油气管线钢焊接局部脆化及断裂机理的研究  

The Study on Welding Local Embrittlement and Fracture Mechanism of Pipeline Steel

作　　者：董玉华[1] 高惠临[2] 

机构地区：[1]西安交通大学材料科学与工程学院 [2]西安石油学院

出　　处：《压力容器》2001年第3期26-30,共5页Pressure Vessel Technology

基　　金：中国石油天然气集团公司石油管力学与环境行为重点试验室基金

摘　　要：采用焊接热模拟方法和现代物理测试技术研究了管线钢焊接热影响区的韧性变化规律。结果表明 ,多道焊中 ,当二次热循环峰值温度处于 (α +γ)临界区时 ,管线钢HAZ的韧性最低 ,表现为临界粗晶区局部脆化。拉伸试验和冲击试验结果表明 ,管线钢临界粗晶热影响区在断裂过程中 ,存在夹杂物形核、铁素体与M—A组元界面形核和M—A组元内部形核三种方式。This paper has discussed the relationship between toughness and microstructure of heat-affected zone of pipeline steel by thermal simulation test and scanning electron microscope (SEM). It has been found that intercritically reheated coarse-grained HAZ (IRCGHAZ) of experimental steel has the lowest toughness during multi-pass welding. This phenomenon is caused due to coarse M-A constituent formed in the second thermal cycle and microstructure inhabitance. In order to investigate fracture mechanism, the fracture surfaces of notched tensile specimen and impact specimen are observed. The results show that microcrack can be initiated at MnS inclusion, interface between ferrite and M-A constituent, as well as inside M-A constituent. M-A constituent can′t prevent propagation of crack.

关 键 词：管线钢 再热临界粗晶热影响区 组织遗传 断裂 M-A组元 局部脆化 油气管 焊接 

分 类 号：TE973.3[石油与天然气工程—石油机械设备]