Heat treatment process of casting aluminum alloy

Usually shape casting of aluminum alloy castings is more complex, uneven thickness, coarse grains, segregation is serious, so the need for appropriate after heat treatment, can be normal use, usually the heat treatment process of annealing, quenching, aging and stabilizing tempering.The purpose of casting aluminum alloy is to eliminate the internal stress of casting.Eliminate casting segregation and change the shape of acicular composition in alloy tissues;Improve the mechanical properties of aluminum alloy;The size, organization and performance of the parts at high temperature;Improved casting machining.

(1) annealing on dedicated aluminum annealing furnace, furnace charging at room temperature to 280 ~ 300 ℃, according to the casting thickness and the size of the furnace charging quantity and put in the form of reasonable heat preservation time, generally for 2 ~ 3 h, can complete the annealing process, then scattered over the cooling machine casting power cuts open the oven door be cold, it is forbidden to piled up.

(2) quenching and aging considering the casting aluminum alloy contains more impurities, uneven and there will be a low melting eutectic organization, so the temperature of the quenching heating temperature is lower than the maximum solubility.Quenching heating temperature is 500 ~ 535 ℃, lower than 350 ℃ oven, should slow heating, heat preservation time on 2 ~ 20 h, considering to prevent deformation and cracking of complex parts, casting aluminum alloy in 80 ~ 100 ℃ water cooling.When choosing quenching temperature, the influence of the above factors should be taken into account to avoid overheating or overheat.The purpose of aging and the effect of @ trade small make up have been introduced, it is divided into the total limitation and the incomplete aging of two kinds, should according to the specific requirement of the part to choose reasonably, no longer detailed here.