Abstract: To form a welded joint having a sufficiently high fracture toughness value ?c by butting welding high strength steel plates having a yield strength of the 355 MPa class or more and a plate thickness of over 50 mm by electron beam welding, the butt welded joint is made one where the hardness of the weld metal is 110% to 220% of the hardness of the base material and where the width of the weld metal is 20% A or less of the base material plate thickness.

Abstract: To form a welded joint having a sufficiently high fracture toughness value ?c by butting welding high strength steel plates having a yield strength of the 355 MPa class or more and a plate thickness of over 50 mm by electron beam welding, the butt welded joint is made one where the hardness of the weld metal is 110% to 220% of the hardness of the base material and where the width of the weld metal is 20%A or less of the base material plate thickness. More preferably, the amount of O in the weld metal of the welded joint is made 20 ppm or more and the amount of oxides of a grain size of 2.0 ?m or more is made 10/mm2 or less; the weld metal of the welded joint is made to contain Ni in an amount of 1 to 4 mass % and contain it in more than an amount of 0.2 mass % or more of the content of the base material; or, when using as the base material a steel material containing as Ni in an amount of 2.5 mass % or more, making the content of Ni contained in the weld metal of the welded joint, by mass %, over 4% to 8%.

Abstract: A flat type commutator is provided which secures fixing of carbon (graphite) commutator pieces to both metal plates with terminals attached thereto for connecting winding and electrically insulating support, and which can be manufactured easily and at a low manufacturing cost. The flat type commutator has a brush slide-contact surface which is perpendicular to the axial direction of a rotor, wherein a plurality of commutator pieces (3), which are mutually isolated by slits (4), are directly fixed to an electrically insulating support (1), and a metal plate (5) for connecting the commutator pieces, each having terminals (6) for connecting windings is fixed on the outer peripheral surface of each commutator piece (3) which is parallel with the axial direction of the rotor.

Abstract: There is provided a flat type commutator which secures fixing of carbon (graphite) commutator pieces to both metal plate with terminals attached thereto for connecting winding and electrically insulating support, and which can be manufactured easily and at a low manufacturing cost.A flat type commutator with the brush slide-contact surface thereof being perpendicular to the axial direction of a rotor, wherein a plurality of commutator pieces 3 mutually isolated by slits 4 are directly fixed to an electrically insulating support 1, and a metal plate 5 for connecting said commutator pieces, each having terminals 6 for connecting windings is fixed on the outer peripheral surface of said each commutator piece 3 which is in parallel with the axial direction of the rotor.

Abstract: Disclosed is a process for manufacturing a building construction steel having excellent high-temperature characteristics, which can be marketed at an economically reasonable price. According to this process, a slab having a steel composition in which appropriate amounts of Mo and Nb are added to a low-C and low-Mn steel is heated at a high temperature and rolling is finished at a relatively high temperature, or a slab having a steel composition in which an appropriate amount of Mo is added to a low-C and low-Mn steel composition is heated at a high temperature, rolling is finished at a relatively high temperature, and at the subsequent air-cooling step, water cooling is started at a temperature of a ferrite fraction of 20 to 50% during the transformation from austenite to ferrite, water cooling is carried out to an arbitrary temperature lower than 550.degree. C., followed by air cooling.

Abstract: Disclosed is a process for manufacturing a building construction steel having excellent high-temperature characteristics, which can be marketed at an economically reasonable price. According to this process, a slab having a steel composition in which appropriate amounts of Mo and Nb are added to a low-C and low-Mn steel is heated at a high temperature and rolling is finished at a relatively high temperature, or a slab having a steel composition in which an appropriate amount of Mo is added to a low-C and low-Mn steel composition is heated at a high temperature, rolling is finished at a relatively high temperature, and at the subsequent air-cooling step, water cooling is started at a temperature of a ferrite fraction of 20 to 50% during the transformation from austenite to ferrite, water cooling is carried out to an arbitrary temperature lower than 550.degree. C., followed by air cooling.

Abstract: A brush device for a miniature electric motor of a type, wherein the commutator brush is inserted into a brush holding member made of a leaf spring which is generally bent in the form of a letter "L", one side of which is in a slightly bent form at about the middle portion thereof with a brush fitting portion being provided at the extreme end thereof, and the other side of which is rectilinear with a fitting portion to the main body of the motor being provided at the extreme end thereof.

Abstract: A brush device for a miniature electric motor constructed with a brush holder made of a leaf spring having a pair of flaps for holding a commutator brush, which are opposed each other along the longitudinal direction of a flat surface part, and which are formed in an inwardly bent shape, a guide member for insertion of the commutator brush formed at a corner of each of the pair of flaps, and a fitting member for the brush holder onto the main body of the motor; and a commutator brush having a head part to be inserted and held between said pair of flaps provided along the side edges of the flat surface part of the brush holder.