Numerical Simulation and Parameter Optimization of Quenching Temperature Field for Large-Scale Thin-Wall Aluminum Alloy

To explore the influence of the non-uniformity of quenching temperature on large-scale thin-wall multi-chamber aluminum alloys, uncover the influence patterns of process parameters and develop an optimization strategy, a numerical model describing the quenching process of large-scale thin-wall aluminum alloys was established based on the Workbench software platform, which was used to systematically analyze the effects of quenching method, cooling strength, nozzle spacing and operating speed on the temperature field. Then, a response surface method was employed to perform multi-objective optimization of key process parameters, and a three-dimension heat transfer model was established to address the structural characteristics and quenching process requirements of large-scale thin-wall aluminum alloys. By incorporating the convective heat transfer boundary conditions between the profile and the cooling medium, and by integrating the actual nozzle arrangement in actual production, numerical simulations were conducted to analyze the evolution of temperature field in the quenching process. The results show that the use of stepped quenching can improve the uniformity of the temperature field during the quenching of profiles and ensure the critical cooling rate in the sensitive area. With the increase of cooling intensity of the strong cooling zone, the cooling rate of the profile increases, while the uniformity of the temperature field decreases. With the increase of longitudinal nozzle spacing in the strong cooling zone, the temperature difference of the profile in the strong cooling zone decreases, and at the same time, the cooling rate of the profile slows down. With the increase of running speed of the profile, the cooling rate of the profile first increases and then decreases. Response surface analysis results indicate that the optimal quenching process parameters for large-scale thin-wall aluminum alloys are: a cooling intensity of 0.92 in the strong cooling zone, a profile running speed of 27.6 mm/s, and a longitudinal nozzle spacing of 280 mm in the strong cooling zone. By employing an alternating cooling mode of mist and high-intensity jet cooling in the strong cooling zone, the optimized scheme successfully reduces the quenching temperature difference to 19.8 ℃ and eliminates temperature recovery.