X80管线钢埋弧焊接头冲击韧性及其断口形貌分析

摘要

The Charpy impact test at temperature range of-80-20℃ was conducted for X80 pipeline steel welded joints fabricated with submerged-arc welding.The impact absorption energy and brittle section rates were tested,and the fracture morphologies were observed with Scanning Electron Microscopy (SEM).The fracture modes and fracture morphologies of X80 pipeline steel joints were analyzed,and the ductile-brittle transition temperature of the joints and mechanical behaviors of the impact fractures were studied.The results show that the fracture at room temperature occurred in dimple fracture mode,and the ductile-brittle transition temperature of the joint was-28℃.The fracture characteristics were changed from toughness to brittleness fracture,and the joint fractured mainly in cleavage mode.%对X80管线钢埋弧焊焊接接头进行了-80～20℃温度范围的夏比冲击实验.测试了其冲击吸收功和脆性断面率,用扫描电镜观察了其断口形貌,分析了焊接接头断裂形式和断口形貌,讨论了焊接接头的韧脆转变温度和冲击断裂的力学行为.结果表明,室温时断口为韧窝状分布,焊接接头的韧脆转变温度为-28℃；断口形貌由韧性断裂向脆性断裂转变,断口主要表现为解理断裂.