In order to determine the deformation process window and inquire the cause of internal cracks and voids, three-roll planetary rolling process was modeled by three-dimensional finite element method, and internal cracks and voids were investigated by real rolling of a bismuth-containing austenitic stainless steel bar. It shows that improper process parameters will lead to cracks and voids in the rolled bar. The Brozzo ductile fracture criteria revised can be used to determine the damage factor. The deformation process window to avoid internal cracks and voids can be described by rolling elongation and temperature. The three positive principal stresses in the center of the rolled bar, the alternating stress caused by periodically discontinuous contact between the rolls and the rolled piece, and the uneven radial strain distribution can be counted to be the main reasons for internal cracks and voids in the rolled bar. This study shows that the elongation has an upper limitation for avoiding internal cracks and voids in the bismuth-containing austenitic stainless steel bar rolled by three-roll planetary mill.

为确定变形过程窗口并探究内部裂纹和空洞的产生原因，采用三维有限元方法对三辊行星轧制过程进行建模，并通过含铋奥氏体实际轧制研究了三辊行星轧制过程中的内部裂纹和空洞不锈钢棒。说明不正确的工艺参数会导致轧制棒材出现裂纹和空洞。修正后的 Brozzo 韧性断裂准则可用于确定损伤系数。避免内部裂纹和空隙的变形过程窗口可以用轧制伸长率和温度来描述。轧制棒材中心的三个正主应力，轧辊与轧件周期性不连续接触引起的交变应力，径向应变分布不均可以认为是轧制棒材内部出现裂纹和空洞的主要原因。本研究表明，在三辊行星式轧机轧制的含铋奥氏体不锈钢棒材中，延伸率对于避免内部裂纹和空隙有一个上限。