| 摘要 |
PROBLEM TO BE SOLVED: To provide a preventive conservation method and device that has a simple configuration, and reduces tensile residual stress and sensitization by utilizing thermal shock strain. SOLUTION: For the surface region of a welding part in a tensile stress state, the surface region being heated-up by a high-frequency heating coil 1 is quickly cooled by jetting a coolant from a nozzle 11, thus generating transitional temperature difference between the surface region and a part directly under a surface layer, applying tensile thermal shock stress to the surface layer for generating tensile strain, and at the same time for partially allowing the surface layer to yield. Then, cooling is stopped for heat-up for allowing the thermal shock stress to disappear. The surface of the welding part is improved to a state where deformation is elastically returned for relieving tensile stress or a compression residual stress state from a partial yield state. Heating and cooling speed is adjusted, thus reducing the sensitization of welding thermal influence part.
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