On the Distortion and Warpage of 7249 Aluminum Alloy After Quenching and Machining

Abstract

The objective of this study is to determine the effect of solution treatment temperature, quenching media, and various machining sequences on the warpage behavior of aluminum 7249 alloy aged to T6 and T7¢ tempers. Large extrusions of 7249 aluminum alloy with fins were cut into 108 ''T'' sections. The samples were solution-treated, aged, and machined. Three solution temperatures (445, 474, and 505°C), two quenching media (water and 20% polyalkylene glycol), two aging treatments (T6 and T7¢), and three machine sequences were used. The flatness of the samples was measured on the surfaces orthogonal to the z-axis. Three points were on top of both shoulders (six total), six were at the bottom of the sample, and six were on the top of the fin, in the cases where the fin was not milled off. They were then averaged together by surface to represent the overall warpage of each sample.

Effect of Cutting Parameters on Machining Induced Distortion in Thin Wall Thin Floor Parts

“…Further, they showed, machining induced residual stresses as main cause for distortion for workpieces machined below 5-6 mm thickness and quenching stresses are responsible for workpieces greater than 10 mm thick. Keleshian et al, [24] performed heat treatment and machining experiments on aluminium alloy 7249 and concluded that water quenching and peak aged components give more warpage. Ye et al, [25] concluded that more fluctuant residual stress distribution was found at the final path of milling on aeronautical monolithic components.…”

Volume of Material Removal on Distortion in Machining Thin Wall Thin Floor Components

“…Depth of cut and width of cut were found to be significant contributors in machining distortion [12]. Keleshian, N, et al, in their work conducted machining experiments on aluminium alloy 7249 and observed that solution treatment temperature, quenching media, and various machining sequences affect distortion [13]. Chatelain, Jean-François, Jean-François Lalonde, and Antoine S. Tahan conducted experiments on a thin representative part to compare distortions with and without existing residual stresses in work pieces and concluded that initial residual stresses embedded within raw material has an effect on the final part deformation [5].…”

Análise de corrosão e comportamento mecânico de ligas de alumínio aeronáutico 7075-T6 após tratamento térmico usando a técnica >i<uphill>/i<

“…Nesta fase, não há praticamente influência de tensões residuais na microestrutura que seriam capazes de causar algum tipo de distorção (Keleshian et al, 2011).…”