| 摘要 |
1,118,104. Photo-electric weld investigation. SIEMENSSCHUCKERTWERKE A. G. June 13, 1966 [June 11, 1965; May 6, 1966], No.26327/66. Heading G1A. [Also in Division B3] The quality of a weld seam is evaluated by a radiation system while the weld is still hot. In the welding of an end-cap 21 on to the casing tube 2 of a nuclear reactor fuel rod, a non-consumable tungsten electrode 3 is used in an inert gas atmosphere. The weld is produced while the tube 2 rotates about its own axis and is examined by a detector D receiving X-rays, from an X-ray tube source, which are scattered by the weld seam. The output from the detector, which may be a geiger tube, represents the quality of the weld seam, depending on the porosity &c. of the seam and is amplified, indicated (device 4) and recorded. A signal from device 4 is fed to the unit 6 which. controls the welding current and electrode positioning. Thus, any necessary adjustment to welding conditions, as indicated by the signal on line 42, can be carried out by unit 6 and further welding operations carried out under these conditions. A previous calibration of the apparatus allows this to be done. When a weld seam is satisfactory or is so bad as to necessitate rejection, a signal over line 41 to control device 5 is transmitted to remove the tube 2 to the correct location. Alternatively an operator can read the indication provided at 4 and manually correct the welding conditions or reject tubes 2. Instead of the back scattering configuration of the radiation system, two transmission arrangements are described, one, Fig. 2 (not shown) with the radiation passing through an edge of the tube and the other Fig. 3 (not shown) directly through the centre of the tube. In the Fig. 2 arrangement the detector and source are mounted to follow small movements or circumferential irregularities of the workpiece. Alternative sources may be used e.g. radio-active or neutron. Provision for axial as well as rotational movement of the tube 2 can be made. A mirror system may be provided for viewing the welding operation. |
