Al-Mg-Cu series aluminum alloy L profile product with high stress corrosion resistance for large airplanes and manufacturing method of Al-Mg-Cu series aluminum alloy L profile product

The invention provides a preparation method of an Al-Mg-Cu series aluminum alloy L-shaped extrusion material with high stress corrosion cracking resistance for a large aircraft. The preparation method mainly comprises the steps of alloy component proportioning, casting, round cast ingot uniform heat treatment, extrusion treatment, pre-stretching, pre-sawing, solid solution heat treatment, stretch straightening and natural aging. The stress corrosion cracking resistance of the aluminum alloy L-shaped extrusion material prepared through the method is remarkably higher than the acceptance inspection requirement of an existing mainstream aviation main engine plant, the stress corrosion cracking resistance of different positions of the L-shaped extrusion material can be further improved in a targeted mode through the mode of arranging the extrusion die holes, and the stress corrosion cracking resistance of the L-shaped extrusion material is improved. The Al-Mg-Cu series aluminum alloy is more widely applied, the s