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采用OM,SEM,TEM等手段对33 mm X80M钢的母材及环焊接头的微观组织和析出物的组织状态进行了分析。结果表明,母材组织以针状铁素体为主,含有少量的准多边形铁素体和M/A组织,析出物主要为Nb和Ti的碳氮化物。经过环焊后,热影响区的细晶区组织为多边形铁素体和粒状贝氏体,粗晶区组织为粒状贝氏体和针状铁素体,焊缝组织为准多边形铁素体和晶内针状铁素体。通过TEM观察,焊缝中薄膜状的M/A组织分布于板条贝氏体之间,析出物主要是AlN、TiN和Al_2O_3复合物。
The microstructures and precipitates of the base metal and the ring welded joint of 33 mm X80M steel were analyzed by means of OM, SEM and TEM. The results show that the matrix is dominated by acicular ferrite and contains a small amount of quasi-polygonal ferrite and M / A. The precipitates are mainly carbonitride of Nb and Ti. After the ring welding, the heat-affected zone fine-grained zone of polygonal ferrite and granular bainite, coarse-grained zone of granular bainite and acicular ferrite, weld microstructure of quasi-polygonal ferrite and Intragranular acicular ferrite. Through TEM observation, the film-like M / A structure in the weld is distributed between the lath bainite and the precipitates are mainly AlN, TiN and Al 2 O 3 composites.