碳锰钢压缩过程中非均匀应变与再结晶之间关系的研究

采用有限元方法模拟了热模拟试验的变形过程,分析了热模拟变形过程中的非均匀应变对奥氏体动态再结晶及晶粒尺寸的影响.结果表明,在等效应变最大的区域,奥氏体动态再结晶并非最完全,而剪应变对动态再结晶的影响则较大,在剪应变最大的区域,再结晶最完全,晶粒最细小.在试验所设定的最大变形量为62%的变形条件下,等效应变对晶粒细化的影响存在一个临界值,当等效应变大于0.96时,不完全动态再结晶区域的奥氏体晶粒得不到进一步细化,而随着剪应变的增加,奥氏体晶粒不断细化,可见剪应变对奥氏体晶粒尺寸的影响更大.因此,用等效应变等于实际应变处的晶粒尺寸来考察实际晶粒尺寸的方法,存在着不合理性.

Investigation on Relationship of Uneven Strain and Recrystallization During C-Mn Steel Compression

The thermal simulation of compression was carried out by finite element method.The effect of uneven distribution of strain during compression on dynamic recrystallization and grain size of austenite was analyzed.The results show that dynamic recrystallization of austenite in the zone of largest effective plastic strain doesn't be most complete,while shear strain has more strong effect on dynamic recrystallization.Dynamic recrystallization occurs most completely in the zone of largest shear strain,making grain size minimum.Under the given deformation condition with largest strain of 62%,there is a critical value for the effect of effective plastic strain on grain refinement.When the effective plastic strain is larger than 0.96,the austenite grains in non-complete dynamic recrystallized zone can't be refined further.However,austenite grains are refined continuously with the increasing of shear strain.Thus,shear strain has much more effect on austenite grain refinement.The method in which the zone where the effective plastic strain equals to real strain is chosen to determine the grain size,is not reasonable,and further research is required.