Fundamental Assessments of Application of Fluidized Bed Furnaces to Solution and Aging Treatments in Al-Mg-Si Castings

The feasibility of applying the fluidized bed furnace to the solution and aging treatments of aluminum alloys was assessed by examining concerns such as the efficiency of heat treatments and delay of quenching, together with its merits such as the shortening of heat treatment and the possibility of high temperature heat treatments. It was concluded that this method realizes high efficiency of heat treatments, which is comparable to that attainable with the combination of a salt bath and oil bath. By suppressing the delay time within 20 to 30sec. after the removal of works from the fluidized bed furnace, no degradation in mechanical properties occurs. The allowable delay time is dependent on the work size. The solution treatment time can be shortened to 60min. or below. Good mechanical properties were obtained even with a short solution treatment time of 15min. depending on the size and thickness of the work. This also enables suppression of pore growth at the same time. In addition, high temperature heat treatment at around ternary eutectic temperatures was realized by precise temperature control, thereby realizing superior mechanical properties and shorter heat treatment time