Abstract: A round superconductor wire and method for fabricating same are disclosed. Embodiments are directed to a round superconductor wire including at least two superconductor tapes wound on a wire former. Each superconductor tape includes: bottom stabilizer and silver layers; substrate disposed above the bottom silver layer; buffer film stack disposed above the substrate; superconductor film disposed above the buffer film stack; top silver layer disposed above the superconductor film; and top stabilizer layer disposed above the top silver layer. At least one of the bottom stabilizer layer, bottom silver layer, substrate, buffer film stack, superconductor film, top silver layer, or top stabilizer layer is of a different width, thickness, or material composition in one of the superconductor tapes than in another of the superconductor tapes. These and other embodiments achieve a round superconductor wire having improved current density in high magnetic field applications when made in small diameters.

Abstract: According to one embodiment, an oxide superconductor includes an oriented superconductor layer and an oxide layer. The oriented superconductor layer contains fluorine at 2.0×1016-5.0×1019 atoms/cc and carbon at 1.0×1018-5.0×1020 atoms/cc. The superconductor layer contains in 90% or more a portion oriented along c-axis with an in-plane orientation degree (??) of 10 degrees or less, and contains a LnBa2Cu3O7-x superconductor material (Ln being yttrium or a lanthanoid except cerium, praseodymium, promethium, and lutetium). The oxide layer is provided in contact with a lower surface of the superconductor layer and oriented with an in-plane orientation degree (??) of 10 degrees or less with respect to one crystal axis of the superconductor layer. Area of a portion of the lower surface of the superconductor layer in contact with the oxide layer is 0.3 or less of area of a region directly below the superconductor layer.

Abstract: A method for manufacturing a base material 2 for a superconductive conductor which includes: a conductive bed layer forming process of forming a non-oriented bed layer 24 having conductivity on a substrate 10; and a biaxially oriented layer forming process of forming a biaxially oriented layer 26 on the bed layer 24.

Abstract: Disclosed are an oxide superconductor tape and a method of manufacturing the oxide superconductor tape capable of improving the length and characteristics of superconductor tape and obtaining stabilized characteristics across the entire length thereof. A Y-class superconductor tape (10), as an oxide superconductor tape, comprises a tape (13) further comprising a tape-shaped non-oriented metallic substrate (11), and a first buffer layer (sheet layer) (12) that is formed by IBAD upon the tape-shaped non-oriented metallic substrate (11); and a second buffer layer (gap layer) (14), further comprising a lateral face portion (14a) that is extended to the lateral faces of the first buffer layer (sheet layer) (12) upon the tape (13) by RTR RF-magnetron sputtering.

Abstract: A transmission system is provided with a superconductive cable having three phase conductors and a cryostat, surrounding the phase conductors, and encasing a hollow space, for conducting a cooling agent. For the three phase conductors, a common neutral conductor is provided, being made of electrically normally conducting material, carried out as insulating round conductor and placed outside the cryostat and next to it. The cryostat is made of a circumferentially enclosed, thermally insulated sheath.

Abstract: A tape-shaped base for a superconducting wire, which simplifies the intermediate layer and thus enables production of a superconducting wire at lower cost, and which is capable of improving the characteristics (such as electrical conduction and handling properties) of a superconducting wire; and a superconducting wire. Specifically disclosed is a tape-shaped base for a superconducting wire, which is obtained by forming an intermediate layer on a metal substrate. In the tape-shaped base for a superconducting wire a biaxially oriented layer of the intermediate layer is configured of a niobium monoxide (NbO) layer that is formed by depositing vapor deposition particles from a vapor deposition source on a film formation surface.

Abstract: The phase transition temperature, at which the crystal lattice of LMO that constitutes an oxide layer as an intermediate layer or as a part of an intermediate layer becomes cubic, is lowered. A substrate for a superconducting wire rod includes an oxide layer (LMO layer (22)) which contains, as a principal material, a crystalline material represented by the compositional formula: Laz(Mn1?xMx)wO3+? (wherein M represents at least one of Cr, Al, Co or Ti, ? represents an oxygen non-stoichiometric amount, 0<w/z<2, and 0<x?1).

Abstract: A cryogenically-cooled HTS cable is configured to be included within a utility power grid having a maximum fault current that would occur in the absence of the cryogenically-cooled HTS cable. The cryogenically-cooled HTS cable includes a continuous liquid cryogen coolant path for circulating a liquid cryogen. A continuously flexible arrangement of HTS wires has an impedance characteristic that attenuates the maximum fault current by at least 10%. The continuously flexible arrangement of HTS wires is configured to allow the cryogenically-cooled HTS cable to operate, during the occurrence of a maximum fault condition, with a maximum temperature rise within the HTS wires that is low enough to prevent the formation of gas bubbles within the liquid cryogen.

Abstract: Disclosed is an iron-based superconducting wire comprising a tubular material formed mainly from iron, and an iron-based superconductor formed in the tubular material, wherein the iron-based superconductor contains the iron forming the tubular material as a chemical constituent element of the iron-based superconductor.

Abstract: A method of producing a superconductive material involves the step (1) of applying a solution of an organic compound of metals, oxides of the metals forming a superconductive material, onto a support body to be subsequently dried, a provisional baking step (2) of causing organic components of the organic compound of the metals to undergo thermal decomposition, and a main baking process step (3) of causing transformation of the oxides of the metals into the superconductive material, thereby producing an epitaxially-grown superconductive coating material, wherein at the time of irradiation of a surface of the support body coated with the solution of the organic compound of the metals for forming the superconductive material, and/or of a surface of the support body, opposite to the surface coated with the solution of the organic compound of the metals, with the laser light, during a period between the steps (1) and (2).

Abstract: A rolled superconducting article includes: a cylindrical bobbin having a post in a cylindrical shape; a superconducting strip wound on the cylindrical bobbin in a rolled shape with a predetermined tension applied, wherein the superconducting strip is formed of a superconducting thin film, which is coated with a metal coating layer on a facing surface of the superconducting thin film, and a stabilizing substrate wound on the superconducting strip, wherein the stabilizing substrate is coated with a metal coating layer on a facing surface of the stabilizing substrate; an anti-bonding substrate wound on an outer surface of the stabilizing substrate with a predetermined tension applied; wherein the superconducting thin film is thermally adhered to the stabilizing substrate by heat-treating the rolled superconducting strip with the anti-bonding substrate wound therearound.

Abstract: An induction heating apparatus that can operate at current frequencies of greater than 60 Hz and at least 1 kW. The induction heating apparatus includes a high frequency power supply, a superconductive induction coil, and a fluid cooling system. A fluid cooling system is designed to cause a cooling fluid to flow at least partially about and/or through the superconductive induction coil.

Abstract: Novel articles and methods to fabricate same with self-assembled nanodots and/or nanorods of a single or multicomponent material within another single or multicomponent material for use in electrical, electronic, magnetic, electromagnetic and electrooptical devices is disclosed. Self-assembled nanodots and/or nanorods are ordered arrays wherein ordering occurs due to strain minimization during growth of the materials. A simple method to accomplish this when depositing in-situ films is also disclosed. Device applications of resulting materials are in areas of superconductivity, photovoltaics, ferroelectrics, magnetoresistance, high density storage, solid state lighting, non-volatile memory, photoluminescence, thermoelectrics and in quantum dot lasers.

Abstract: A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

Abstract: Superconductor cable having a plurality of flat, tape-shaped ribbon superconductor wires assembled to form a stack having a rectangular cross section, the stack having a twist about a longitudinal axis of the stack. Multiple superconductor cables including twisted stacked-cables of the flat-tape-shaped superconductor wires, and power cable comprising the twisted flat-tape stacked cables are disclosed. Superconducting power cable disposed within and separated from an electrical insulator with a space passing cryo-coolant between the superconducting cable and insulator is also disclosed.

Abstract: A superconducting cable (1; 10; 30) has a channel (4, 38) for a cooling liquid, a tubular support structure (5, 37), at least two layers (2, 3; 11-15; 31, 32, 35, 36) comprising high Tc conductors (2a, 3a) which comprise a high Tc material, and an insulation (7, 17), in particular a tubular insulation (7). The conductors (3a) of the outer layer (3; 13-15; 33, 36) comprise a first high Tc material that is different from a second high Tc material of the conductors (2a) of the inner layer (2; 11-12; 32, 35), wherein the first high Tc material exhibits lower AC losses as compared the second high Tc material, and that the high Tc conductors (3a) of the outer layer (3; 13-15; 33, 36) comprise normal-conducting interruptions (41, 42, 43). The superconducting cable exhibits reduced AC losses.

Abstract: Disclosed herein is a superconducting strip having a metal coating layer and a method of manufacturing the superconducting strip.

Abstract: A superconducting electrical cable is specified, which is surrounded by a cryostat (3), which comprises two concentric metallic tubes (4, 5) which enclose thermal insulation between them and is used to carry a cooling medium. The cable has at least one superconductor (1), which is composed of superconducting material, as well as a normal electrical conductor (7), which is composed of normally conductive material and is electrically conductively connected to the superconductor. The normal conductor (7) is arranged outside of but resting on the cryostat (3).

Abstract: A superconducting wire having at least a superconducting thin film and a stabilizing film formed one on top of another in order on a substrate having a predetermined width and a predetermined length, the superconducting wire having at least one cut made along a direction of the length of the superconducting wire, the superconducting wire being bendable at the cut in a width direction.

Abstract: Disclosed is a superconducting wire and a method for manufacturing the same, in which spacer are inserted into each space formed between modules, the spacers being different kinds according to a shape of each space when a restacking billet is manufactured in an internal diffusion method for manufacturing a Nb3Sn superconducting wire. One of a copper spacer and a low tin/copper spacer having a sectional area rate of copper/tin more than 6.0 is arranged between three modules as well as between two modules and a diffusion preventing tube, and a high tin/copper spacer having a sectional area rate of copper/tin less than 0.01˜1.5 or a middle tin/copper spacer having a sectional area rate of copper/tin less than 1.5˜6.0 is arranged between four modules.

Abstract: A crystalline article includes a single-crystal ceramic fiber, tape or ribbon. The fiber, tape or ribbon has at least one crystallographic facet along its length, which is generally at least one meter long. In the case of sapphire, the facets are R-plane, M-plane, C-plane or A-plane facets. Epitaxial articles, including superconducting articles, can be formed on the fiber, tape or ribbon.

Abstract: A thin film superconductive wire material (16) and an electro conductive tape (15) are immersed in a solder bath (35) containing a solder, which includes Sn(tin) and Bi (bismuth), to bond the thin film superconductive wire material (16) and the electro conductive tape (15) and a composite superconductive wire material (10) is formed.

Abstract: In a fabrication method of a MgB2 superconducting tape and wire by filling a tube with a MgB2 superconducting powder and forming it into a tape or wire, a fabrication method of a MgB2 superconducting tape (and wire) which is characterized by using a MgB2 superconducting powder having a high critical current density (Jc) owing to its lowered crystallinity and having potential for excellent grain connectivity as the MgB2 superconducting powder. Provided are a fabrication method of a MgB2 superconducting tape and wire which can fabricate a MgB2 superconducting tape and wire having a level of Jc sufficiently high for practical applications and homogeneous quality throughout its length by an ex-situ process employing a material of the composition suitable for its working environment as the sheath material, and a MgB2 superconducting tape and wire thereby fabricated.

Abstract: Bond wires for integrated circuits are implemented using a variety of methods. Using one such method, a composite bond wire is produced for use in an integrated circuit. A conductive material is melted and mixed with a material of particles less than 100 micrometers in size to create a mixture. The mixture is used to create the composite bond wire. A composite wire having an inner core and an outer layer having a higher conductivity than the inner core is also provided. The outer layer is designed to be thicker than the skin depth at the operating frequency for carrying AC signals.

Abstract: A method of fabricating a superconducting coil is provided which includes fabricating individual coil windings by depositing, shaping and texturing superconductive material in situ on a former which has a substantially curved surface.

Abstract: Novel articles and methods to fabricate same with self-assembled nanodots and/or nanorods of a single or multicomponent material within another single or multicomponent material for use in electrical, electronic, magnetic, electromagnetic, superconducting and electrooptical devices is disclosed. Self-assembled nanodots and/or nanorods are ordered arrays wherein ordering occurs due to strain minimization during growth of the materials. A simple method to accomplish this when depositing in-situ films is also disclosed. Device applications of resulting materials are in areas of superconductivity, photovoltaics, ferroelectrics, magnetoresistance, high density storage, solid state lighting, non-volatile memory, photoluminescence, thermoelectrics and in quantum dot lasers.

Abstract: A method and apparatus for manufacturing superconducting tape through an integrated process, including the steps of: heat-treating a substrate wound on a drum in a reaction chamber; continuously depositing components, constituting a buffer layer, a superconducting layer, a contact resistance layer, and a protective layer of the superconducting tape, which are supplied from a deposition chamber, on the substrate; and heat-treating the substrate deposited with the components.

Abstract: An RE123-based oxide superconductor characterized by comprising a conductive layer containing an REBa2Cu3O7-?-based oxide superconductor formed using a mixed material of at least RE2BaO4 and a Bax—Cuy—Oz-based material and a holding member which holds said conductive layer, where, RE is one type or more of elements selected from La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and Y.

Abstract: The invention relates to a method for producing a high temperature superconductor (HTSC) from a strip including an upper side precursor layer and which, for continuous sintering of the precursor layer within a furnace in the presence of a fed-in reaction gas, is drawn across a support. A furnace for performing the method is also described.

Abstract: A superconductive cable is provided which upon normal state, restricts flowing of electric current to a former to the maximum extent to thereby keep a cryogenic state in the superconductive cable stable. The superconductive cable includes a former surrounded by a superconductive layer and a cryostat provided at the outside of the superconductive layer, wherein the former includes a metal wire-wound part around which a plurality of wires is wound and an eddy-current prevention layer provided on the outer face of the wire-wound part, and the metal wires and the eddy-current prevention layer are made of a copper alloy.

Abstract: Under one aspect, a method of making a superconductor wire includes providing an oxide superconductor layer overlaying a substrate; forming a substantially continuous barrier layer over the oxide superconductor layer, the barrier layer including metal; depositing a layer of metal particles over the barrier layer, said depositing including applying a liquid including metal particles over the barrier layer; and sintering the layer of metal particles to form a substantially continuous metal layer over the barrier layer. In one or more embodiments, the oxide superconductor layer is oxygen-deficient, and the method may include oxidizing the oxygen-deficient oxide superconductor layer. At least a portion of the sintering and the oxidizing may occur simultaneously, for example by performing them at an oxygen partial pressure and a temperature sufficient to both sinter the metal particles and to oxidize the oxygen-deficient oxide superconductor layer.

Abstract: A process for growth of boron-based nanostructures, such as nanotubes and nanowires, with a controlled diameter and with controlled chemical (such as composition, doping) as well as physical (such as electrical and superconducting) properties is described. The boron nanostructures are grown on a metal-substituted MCM-41 template with pores having a uniform pore diameter of less than approximately 4 nm, and can be doped with a Group Ia or Group IIa electron donor element during or after growth of the nanostructure. Preliminary data based on magnetic susceptibility measurements suggest that Mg-doped boron nanotubes have a superconducting transition temperature on the order of 100 K.

Abstract: A superconducting cable enables the cooling of the superconducting conductor with high efficiency and has a sufficient insulating strength. A method of controlling the temperature of the coolants used in the cable is offered. The superconducting cable comprises a heat-insulated pipe that houses a cable core provided with a superconducting conductor made of a superconducting material. The cable core is also provided with a poorly heat-conductive pipe placed at the outer side of the outer circumference of the superconducting conductor. The inside and outside of the poorly heat-conductive pipe are separately filled with different types of coolants having different purposes. The poorly heat-conductive pipe is filled with a conductor-use coolant for cooling the superconducting conductor so as to maintain it at the superconducting state. The heat-insulated pipe is filled with an insulation-use coolant for performing electric insulation of the superconducting conductor.

Abstract: There is provided a superconductive cable capable of absorbing an amount of contracting a superconductive wire member in cooling by a simple constitution. A superconductive cable according to the invention is a cable including a superconductive wire member constituting a superconductive layer (a conductor layer 13, a return line conductor 17) by being wound spirally, a stress relaxation layer (an inner side stress relaxation layer 12, and insulating layer/outer side stress relaxation layer 16) provided on an inner side of the superconductive layer, and a cable constituting member (a former 11) provided on an inner side of the stress relaxation layer. The cable is constituted to absorb an amount of contracting the superconductive layer in accordance with cooling the superconductive wire member by a refrigerant in a diameter direction by the stress relaxation layer.

Abstract: A superconducting wire includes first and second superconducting layers disposed on one or more substrates in stacked relationship, the first superconducting layer comprising a high temperature superconducting oxide of a first composition and the second superconducting layer comprising a high temperature superconducting layer of a second composition, wherein the first and second compositions are different. The first superconductor layer optionally includes a high temperature superconductor composition selected to provide enhanced critical current (Ic(c)) in the presence of magnetic fields perpendicular to surface of the superconducting layer (H//c). The second superconductor layer optionally includes a high temperature superconductor composition selected to provide enhanced critical current (Ic) in the presence of magnetic fields parallel to surface of the superconducting layer (H//ab).

Abstract: Tape-shaped superconducting wires, and a superconducting coil formed from said wires, wherein a plurality of electrically separated superconducting film parts, each having a rectangular cross section and arranged in parallel, form parallel conductors, providing superconducting wires capable of containing losses incurred in the presence of alternating current (A/C). A superconducting coil is made by winding the superconducting wires, wherein the coil structure contains at least a part wherein perpendicular interlinkage magnetic fluxes acting among conductor elements of the parallel conductors by the distribution of magnetic fields generated by the superconducting coils cancel mutually in order to contain circulating current within the wires and to make shunt current uniform, thereby providing a low-loss A/C superconducting coil.

Abstract: In a metal sheath MgB2 superconducting wire, it is intended to achieve a wire having increased current density and a long length at the same time, by densitying superconducting core part. The superconducting wire is manufactured by forming diffusion hardened layer on the inner surface of the sheath such that the hardness of the inner surface becomes higher than that of the outer surface, filling MgB2 superconductor, and further if necessary, a critical current density increasing material such as indium, copper, and tin, in a metal sheath, to subject it to wire drawing. For the metal sheath, a material with toughness such as steel is used. Even if the sheath is made to a long wire, it does not break, thereby, enabling to density superconducting core part.

Abstract: Tape-shaped superconducting wires, and a superconducting coil formed from said wires, wherein a plurality of electrically separated superconducting film parts, each having a rectangular cross section and arranged in parallel, form parallel conductors, providing superconducting wires capable of containing losses incurred in the presence of alternating current (A/C). A superconducting coil is made by winding the superconducting wires, wherein the coil structure contains at least a part wherein perpendicular interlinkage magnetic fluxes acting among conductor elements of the parallel conductors by the distribution of magnetic fields generated by the superconducting coils cancel mutually in order to contain circulating current within the wires and to make shunt current uniform, thereby providing a low-loss A/C superconducting coil.

Abstract: Laminated, biaxially textured superconductors include Ir-based buffer layers and/or substrates.

Abstract: An electrode is steeped in a solution of Mg and B and a negative voltage is applied to the electrode so as to precipitate superconductive MgB2 on the electrode. Superconductive MgB2 is easily manufactured in various forms and at low costs without any special device.

Abstract: A method of manufacturing a superconducting wire is provided. The method is provided with the steps of filling a raw material powder in a metal pipe, the raw material powder being composed of an oxide superconductor or a precursor to become an oxide superconductor through heat treatment; heating the metal pipe filled with the above-described raw material powder to 400° C. or more and 800° C. or less; depressurizing the inside of the above-described heated metal pipe to 100 Pa or less; sealing an opening at an end portion of the metal pipe under the above-described depressurized condition; and subjecting the sealed metal pipe containing the above-described raw material powder to wire drawing, wherein the packing density of the above-described raw material powder is controlled at 10 percent or more and 40 percent or less and, thereby, the degasification of the inside of the metal pipe is adequately performed, so that the critical current density can be increased.

Abstract: In the present invention, a superconducting (sc) ceramic filament is enclosed in a silver sheath which is sealed therearound by applying silver powder between the surfaces of said sheath, pressing the surfaces and powder into contact and then applying sufficient heat to fuse them together, which heat is below the melting point of the surfaces and powder and then sintering the so enclosed ceramic filament, which upon cooling, forms a superconductor.

Abstract: Disclosed herein is method for making a wire comprising contacting a first end of a first superconducting wire with a second end of a second superconducting wire, wherein the superconducting wire comprises a superconducting filament having a superconducting composition comprising magnesium diboride; heating the first end of the first superconducting wire with the second end of the second superconducting wire at a point to form a joint, wherein the superconducting filament having the superconducting composition is in continuous electrical contact with any other part of the superconducting filament after the formation of the joint.

Abstract: A method of manufacturing a Fe-sheathed MgB2 wire includes the steps of: I. Selecting a carbon steel tube with 0.1% to 0.3% carbon; a. Crimping a first end of the tube; b. Selecting a Mg powder at least 99.8% pure, and sized for 325 mesh; c. Selecting a B powder, at least 99.99% pure, and sized for 325 mesh; d. Stoichiometrically mixing the Mg and B powders to form a mixture powder; e. Milling the mixture powder by using high-energy ball mill for 0.5 to 6 hours and using stainless steel mixing balls and vial, wherein the mass ratio of ball to powder is 20:1, to form a milled powder; f. Filling and packing the tube in an argon atmosphere with the milled powder to create a packing density of about 1.5 g/cm3; g. Crimping the second end of the tube to create a powder-filled tube; h. Rolling the powder-filled tube to create the Fe-sheathed MgB2 wire; and i. Annealing the as-rolled wire at 600 to 900° C. for 0.5 to 3 hours at high purity argon environment to create superconducting wire.

Abstract: A method for reducing ac loss in a superconducting coil of cable-in-conduit type superconductor made from chrome-coated compound superconducting strands, characterized in that when a superconducting coil is produced by the wind-and-react technique, bending or twist strain is applied in an amount of 0.15˜0.3% to the conductor cable portion after it has been heat-treated to form the superconducting compound, thereby separating the individual superconducting strands the chrome coat on which sintered as the result of heat treatment and further characterized in that the applied bending or twist strain is thereafter reverted to 0.1% or less, thereby reducing the ac loss of the superconducting coil.

Abstract: A method is described for the production of superconductive wires based on hollow filaments made of MgB2, which comprises: a) the formation of a composite billet by means of the coaxial insertion in a tubular metallic container of a cylindrical bar made of metallic magnesium and amorphous boron powder in the interspace between the container and bar, said powder being pressed between the metallic container and the magnesium bar, in such a quantity that the weight ratio magnesium/boron is higher than 1.2; b) at least one plastic deformation treatment of the composite billet thus obtained until a wire with a pre-fixed diameter is obtained, with the subsequent winding of the wire onto a support; c) a thermal treatment of the filament product thus obtained, at a temperature ranging from 700° C. to 950° C. for a time ranging from 15 minutes to three hours.

Abstract: Superconducting cables and magnetic devices are disclosed.

Abstract: A fully transposed composite superconductor can be especially used for AD devices and contains subconductors composed according to the Roebel bar principle and containing TC superconducting material. Superconductors are provided, that can be laterally bent in the plain of their width B so that the bending radius R is more than 100 times the width B and the bending zone length Hsue et al. '352 publication is more than 20 times the width B. The device for producing the conductor includes devices disposed in series for combining, bending, assembling to a Roebel bar, and fixating the subcontractors.

Abstract: Superconducting cable (1) comprising: a) a layer (20) of tapes comprising superconducting material, b) a tubular element (6) for supporting said layer (20) of tapes comprising superconducting material, c) a cooling circuit, adapted to cool the superconducting material to a working temperature not higher than its critical temperature, characterized in that said tubular element (6) is composite and comprises a predetermined amount of a first material having a first thermal expansion coefficient and a second material having a thermal expansion coefficient higher than that of said first material, said thermal expansion coefficients and said amounts of said first and second material being predetermined in such a way that said tubular element has an overall thermal shrinkage between the room temperature and said working temperature of the cable such as to cause a deformation of said tapes comprising superconducting material lower than the critical deformation of the same tapes.

Abstract: A manufacturing method for a superconducting wire which is a fine line made of an oxide superconductor, including the steps of forming the fine line by drawing a metal pipe filled with materials for the oxide superconductor, causing the materials to react to produce the oxide superconductor, heating the metal pipe at a temperature which is higher than the melting point of the metal material constituting the metal pipe.