【摘要】 采用升降法在拉压载荷的作用下,对B780CF高强钢板原始态(调质态)、退火态(调质后退火)以及焊接接头退火态(调质板焊接后退火)的疲劳性能进行测试,得出应力比为-1条件下的B780CF原始态、退火态以及焊接接头退火态的疲劳极限分别为400 MPa,415 MPa和360 MPa。经历焊接热循环和消应力退火之后,B780CF焊接接头的冲击韧性急剧下降,热影响区粗晶区晶粒粗化,细晶区与母材之间的过渡区软化,并沿晶界析出托氏体;经扫描电镜的观察显示,高强钢板及其焊接接头的疲劳裂纹可萌生于疲劳试样的表面,也可萌生于疲劳试样内部的夹杂物和组织异常区域。更多还原

【Abstract】 The fatigue properties of the B780 CF high strength steel plate in the original state( quenched and tempered state),annealed state( annealing after tempering),and the annealing state of the welded joint( quenched and tempered plate after annealing) were tested by the lifting method under the action of tension and compression,respectively. The fatigue limit of the B780 CF original state,the annealed state and the welded joint annealed under the stress ratio of -1 are 400 MPa,415 MPa and 360 MPa,respectively. The impact toughness of B780CF welded joints decreased sharply after welding and thermal annealing,and the grains in the thick zone of the heat affected zone were seriously coarsened. The softening zone existed in the transition zone and the smectite was precipitated along the grain boundary. Scanning electron microscopy observations show that high strength steel plate and welded joint fatigue source area are located in the surface of the sample,also in the defects and the tissue microstructure of the sample.更多还原