For high-strength aluminum alloys at the solution temperature

it is difficult to achieve the best formability during the hot stamping and cold die quenching process (heat treatment

forming and in-die quenching

HFQ)

and forming defects such as cracks would occur easily. To solve this problem

this paper introduces a pre-cooling treatment

which could cool the solid solution sheet to target temperature. In the quenching sensitivity temperature range

the mechanical properties of an AA7055 high-strength aluminum alloy sheet were tested under different pre-cooling temperatures after solid solution. It is found that the largest elongation and the best formability are obtained at pre-cooling temperature of 350℃. Taking structural parts with typical characteristics as an example

the HFQ process tests with different pre-cooling conditions and original sheet materials were carried out. It is found that the surface quality of the F–state sheet is better than that of the O–state one

and F-state sheet has better formability under the same process flow. The traditional HFQ comparative forming experiment was carried out on the F–state sheet

and the F–state sheet was severely broken without pre-cooling treatment. The uniaxial tensile tests were carried out on the typical positions of the well-formed parts. And it proves that the strength of the formed part is the lowest at the pre-cooling temperature of 350℃

which is near the nose tip temperature for quenching sensitivity. Taking into account the formability and strength

the pre-cooling temperature should be 400℃.