Semi-solid forming of free solidification surface of strip cast Al-Si alloy by melt drag process

To produce sound free solidification surface of the strip, melt drag process, which is one of single roll processes, was improved. An additional roll (forming roll) was attached to the outer side of the nozzle of the original melt drag process. In this work, forming of the free solidification surface of the strip was applied at the semi-solid phase by the forming roll. Free solidification surface can be formed in the smooth and flat shape, and thickness distribution of the cross section becomes uniform. The strip with 0.5 to 1.5mm thickness can be cast. Roll speed of this process is as fast as that of the original melt drag process (20-70m/min). The semi-solid region is formed by a roll and the forming load is very low, thus, the strip does not stick to the roll. Formability of the free solidification surface depends on the flow stress at the semi-solid phase.