Abstract: A method for producing isopropyl alcohol is provided in which propylene is hydrated directly with water to produce isopropyl alcohol, the method including: a distillation step in which crude isopropyl alcohol is distilled; and a filtration step in which the isopropyl alcohol obtained in the distillation step is filtered through a filter having an ion-exchange group.

Abstract: A method for producing isopropyl alcohol is provided in which propylene is hydrated directly with water to produce isopropyl alcohol, the method including: a distillation step in which crude isopropyl alcohol is distilled; and a filtration step in which the isopropyl alcohol obtained in the distillation step is filtered through a filter having an ion-exchange group.

Abstract: The purpose of the present invention is to provide a stainless steel member and a production method thereof, said stainless steel member having a passivation layer formed on a surface of a base material formed from stainless steel, wherein the film thickness of the passivation layer is 2-20 nm, and the concentration of chromium atoms in the outermost surface of the passivation layer is 0.1-2.3 by atomic percentage. Also provided are a device or container, the liquid-contact part of which in contact with a semiconductor treatment liquid is formed from the stainless steel member, a semiconductor treatment liquid production method for producing the semiconductor treatment liquid by using the device, and a semiconductor treatment liquid storage method for storing the semiconductor treatment liquid in the container.

Abstract: The purpose of the present invention is to provide a stainless steel member and a production method thereof, said stainless steel member having a passivation layer formed on a surface of a base material formed from stainless steel, wherein the film thickness of the passivation layer is 2-20 nm, and the concentration of chromium atoms in the outermost surface of the passivation layer is 0.1-2.3 by atomic percentage. Also provided are a device or container, the liquid-contact part of which in contact with a semiconductor treatment liquid is formed from the stainless steel member, a semiconductor treatment liquid production method for producing the semiconductor treatment liquid by using the device, and a semiconductor treatment liquid storage method for storing the semiconductor treatment liquid in the container.

Abstract: A cup member has a cylindrical portion, a bottom portion, and a short shaft portion having a solid shaft shape and including a joining end surface at an end portion thereof. A shaft member has a solid shaft shape and includes a joining end surface at one end thereof. The joining end surfaces of the cup and shaft members are brought into abutment against each other and welded from a radially outer side to form a welded portion. At this time, center segregation is prevented from interfering with the welded portion. The cup member is formed by forging including upsetting a billet having a columnar shape successively in a plurality of stages, extruding the cylindrical portion and the short shaft portion, and ironing the cylindrical portion. In the course of the upsetting, a region of the billet corresponding to a bottom side of the cup member is narrowed.

Abstract: A cup member has a cylindrical portion, a bottom portion, and a short shaft portion having a solid shaft shape and including a joining end surface at an end portion thereof. A shaft member has a solid shaft shape and includes a joining end surface at one end thereof. The joining end surfaces of the cup and shaft members are brought into abutment against each other and welded from a radially outer side to form a welded portion. At this time, center segregation is prevented from interfering with the welded portion. The cup member is formed by forging including upsetting a billet having a columnar shape successively in a plurality of stages, extruding the cylindrical portion and the short shaft portion, and ironing the cylindrical portion. In the course of the upsetting, a region of the billet corresponding to a bottom side of the cup member is narrowed.

Abstract: After molding a preliminarily molded product as a material, the preliminarily molded product is put into a full-enclosed forging die so that a product is molded with the full-enclosed forging die. A shear-drop suppressing portion for suppressing thickness reduction on a boss-portion side of an outer peripheral portion of a leading end surface of each of shaft portions of the product is formed on the preliminary leading-end surface configuring a leading end surface of each of the shaft portions of the product in the preliminarily molded product. When the preliminarily molded product is put into the full-enclosed forging die and the product is to be molded, a relief portion is formed between the leading end surface of each of the shaft portions to be molded and a cavity of the full-enclosed forging die.

Abstract: After molding a product-to-be-preliminarily-molded to form a preliminarily molded product as a material, the preliminarily molded product is put into a full-enclosed forging die so that a product is molded with the full-enclosed forging die. On a preliminary leading-end surface to be formed as a leading end surface of a shaft portion of the product formed of the preliminarily molded product, there is formed a shear-drop suppressing portion for suppressing thickness reduction on a boss-portion side of an outer peripheral portion of the leading end surface of the shaft portion of the product. At a time of putting the preliminarily molded product into the full-enclosed forging die so as to mold the product, a relief portion is formed between the leading end surface of the shaft portion to be formed and a cavity of the full-enclosed forging die.

Abstract: After molding a product-to-be-preliminarily-molded to form a preliminarily molded product as a material, the preliminarily molded product is put into a full-enclosed forging die so that a product is molded with the full-enclosed forging die. On a preliminary leading-end surface to be formed as a leading end surface of a shaft portion of the product formed of the preliminarily molded product, there is formed a shear-drop suppressing portion for suppressing thickness reduction on a boss-portion side of an outer peripheral portion of the leading end surface of the shaft portion of the product. At a time of putting the preliminarily molded product into the full-enclosed forging die so as to mold the product, a relief portion is formed between the leading end surface of the shaft portion to be formed and a cavity of the full-enclosed forging die.

Abstract: A method for forming a wheel bearing apparatus where the end portion of the cylindrical portion is pre-formed as a cylinder prior to its plastic deformation to form the caulking portion. A caulking tool with a punch and a swing shaft abuts against the end portion of the cylinder at a predetermined inclined angle relative to the inner circumferential surface of the cylinder. Teeth on the punch form the face-spline by plastically deforming the end face of the caulking portion. The swing shaft central axis is inclined at an angle relative to a central axis of the wheel hub. The face-spline is formed simultaneously with the formation of the caulking portion by advancing the caulking tool toward the wheel hub. A main shaft is rotated to cause a swing motion of the caulking tool.

Abstract: A manufacturing method for a tripod type constant velocity universal joint includes, when forging a raw-shaped material corresponding to each of three journals into a journal shape using a molding surface of a die and in a state where a relief portion is provided on a raw-shaped-material-leading-end-side of the die, molding an outer peripheral surface of the raw-shaped material into a projected round shape. The molding occurring with a tapered surface formed on the molding surface with which the outer peripheral surface of the raw-shaped material is held in contact and a recessed round surface formed between the molding surface and the tapered surface.

Abstract: A forging method and a full-enclosed forging die contribute to the alleviation of an enclosing force applied to dies and in which a relatively small enclosing apparatus can be used even with respect to larger-sized products. A tripod type constant velocity universal joint is formed with a tripod member molded with the full-enclosed forging die. The full-enclosed forging die includes openable/closable dies and punches for pressing a material between the dies. From the forging die, the tripod member including a boss portion and shaft portions protruded radially from the boss portion is molded.

Abstract: Provided is a manufacturing method for a tripod type constant velocity universal joint including: an outer joint member having an inner peripheral surface provided with: three track grooves extending in an axial direction; and roller-guide surfaces extending in the axial direction on both sides of each of the three track grooves; a tripod member including three journals each projected into a radial direction; and a roller unit supported rotatably around each of the three journals of the tripod member and inserted rollably in each of the three track grooves of the outer joint member, the manufacturing method including, when forging a raw-shaped material corresponding to each of the three journals into a journal shape with use of a molding surface of a die, under a state in which a relief portion is provided on a raw-shaped-material-leading-end-side of the die, molding an outer peripheral surface of the raw-shaped material into a projected round shape with use of a tapered surface formed on the molding surface

Abstract: Provided are a forging method, a forged-product molding apparatus, and a tripod type constant velocity universal joint which contribute to reduction of shear drop and avoidance of an increase in processing load generated through contact of a leading end surface of a shaft portion and dies even when an excessively-heavy raw material is mixed so that a life of the die can be prolonged. After molding a product-to-be-preliminarily-molded to form a preliminarily molded product (20A) as a material, the preliminarily molded product (20A) is put into a full-enclosed forging die (30) so that a product is molded with the full-enclosed forging die (30).

Abstract: Provided are a forging method and a full-enclosed forging die which contribute to alleviation of an enclosing force applied to dies and in which a relatively small enclosing apparatus can be used even with respect to larger-sized products. Further, provided is a tripod type constant velocity universal joint using a tripod member molded with such a full-enclosed forging die. Using a full-enclosed forging die including openable/closable dies (11, 12) and punches (14, 15) for pressing a material between the dies (11, 12), a product (tripod member) (16) including a boss portion (18) and shaft portions (17) protruded radially from the boss portion (18) is molded.

Abstract: A wheel bearing device includes a hub ring, a double-row bearing and a constant velocity universal joint which are unitized together. At least one of double-row inner raceways of the bearing and a wheel mounting flange are formed on a hub ring. The hub ring and a stem portion of a joint outer ring of the constant velocity universal joint are fitted through a torque transmission assembly, wherein a pilot member as a separate element having a wheel guide portion and a brake guide portion is fitted to a side-end portion of the wheel mounting flange of the hub ring, and the hub ring and the pilot member are fixed to the joint outer ring by swaging.

Abstract: A method for forming a wheel bearing apparatus where the end portion of the cylindrical portion is pre-formed as a cylinder prior to its plastic deformation to form the caulking portion. A caulking tool with a punch and a swing shaft abuts against the end portion of the cylinder at a predetermined inclined angle relative to the inner circumferential surface of the cylinder. Teeth on the punch form the face-spline by plastically deforming the end face of the caulking portion. The swing shaft central axis is inclined at an angle relative to a central axis of the wheel hub. The face-spline is formed simultaneously with the formation of the caulking portion by advancing the caulking tool toward the wheel hub. A main shaft is rotated to cause a swing motion of the caulking tool.

Abstract: A closed forging die and a forging method with which sagging can be reduced, a constant velocity joint and a universal joint can be made compact and lightweight, removal of a shaft tip thereof by machining prior to heat treatment is not required, and material costs and machining costs can be reduced by using a closed forging die includes openable dies, and punches that move in an opening/closing direction of the dies to pressurize a material in the dies. By using the die, a product having shaft portions formed radially is manufactured. A clearance is provided to each of the formed shaft portions between a tip surface, and abutting portions are provided to the dies side abutting against at least a tip side of an outer circumferential surface of the shaft portions.

Abstract: A wheel bearing device includes a hub ring, a double-row bearing and a constant velocity universal joint which are unitized together. At least one of double-row inner raceways of the bearing and a wheel mounting flange are formed on a hub ring. The hub ring and a stem portion of a joint outer ring of the constant velocity universal joint are fitted through a torque transmission assembly, wherein a pilot member as a separate element having a wheel guide portion and a brake guide portion is fitted to a side-end portion of the wheel mounting flange of the hub ring, and the hub ring and the pilot member are fixed to the joint outer ring by swaging.

Abstract: A wheel bearing device includes a hub ring, a double-row bearing and a constant velocity universal joint which are unitized together. At least one of double-row inner raceways of the bearing and a wheel mounting flange are formed on a hub ring. The hub ring and a stem portion of a joint outer ring of the constant velocity universal joint are fitted through a torque transmission assembly, wherein a pilot member as a separate element having a wheel guide portion and a brake guide portion is fitted to a side-end portion of the wheel mounting flange of the hub ring, and the hub ring and the pilot member are fixed to the joint outer ring by swaging.