Process parameters optimization of Ti-6Al-4V alloy sheet during hot stretch-creep forming
(1. School of Mechanical and Electrical Engineering, Beijing Institute of Graphic Communication,
Beijing 102600, China;
2. School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China)
Beijing 102600, China;
2. School of Mechanical Engineering and Automation, Beihang University, Beijing 100191, China)
Abstract: Hot stretch-creep forming (SCF) is a novel technique to produce hard-to-form thin-walled metal components. Comprehensively considering the analysis results of the springback angle, yield strength and microstructure, four hot SCF process parameters including temperature, stretch velocity, post stretch percentage and dwelling time of a Ti-6Al-4V alloy sheet were optimized using an orthogonal experiment. The results reveal that temperature is the most important factor on springback angle. The yield strength of the deformed material in 0° direction increases, while those in directions of 45° and 90° fluctuate around the original value. After hot SCF, the shape of some a phases changes from short thin grains to long slender ones, and the microhardness changes very little. The optimized parameters with temperature of 700 °C, stretch velocity of 5 mm/min, post stretch percentage of 2% and dwelling time of 8 min are achieved finally.
Key words: Ti-6Al-4V alloy; hot stretch-creep forming; springback; orthogonal experiment; optimization