The research attempts to create unialloy aluminum with alloys for casting. We attempt to create a unialloy by producing the raw sheet for sheet metal forming with a twin roll caster and producing the preform for casting with diecasting. It is thought that the high cooling speed will improve ductility due to finer crystal grains and crystallized and precipitated products, and therefore enable plastic working despite it being an alloy for casting. Detoxification is also thought to be possible because the finer intermetallic compound including Fe will limit deterioration in ductility.