Theoretical And Experimental Research On Age Forming Of LY12CZ Aluminum Alloy Material

From the 1980's, Age Forming Process, which is designed to fabricate aircraft panels, has achieved great advantages. But it has not been used in factories nationally, the main obstacle is the lack of basic research on this area, especially it is hard to estimate and revise the springback, which affect the forming quality.Base on the former achievements, the processes of age forming are analyzed by the MAXWELL stress relaxation model, the relaxation time factor r is got by the Lagrange interpolation method. But the results coming from the stress relaxation have much more warp compared to the one from the experiments.Base on the theory analysis, a series of age forming experiments which shaped LY12CZ aluminum alloy in single small curvature were designed to analyze thethree main factors including the relative radius of the tool (Rt /h) , agingtemperature (T), and keeping time (t), which influence the springback, the orderand regression model of each factor which affect the springback were got. Finally, a synthesized springback formula about various factors was found. It has been showed by lots of experiments that there is a liner relationship between the springback andthe logarithm of keeping time (ln t), and between the logarithm of springback (ln P) and the reciprocal of aging temperature as well.An idea of Critical Condition of Springback is presented in the article, the influence of various shaped conditions to the strength(σ₀.2,σ_b) of LY12CZaluminum alloy is analyzed, the method of how to choose a optimum shaped condition is pointed out, and the arithmetic to inverse calculate the tool's radius from the part's is carried out by Newton-Raphson iterative method.Some application examples are presented to examine the correctness and validity of the springback formula and the reverse calculating arithmetic.