Prediction of article quality with multipass deformation and intermediate heat treatment

See adjacent abstract. The effect of plastic deformation and heat treatment on the recrystallized grain size of sheet specimens of aluminum alloys D16AM, D19AM, and AK4 was studied experimentally. Primary recrystallization diagrams were constructed and used to determine the thermomechanical operations required to obtain a grain size not greater than the allowable value d sub g = 0.10-0.20 mm. A mathematical model was developed to calculate the limiting deformation for grain growth during multistage deformation with intermediate heat treatment, and diagrams were constructed to estimate the effect of the deformed state on the value of the critical deformation for the given Al alloys. The model was used to develop procedures for multistage stretch-forming operations which would reliably provide articles with surfaces of guaranteed quality.