保溫時間的選擇原則是使強化相在正常熱處理溫度下滿意溶解，使固溶充分均勻，晶粒細化。
　　The selection principle of holding time is to make the strengthening phase dissolve satisfactorily under normal heat treatment temperature, to make the solid solution fully and evenly, and to refine the grains.
　　鋁合金硬化占用時間的性質(zhì)主要是根據(jù)淬火加熱溫度、合金、類型的產(chǎn)品和之前固溶體狀態(tài)組織(加強階段特征和大小分布),產(chǎn)品的形狀(包括截面厚度的大小),加熱模式(鹽浴爐和空氣循環(huán)爐、連續(xù)或不連續(xù)加熱),加熱介質(zhì)和冷卻方式和水平的裝爐,和組織因素來確定績效要求。
　　The properties of hardening time of aluminum alloy are mainly based on quenching temperature, alloy, type of products and previous solid solution state structure (strengthening stage characteristics and size distribution), product shape (including the size of section thickness), heating mode (salt bath furnace and air circulation furnace, continuous or discontinuous heating), heating medium, cooling mode and horizontal charging, And organizational factors to determine performance requirements.

　　對于同一牌號的合金，在確定保持時間時應考慮以下因素
　　For the alloy of the same brand, the following factors should be taken into account when determining the holding time
　　(1)產(chǎn)品的形狀。淬火加熱的保溫時間與產(chǎn)品的形狀(包括截面厚度的大小)密切相關。截面厚度越大，保溫時間越長。對于大截面的半成品和形狀變化小的工件，應適當延長淬火時間，使淬火階段充分溶解。大型鍛件和模具鍛件的保溫時間是薄件的幾倍。
　　(1) The shape of the product. The holding time of quenching heating is closely related to the shape of the product (including the thickness of the section). The greater the section thickness, the longer the holding time. For the semi-finished products with large cross-section and the workpieces with small shape change, the quenching time should be appropriately extended to make the quenching stage fully dissolved. The holding time of large forgings and die forgings is several times that of thin ones.
　　(2)加熱溫度。淬火加熱的保溫時間與加熱溫度密切相關。加熱溫度越高，強化相融入固溶的速度越快，保溫時間越短。
　　(2) Heating temperature. The holding time of quenching is closely related to the heating temperature. The higher the heating temperature is, the faster the strengthening phase melts into solid solution and the shorter the holding time.
　　(3)塑性變形程度及產(chǎn)品類型。熱處理前加壓加工可以加速強化相的溶解。變形程度越大，強化相尺寸越小，保溫時間越短。如果冷變形后的工件在加熱過程中發(fā)生再結(jié)晶，應注意防止再結(jié)晶晶粒過大。臨界變形程度不應在固溶處理前進行處理。為了保持擠出效果，應縮短擠壓產(chǎn)品的保溫時間。對于擠壓變形程度較大的擠壓材料模鍛件，如果淬火加熱保溫時間過長，由于再結(jié)晶過程，部分或全部擠壓效果消失，降低產(chǎn)品的縱向強度。擠壓變形程度越大，保溫所需時間越短。
　　(3) Degree of plastic deformation and product type. Pressure processing before heat treatment can accelerate the dissolution of strengthening phase. The larger the deformation degree, the smaller the strengthening phase size and the shorter the holding time. If recrystallization occurs in the process of heating after cold deformation, care should be taken to prevent excessive recrystallization grains. The critical deformation degree should not be treated before solution treatment. In order to keep extrusion effect, the heat preservation time of extruded products should be shortened. If the time of quenching and heat preservation is too long, some or all of the extrusion effect will disappear due to the recrystallization process, and the longitudinal strength of the product will be reduced. The greater the degree of extrusion deformation is, the shorter the time of heat preservation is.
　　(4)原組織。產(chǎn)品提前淬火后，再加熱已溶火，可顯著縮短保溫時間。退火前硬化階段的溶解速率明顯慢于冷加工階段的溶解速率。
　　(4) Original organization. After the product is quenched in advance and reheated, the heat preservation time can be shortened significantly. The dissolution rate in the hardening stage before annealing is significantly slower than that in the cold working stage.
　　(5)坯料均勻度。對于均質(zhì)不足的產(chǎn)品，殘留強化階段較多且較大，因此保溫時間應延長。固溶處理和同質(zhì)化的共同目的是完全溶解硬化階段,但總的來說,均勻化退火窯的精度較低,所以很容易過于熱衷的均一化溫度提高,為了充分消除非平衡結(jié)晶相。此外,齊次退火時間長,經(jīng)濟效益較低,所以鏈接均化和淬火過程可以被認為是根據(jù)產(chǎn)品合金的性質(zhì)和處理技術(shù)解決的問題充分固溶強化階段,因為加強階段結(jié)構(gòu)大變形嚴重破碎后,尺寸更小,固溶淬火更容易得到解決。
　　(5) Evenness of blank. For products with insufficient homogeneity, the residual strengthening stage is more and larger, so the holding time should be extended. The common purpose of solution treatment and homogenization is to completely dissolve and harden, but generally speaking, the accuracy of homogenization annealing furnace is low, so it is easy to increase the homogenization temperature too enthusiastically, in order to fully eliminate the non-equilibrium crystalline phase. In addition, the homogeneous annealing time is long and the economic benefit is low, so the link homogenization and quenching process can be considered as the full solution strengthening stage according to the properties of the product alloy and the problems solved by the treatment technology, because in the strengthening stage, after the large deformation of the structure is seriously broken, the size is smaller and the solution quenching is easier to be solved.
　　(6)組織和績效要求。當需要產(chǎn)品粒度時，應考慮縮短停留時間。此外，還開發(fā)了雙淬和分級淬火工藝，以獲得細晶粒組織。二次淬火是指在同一高溫下使用兩次短時間淬火，但兩次淬火保溫時間之和與原保溫時間相同，其原理是不給晶粒生長時間和機會;分級淬火階段采用低溫來完成組織中亞晶粒的發(fā)育，降低了再結(jié)晶的驅(qū)動力，使晶粒在第二階段的高溫溶液中不易長大。當產(chǎn)品具有較高的腐蝕性能、斷裂韌性和疲勞性能要求時，如航空鋁合金等淬火保溫時間應至少延長一倍。
　　(6) Organization and performance requirements. When product granularity is needed, the reduction of residence time should be considered. In addition, double quenching and step quenching processes were developed to obtain fine grain structure. Secondary quenching refers to the use of two short-term quenching at the same high temperature, but the sum of the two quenching holding times is the same as the original holding time, the principle of which is not to give the grain growth time and opportunity; the first stage of graded quenching uses low temperature to complete the development of sub grains in the structure, reducing the driving force of recrystallization, so that the grains are not easy to grow in the high temperature solution of the second stage. When the products have high requirements of corrosion, fracture toughness and fatigue properties, such as aviation aluminum alloy, the quenching and holding time should be extended by at least one time.
　　其他因素，如合金的性質(zhì)、加熱條件、加熱介質(zhì)和爐容量也必須考慮。可熱處理強化鋁合金各強化相的溶出速率不同。例如，Mg2Si的溶解速度比Mg2Al3快。淬火和保溫時間必須保證強化相能充分溶解，才能使合金得到大的強化效果。但加熱時間不宜過長。在某些情況下，長時間的加熱會降低合金的性能。對于某些在加熱溫度下晶粒較粗的合金(如6063、2A50等)，應縮短保溫時間，在保證硬化的條件下避免晶粒長大。對于數(shù)量大、尺寸大的零件，保溫時間要長一些。爐量小，零件間距大，保溫時間短。
　　Other factors, such as alloy properties, heating conditions, heating medium and furnace capacity, must also be considered. The dissolution rate of each strengthening phase is different. For example, the dissolution rate of Mg2Si is faster than that of Mg2Al3. Quenching and holding time must ensure that the strengthening phase can be fully dissolved, so that the alloy can get the maximum strengthening effect. But the heating time should not be too long. In some cases, heating for a long time will reduce the properties of the alloy. For some alloys with coarse grains (such as 6063, 2A50, etc.) at heating temperature, the holding time should be shortened to avoid grain growth under the condition of ensuring hardening. For large quantity and large size parts, the heat preservation time is longer. Small furnace capacity, large distance between parts and short holding time.
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