The selection principle of holding time for solution treatment of aluminum plate is to make the strengthening phase dissolve satisfactorily at normal solution heat treatment temperature, and make the solid solution fully uniform and grain fine. The holding time of aluminum plate quenching is mainly based on the quenching heating temperature, the nature of alloy, the type of products, the microstructure before solution (the distribution characteristics and size of strengthening phase) and the shape of products (including the size of cross-section thickness), heating mode (salt bath furnace and air circulation furnace, continuous or discontinuous heating), heating medium, cooling mode and charging quantity, as well as the requirements of microstructure and properties. For the same brand of aluminum alloy, the following factors should be considered in determining the holding time:
(1) The shape of the product. The holding time during quenching is closely related to the shape of the product (including the size of the section thickness). The larger the section thickness is, the longer the holding time is. For semi-finished products with large cross-section and workpieces with small deformation, the strengthening phase is coarse, and the holding time should be appropriately extended to make the strengthening phase fully dissolve. The holding time of heavy forgings and die forgings is several times longer than that of thin ones;
(2) Heating temperature of aluminum plate. The higher the heating temperature is, the faster the strengthening phase dissolves into the solid solution, and the longer the holding time is;
(3)塑性变形程度及6061铝板制品种类。热处理前的压力加工可加速强短些化相的溶解。变形程度越大，强化相尺寸越小，保温时间可短些。经 冷变形的工件在加热过程中要发生再结晶，应注意防止再结晶晶粒过 分粗大。固溶处理前不应进行临界变形程度的加工。
(3) Plastic deformation degree and 6061 aluminum products. The pressure processing before heat treatment can accelerate the dissolution of short and strong phases. The larger the deformation, the smaller the size of strengthening phase and the shorter the holding time. The recrystallization of cold deformed workpieces during heating should be avoided. The critical deformation should not be processed before solution treatment.
挤压制品的保温 时间应当缩短，以保持挤压效应。对于采用挤压变形程度很大的挤压材做毛料的模锻件，如果淬火加热的保温时间过长，将由于再结晶过程的发生，而导致局部或全部挤压效应的消失，使制品的纵向强度降 低。挤压时的变形程度越大，需要保温的时间就越短。
The holding time of extruded products should be shortened to maintain the extrusion effect. If the holding time of quenching heating is too long, the partial or total extrusion effect will disappear due to the recrystallization process, and the longitudinal strength of products will be reduced. The greater the degree of deformation, the shorter the holding time.