摘要
利用扫描电镜和透射电镜技术系统地研究了多层焊对奥氏体不锈钢焊缝组织变化和M_(23)C_6碳化物析出规律的影响。观察到重热作用使δ-铁素体部分发生溶解,转变为奥氏体或其它第二相,并变得破碎和细小呈球形分布,类似于焊接热影响区的组织变化规律。发现打底层(第1焊层)中所有δ/γ晶界上均有M_(23)C_6析出;第2焊层中仅部分δ/γ晶界上有M_(23)C_6析出;盖面层(第3焊层)中没有M_(23)C_6析出。这种变化与多层焊热循环及Cr,Ni在δ/γ晶界附近的偏析和材料的碳含量有关。M_(23)C_6与奥氏体之间存在立方/立方取向关系。
This paper studies the effect of multi-layer welding on microstructural change and M23C6 precipita-tion in austenltic stainless steel weld metal by means of the scanning electron microscope (SEM)and transmission electron microscope(TEM). It is observed that because of the action of multiple reheating, δ ferite δ-Fe)dissolves partly and transforms into austenite of other secondary phases. It also breaks into small and spherical grains. The change in microstructure seems like that in the heat-affected zone. TEM observation shows that in the root layer(first layer) ,M23C6 carbides precipitate along all δ/γ intertace; in the second layer M23C6 carbides exist only on part of the interface;and in the cover layer (third layer)no carbide is seen along the interface. These are considered to be associated with the multiple ther-mal cycling,segregations of Cr and Ni around the δ/γ interface and carbon content in the filler and these materials.There is a cube/cube orientation relationship between M23C6 and austenite.
基金
国家自然科学基金 59301008
湖北省自然科学基金
关键词
焊缝
电子显徽术
奥氏体不锈钢
welds
electron microscopy
austenitic stainless steel
