| The application of activating fluxes in all-position welding for tube-to-tubesheet was studied.The activating fluxes were deposed on the metal surface by a brusher without the groove preparation or chamfer for the low-carbon steel tube of 3mm thick,the optimal welding parameter is obtained through the experiments. At the same time, we took detailed analysis on the the impact of activating fluxes on the force state of the pool and relation between the force state of the tubesheet in all kinds of locations and the welding current. According to the theoretical analysis on penetration increase mechanism,the force state of the pool in all kinds of locations and welding heat accumulation, we set sections on the tubesheet, adjusting norms of welding process parameters with different starting points of welding,different welding current,and different welding speed,finding the differences between them on affecting the formation of weld,making analysis on the results of the welding results, at last,we obtain the best welding parameters.According to the request of GB151-1999,we test the weld of the work-pieces which meet the requirements of the appearance, including appearance inspection,dye penetrant inspection testing,pull-out force testing and hardness testing. Testing results show that the indicators are in line with relevant standards. By this process, the range of use for activating fluxes can be expanded, the demand of welding wire is decreased, the efficiency of welding is improved substantially, furthermore, the limitation of the need to open groove when the welding of tube-to-tubesheet is broken.
|
PDF Full Text Request