A Search About The Welding Technology Of The Rectangle Thin Tubesheet Heat Exchanger

Normal heat exchanger has a circular tubesheet, which is thick, mormallr more than 60 mm. Rectangle thin tubesheet is rare. Compared to the circular tubesheet, the rectangle thin tubesheet has a high request for welding technology. Once there are welding defects and deformations of tubesheet, the tightness of heat exchanger will be endangered. This may cause serious safety problems. So keeping the quality of welding joints and controling the deformation of tubesheet is the key point of heat exchanger production.This research targeted the E-411 series of rectangle thin tubesheet heat exchangers made by Beijing Yan Hua Zheng Bang Equipment Overhaul Co Ltd.Finite elements numerical simulation is used to compute the welding stress field and deformation of tubesheet. Optimizations are came up with according to the output. This improved the quality of heat exchanger and provided some therory and technology support for the coming similar reaearch. The following are the contents of our research.1. Optimizations of welding parameters. Five groups of different welding parameters including different welding voltage, different welding current and different welding velocity according to the real production. According the numerical simulation results, we can get the best welding parameters.2. Optimizations of welding sequences. Differnet welding sequence may affect the deformation of tubesheet. Two kinds of welding sequences are tested:parallel sequence and radial sequence. According to the comparison of numerical simulation results, we can fine the best welding sequencee.3. Control the tubesheet deformation. A new designed welding fixture is introduced. Its function will be verified by numerical simulation and experiments.