Discretized stepped multilayer structure superplastic forming / diffusion bonding method

Abstract

The application discloses a discrete stepped multilayer structure superplastic forming / diffusion bonding method, and belongs to the field of metal sheet plastic forming. A split surface of a reinforcing block is reasonably designed according to the feature structure of a discrete reinforcing area of a part, and a milling and laser positioning welding process is adopted to realize assembly of the stepped multilayer structure of the reinforcing area before SPF / DB forming. The thickness specification of an outer skin is reasonably designed, the rigidity of the outer skin during SPF / DB forming is improved, and process compensation is performed on collapse and depression of the outer skin during forming. Finally, the precision of the part is improved through overall milling of the part after SPF / DB forming. Laser welding is adopted to replace argon arc welding to realize sealing between the inner skin and the outer skin. During diffusion bonding, an internal suction and external pressure mode is adopted, the inner and outer pressure difference is adjusted, the outer surface of the upper skin is adhered to a die, beneficial friction between the two is utilized, the elongation deformation amount of the outer skin is controlled, and depression defects caused in the superplastic process due to deformation growth of the outer skin in the diffusion process are inhibited.

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