【摘要】 通过SEM,TEM,EBSD和示波冲击实验研究了450℃回火对X100管线钢显微组织和冲击断裂过程的影响。结果表明:X100管线钢的组织为板条贝氏体(LB)、针状铁素体(AF)和粒状贝氏体(GB)和平行排列的细小片状马氏体/奥氏体(M/A)组元,原始奥氏体晶粒被晶内和晶界处的亚结构分割细化。回火后,平行排列的M/A组元消失,LB结构弱化,大角度晶界比例下降。实验温度降低,X100管线钢的冲击功(E)、裂纹形成能(E1)和韧性扩展能(E2)变化较小;回火后,E、E1、E2、脆性断裂扩展能(E3)降低,脆性断裂趋势增大,脆性断裂止裂性能变差。更多还原

【Abstract】 Effects of tempering at 450 ℃ on microstructure and impact fracture process of X100 pipeline steel was investigated by SEM,TEM,EBSD and instrumented impact test.The results indicate that microstructure of the X100 pipeline steel consists of lath bainite(LB),acicular ferrite(AF),granular baintie(GB) and parallel arrangement of martensite/austenite(M/A) constituents.Prior austenitic grains are refined by sub-regions’ division.The LB structure weaken and parallel arrangement of M/A constituents disappear and high angle grain boundary(HAGB) decrease after tempering.With the reducing of test temperature,the X100 pipeline steel’s impact energy(E),crack formation energy(E1),ductility fracture propagating energy(E2) change little,while the E,E1,E2 and brittle fracture energy(E3) of the steel decrease significantly,brittle fracture tendency increases,brittle fracture arrest properties become worse gradually after tempering.更多还原