热模拟平面应变条件下的热轧织构研究

以微合金钢为材料,采用光学显微镜和EBSD,研究热模拟平面应变实验条件下再结晶奥氏体和变形奥氏体的织构演变.研究发现,在热模拟平面应变实验的压缩过程中,试样的两个自由端限制了变形区金属的宽向流动,达到了很好的平面应变状态.对于再结晶奥氏体相变工艺,由于相变前奥氏体发生再结晶,无畸变保留,奥氏体分解为仿晶界铁素体、贝氏体和少量的珠光体,织构为{100}011α;对于变形奥氏体相变工艺,未再结晶区的变形促进了铁素体相变,使奥氏体分解为铁素体和珠光体组织,织构为{332}113α和{113}110α.此两种工艺条件下的织构,皆为平面应变条件下的奥氏体相变织构,即热模拟平面应变实验可以达到很好的平面应变状态,可用于研究热轧过程的织构演变.

Simulation of Hot Rolling Texture Under Plane Strain Condition by Thermo-mechanical Simulator

The texture evolution of recrystallized austenite and deformed austenite in the plane strain compression test was investigated using optical microscope and electron backscattered diffraction (EBSD) by thermo-mechanical simulator. The results show that the plane strain state can be obtained because the two free-ends of the sample limit the transverse metal flow in the deforming zone. For the process of transformation texture of recrystallized austenite, the austenite transforms to allotriomorphic ferrite, bainite and a little pearlite, because recrystallization of austenite occurs and there is not obvious lattice distortion before transformation, and the transformation texture is100<011>_α. For the process of transformation texture of deformed austenite, the austenite transforms to ferrite and pearlite due to the deformation in non-recrystallized austenite region, and the transformation textures are332<113>_αand 113<110>_α. The textures of the two processes are the typical transformation textures of hot rolling under plane strain. Thus, the plane strain compression test by thermo-mechanical simulator can create excellent plane strain state which is appropriate to investigate the evolution of hot rolling texture.