摘要
某客运专线运营初期,移动闪光焊接头发生了多起断裂事故。为明确接头的断裂原因,采用宏观形貌观察、扫描电镜观察、能谱分析、金相组织分析、化学成分分析等手段,结合现场实际运行情况对断裂焊接接头进行了分析。结果表明:焊接接头轨腰熔合线处由于焊接时进入氧气形成了氧化物,使其冶金结合力降低而产生了未焊合缺陷,是造成焊接接头横向断裂的主要原因;冬季温度拉应力较大,在缺陷处产生应力集中,是导致钢轨在服役初期就出现大量断裂的原因。焊接时防止因空气进入而破坏保护气氛,同时适当提高加速闪光阶段的位移速度,可有效避免未焊合缺陷。
At the operation beginning of one passenger dedicated railway,there were many fracture accidents of mobile flash welding joint. In order to clarify the fracture cause of the joint,the fracture welding joint was analyzed by means of macro morphology observation,scanning electron microscope observation,energy spectrum analysis,metallographic structure analysis and chemical composition analysis combined with the actual operation on site. The results show that the main reason for the transverse fracture of the welding joint is that the fusion line at the rail waist of the welding joint forms oxides due to the entry of oxygen during welding,which reduces its metallurgical adhesion and produces unwelded defects. The high temperature tensile stress in winter and the stress concentration at the defect position are the reasons for many rail fractures in the early stage of service. During welding,the protective atmosphere is prevented from being damaged due to the entry of air,and the displacement speed in the accelerated flash stage is appropriately increased,which can effectively avoid the occurrence of unwelded defects.
作者
张倩
ZHANG Qian(Metals and Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)
出处
《铁道建筑》
北大核心
2022年第1期54-58,共5页
Railway Engineering
关键词
客运专线
未焊合缺陷
试验研究
移动闪光焊接头
横向断裂
温度拉应力
passenger dedicated railway
unwelded defect
experimental research
mobile flash welding joint
transverse fracture
temperature tensile stress
