Abstract: A welding device for gas shielded arc welding includes: a portable welding robot mounted with a welding torch including a nozzle that guides jetting of shielding gas and a contact tip that performs energization on a consumable electrode; a feeding device that supplies the consumable electrode to the welding torch; a welding power source that supplies electric power to the consumable electrode via the contact tip; a gas supply source that supplies the shielding gas to be jetted from a nozzle end; and a control device that controls the portable welding robot. When the welding torch is seen from a side of jetting of the shielding gas, the contact tip is placed in an inside of an opening of the nozzle, the nozzle and the contact tip have a relatively movable structure, and an inner diameter of the nozzle end is within a range of 10-20 mm.

Abstract: In this welding control method for a portable welding robot that moves along a guide rail, for using the portable welding robot to weld a workpiece including a groove: a groove shape detection position is established in at least one location in a welding sector extending from a welding starting point to a welding end point; the groove shape at a groove shape detection position Pn is sensed by means of a detecting means of the portable welding robot, which is moving along the guide rail; groove shape information is calculated from detection data obtained by the sensing; and a welding condition is acquired on the basis of the groove shape information.

Abstract: An object of the present invention is to enhance a coercive force of magnetic particles by promoting formation of a continuous R-rich grain boundary phase in a crystal grain boundary of a magnetic phase of the particles, and to thereby obtain R-T-B-based rare earth magnet particles further having a high residual magnetic flux density. The present invention relates to production of R-T-B-based rare earth magnet particles capable of exhibiting a high coercive force even when a content of Al therein is reduced, and a high residual magnetic flux density, in which formation of an R-rich grain boundary phase therein can be promoted by heat-treating Al-containing R-T-B-based rare earth magnet particles obtained by HDDR treatment in vacuum or in an Ar atmosphere at a temperature of not lower than 670° C. and not higher than 820° C. for a period of not less than 30 min and not more than 300 min.

Abstract: The present invention provides R-T-B-based rare earth magnet particles comprising no expensive rare resources such as Dy and having an excellent coercive force which can be produced by HDDR treatment without any additional steps. The present invention relates to R-T-B-based rare earth magnet particles comprising crystal grains comprising a magnetic phase of R2T14B, and a grain boundary phase, in which the grain boundary phase has a composition comprising R in an amount of not less than 13.5 atom % and not more than 35.0 atom % and Al in an amount of not less than 1.0 atom % and not more than 7.0 atom %. The R-T-B-based rare earth magnet particles can be obtained by controlling heat treatment conditions in the DR step of the HDDR treatment in the course of subjecting a raw material alloy to the HDDR treatment.

Abstract: An object of the present invention is to enhance a coercive force of magnetic particles by promoting formation of a continuous R-rich grain boundary phase in a crystal grain boundary of a magnetic phase of the particles, and to thereby obtain R-T-B-based rare earth magnet particles further having a high residual magnetic flux density. The present invention relates to production of R-T-B-based rare earth magnet particles capable of exhibiting a high coercive force even when a content of Al therein is reduced, and a high residual magnetic flux density, in which formation of an R-rich grain boundary phase therein can be promoted by heat-treating Al-containing R-T-B-based rare earth magnet particles obtained by HDDR treatment in vacuum or in an Ar atmosphere at a temperature of not lower than 670° C. and not higher than 820° C. for a period of not less than 30 min and not more than 300 min.

Abstract: A welding device for gas shielded arc welding includes: a portable welding robot mounted with a welding torch including a nozzle that guides jetting of shielding gas and a contact tip that performs energization on a consumable electrode; a feeding device that supplies the consumable electrode to the welding torch; a welding power source that supplies electric power to the consumable electrode via the contact tip; a gas supply source that supplies the shielding gas to be jetted from a nozzle end; and a control device that controls the portable welding robot. When the welding torch is seen from a side of jetting of the shielding gas, the contact tip is placed in an inside of an opening of the nozzle, the nozzle and the contact tip have a relatively movable structure, and an inner diameter of the nozzle end is within a range of 10-20 mm.

Abstract: R-T-B-based rare earth magnet particles are produced by an HDDR treatment which comprises a first stage HD step of heating particles of a raw material alloy having a composition of R, B and Co in an inert atmosphere or in a vacuum atmosphere and then replacing the atmosphere with a hydrogen-containing gas atmosphere in which the raw material alloy particles are held in the same temperature range and a second stage HD step of heating a material obtained in the first stage HD step in which the material is held in the hydrogen-containing gas atmosphere.

Abstract: The present invention provides R-T-B-based rare earth magnet particles comprising no expensive rare resources such as Dy and having an excellent coercive force which can be produced by HDDR treatment without any additional steps. The present invention relates to R-T-B-based rare earth magnet particles comprising crystal grains comprising a magnetic phase of R2T14B, and a grain boundary phase, in which the grain boundary phase has a composition comprising R in an amount of not less than 13.5 atom % and not more than 35.0 atom % and Al in an amount of not less than 1.0 atom % and not more than 7.0 atom %. The R-T-B-based rare earth magnet particles can be obtained by controlling heat treatment conditions in the DR step of the HDDR treatment in the course of subjecting a raw material alloy to the HDDR treatment.

Abstract: An object of the present invention is to enhance a coercive force of magnetic particles by promoting formation of a continuous R-rich grain boundary phase in a crystal grain boundary of a magnetic phase of the particles, and to thereby obtain R-T-B-based rare earth magnet particles further having a high residual magnetic flux density. The present invention relates to production of R-T-B-based rare earth magnet particles capable of exhibiting a high coercive force even when a content of Al therein is reduced, and a high residual magnetic flux density, in which formation of an R-rich grain boundary phase therein can be promoted by heat-treating Al-containing R-T-B-based rare earth magnet particles obtained by HDDR treatment in vacuum or in an Ar atmosphere at a temperature of not lower than 670° C. and not higher than 820° C. for a period of not less than 30 min and not more than 300 min.

Abstract: R-T-B-based rare earth magnet particles are produced by an HDDR treatment which comprises a first stage HD step of heating particles of a raw material alloy having a composition of R, B and Co in an inert atmosphere or in a vacuum atmosphere and then replacing the atmosphere with a hydrogen-containing gas atmosphere in which the raw material alloy particles are held in the same temperature range and a second stage HD step of heating a material obtained in the first stage HD step in which the material is held in the hydrogen-containing gas atmosphere.

Abstract: There are provided a pharmaceutical raw material capable of exhibiting a uniform functionality and producing magnetic particle-containing drugs for diagnosis and medical treatments with a high reproducibility. The pharmaceutical raw material comprises a monodisperse colloid sterile aqueous solution of magnetic iron oxide fine particles having an average particle diameter of 5 to 30 nm, a saturation magnetization of 50 to 90 Am2/kg and a coercive force of 0.1 to 1.6 kA/m. The pharmaceutical raw material can be produced by forming magnetic iron oxide fine particles in the form of a colloid aqueous solution, purifying the resultant colloid aqueous solution of superparamagnetic iron oxide particles by water-washing and removing water-soluble salts by-produced upon the reaction from the reaction solution by an ordinary method, and replacing a dispersing medium of the purified colloid aqueous solution with ultrapure water.

Abstract: There are provided a pharmaceutical raw material capable of exhibiting a uniform functionality and producing magnetic particle-containing drugs for diagnosis and medical treatments with a high reproducibility. The pharmaceutical raw material comprises a monodisperse colloid sterile aqueous solution of magnetic iron oxide fine particles having an average particle diameter of 5 to 30 nm, a saturation magnetization of 50 to 90 Am2/kg and a coercive force of 0.1 to 1.6 kA/m. The pharmaceutical raw material can be produced by forming magnetic iron oxide fine particles in the form of a colloid aqueous solution, purifying the resultant colloid aqueous solution of superparamagnetic iron oxide particles by water-washing and removing water-soluble salts by-produced upon the reaction from the reaction solution by an ordinary method, and replacing a dispersing medium of the purified colloid aqueous solution with ultrapure water.

Abstract: The magneto rheological fluid of the present invention comprises magnetic particles, a dispersing medium and polyethyleneoxide as a viscosity modifier, the polyethyleneoxide being contained in an amount of 0.5 to 5% by weight based on the weight of the magnetic particles. The magneto rheological fluid of the present invention can exhibit an excellent dispersion stability, and, more specifically, can exhibit an excellent dispersion stability and can be prevented from suffering from sedimentation of magnetic particles contained therein.

Abstract: The present invention is a method for making highly stable magnetic alloy particles with high coercivities and high saturation magnetization comprising the steps of:a) providing a precursor selected from the group consisting of iron oxide hydroxide particles and iron oxide particles, wherein the precursor particle comprises from about 15 to about 45 atomic % Co based on amount of Fe present,b) reducing the precursor particles to magnetic alloy particles,c) passivating the magnetic alloy particles in an oxygen-containing atmosphere at a temperature between about 20.degree. and 100.degree. C.,d) annealing the passivated magnetic alloy particles in an inert atmosphere at a temperature from about 120.degree. to about 450.degree. C., ande) further oxidizing the annealed magnetic alloy particles in an oxygen-containing atmosphere.

Abstract: Disclosed herein are spindle-shaped magnetic iron based alloy particles containing at least one selected from the group consisting of Ni, Al, Si, P, Co, Mg, B and Zn, which have a particle length of 0.05 to 0.40 .mu.m, a crystallite size of 110 to 180 .ANG., a specific surface area of 30 to 60 m.sup.2 /g, a coercive force of 1,300 to 1,700 Oe and a saturation magnetization (.sigma.s) of not less than 100 emu/g and a process for producing the same.

Abstract: Disclosed herein are granulated particles for magnetic particles for magnetic recording, comprising: acicular ferric hydroxide oxide particles or acicular iron oxide particles; and at least one selected from the group consisting of semisynthetic starch and semisynthetic cellulose and having a bulk density of not less than 0.3 g/cm.sup.3 and a powdering ratio of not more than 40%, and a process for producing the granulated particles, and magnetic particles obtained from such granulated particles.

Abstract: Disclosed herein are spindle-shaped magnetic iron based alloy particles containing at least one selected from the group consisting of Ni, Al, Si, P, Co, Mg, B and Zn, which have a particle length of 0.05 to 0.40 .mu.m, a crystallite size of 110 to 180 .ANG., a specific surface area of 30 to 60 m.sup.2 /g, a coercive force of 1,300 to 1,700 Oe and a saturation magnetization (.sigma.s) of not less than 100 emu/g and a process for producing the same.

Abstract: Disclosed herein are acicular magnetic iron based alloy particles for magnetic recording, containing 1.5 to 10 mol % of B based on Fe (calculated as B) and 1.5 to 10 mol % of Co based on Fe (calculated as Co) in the vicinity of the surfaces of said particles and having a saturation magnetization of not less than 125 emu/g and an S.F.D. value of not more than 0.50, and a process for producing the same.

Abstract: Disclosed herein are acicular magnetic iron based alloy particles for magnetic recording, containing 1.5 to 10 mol % of B based on Fe (calculated as B) and 1.5 to 10 mol % of Co based on Fe (calculated as Co) in the vicinity of the surfaces of said particles and having a saturation magnetization of not less than 125 emu/g and an S.F.D. value of not more than 0.50, and a process for producing the same.

Abstract: Disclosed herein are magnetic iron oxide particles comprising spindle-like magnetite or maghemite particles having an aspect ratio(major:minor) of less than 4:1 and containing 0.1 to 20 atomic % of Si to Fe, and a process for producing the same.