Hideki Inui

Semisolid Roll Casting of Aluminum Alloy Strip and Its Properties

A356 was cast into the strip by the semisolid strip casting using an unequal diameter twin roll caster. This process was one of the rheocasting. The semisolid slurry was made by a cooling slope. Solid fraction was about 5%. The casting speed was 20 m/min, and the thickness was 4.4 mm. The as-cast strip could be cold rolled down to 1 mm. The result of tension test of 1mm-thickness-T4 heat-treated strip was as below. Tensile stress was 223 MPa, 0.2 proof stress was 123 MPa and elongation was 21.8%. Deep drawing could be operated to 1 mm-thickness T4 sheet, and L.D.R was attained to 2.0. In some condition, 180 degrees bending could be operated without crack at outer surface. These results mean that semisolid roll cast A356 strip may be able to use for press forming.

Strip Casting of 6061 and Recycled 6061 Alloy by an Unequal Diameter Twin Roll Caster

A 6061 aluminium alloy and an alloy with increased Fe content, representing recycled 6061 aluminium alloy were cast into strips at speed of 30m/min by an unequal diameter twin roll caster. The Fe content of 6061 aluminium alloy and the model of recycled 6061 aluminium alloy was 0.36 mass% and 0.59 mass%, respectively. Ripple marks, which are typical surface defect of roll cast strips, did not occur on the surface of both as-cast strips. Fe content did not influence the surface condition of the roll-cast-strip. The as-cast strip was cold rolled down to 1 mm, T4 heat treatment was conducted, and then subjected to180 degrees bending test. The result of 180 degrees bending test shows that roll cast 6061 aluminium alloy and 6061 aluminium alloy with increased Fe as recycled had bending ability as same as that of roll-cast 6022 aluminium alloy. In the strip cast by the twin roll caster of the present study, increased Fe content did not influence on the result of the180 degrees bending test.