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TitlePrestresse sialon aluminium-casting riser tubes
Publication TypeJournal Article
Year of Publication2013
AuthorsRyan, M.J., Young R., Manning D., White G.V., Brown I.W.M., Chen C.Y., and Stanley R.
JournalJournal of the Australian Ceramic Society
Pagination44 - 47
Date Published2013
ISSN0004881X (ISSN)
Keywordsaluminum, Casting, Low pressure die casting, Metal working, Models, Pre-stressed, Riser tube, Sialon, Silicon carbide, Silicon carbide ceramic, Strength of materials, Temperature fluctuation, Tensile stress, Tube replacements, Tubes (components), Working temperatures
AbstractO-sialon-bonded silicon carbide ceramic confers increased life on the riser tube, which conducts molten aluminium from furnace to die in a low pressure die casting machine. The tube may still be vulnerable to stress due to cyclical temperature fluctuations during poorly-controlled process start-up or tube replacement operations. Patterns of breakage suggest the presence of tensile hoop and axial stresses in the riser tube near the furnace roof fixture. Our modelling shows that initial stress values here can approach the material strength. We have tested and modelled pre-compression of the critical region by a metal sleeve shrunk to the riser tube. We have shown that although designed (30 MPa) tube compression can be applied at the working temperature sleeve tensile stresses at room temperature exceed the yield strength of the metal, and destructively high hoop and axial tensile stresses are induced in the tube beneath the sleeve ends. Managed pre-heating best protects the riser tube at start up.

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