and a condenser for condensing the atoms or molecules of carbon and the atoms of said metal to form single-wall carbon nanotubes.

Abstract: A plasma spray apparatus in the form of a gun is utilized to apply an antifoulant coating to marine vessels. The apparatus includes a plasma generator, an electrophoresis element, a heating element, a shield gas element, a liquid cooling system, a forced air system, and a vacuum system. The plasma generator ionizes gas to create a plasma stream, which is utilized in part to supply energy to the heating element that heats a powder material. The heated powder material is exposed to the electrophoresis element to create a covalently bonded coating material. The coating material is injected into the plasma stream and is applied to a target surface. The shield gas element injects a gas flow to surround and protect the plasma and coating material stream as the stream is in flight to the target surface. The liquid cooling system cools portions of the plasma generator and heating element. The forced air system cools a portion of the target surface as the coating material is being applied.

Abstract: A process and apparatus for synthesizing a nanopowder is presented. In particular, a process for the synthesis of nanopowders of various materials such as metals, alloys, ceramics and composites by induction plasma technology, using organometallic compounds, chlorides, bromides, fluorides, iodides, nitrites, nitrates, oxalates and carbonates as precursors is disclosed. The process comprises feeding a reactant material into a plasma torch in which is generated a plasma flow having a temperature sufficiently high to yield a superheated vapor of the material; transporting said vapor by means of the plasma flow into a quenching zone; injecting a cold quench gas into the plasma flow in the quenching zone to form a renewable gaseous cold front; and forming a nanopowder at the interface between the renewable gaseous cold front and the plasma flow.

Abstract: A wire arc spray system use at least one first wire and second wire that include a composite wire including a first material at a core region thereof and a cladding including a second material surrounding the core region. A controller controls operation to propel heated material created by the arcing of the first wire and the second wire at the arc point to a surface to be coated. A wire arc spray methodology for creating a porous metal coating with all-metal wires is also provided.

Abstract: An improved automatic feedback control scheme enhances plasma spraying of powdered material through reduction of process variability and providing better ability to engineer coating structure. The present inventors discovered that controlling centroid position of the spatial distribution along with other output parameters, such as particle temperature, particle velocity, and molten mass flux rate, vastly increases control over the sprayed coating structure, including vertical and horizontal cracks, voids, and porosity. It also allows improved control over graded layers or compositionally varying layers of material, reduces variations, including variation in coating thickness, and allows increasing deposition rate. Various measurement and system control schemes are provided.

Abstract: A device and a method for plasma spraying are disclosed. The device comprises, a cathode, an anode, a plasma channel formed by the anode and intermediate electrodes, and one or more flowable material injectors. The plasma channel has a throttling portion that divides the plasma channel into a high pressure portion near the cathode formed by at least one intermediate electrode and a low pressure portion near the anode. During operation, a plasma generating gas is heated by the arc maintained between the cathode and the anode, forming plasma. When the plasma passes through the throttling portion, its speed increases to a supersonic speed, and at the same time its static pressure drops. Flowable materials are injected in the plasma flow in the low pressure portion. The particles in the flowable materials are heated by the plasma and the resultant heated particles and plasma are output from the outlet of the plasma channel.

Abstract: A machine for the treatment of containers, includes at least one container-treatment station. The machine is of the type in which each treatment station comprises a cover having a nozzle which is provided with: gripping elements for seizing the outside of the container, and impervious connection elements between the inside of the container and a vacuum pumping chamber which is provided in the cover. In addition, the machine is of the type in which the impervious connection elements include a cartridge which is mounted in the cover. The cartridge includes an axial segment, known as the connection segment, which extends inside the pumping chamber and which is equipped with radial holes. The pumping chamber is connected to the interior of the cartridge via the radial holes.

Abstract: An installation for the plasma processing of a continuous material (1) includes an evacuatable discharge chamber (3a, 3b) and a device for setting a gas atmosphere in the discharge chamber (3a, 3b). The device for setting a gas atmosphere includes a prechamber system (10, 11, 12) and a postchamber system (2), with sluice openings between the chambers (2, 3a, 3b, 10, 11, 12). The continuous material (1) is guided with low friction through the prechamber system (10, 11, 12) and the postchamber system (2). The device for setting a gas atmosphere includes a recovery system wherein gas can be recirculated from a postchamber (2a . . . 2k) into a prechamber (10, 11, 12) and/or postchamber (2a . . . 2k) having a higher pressure level so that processing is effected in a gas-saving manner.

Abstract: A plasma apparatus is provided including a cathode module, an anode module, and at least one inter-electrode insert located between the cathode module and the anode module. The cathode module includes at least one cathode, and a pilot module may be provided adjacent to the cathode module. The pilot module may assist ignition of the plasma apparatus. The inter-electrode insert may have an upstream and a downstream transverse surface. Both the upstream transverse surface and the downstream transverse surface are angled in a downstream direction.

Abstract: A method and apparatus for forming layers on a target. The apparatus and method employ a direct current plasma apparatus to form at least one layer using a plasma jet containing precursors. In some embodiments, the direct current plasma apparatus utilizes axial injection of the precursors through the cathode (in an upstream and/or downstream configuration) and/or downstream of the anode. In some embodiments, the direct current plasma apparatus can comprise a laser source for remelting the layer using a laser beam to achieve in-situ densification thereof.

Abstract: A method of forming a metal oxide film by the plasma CVD method and which includes reacting chiefly an organometal by a glow discharge in a low output region and, then, reacting the organometal with an oxidizing gas by the glow discharge in a high-output region to form a metal oxide film on the surface of a plastic substrate via an organic layer. This method forms a thin film having excellent adhesiveness, softness and flexibility on the surface of a plastic substrate relying on the plasma CVD method.

Abstract: A variable orifice torch for use in a solid free form fabrication system for manufacturing a component from successive layers of metal feedstock material. The variable orifice torch includes a torch structure defining a torch nozzle formed of a highly conductive bulk material. The variable orifice torch further includes a gas flow channel and a variable orifice defined therein. An arc electrode is disposed within the gas flow channel. The variable orifice is defined in the torch nozzle and in alignment with the arc electrode. The variable orifice is coupled to the torch structure in a manner operable to control a flow gas therethrough by varying the size of an aperture defined by the variable orifice.

Abstract: The invention relates to the field of methods of depositing a material on a substrate. It relates to a method of depositing, onto a substrate, a material that acts as a thermal barrier and that prior to deposition is in powder form. The powder is introduced into the plasma jet of a first plasma torch and into the plasma jet of at least one second plasma torch, the first plasma torch and at least the second plasma torch being disposed in an enclosure and oriented in such a manner that their plasma jets cross, so as to create a resultant plasma jet in which the powder is vaporized, the substrate being placed on the axis of the resultant plasma jet.

Abstract: A hybrid nozzle for use in a plasma spray gun, especially for plasma spraying silicon to form semiconductor devices such as solar cell. The outlet of the gun includes a two-piece annular electrode against which the plasma is ignited and through which the plasma plume exits the gun together with entrained silicon. In one embodiment, the upstream part is composed of graphite to allow ignition of the plasma and the downstream part is composed of pure silicon. In another aspect, the silicon feedstock is injected into the plasma plume through ports formed through the silicon part.

Abstract: A handheld air plasma spray is designed. Plasma is generated by a magnetized arc torch running at 60 Hz and is in non-equilibrium state; thus, the plasma effluent has relatively low temperature (touchable) and yet contains high energy electrons (>5 eV) capable to dissociate oxygen molecules to atomic oxygen. The emission spectroscopy of the torch indicates that the plasma effluent carries an abundance of atomic oxygen, which can effectively kill all kind microbes. Moreover, the experimental results show that this plasma can rapidly clot blood. This invention is for sterilization and blood coagulation applications.

Abstract: A microplasma spray coating apparatus includes a microplasma apparatus with an anode, cathode, and an arc generator for generating an electric arc between the anode and cathode. An arc gas emitter injects inert gas through the electric arc. The electric arc is operable for ionizing the gas to create a plasma gas stream. A powder injector nozzle extends through the anode and injects powdered material into the plasma stream for transfer to the workpiece.

Abstract: A solid free-form (SFF) method is used to manufacture a component from successive layers of feedstock material with low ductility. A plasma stream is created by energizing a flowing gas using an arc electrode, the arc electrode having a variable magnitude current supplied thereto. The plasma stream is directed to a predetermined targeted region to preheat the predetermined targeted region prior to deposition. The current is adjusted and the feedstock material is introduced into the plasma stream to deposit molten feedstock in the predetermined targeted region. The current is adjusted and the molten feedstock is slowly cooled at an elevated temperature, typically above the brittle to ductile transition temperature of the feedstock material, in a cooling phase to minimize the occurrence of material stresses.

Abstract: A method and apparatus for microplasma spray coating a portion of a substrate, such as a gas turbine compressor blade, without masking any portions thereof. The apparatus includes a microplasma gun with an anode, cathode, and an arc generator for generating an electric arc between the anode and cathode. An arc gas emitter injects inert gas through the electric arc. The electric arc is operable for ionizing the gas to create a plasma gas stream. A powder injector injects powdered material into a plasma stream. A localized area of the compressor blade is coated with the powdered material without having to mask the compressor blade.

Abstract: The present invention is related to a cable management system for a plasma cutter. The cable management system uses a flexible strap that is affixed to the housing of the plasma cutter and a loop is formed in the cable. The loop can be opened to align and position the cable with respect to the strap and the loop then can be easily closed to encircle the cable to secure the cable to the housing of the plasma cutter. By the present system, the portable plasma cutter can be transported by a user and the cables are securely fastened to the housing so as to prevent the cable from dragging or otherwise present a burden to the transportation of the plasma cutter.

Abstract: The present invention provides a standard interface for providing mechanical location, mechanical orientation, electrical connections, and water chamber seals for the exchange of a variety of plasma forming nozzles each associated with a specific plasma plume characteristic. The flexibility of the nozzle attachment is improved over prior designs by providing a standard exterior nozzle configuration and nozzle clamping assembly on the plasma gun so that multiple nozzles configurations (giving different plasma flow properties) can easily be used with the same devices. The joining of the nozzle to the receptacle forms a channel for cooling liquid to flow from the plasma gun through the nozzle to a return path in the plasma gun and creates an electrical contact between the plasma gun and the nozzle.

Abstract: A plasma apparatus is provided including a cathode module, an anode module, and at least one inter-electrode insert located between the cathode module and the anode module. The cathode module includes at least one cathode, and a pilot module may be provided adjacent to the cathode module. The pilot module may assist ignition of the plasma apparatus. The inter-electrode insert may have an upstream and a downstream transverse surface. Both the upstream transverse surface and the downstream transverse surface are angled in a downstream direction.

Abstract: A solid free form fabrication (SFF) system and method is used to fabricate a three-dimensional structure in a continuous manner from successive layers of feedstock material. The system includes a gas shielding structure that is configured to protect a targeted region from oxidation. The system further includes a positioning arm coupled to the deposition head and moveable to align the deposition head with a targeted region of the three-dimensional structure and a plurality of control components coupled to the positioning arm for controlling a position of the positioning arm and operation of the deposition head. The gas shielding structure is formed as either a parallelepiped structure or a half disc structure and may be conformable to at least one surface of the three-dimensional structure.

Abstract: The invention provides a compact spray nozzle having an improved tip for reproducibly forming droplets from small amounts of liquid with improved operational stability and spray pattern quality compared to prior art atomizing devices. The invention further provides a method for manufacturing the nozzle tip by machining comprising the step of machining the orifice and the inner section and/or the centering section in one setup.

Abstract: Microspray apparatus and methods involve injecting powdered material into a plasma gas stream. The material comprises first and second component powders. The second powder is a majority by the weight of the powdered material. The first powder acts as a melting point depressant. The first and second powders may have similar compositions but with the first powder including a greater quantity of a melting point depressant element.

Abstract: A twin plasma apparatus including an anode plasma head and a cathode plasma head. Each of the plasma heads includes an electrode and a plasma flow channel and a primary gas inlet between at least a portion of the electrode and the plasma flow channel. The anode plasma head and the cathode plasma head are oriented at an angled toward one another. At least one of the plasma flow channels includes three generally cylindrical portions. The three generally cylindrical portions of the plasma flow channels reduce the occurrence of side arcing.

Abstract: The reliability of a valve gear in which a cobalt-based alloy is welded by plasma powder building-up welding is improved. Disclosed is a valve gear including a bearing 2 having a sliding surface against a valve shaft 1, the valve gear being characterized in that: a welded layer 12 made of a heat-resistant cobalt-based alloy, based on plasma powder building-up, is formed on the sliding surface against the valve shaft 1; and the welded layer 12 includes a first welded layer 12a formed on the surface of the bearing 2, having a dilution ratio of 5 to 25% and a second welded layer 12b formed on the first welded layer 12a, having a dilution ratio of 50% or less of the dilution ratio of the first welded layer 12a. The dilution ratio is a parameter indicating the penetration amount of the welding metal into the base metal, and means a value obtained by B/A×100 (%) wherein A represents the total amount of the welded metal and B represents the amount of the welding metal penetrating into the base metal.