Abstract: A carburized shaft part having a predetermined composition, a C content at a surface layer part of a mass % of 0.60 to 1.00%, at least one hole at an outer circumferential surface, a total volume ratio of martensite and retained austenite of 97% or more at a structure at a position of a 1 mm depth from the outer circumferential surface in an axial direction of the hole and a position of a 20 ?m depth from the surface of the hole, a maximum retained austenite volume ratio (R1) of 10.0 to 30.0% at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a range up to a 200 ?m depth from the surface of the hole, and a retained austenite reduction ratio of 20% or more found from R1 and the retained austenite volume ratio (R2) at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a position of a 20 ?m depth from the surface of the hole by the formula (A): ??=(R1?R)/R1×100.

Abstract: A shaft part excellent in static torsional strength and torsional fatigue strength containing, by mass %, essential elements of C: 0.35 to 0.70%, Si: 0.01 to 0.40%, Mn: 0.5 to 2.6%, P: 0.050% or less, S: 0.005 to 0.020%, Al: 0.010 to 0.050%, N: 0.005 to 0.025%, and O: 0.003% or less, further containing optional elements, having a balance of Fe and impurities, having a chemical composition satisfying formula (1), having at least one hole at an outer circumferential surface, having a volume ratio (R1) of 4 to 20% of retained austenite at a position of a 2 mm depth from the outer circumferential surface, having a volume ratio of retained austenite at a position of a 2 mm depth from the outer circumferential surface in an axial direction of the hole and at a position of a 20 ?m depth from the surface of the hole as R2, and having a reduction rate ?? of 40% or more of retained austenite found by the formula (A): ??=[(R1?R2)/R1]×100: Formula (1): 15.0?25.9C+6.35Mn+2.88Cr+3.09Mo+2.73Ni?27.

Abstract: A shaft part excellent in static torsional strength and torsional fatigue strength containing, by mass %, essential elements of C: 0.35 to 0.70%, Si: 0.01 to 0.40%, Mn: 0.5 to 2.6%, P: 0.050% or less, S: 0.005 to 0.020%, Al: 0.010 to 0.050%, N: 0.005 to 0.025%, and O: 0.003% or less, further containing optional elements, having a balance of Fe and impurities, having a chemical composition satisfying formula (1), having at least one hole at an outer circumferential surface, having a volume ratio (R1) of 4 to 20% of retained austenite at a position of a 2 mm depth from the outer circumferential surface, having a volume ratio of retained austenite at a position of a 2 mm depth from the outer circumferential surface in an axial direction of the hole and at a position of a 20 ?m depth from the surface of the hole as R2, and having a reduction rate ?? of 40% or more of retained austenite found by the formula (A): ??=[(R1?R2)/R1]×100: Formula (1): 15.0?25.9C+6.35Mn+2.88Cr+3.09Mo+2.73Ni?27.

Abstract: A steel material excellent in rolling fatigue property, the steel material including, in mass %: C: 0.10% to 1.50%, Si: 0.01% to 0.80%, Mn: 0.10% to 1.50%, Cr: 0.02% to 2.50%, Al: 0.002% to less than 0.010%, Ce+La+Nd: 0.0001% to 0.0025%, Mg: 0.0005% to 0.0050%, O: 0.0001% to 0.0020%, Ti: 0.000% to less than 0.005%, N: 0.0180% or less, P: 0.030% or less, S: 0.005% or less, Ca: 0.0000% to 0.0010%, V: 0.00 to 0.40%, Mo: 0.00 to 0.60%, Cu: 0.00 to 0.50%, Nb: 0.000 to less than 0.050%, Ni: 0.00 to 2.50%, Pb: 0.00 to 0.10%, Bi: 0.00 to 0.10%, B: 0.0000 to 0.0050%, and the balance being Fe and an impurity, wherein a fatigue-initiating inclusion detected by an ultrasonic fatigue test contains one or more of Ce, La, and Nd, and Mg, Al, and O, and a composition ratio in the fatigue-initiating inclusion satisfies Formula (1).

Abstract: A carburized shaft part having a predetermined composition, a C content at a surface layer part of a mass % of 0.60 to 1.00%, at least one hole at an outer circumferential surface, a total volume ratio of martensite and retained austenite of 97% or more at a structure at a position of a 1 mm depth from the outer circumferential surface in an axial direction of the hole and a position of a 20 ?m depth from the surface of the hole, a maximum retained austenite volume ratio (R1) of 10.0 to 30.0% at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a range up to a 200 ?m depth from the surface of the hole, and a retained austenite reduction ratio of 20% or more found from R1 and the retained austenite volume ratio (R2) at a position of a 1 mm depth from the outer circumferential surface in the axial direction of the hole and a position of a 20 ?m depth from the surface of the hole by the formula (A): ??=(R1?R)/R1×100.

Abstract: There is provided an induction hardening steel excellent in quenching crack resistance. The induction hardening steel of the present embodiment includes, by mass percent, C: 0.35 to 0.6%, Si: at least 0.01% and less than 0.40%, Mn: 1.0 to 2.0%, S: more than 0.010% and at most 0.05%, Cr: 0.01 to 0.5%, Al: 0.001 to 0.05%, N: Ti/3.4 to 0.02%, and Ti: 0.005 to 0.05%, the balance being Fe and impurities, and satisfies the following formula (1): 2S-3Ti<0.040??(1) where, into each element symbol in formula (1), the content (mass %) of the corresponding element is substituted.

Abstract: [Problem] It is an object to provide a joining method, whereby even ceramics having an extremely small dielectric loss factor such as aluminum nitride can be joined efficiently and tightly. [Means for Resolution] A method of joining ceramics of the present invention is a method of heating ceramics of the same kind or different kinds by inducing self-heating of the ceramics by electromagnetic wave irradiation and thereby joining the ceramics together, and includes preheating a surface to be joined of the ceramic by a heating means that includes an auxiliary heating means other than the self-heating.

Abstract: [Problem] It is an object to provide a joining method that enables to join aluminum nitride sinters together efficiently and tightly. [Means for solution] A method of joining an aluminum nitride sinter includes placing an inclusion including a sintering aid between a surface to be joined of one aluminum nitride sinter and a surface to be joined of the other aluminum nitride sinter, and heating the inclusion by electromagnetic wave irradiation, thereby joining the aluminum nitride sinters together.

Abstract: A process for producing a ceramic sinter or inorganic film in which anisotropic particles or anisotropic crystals have been oriented; or a process for producing a bonded composite material which comprises a base sample and another material tenaciously bonded to a surface of the base. The processes are characterized by imposing a centrifugal force during buming (heating).

Abstract: The present invention is to produce an aluminum nitride powder which is turned into a sintered body at a temperature of not more than 1600° C., thereby obtaining a sintered aluminum nitride in which the density and thermal conductivity are high and which can be properly used as a substrate material. Using a vapor phase reaction apparatus shown in FIG. 1, ammonia gas was fed from a reactor 2 heated at from 300 to 500° C. and maintained at that temperature by a heating section 1 via a feeding tube 4 while being regulated by a flow regulator 3. At the same time, while being regulated by the flow regulator 5, nitrogen gas containing an organic aluminum compound is fed via a feeding tube 6 to obtain an aluminum nitride powder. The aluminum nitride powder is subjected to a heat treatment at from 1100 to 1500° C. in a reducing gas atmosphere and/or an inert gas atmosphere to obtain an aggregate aluminum nitride powder.

Abstract: The present invention provides a rotor, a shaft or a sample holder for a centrifugal sintering system, and the present invention relates to a ceramic member for a centrifugal sintering system which is a member consisting of a rotor, a shaft or a sample holder for use in a centrifugal sintering system imparting a centrifugal force field and a temperature field to a molded body of ceramics or metal powder or a ceramic precursor film wherein a rotor for turning a sample holder, a shaft or a sample holder is composed of ceramics, to the ceramic member wherein the rotor which turns the sample holder is composed of conductive silicon carbide ceramics and the rotor alone is selectively caused to self heat by induction heating means to indirectly heat the sample, and to the ceramic member wherein the sample holder is composed of a material with a large dielectric loss and the sample holder alone is selectively heated using dielectric heating means to indirectly heat the sample.

Abstract: The present invention is to produce an aluminum nitride powder which is turned into a sintered body at a temperature of not more than 1600° C., thereby obtaining a sintered aluminum nitride in which the density and thermal conductivity are high and which can be properly used as a substrate material. Using a vapor phase reaction apparatus shown in FIG. 1, ammonia gas was fed from a reactor 2 heated at from 300 to 500° C. and maintained at that temperature by a heating section 1 via a feeding tube 4 while being regulated by a flow regulator 3. At the same time, while being regulated by the flow regulator 5, nitrogen gas containing an organic aluminum compound is fed via a feeding tube 6 to obtain an aluminum nitride powder. The aluminum nitride powder is subjected to a heat treatment at from 1100 to 1500° C. in a reducing gas atmosphere and/or an inert gas atmosphere to obtain an aggregate aluminum nitride powder.

Abstract: The invention provides a low-carbon free cutting steel containing no lead and is at least comparable in machinability to the conventional leaded free cutting steels and composite free cutting steels and furthermore has excellent finished surface characteristics. The steel is a low-carbon free cutting steel which comprises, on the percent by mass basis, C: 0.05 to under 0.20%, Mn: 0.4-2.0%, S: 0.21-1.0%, Ti: 0.002-0.10%, P: 0.001-0.30%, Al: not higher than 0.2%, 0: 0.001-0:03% and N: 0.0005-0.02%, with the balance being Fe and impurities, and which satisfies the relations (a) and (b) given below concerning the inclusions contained in the steel: (A+B)/C?0.

Abstract: A process for producing a ceramic sinter or inorganic film in which anisotropic particles or anisotropic crystals have been oriented; or a process for producing a bonded composite material which comprises a base sample and another material tenaciously bonded to a surface of the base. The processes are characterized by imposing a centrifugal force during buming (heating).

Abstract: A steel for machine structural use which comprises, on the percent by mass basis, C: 0.1 to 0.6%, Si: 0.01 to 2.0%, Mn: 0.2 to 2.0%, S: 0.005 to 0.20%, P: not more than 0.1%, Ca: 0.0001 to 0.01%, N: 0.001 to 0.02% and Al: not more than 0.1%, with the balance being Fe and impurities, with a value of [Ca]e defined by [Ca]e=T.[Ca]?(T.[O]/(O)ox)×(Ca)ox of not more than 5 ppm or with a proportion of MnO contained in oxide inclusions of not more than 0.05 and a value of Ca/O of not more than 0.8 is excellent in machinability and, therefore, it can be used as a steel stock for various machine structural steel parts, such as in industrial machinery, construction machinery and conveying machinery such as automobiles. It is substantially free of Pb, hence suited for use as a steel friendly to the global environment. [Ca]e is the effective Ca concentration index (ppm by mass), T.[Ca] and T.

Abstract: It is an object to provide a method of manufacturing a porous medium having a grading porous structure, and there are provided a method of manufacturing a porous medium having a grading porous structure, comprising the steps of installing a sample consisting of a powder compact or a porous body in a rotating body, and heating the sample while applying a centrifugal force to the sample through high-speed rotation of the rotating body to produce a porous medium having a grading porous structure in which the pore size and the porosity change gradually by using the pressure grading in the sample arising through the centrifugal force, and such a method wherein the pore size and the porosity of the sample are predicted based on a linear shrinkage factor calculated through the equation:

Abstract: The invention provides a steel for machine structural use, which is excellent in machinability, comprising, in percent by mass, C: 0.1-0.6%. Si: 0.01-2.0%, Mn: 0.2-2.0%, S: 0.005-0.2%, Al: not more than 0.009%, Ti: not less than 0.001% but less than 0.04%, Ca: 0.0001-0.01%, O (oxygen): 0.0010-0.01%, and N: not more than 0.02% and satisfying the following relations (1) to (3): n0/S (%)≧2500  (1) n1/n0≦0.1  (2) n2≧10  (3) where n0: total number of sulfide inclusions not smaller than 1 &mgr;m per mm2 of a cross section parallel to the direction of rolling (number/mm2); n1: number of MnS inclusions having not smaller than 1 &mgr;m and containing not less than 1.

Abstract: By limiting steel compositions with respect to special components and controlling contents of Ti, Zr and S in a steel to a suitable range, fine Ti and Zr sulfides are generated so that a cast steel having excellent internal quality and machinability after casting can be ensured. Then, by casting this cast steel a mold having excellent machinability, whose internal quality as cast is comparable to that of a forged steel product, can be produced. Therefore, the mold of the present invention can be widely applied to use, which severely requires excellent surface properties in products for deep-engraving in which a worked surface reaches the internal portion of the section material or for finishing.

Abstract: A method and an apparatus for sintering a compact of particulate material for a ceramic or of particles of a metal, or a ceramic precursor film, wherein the sintering is performed by heating and burning the compact or the ceramic precursor film while applying centrifugal force to the compact or the ceramic precursor film.

Abstract: The invention provides a low-carbon resulfurized free cutting steel containing no lead and at least comparable in machinability to the conventional leaded free cutting steels. The steel consists of, by mass percent, C: 0.05-0.19%, Mn: 0.4-2.0%, S: 0.21-1.0%, Ti: 0.03-0.30%, Si: not more than 1.0%, P: 0.001-0.3%, Al: not more than 0.2%, O (oxygen): 0.0010-0.050% and N: 0.0001-0.