The Improvement of Surface Quality of Continuous Rheocast Bars of Steel and High Melting Point Alloys.

A new continuous rheocasting process for steels and high temperature alloys has been developed by Inland Steel incorporating a dual chamber casting machine utilizing separate electromagnetic stirrers around each chamber. Initial casts on the rheocaster were plagued by breakouts and very rough as-cast surface morphology. The mechanism for solidification and formation of cast surface morphologies on as-rheocast bars has been determined and verified by comparing predicted surface morphologies to actual surface morphologies. The mechanism was then used to develop new withdrawal patterns to eliminate sticker breakouts and obtain good surface quality.