摘要
通过焊接热模拟和厚板焊接接头ＣＴＯＤ断裂性能试验，研究了直接淬火回火钢焊接热影响区局部脆性区组织和性能及对厚板焊接接头断裂韧性的影响。结果表明，在γ＋α二相区内再次加热的粗晶区（ＩＣＣＧＨＡＺ）具有最低冲击韧性值，是焊接接头中最薄弱环节。该区在原奥氏体晶界上分布着“项链”状ＭＡ组元，引发多层焊热影响区脆断起裂，降低热影响区断裂韧性。局部脆性区韧性的高低和尺寸的大小是控制直接淬火回火钢多层焊热影响区断裂韧性的主要因素之一。局部脆性区韧性低，整体焊接接头断裂性能差；局部脆性区尺寸大，热影响区断裂韧性低。
In this paper, the microstructure and toughness properties of local brittle zones (LBZ) in heat-affected zone (HAZ) were studied by welding thermal simulation and effect of local brittle zones on HAZ fracture toughness of thick weldments was investigated using CTOD fracture mechanics tests in a direct quenched and tampered steel.The results show that the lowest toughness from Charpy-V test was located at the intercritically reheated coarse grained heat-affected zone (ICCGHAZ), which is the weakest link in the multipass weldment. MA (Martensite-austenite) islands distributed mainly at the prior austenite grain boundary in ICCGHAZ give rise to the initiation of cleavage crack, which results in the low fracture toughness of HAZ in thick weldment. The large size and the poor toughness of LBZ have the negative effect on HAZ fracture toughness.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
1998年第3期147-153,共7页
Transactions of The China Welding Institution
基金
国家教委归国人员基金
关键词
直接淬火回火钢
热影响区
局部脆性区
断裂韧性
direct quenched and tempered steel, heat-affected zone, local brittle zones, CTOD fracture toughness.
