MICROSTRUCTURALLY REFINED MULTIPHASE CASTINGS

摘要

The present invention relates to eutectic alloy systems, such as white irons, in which a primary phase grows out of the melt when the melt is cooled below the liquidus temperature and comprises pouring the molten metal alloy at a temperature at or above the liquidus in a stream into a casting mould to form a casting and introducing a particulate material into the stream of molten metal to extract heat from the molten metal alloy to undercool the molten metal alloy from the pour temperature into the primary phase solidification range between the liquidus and the solidus temperatures of the alloy and thereby initiate primary phase nucleation and restrict primary phase growth. The primary function of the particulate material is to act as a heat sink but the particulate material may at least partially dissolve in the melt and may act as a seeding agent for the primary phase. The invention is described with particular reference to high chromium hypereutectic white irons.