| 摘要 |
PURPOSE:To prevent any crack and changes of a material quality at a welding part from being produced by forming a tension band for clamping an outer periphery of a panel side wall part of an explosionproof cathode-ray tube with a soft steel material having limited carbon contents to a specific range. CONSTITUTION:An explosionproof cathode-ray tube is constructed such that a tape 5 is wound around an outer periphery of a panel side wall part 21 of the cathode-ray tube comprising a panel 2, a funnel 3, and a neck 4, and a support fitment 6 is arranged on four corner parts of the panel side wall part, and thereafter a tension band 7 made of a soft steel material having carbon contents ranging from 0.25-0.05wt% is heated from 250-400 deg.C, clamped with application of tension thereto, and overlapped portions of both ends of the tension band is spot-welded. Thus, if the carbon contents of the soft steel are limited to a specific range, hardness of the tension band 7 after the clamping at the welded portions 8 can be made proper, whereby any crack and changes of material qualities in heating can be prevented, allowing quality of the tube to be improved. |
