摘要
依据奥氏体转变为马氏体时的体积膨胀原理 ,自行研制成功低相变点焊条(LowTransformationTemperatureElectrode ,LTTE)。低相变点焊条的熔敷金属组织为低碳马氏体和残余奥氏体 ,其相变开始点MS 在 140～ 32 5℃之间 ,相应变结束点Tf 在室温附近。在焊接冷却至低温阶段 ,焊缝金属发生马氏体相变 ,相变体积膨胀将会降低焊接热场造成的残余拉伸应力 ,甚至出现残余压缩应力 ,从而提高了焊接接头的疲劳强度。利用所研制的低相变点焊条和普通E5 0 15焊条分别对具有较大焊接残余应力和较大应力集中的纵向角接板焊接接头进行焊接 ,疲劳试验证明 ,前者焊接接头的疲劳强度比后者提高 40 %左右 (在 2× 10 6循环次数下 ) ,疲劳寿命提高 2 5倍。
A new low transformation temperature electrode(LTTE) is developed based on the volume expansion principle that weld metal begins to transform from austenite to martensite at range of 140℃～325℃ and finishes about room temperature.The microstructure of the weld metal for LTTE is low carbon martensite at room temperature.During the transformation,the expansion of the weld metal can reduce the tensile residual stress existed in the weld or in some cases form the compressive residual stress around the weld.These can enhance the fatigue strength of welded joints.The fatigue specimens of welded joints with longitudinal stiffeners welded by LTTE and E5015 electrodes are selected to conduct fatigue test,which have high tensile residual stress and stress concentration.It is shown that the former fatigue strength is improved about 40% than the latter at 2×10 6 cycles.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2001年第5期37-40,共4页
Transactions of The China Welding Institution
基金
国家自然科学基金资助项目 ( 5 0 175 0 79)
关键词
低相变点焊条
相变应力
焊接接头
疲劳强度
残余压应力
low transformation temperature electrode
fatigue strength
compressive residual stress
phase stress
welded joints
