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拉深工艺是工业制造中使用极为广泛的一种成型工艺,拉深过程中特别是在多次变形或变形量较大的冷拉深环节,容易发生加工硬化现象,一方面使得后续加工变得困难;另一方面,由于塑性和韧性的降低,工件在变形过程中或变形一段时间后容易发生开裂。采用光纤耦合半导体激光器,对发生加工硬化的304不锈钢容器器壁进行了激光软化处理,研究了加工硬化区域材料在激光辐照这种非平衡条件下的组织相变与再结晶现象,同时,利用COMSOL软件对该工艺的温度场等进行了模拟。研究发现,当所使用的激光参数使得扫描区域的最高温度在724℃至1 040℃之间时,加工硬化区域的板条状马氏体均转变成奥氏体,其中,最高温度在724~850℃之间时,材料硬度大幅降低并出现再结晶晶粒;最高温度在950~1 040℃之间时,组织发生完全再结晶,硬度降低到未拉深之前的水平。
Deep drawing process is a kind of forming process which is widely used in industrial manufacturing. During the deep drawing process, especially in the deep drawing process with many deformations or large deformations, the work hardening phenomenon easily occurs. On the one hand, the subsequent processing becomes Difficult; on the other hand, due to plasticity and toughness decreased, the workpiece during the deformation or deformation prone to cracking after a period of time. The fiber-coupled semiconductor laser was used to laser-soften the 304 stainless steel container wall. The phase transformation and recrystallization of the material in the work-hardened region under the unbalanced laser irradiation were studied. At the same time, COMSOL software for the process of temperature field simulation. The study found that when the laser parameters used so that the maximum scanning temperature range of 724 ℃ to 1040 ℃, the work hardening region of the martensite are transformed into austenite, of which the maximum temperature of 724 ~ 850 ℃, the hardness of the material is greatly reduced and recrystallized grains appear. When the maximum temperature is between 950 and 1 040 ℃, the microstructure recrystallizes completely and the hardness decreases to the level before undrawn.