The line heating method is applied to the bending work of hull steel plate and to the amending of distortion of welded members such as ship's hull and girder bridge. The heat surface of steel plate is generally cooled by water. But it is not clear whether water cooling on the heat side surface of steel plate is the most effective one for the above-mentioned works.
The authors proposed “Back side water cooling method” as one of the water cooling methods of the line heating. The method is continuous water cooling on the back side of heat surface in heat process. Furthermore, they compared it with both air cooling method and water cooling on the heat side surface of steel plate.
As a experimental result, the following fact is clarified : The quantity of final angular distortion by back side water cooling was more than that obtained in case of air cooling or water cooling on the heat side surface of steel plate. Furthermore, the effect of back side water cooling on angular distortion was especially conspicuous as the heat temperature on surface increases and the plate thickness is thinner.