Two-Stage Superplastic Forming of a V-Shaped Aluminum Sheet into a Trough with Deep and Irregular Contour

• Published in: Journal of materials engineering and performance 2013-08, Vol.22 (8), p.2241-2246
• Main Authors: Lan, Hsien-Chin, Fuh, Yiin-Kuen, Lee, Shyong, Chu, Chun-Lin, Chang, Tien-Chan
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Engineering Design; Exact sciences and technology; Forming; Materials Science; Metals. Metallurgy; Production techniques; Quality Control; Reliability; Safety and Risk; Tribology
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-013-0511-5

A sheet metal trough of aluminum alloy is manufactured by a two-stage gas forming process at 500 °C. The product with sloped side walls is of ~1.2 m length and ~260 mm opening width, comprising two near-conical-shaped sinks at two ends. The depth of one sink apex is ~350 mm, which results in the depth/width ratio reaching 1.4. To form such a deep and irregular trough, a superplastic aluminum alloy 5083 initially bent into a V-shaped groove was prepared prior to the gas forming work. Within a single die, gas pressure is used to form the V-shaped blank into a preform die cavity prior to the pressure being reversed to form the sheet into the final component cavity. The preforming of the V blank creates a uniform length of line in order to improve the thickness profile of the final part. In this work, a preform has been designed to improve the forming of a complex component by providing a superior thickness profile as compared to a conventional single-stage forming cycle. However, a serious wrinkling situation was encountered, the cause of which has been analyzed using basic mechanics as well as numerical simulation.