Study on thermal stress distribution of repair welding process for gasification furnace flange

The processing of repair welding online has been designed in this paper for seal section on flange connected with nozzle on the gasification furnace for coal-water slurry gasify in a Coal chemicals CO. LTD. The method of finite element has been used to study the thermal field, thermal stress and deformation in the flange, piping and the connected bolts during the heat treatment through welding with the process of modeling, meshing, solving, data processing and the results analysis. Conclusions have been obtained as following: the flange repair process designed in this paper is feasible for the gasification furnace; spring deformation happens during the heat treatments for flange, piping and the corresponding bolts without plastic deforming except the part of heat band and below; one method of finite element has been discussed in this paper for thermal stress distribution study, which is useful for similar projects solution.