| 摘要 |
PURPOSE:To prevent the welding defect caused by discharge by providing an x-ray detector. CONSTITUTION:In the stationary state where an electron beam 9 is radiated and welding is performed, an x-ray generation source is located only on a work surface and the amount of the incidence of x rays on an x-ray detector 17 is suppressed by a lead plate 18, allowing indication of almost zero. Then, when metallic vapor flows backward in an electron beam irradiator during welding and arrives at a grid 6 and an electrode section such as an anode section 10, the dielectric strength between the grid 6 and anode 10 in the upper electron gun chamber 1 is deteriorated and discharge current flows between them. Accordingly a welding defect, such as boring a hole in an interrupted work takes place suddenly during the welding process. When discharge current is applied, x rays are also generated secondarily from the surface of the anode 10. If the existence of the generation of these x rays is monitored by the x-ray detector 17, the existence of discharge phenomena can be detected with good response independently of the beam current. As a result, whenever the discharge phenomena are generated, they can immediately be caught as signals and high responce control can be obtained and then the welding defect can be prevented. |
