Validation of a systematic approach to modeling spray quenching of aluminum alloy extrusions, composites, and continuous castings
- Purdue Univ., West Lafayette, IN (United States)
- Naval Air Warfare Center, Indianapolis, IN (United States)
Optimal cooling of aluminum alloys following the high temperature extrusion process suppresses precipitation of intermetallic compounds and results in a part capable of possessing maximum strength and hardness after the subsequent age-hardening process. Rapid quenching suppresses precipitation but can lead to large spatial temperature gradients in complex-shaped parts causing distortion, cracking, high residual stress, and/or nonuniform mechanical properties. Conversely, slow cooling significantly reduces or eliminates these undesirable conditions but allows considerable precipitation resulting in low strength, soft spots, and/or low corrosion resistance. This study presents a systematic method of locating and operating multiple spray nozzles for any shaped extrusion such that uniform, rapid cooling and superior mechanical and metallurgical properties are achieved. A spray nozzle database was compiled by measuring the distribution of spray hydrodynamic parameters (volumetric spray flux, mean drop diameter, and mean drop velocity) throughout the spray field of various industrial nozzles. Spray heat transfer correlations, which link the local spray hydrodynamic parameters to the heat transfer rate in each of the boiling regimes experienced by the surface, defined the spatially nonuniform boundary conditions in a numerical model of the quenching process which also accounted for interference between adjacent spray fields. The quench factor technique relates, predicted thermal history to metallurgical transformations occurring within the extrusion to predict hardness distribution. The validity of this unique approach was demonstrated by comparing model predictions to the temperature response (and hardness after artificial aging) of an L-shaped Al 2024-T6 extrusion to quenches with multiple, overlapping water sprays.
- OSTI ID:
- 484296
- Report Number(s):
- CONF-961140-; TRN: 97:000168-0058
- Resource Relation:
- Conference: 2. international conference on quenching and the control of distortion, Cleveland, OH (United States), 4-7 Nov 1996; Other Information: PBD: 1996; Related Information: Is Part Of 2nd International conference on quenching and the control of distortion; Totten, G.E.; Howes, M.A.H.; Sjoestrom, S.J.; Funatani, Kiyoshi [eds.]; PB: 652 p.
- Country of Publication:
- United States
- Language:
- English
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