Technology ofheat treatment is divided into the following four categories
Annealing treatment of aluminium alloy heat treatment ：Heated castings to high temperature (about 300℃)，after insulation ，technology of furnace cooling ,called anneal. Annealing treatment can eliminate innerstress of castings ，stabilize size of castings，increase plasticity of castings.
Solution treatment of aluminium alloy heat treatment: The casting is heated to high temperatures as much as possible，rapid cooling after heat preservation for long enough time. Solution treatment can improve the strength and plasticity of castings，perfect decay resistance of alloy.
Aging treatment of aluminium alloy heat treatment: Adopt aging treatment of lower aging temperature or shorter soaking time,called incomplete artificial aging. Adopt aging treatment of higher aging temperature or longer soaking time ，called complete artificial aging. Incomplete artificial aging can make castings get better synthesized mechanical property，that is to say ,higher strength，better plasticity and tenacity，but maybe corrosion stability is lower.
Complete artificial aging can make castings get largest strength，that is to say，largest strength of extension, elongation is lower.
The passage above talks about process classification and effects of aluminium alloy heat treatment.