摘要
采用热模拟技术和显微分析技术，研究了焊接热循环对X70管线钢热影响区的组织和冲击韧性的影响。结果表明：粗晶区和临界粗晶区是X70管线钢热影响区中冲击韧性较差的区域，其中粗晶区冲击韧性恶化主要由晶粒粗化及粒状贝氏体和上贝氏体等非平衡中温转变产物数量增多造成，且粗晶区的冲击韧性随着t8/5们的增加而降低；粗大、高碳且呈网络状分布的M-A组元是导致临界粗晶区冲击韧性较低的原因。
In use of thermal simulation and microscope analysis, the influence of welding cycle on the microstmcture and impact toughness of the heat affected zone of X70 pipeline steel is investigated The results show that the coarse-grained heat affected zone （CGHAZ） and critical reheated CGHAZ are the zones with worse impact toughness. The deterioration of impact toughness of CGHAZ is caused by the coarsening of crystal grains and the increasing amount of microstructures like granular bainite and upper bainite which are created by imbalanced temperature transformation. Besides, as the increase of t8/5 , the impact toughness of CGHAZ decreases. The networks of coarse blocky and high C M-A constituent are the main causes to the deterioration of impact toughness of critical reheated CGHAZ.
出处
《首钢科技》
2009年第4期40-45,49,共7页
Shougang Science and Technology
