| 摘要 |
PURPOSE:To stably obtain a highly tough joint without welding defects by grasping accurately the heat input at the preheating stage and shifting it to the flashing stage after a proper value in accordance with the material temperature at the time of welding is attained. CONSTITUTION:At the time of flash-welding annular steels such as chains, etc., which are bent and worked annularly at the room temperature 1100 deg.C, a secondary current flowing through a welding machine when the weld zone end faces are brought into contact with each other with the starting of the preheating is detected. A parameter Qp is calculated according to formulas by using this detected value. After this calculated value Qp attains the range of 3700-7700, it is automatically shifted to the flashing stage. By this method, the preheating heat input can be controlled to the proper value and the satisfactory joint without welding defects and hot cracking can be obtained.
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