| 摘要 |
PURPOSE:To efficiently execute quenching to inner circumferential face of a steel material by using a condenser lens having focal length decided from distance from a steel material to be worked opening part to irradiation part, width of the irradiation part and inner diameter of the steel material at the time of quenching the inner circumferential face of cylindrical steel material to be processed with laser beam irradiation. CONSTITUTION:The laser beam 2 from CO2 laser beam generator 1 is reflected with a reflecting mirror 3 and made incident to the condenser lens 5 having focal length F in a laser beam machining nozzle 4 with incident spot diameter S, and the focus 6 is formed at lower part of the condenser lens 5 and the cylindrical steel material 7 to be processed is set at the position deviated out of the focus by the distance (d) to execute the quenching to the inner circumferential face thereof. Then the condenser lens 5 having the focal length (F) of the value obtd. with the distance L from the opening end 10 of steel material 7 to be processed to the irradiation part 9 to be quenched, the width X of irradiation part 9 and the inner diameter A of the steel material 7 to be processed is used, and further, the focus forming position 6 is made to coincide with the opening end 10 to make the laser beam incident angle theta max. By this method, the laser beam quenching is efficiently executed. |
