Abstract: A laser peening apparatus for manufacturing a rotor using an electrical steel sheet with low iron loss for enabling high speed rotation of a motor. The laser peening apparatus includes a laser irradiating device for irradiating with a laser through a liquid the rotor made of an electrical steel sheet with low iron loss, and a drive device for moving the rotor relative to an irradiation spot of the laser so that the laser irradiates along a bridge side on an inner circumference of a magnet insertion window of the rotor.

Abstract: An electrical-steel-sheet formed body is provided with an opening portion into which a permanent magnet is inserted, and an outer-peripheral hardened portion formed on the electrical-steel-sheet formed body at an outer periphery side thereof for the opening portion and having a higher hardness than a remaining area of the electrical-steel-sheet formed body. The electrical-steel-sheet formed body can be used as the rotor of the built-in permanent magnet type rotary electric machine, and the built-in permanent magnet type rotary electric machine can be obtained.

Abstract: An electrical-steel-sheet formed body is provided with an opening portion into which a permanent magnet is inserted, and an outer-peripheral hardened portion formed on the electrical-steel-sheet formed body at an outer periphery side thereof for the opening portion and having a higher hardness than a remaining area of the electrical-steel-sheet formed body. The electrical-steel-sheet formed body can be used as the rotor of the built-in permanent magnet type rotary electric machine, and the built-in permanent magnet type rotary electric machine can be obtained.

Abstract: During melting and jointing members 2, 3 to weld the members by applying a laser beam 5 to the members while supplying a filler wire 13 to the locally heated portion of the members, welding plasma intensities are measured by sensors 8, 9 from both sides of the locally heated portion with reference to an advancing direction of welding. When the welding plasma intensities measured from both sides of the locally heated portion are largely different from each other, the relative deviation between the laser beam 5 and the filler wire 13 is large, so that a good welding may be difficult to be carried out.

Abstract: A laser hardening device for forming a hardened layer on the surface of an object irradiated by a laser beam is so arranged as to emit a laser beam which is linearly polarized in the incidence plane containing the normal to the surface and the optic axis of the laser beam irradiating the surface. The device comprises a first concave mirror for condensing the laser beam the incidence plane, and a second concave mirror for condensing the laser beam in a perpendicular plane to the incidence plane, the first concave mirror being disposed closer than the second concave mirror to the laser oscillator in the path of the laser beam. Laser beam is therefore absorbed at a high absorption rate by the object, and a hardened layer is formed without coating a laser absorption agent onto the object. The incidence angle of the laser is preferably no less than 60 degrees, and by arranging that the laser beam is parallel on the irradiated surface, a uniform, hardened layer is obtained.

Abstract: A laser processing arrangement includes a laser oscillator which outputs a laser beam. The laser beam path is established such that the beam reflects from a flat surfaced mirror to a concave mirror and then to a second concave mirror before irradiating a work piece under processing. The arrangement further includes a temperature sensor associated with a temperature detecting means. The temperature detecting means is connected to a control unit which controls moving means connected to movable axes of a processing surface in order to move the work piece relative the laser beam. The control unit is further effective to control the laser oscillator according to a desired temperature range for processing. The temperature sensor is preferably positioned within 45.degree. of the laser beam and the angle of incidence of the laser beam is selected so as to be smaller than a brewster angle of the material of the work piece.

Abstract: A method of laser transformation hardening adapted to irradiate a laser beam in a sense of P polarization on a work piece at an angle of incidence to a surface of the work piece of 60.degree. or more which comprises steps of: forming a plurality of triangular ridges on a horizontal plane adjacent to a surface of the work piece, having a first plurality of inclined surfaces inclined at a first angle to the horizontal plane and a second plurality of inclined surfaces inclined at a second angle to the horizontal plane, the first angle being smaller than the second angle; and irradiating the laser on the work piece at the angle of incidence to the surface of the work piece of 65.degree. to 70.degree. from a direction on the side of the second plurality of inclined surface.

Abstract: A case hardening steel which consists essentially of 0.03-0.2 wt % of C, 1.0-3.0 wt % of Si, 0.2-2.0 wt % of Mn, 0.05-0.5 wt % of V and the balance of Fe. The primary advantage of this steel is fineness of grain size after carburizing at relatively high temperatures. Even when carburizeed at or above 950.degree. C., the grain size number is not smaller than 6 in both the hardened case and the core. Optionally the steel may contain up to 2.0 wt % of Ni, up to 2.0 wt % of Cr and/or up to 0.5 wt % of Mo for the reinforcing purpose, and/or up to 0.1 wt % of Al, up to 0.3 wt % of Ti, up to 0.1 wt % of Zr, up to 0.03 wt % of N and/or up to 0.5 wt % of Nb+Ta for the purpose of depressing the grain growth.