采用手工电弧焊和自动埋弧焊分别对9Ni钢板进行焊接，通过拉伸、弯曲、冲击试验以及组织、断口观察等研究两种焊接接头的组织和力学性能。结果表明：两种焊接接头的焊缝组织均由奥氏体组成，热影响区均以马氏体为主;手工电弧焊接头焊缝的结晶形态呈树枝状，偏析程度较大，热影响区的马氏体粗大，自动埋弧焊接头焊缝的结晶形态为细小的胞状树枝晶，偏析程度较轻，热影响区的板条马氏体细小,板条束较多;两种焊接接头均具有良好的拉伸性能和弯曲性能，自动埋弧焊接头的低温冲击韧性优于手工电弧焊接头的;自动埋弧焊焊接接头冲击断口上的韧窝更大更深，且分布均匀。

9Ni steel plates were welded by manual arc welding and automatic submerged arc welding, respectively, and microstructure and mechanical properties of two kinds of welded joints were studied by tension, bending and impact testing, as well as microstructure and fracture observing. Results show that the microstructure of weld metal in the two welded joint all consistsed of austenitic, and that of heat affected zone all consistsed of martensitic. Crystal morphology of weld metal of manual arc welded joint was dendritic crystal, segregation degree was relatively large and martensitic in heat affected zone was bulky. Crystal morphology of weld metal of automatic submerged arc welded joint was cellular dendrites, segregation degree was relatively low, lath martensitic in heat affected zone was thin and martensite lath bundle was relatively more. For the two welded joint, tensile properties and blending properties were well, and impact toughness of the automatic submerged arc welded joint at low temperature was better than that of the manual arc welded joint. The dumples on impact fracture of automatic submerged arc welded joint were bigger and deeper, and they distributed evenly.