带极埋弧堆焊EQ309L不锈钢的微观组织EBSD分析

EBSD Analysis of Microstructure of EQ309L Stainless Steel After Band Electrode Submerged Arc Overlay Welding

采用带极埋弧堆焊在Q345R基体表面堆焊EQ309L不锈钢焊带。运用电子背散射衍射(EBSD)表征技术,观测了Q345R和EQ309L之间的EQ309L侧、Q345R侧和界面的微观组织特征。结果表明:在Q345R基体上大部分晶粒内部畸变严重,观测到明显的沿原轧制方向的条带状晶粒。在过热粗晶区域,Q345R基体的平均晶粒尺寸为30~40μm,晶粒粗化不严重;在细晶区,Q345R基体的平均晶粒尺寸为10~20μm。Q345R基体侧熔合线向堆焊层延伸35~40μm后的区域是过渡区,该区域具有体心立方(bcc)结构。EQ309L层晶粒粗大,呈柱状晶形貌,具有明显的<100>织构特征。

Band electrode submerged arc overlay welding was used to weld welding strip of EQ309 L stainless steel on the surface of Q345 R matrix. The microstructure of EQ309 L side, Q345 R side, and their interfaces were observed by electron backscattered diffraction(EBSD) technique. Results show that most grains in Q345 R matrix are seriously distorted, and the banded grains along the original rolling direction can be clearly observed. The average grain size of Q345 R matrix is 30~40 μm in the overheated coarse-grain region, and the grain coarsening is not severe. The average grain size of the fine-grain region is 10~20 μm in the Q345 R matrix. The transition zone is 35~40 μm away from the fusion line of Q345 R matrix, and it has body-centered cubic(bcc) structure. The EQ309 L layer has coarse grains, showing the microstructure of columnar crystal with obvious <100> texture.