ULCB钢的奥氏体形变组织研究

Study on austenite deformed structure of ULCB steels

采用单道次压缩实验方法，用THERMECHMASTORZ热模拟试验机在1100～850℃、变形速率2S^-1和变形量10％～50％的应变条件下，对900MPa级ULCB钢进行应力-应变曲线和奥氏体形变组织的试验。结果表明，在950℃以下的低温变形中不发生形变再结晶，随着变形量增大，先出现晶内形变带直到晶粒拉长变形。在1000℃以上的高温变形中，当变形量大于临界变形量时发生形变再结晶。随着变形量增大，奥氏体再结晶晶粒面积百分数依次增加，形变组织为部分或完全再结晶奥氏体，奥氏体晶粒平均截距的大小取决于形变再结晶奥氏体的晶粒尺寸和面积百分数。

Tests on the stress-strain curve and the austenite deformed structure of 900MPa ULCB steel have been carried out under the conditions of 1 100～850℃, deformation rate 2 s^-1 and strain rate 10%～50% at a thermo-simulator THERMECH- MASTOR-Z by means of single pass reduction experimental method. Results show that in the low temperature deformation of 950℃ below deformation reerystallization doesn＇ t occur and with the growth up of deformation the inner crystal deformation band appears initially and then the grain size is elongated till deformation. In the high temperature deformation of over 1000℃ the deformation recrystallization occurs when the deformation rate is greater than the critical deformation rate. With increase of the deformation rate the area percentage of the austenite recrystallized grains will increase in turn and the deformed structures are determined to be partial or complete recrystallized austenites and the size of the average sectional distance of the austenite grains depends upon the grain size of the deformed recrystallized austenite and its area percentage.