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

摘要:

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30~40 μm，晶粒粗化不严重；在细晶区，Q345R基体的平均晶粒尺寸为10~20 μm。Q345R基体侧熔合线向堆焊层延伸35~40 μm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。

Abstract:

Band electrode submerged arc overlay welding was used to weld welding strip of EQ309L stainless steel on the surface of Q345R matrix. The microstructure of EQ309L side, Q345R side, and their interfaces were observed by electron backscattered diffraction (EBSD) technique. Results show that most grains in Q345R matrix are seriously distorted, and the banded grains along the original rolling direction can be clearly observed. The average grain size of Q345R 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 Q345R matrix. The transition zone is 35~40 μm away from the fusion line of Q345R matrix, and it has body-centered cubic (bcc) structure. The EQ309L layer has coarse grains, showing the microstructure of columnar crystal with obvious <100> texture.