振动激发金属液原位形核的物理模拟

为了提高铸坯的等轴晶率、细化凝固组织,以30%氯化铵水溶液和铁素体不锈钢为研究对象,分别进行了物理模拟和浇注实验.结果发现:当一种带有冷却结构和高频振动的晶核发射器棒体插入氯化铵溶液时,在棒体表面将迅速形成大量的细小晶粒.这些晶粒在振动作用下被连续不断地弹射至溶液中,成为凝固过程中等轴晶的形核核心;晶核发射器的冷却强度越大、振动频率越高,则形成的晶粒数量越多且粒径越小;铁素体不锈钢液经振动激发形核处理后,凝固组织中的等轴晶率超过了80%.

Physical Analogue of Liquid Metal Original Position Nucleation Stirred by Vibration

In order to increase proportion of equiaxed grain of billet and refine the solidification structure, physical analogue and casting experiments have been carried out with 30% NH4Cl aqueous solution and ferritic stainless steel respectively. The results show that a large number of fine crystal grain are formed on the surface of a crystal nucleus eradiation equipment with cooling system while the vibrating bar of the equipment is inserted into 30% NH4Cl aqueous solution. The crystal grains are ejected to molten pool continuously under the vibrating action of bar and served as crystal nucleus of equiaxed grain during solidification. The higher the cooling intensity and the vibration frequency of the crystal nucleus eradiation equipment, the more the number of the crystal grain, as well as the smaller the particle diameter. The proportion of equiaxed grain of ferritic stainless steel treated with vibration and refrigeration could be increased up to 80%.