EROSION OF FERROUS ALLOYS BY LIQUID ALUMINUM

摘要

Cast iron and/or cast steel pipes, which are commonly used torntransfer molten aluminum, degrade by material loss and cracking.rnThis is a problem for the aluminum production industry becausernof the cost of replacing pipes. Service conditions are severe, notrnonly because liquid aluminum can react with nearly all metals andrntheir oxides but also because of cycles of steep thermal gradients.rnThe scope of this research was therefore to investigate therndegradation of ferrous alloys under the demands of liquid metalrntransfer conditions. Pipe alloys currently employed in servicernwere selected as benchmarks for comparison with candidaternalloys. Two specialized experiments were developed to exposerncandidate materials to erosive and thermal conditions similar tornactual service. The various samples of ferrous alloys wererncompared by their erosive weight loss (by exposure to flowingrnaluminum) and response to thermal cycling (by cyclic exposure tornstatic aluminum). Electron microscopy was used to characterizernthe reaction interfaces and microstructural changes to shed lightrnupon the erosion and thermal fatigue mechanisms. The mainrnoutcome of this work is to recommend the best candidate materialrnfor the service conditions.