摘要
采用MTS landmark 370型液压伺服动静疲劳拉伸试验机研究了应力比(R=σmin/σmax)为0.1时X80大应变管线钢焊接接头的拉拉疲劳寿命;并采用显微硬度计和扫描电镜对焊接接头的硬度及疲劳断口进行了分析。结果表明:焊接接头的疲劳寿命显著低于母材;疲劳裂纹均萌生在焊缝熔合线处;裂纹沿热影响区向内扩展,当裂纹扩展到一定程度时,裂纹沿热影响区快速开裂。焊缝金属咬边所形成的夹杂物、焊缝的应力集中及热影响区性能恶化是疲劳裂纹萌生及快速扩展的原因。
Fatigue properties of welded joint of X80 pipeline steel with excellent deformability were studied on a MTS 370 electro-hydraulic servo universal mechanical testing machine under the condition of stress ratio（R = σmin/ σmax） of 0.1.The hardness and fatigue fracture of the welded joint were studied by means of microhardness test and scanning electron microscopy.The results show that the fatigue properties of the welded joint are notably lower than that of the base metal.The fatigue cracks are initiated on the weld-fusion line,and propagate inward along the welding heat affected zone.As the crack propagates to the critical size,the crack quickly grows along the welded seam to final fracture.The inclusions formed by undercut of the weld metal,stress concentration of the weld joint,and the deterioration of properties of HAZ are responsible for the fatigue crack initiation and quick propagation.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2016年第8期108-112,共5页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51171162)
河北省自然科学基金(E2015203234)
