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用手工电弧焊、埋弧焊两种焊接方法分别对9Ni钢板进行对接焊,通过冲击试验对焊缝金属的低温冲击韧性进行了研究,利用金相显的影响微镜、扫描电镜、透射电镜、EBSD等科研仪器分析和对比了两种焊接方法对焊缝金属的组织、晶粒尺寸及晶界角度特征。试验结果表明:采用手工电弧焊、埋弧焊施焊的焊缝金属在-196℃的平均冲击吸收功分别为86.7和116 J,埋弧焊焊缝金属的冲击吸收功较高。手工电弧焊、埋弧焊焊缝金属的组织均为奥氏体和析出相组成,手工电弧焊的焊缝金属的结晶形态呈树枝状,埋弧焊焊缝金属的结晶形态为胞状树枝晶,偏析分散。手工电弧焊、埋弧焊焊缝金属中奥氏体平均晶粒尺寸分别为132.16和104.97μm。埋弧焊焊缝金属组织偏析分散、奥氏体晶粒尺寸较小是其低温冲击吸收功升高的主要原因,同时埋弧焊焊缝金属中大角度晶界数量的增加也是导致其韧性增加的原因。
The 9Ni steel plates were butt welded by manual arc welding and submerged arc welding respectively. The low temperature impact toughness of the weld metal was studied by impact test. The effects of metallographic microscopy, scanning electron microscope, transmission electron microscope, EBSD and so on Scientific research instrument analysis and comparison of two welding methods on the weld metal microstructure, grain size and grain boundary angle characteristics. The experimental results show that the average absorbed energy at -196 ℃ is about 86.7 and 116 J respectively for SMAW and SAW, and the impact absorption energy of SAW metal is high. Manual arc welding, submerged arc welding of the metal microstructure are austenite and precipitated phase composition, manual arc welding of the weld metal crystal morphology was dendritic, submerged arc welding metal crystalline morphology of dendritic cells, Segregation dispersion. The average grain size of austenite in SMAW and SAW metal was 132.16 and 104.97μm, respectively. Submerged arc welding metal segregation segregation segregation, austenite grain size is its low temperature impact absorption is the main reason for the increase, while submerged arc welding metal in the large-angle grain boundary is also an increase in the number of its increased toughness s reason.