Research On High Chromium Cast Iron Type Electroslag Surfacing Flux And Deposited Metal Microstructure

By compositing a layer of wear-resistant material using surfacing method,the repeated use of scrap parts can be achieved.This method has important meaning for reducing production cost of enterprise.Electroslag surfacing technique shows high repair efficiency in the repair of large and extra large parts. After the repair work,the composite layer is in good organization without de fects, so it has wide application prospect in roller repairing engineering.In this paper has developed a multi flux for electroslag surfacing of high chromium cast iron materials,The flux in the mass fraction of the component are Ca F2 30-40% and 20-25% of alumina, calcium oxide 20-30%, silica 4~9%, oxide magnesium 4 ~ 7%.With proper welding parameters, through the selection of different types of flux, relatively stable welding process and welding type forming quality changes, get good quality of surfacing layer forming. The surfacing metal of heat treatment, the microstructure, hardness were analyzed, the results are as follows:(1) The viscosity and surface tension of the flux increases, surfacing slag defects, the greater the tendency, the higher the content of fluoride flux, surfacing layer porosity formation the greater tendency. The main welding parameters influence the forming quality of surfacing layer, large welding input can reduce the slag and the tendency of porosity formation.(2) The structure of high chromium cast iron hardfacing flux cored wire surfacing metal welding used mainly for austenite and eutectic carbide + primary carbides. After tempering the surfacing layer does not change the organization, with the increase of tempering temperature, the size of primary carbides decreases, the eutectic carbides increased.(3) Appropriate heat treatment temperature can promote the precipitation of the eutectic carbides, thereby improving the hardness of surfacing layer. When the temperature is over 560? during thermal treatment of primary carbide to reduce size is not easy and eutectic carbide distinction, eutectic carbide grew up together as a strip of tissue, significantly increase the hardness of surfacing layer.