Horizontal Twin Roll Strip Casting of Aluminum Alloy A7075

Abstract

Twin roll strip casting of aluminum alloy A7075 using commercial scale machine was operated. Twin roll casting process is able to produce a strip from molten metal directly. Thus this process has a possibility to reduce total cost of sheet making comparing to conventional rolling process. Strip casting process has some disadvantages. Casting speed depends on the material properties. It is difficult to determine the casting conditions. Aluminum alloy A7075 has high tensile strength, and it is known as a material for aerospace application. The sheet is manufactured in small quantities comparing to the other sheet aluminum alloy. It is supposed that the demand of high tensile strength aluminum sheet such as A7075 is going to increase for weight saving of structural material. The aims of this study are to investigate the effect of roll speed on the strip. Strip could not be produced continuously at roll speed of 10 m/min, so the load limit of this experimental apparatus was exceeded. However, a good strip without cracks was produced. Continuous strip was produced at a roll speed of 20 m/min. The strip was consisted of a mat part and a metallic luster part. However, cracks were observed in the white mat part of the board. Continuous strip was produced at a roll speed of 30 m/min. However, rolling cracks were observed at the edges of the strip. It is necessary to control the solidification distance by installing the nozzle.